First "Sneak Peek" Into the Winter Outlook

This is a map that I have compiled of my analogue years for the winter... The winter's used are 2006-2007, 1993-1994, 1969-1970, 1966-1967...

This would indicate a colder than normal winter for the region, but with precipitation near normal with snowfall above normal... I'm not sure if this is going to pan out, but this is the best I can do based on history.

Tomorrow's Thunderstorm Outlook

Weather Outlook for Tomorrow: I could not get a forecast for today out, but I can tell you that tomorrow will be very similar in terms of comfort and humidity... Currently, Fort Wayne International Airport (as of 3 p.m.) is recording a temperature of 86 with a dew point of 72, indicating a very humid and unstable air mass. This is supported by the fact that isolated showers and thunderstorms have developed to the southeast of Fort Wayne along a very weak and old frontal/convergent boundary (the boundary that was supporting an area of showers and thunderstorms earlier this morning across Michigan. Tomorrow's forecast will be very tricky, because it will depend on the timing a currently weak cold front over the Central Plains... A shortwave over southern Canada will ride southeast into the United States, intensifying the cold front and allowing it to slide eastward. As the cold front slides eastward, it will encounter a very humid and deep tropical air mass. The initial air mass ahead of the front will be quite dry, but several hundred miles ahead of the front, the air mass will still be moist and favorable for thunderstorm development.. Because of the initial dry air ahead of the front, I expect that thunderstorms will mainly be capable of producing damaging outflow wind gusts.. There is the possibility that these storms will organize into a linear line of storms by the time they begin affecting our area. I DO NOT believe that these storms will be widespread. In fact, they will be very isolated at first, and any line that does form will more than likely affect areas north of here in Southern Michigan.

For my official forecast, I expect high temperatures in the upper 80's to lower 90's tomorrow, with dew points in the lower 70's. Lows tonight and tomorrow will be in the upper 60's. For tomorrow night, I expect temperatures to drop into the middle 60's. As for the timing of any thunderstorm activity, though they will be widely scattered and isolated (at first, becoming organized by later in the evening, with areas mainly north of Route 6 having a better chance for storms to affect them), will be after 5 or 6...
Tomorrow, I should have an update on what I expect for the end of the week into next week.

Have a great afternoon!

Much Anticipated Pattern Change

After a rather warm and very humid end to the week, many of you are probably waiting for much cooler and drier weather.  I can tell you, that looks to be on the way by the end of the week. Right now, the remnants of the tropical system are slowly weakening just to the south of the area while sliding east at the same time. This is the reason for the extreme humidity and at times rain. On the upper air analysis this morning (Monday), a closed low was sitting over Canada, causing a weak trough to form across the Pacific Northwest. As upper level ridging builds across the far eastern Pacific near the West Coast, this will eventually push the closed low southeastward towards southern Canada and the eastern United States. As the trough moves this way, by Friday and Saturday, it will force a cold front through the area, with a low pressure center forming along the weakening front. At the time, it will be hard to resolve the details on what exactly will happen. The GFS ensembles are showing that a broad trough originating from the closed low will deepen by Saturday, allowing a rather strong high pressure region to cause a much colder air mass to become entrenched across the region. In fact, according to the GFS, temperatures could struggle to make it to the 70's by Sunday and Monday.. After that, warmer temperatures will return, but they will probably still struggle to reach into the 80's.
    What this indicates in the long-term is that the weak El Nino phase occurring in the equatorial Pacific is finally starting to have an effect on the world's weather. An El Nino phase usually favors troughing (which causes below normal surface temperatures) across the south and east. It also favors blocking across Canada, which is quite evident on the GFS ensemble forecast for the weekend. Already, this could be a precursor of what we see during the winter. I am not releasing a winter forecast yet, due to the uncertainty involved this year. In fact, this year's weather conditions are very similar to last fall. So, in fact, weather conditions during the winter could go either way. Most El Nino's across the area favor warmer than normal, and drier than normal conditions. Some El Nino's have been known to cause extensive troughing across the eastern and central United States during the winter, which suppressed the warm than normal conditions across the north and allowed for cold, arctic air to filter into the United States. This kind of pattern is evident when a certain long-term climate variable called the PDO is in its negative phase. While the PDO index has risen over the past few months, it is still negative, which should support a winter of colder than normal weather across most of the eastern United States. As for precipitation, that will be a bit trickier to forecast. It will all depend on whether the southern branch of the jet stream becomes dominant like it was last year. If so, most of our storm systems will come up from the southwest into the region, or they will swing in from the east as they are strengthening along the east coast. Right now, this is just speculation as to what is coming.
     As for the months of September and October, based on trends from what happened in August, I expect that September will likely see slightly above normal temperatures (our average high temperature in September is in the middle 70's.), especially every time the ridge breaks down in the west, which will send a heat surge into the Midwest. In October, if I base it on our last El Nino, then it will likely turn out to be cooler than normal, and wetter than normal. In fact, in October of 2009 (the last El Nino/negative PDO phase), the Midwest was hit by a snowstorm towards the end of the month! While I can see this happening, this October will probably not be characterized by such cold temperatures as it was then. This is because of the fact that El Nino is still struggling to develop across the U.S., and with a still large area of severe drought across the Central Plains, one or two day waves of extremely warm temperatures will still be possible. As for precipitation, with the jet stream dropping southward, and a better connection with Gulf moisture than we did last year, showers and thunderstorms will likely be just as frequent than last year. The only reason last fall was so wet, was because of the predominance of the southern jet stream, and the predominance of cut-off lows that continually formed. So I do NOT expect a wetter fall than last year, but it could still be fairly wet, especially in September.

Labor Day Forecast

For Today's Labor Day forecast: I expect temperatures to warm into the middle 80's under partly cloudy skies.. The remnant tropical low has weakened enough to allow only scattered cloud cover around its center. With a still moist air mass, and enough sunshine, weak to moderate instability will develop across the region. This will allow for the development of scattered showers and thunderstorms by later in the afternoon, especially in Northeast Indiana and Northwest Ohio... This shower and thunderstorm chance will exist through tomorrow. Other than that.. Have a great day!

IMPORTANT FORECAST UPDATE

IMPORTANT UPDATE FOR TOMORROW'S RAINFALL:

Well, here's what's going on: A shortwave over the Central Plains will move into the Western Great Lakes this evening and the overnight hours, bringing a chance for showers and thunderstorms. A str

ong and rapidly developing shortwave will drop south out of southern Canada, eventually phasing with the shortwave by tomorrow mid morning into the early afternoon. This will cause a jet streak to form, resulting in strong UVM (upward vertical motion) across the area, and the formation of rain bands. One of the reasons why I don't believe many thunderstorms will form is because of the fact that the warm, moist air mass gliding over the warm front will produce widespread clouds across the area by the morning hours. The front will intensify during the day, with the latest models suggesting the front will sit right over the area, which will make it very hard to forecast high temperatures. The low pressure system will develop along the front, turning it into an open wave cyclone. Showers and thunderstorms will form in response to the highly moist air mass moving into the region. In areas south of Route 6, there is the possibility that the atmosphere may destabilize by the afternoon, especially if the storm systems forms farther to the north. This could allow for an isolated severe storm, but at this time, it is not likely. Widespread showers and thunderstorms will likely continue into the late evening and possibly overnight hours before tapering off in the dry slot of the developing storm. A few showers and thunderstorms will persist across the area during the morning hours on Friday as the cold front slides through.

As for rainfall amounts, they will range from just over a half an inch mainly south of Fort Wayne, to possibly over two inches in isolated locations. This will be enough to help further ease drought conditions across the area.

As for temperatures, tomorrow's highs will range from the middle 70's to the lower 80's south of Route 6. Clouds will prevail for most of the day, with MAYBE a peak of sunshine in spots.

After a trough builds into the East in response to the storm system deepening the main trough, and allowing a seasonably cold air mass to reside across the area for the weekend, with highs in the lower 70's.

IMPORTANT SEVERE WEATHER UPDATE

 Even though a week ago it was said that this may be a significant severe weather event, it does not look to be that way now. There has been a change in this. Yesterday, it did not look like we would even get a severe weather event. But, it turns out the NCEP models were having problems handling the development of this system, and thus its dynamics. Here is what is likely to happen. Saturday morning, looks to start off clear and sunny across most of the area with some mid level and high level clouds likely across the area, from dying upstream convection. By this time tomorrow, the strong upper level wave that is currently located over South west Canada will likely be located over western Dakota. An ongoing MCS will likely be located over western Minnesota. During the day, as a surge of hot, dry air from the desert, rides up and over the warm, moist air at low levels, strong convective instability will set up. Dew p

oints are expected to rise into the low to mid 70's according to the 06z NAM. By late Saturday afternoon, a few isolated showers and thunderstorms will likely erupt as the cold front approaches the region. By early to mid evening (7 p.m. - 9 p.m.) the cold front will be close enough to the region to allow for the development of numerous thunderstorms to our west, which will likely organize into an MCS on the nose of a rapidly strengthening low level jet. This will likely be our only chance for severe weather if this happens. If the MCS does set up, it will not move very quickly given weak to moderate upper level winds. Though deep layer shear will be increasing, the most important factor will be low level shear. This could allow for damaging winds, especially if the low level winds align in the same direction. Strong upper level divergence from the developing jet streak over the Midwest will likely allow for the development of additional showers and thunderstorms during the overnight hours. Most thunderstorm activity should end by early Sunday morning, giving way to clearing skies and warming temperatures.

Have a great day!

Model Disagreement Continues

There is still considerable disagreement among computer models with the upcoming storm system and associated cold front.

This strong wave which is forecasted to track along the Canadian border will cause a jet streak to form over the Midwest. As I have said before, a jet streak is an area in the jet stream of higher wind speeds. The first thing that this causes is considerably higher vertical sh

ear. Since the jet streak will likely not be located over the area until after the cold front moves through, I would expect that this stronger vertical shear will only have an effect on storms that develop over Wisconsin and Iowa on Saturday afternoon. Second, since jet streaks are associated with winds that are not in geostrophic or gradient wind balance, they will have associated areas of diverging winds, which will destabilize the atmosphere over which the jet is located. An effect that it will have on our area is the fact that it could cause a strengthening of the low level jet, which transports heat and momentum into storms at low levels. If this jet is enhanced, severe storms will be more likely, given stronger low level shear, and continued destabilization of the atmosphere through the overnight hours.

Because of these factors, I have still determined that the main severe weather threat will be damaging winds, due to the fact that MCS development is likely ahead of the cold front in the form of a squall line, with embedded bow echoes.

This will be posted on the blog and I should have an update by afternoon.

Have a great day!

Storms threatening on the Horizon.

1. Morning Update:
   
   Good morning everyone! After a nice morning rain with a few rumbles of thunder (from a dying convective system in association with the upper level disturbance), I expect that the mid level cold pool responsible for the system will allow for moderate instability to develop this afternoon, as solar heating commences. With moisture pooling and convergence along the boundary, dew points will increase into the upper 60's and lower 70's mainly south of Route 6 this afternoon. CAPE values will rise in the range of 1500-2500 across a good portion of the area. This, in combination with the associated cold front and shortwave, will allow for the development of scattered strong thunderstorms this afternoon. The main threats will be heavy rain and gusty winds in the strongest storms. Upper level divergence in association with a developing upper level jet streak will also help prepare the atmosphere for thunderstorm development, and at the same time providing a source of bulk shear, for downdraft/updraft separation. This could allow for some localized severe weather in some areas.
   
   As for timing, I expect that most of the thunderstorm activity will develop around and after 3 this afternoon. It will likely organize into multicell clusters at first, organizing into possibly an MCS south of the area by the late evening hours.
   
   As for the long-range forecast, a weak shortwave could push a weak cold front into the region by Thursday and Friday, causing isolated showers and thunderstorms, but with a surface anticyclone residing from the last cold front, surface moisture will be lacking, limiting storm development. By Sunday, we have bigger issues. Models continue to forecast the movement of a strong shortwave and associated storm system along the Canadian border by Saturday and Sunday. Ahead of the system, a surge of warm air from the Desert Southwest will cause temperatures to jump into the lower and middle 90's on Saturday, and possibly Sunday. A surge of moisture from the Gulf of Mexico will also make the air sticky and humid. The moisture will cause the atmosphere to become unstable by Sunday, with CAPE values as high as 4000 J/kg. With higher shear values, severe weather looks to be a good possibility. The GFS continues to vary considerably with the amount of instability, with the 00z run forecasting 5000 J/kg of instability, while the 06z run is now forecasting 3000 J/kg or less of instability across the area. I will have to continue to monitor the situation, but to me it looks as if another significant severe weather outbreak may be possible.
   
   Have a great day!
   
   Joshua Steiner
   Senior meteorologist

   

Record-breaking Heat Continues

With upper level ridging continuing over the area, I expect that temperatures will continue to rise, especially as the low level flow veers to the southwest and west, which will continue to pump warm air into the region. Highs today will range from the middle to upper 90's under sunny skies. By tonight, as the ridge begins to flatten, warm dry air from the plains will advect into the region, causing temperatures to jump once again on Tuesday, with highs over 100 possible. All of this will continue with humidity levels up once again, which will allow heat indices to rise above 100. By Wednesday, a cold front will approach from the north, and cause a slight chance for showers and thunderstorms. By Thursday and Friday temperatures will drop back into the upper 80's.

Derecho Storm Facts.

Here are some of the facts that I have gathered about the horrific storms that ravaged the area last Friday afternoon.

Originally, the storms formed along a boundary that separated warm, moist air from warm, dry air to the north. The storms formed in far Western Illinois as the boundary lifted northward. An upper level disturbance initiated the violent thunderstorms, and caused them to move eastward into the Chicago area, producing winds of over 60 mph at the time.  In our area, temperatures were quickly warming into the middle 90's, with moist air moving into the region from the southwest, with dew points eventually approaching the low to middle 70's just before the storms hit the Fort Wayne area. Due to the highly unstable and potent air mass in existence across the area, the storms strengthened rapidly as they left Chicago. At the same time, the storms followed the boundary southeastward into the Fort Wayne. Minutes before the first gust of wind hit the Fort Wayne area, Doppler Radar recorded winds of almost 100 mph at an altitude of 2500 feet above the surface, right before that same patch of winds hit the Downtown area.  It was hard for anyone to prepare for the onslaught that was coming, as the line of storms, called a derecho (De-RAY-sho), were moving at a forward speed of nearly 80 mph! Most storms only move at speeds of 20 to 30 mph. As the storms moved through Fort Wayne, the line once again rapidly intensified in the still highly unstable environment. According to the Storm Prediction Center, a wind gust of 91 mph was recorded at Fort Wayne one of the highest wind speeds ever recorded in the area, while winds of 88 mph just to the northeast of Fort Wayne, producing incredible damage, with widespread tree and structural damage all throughout the city. As the storms strengthened, Doppler Radar also detected strong rotation as the storms passed over New Haven. The National Weather Service then issued a Tornado Warning for East Allen County, Paulding County, and Van Wert County. By the time the storms hit Antwerp, winds of almost 80 mph were reported, according to the Storm Prediction Center (National Weather Service), with even greater damage and widespread tree damage throughout the town. When the storms hit Paulding, a wind gust of 84 mph was recorded near PCH hospital. Even though the storms were extremely violent, they produced minimal rainfall amounts, with most areas seeing a quarter to a third of an inch of rain. Even the highest rainfall amounts were only in the range of 0.4 to 0.5 inches. These storms continued to strengthen as they moved southeast out of the area, knocking out power to almost 700,000 households in the state of Ohio. In fact, the derecho continued all the way to the Mid-Atlantic and out into the ocean, causing considerable damage and widespread communication failures in cities such as Washington D.C. Even though the storms cause more damage in the Eastern states then here, we still recorded the highest wind speeds of the entire event! According to the National Weather Service, this is likely one of the worst storms ever to hit the Northeast Indiana, Northwest Ohio region, and likely one of the worst derecho/squall line events in the Mid-Atlantic and Ohio Valley states ever recorded. At one point, the storms caused a total of more than 3 million power outages at the same time, more power outages than Hurricane Irene produced in the Mid-Atlantic states. From what I have heard on news sites and other places, 22 deaths were attributed to be a direct result of the storm, most of them were from people smashed by trees. This will go down as one of the worst derecho events to the United States, behind the series of derechoes that hit the Upper Midwest in 1995 and '96.

I will be writing an article about the formation of derechoes, and how we can prepare for them, in a couple of weeks.

Historic Heat Wave

     After many, many days of 90 degree temperatures in a row, many records were broken that have not been reached since the years of the Great Dust Bowl back in '34, and '36 (some of the hottest years on record at Fort Wayne). In fact, some all time record high temperatures have been breached several times throughout the heat wave.

     Before I describe all of the records that were broken, I want to give you some background information on why this heat wave formed, and what factors likely exaggerated the effects of an especially historic and legendary heat wave. As most of you probably remember, last winter was a very warm and wet (wet as in a lot of rain) winter. In fact, it came out to be one of our warmest on record, with every month of the winter season, December, January, and February recording temperature surpluses over 6 degrees above normal. While no record highs were set until the meteorological winter season had officially ended, we had quite a few days where temperatures were 20 degrees above normal, especially in February. Usually, during a normal winter season, the area receives a good winter freeze for several weeks, holding the moisture from the late Fall rains and early winter snows. During a warm winter though, evaporation rates are way up because the ground isn't frozen for long enough to hold moisture in. This is why coming into March, our top soils were already quite dry, regardless of the heavy winter rains. Usually, when the strengthening solar radiation hits the normally wet soils of our area, some of heat energy goes to evaporating soil moisture (which ultimately is a cooling process), while the rest goes to raising the temperature of the ground, which conducts into the lower atmosphere, causing a rise in surface temperature. When the ground is relatively dry, less heat energy goes to evaporating water, and more heat energy goes into heating the ground, which effectively raises the temperature of the lower atmosphere much higher and more quickly than a normally wet ground would. This also has an effect of reducing the relative humidity of the atmosphere, which ultimately hinders thunderstorm development. By the time the March “heat wave” hit the area, temperatures were much warmer than they otherwise would be, pushing daily temperatures above normal. Higher temperatures correspond to higher evaporation rates, which deprive the soil of its moisture. At the same time, the synoptic scale wind patterns, driven by the ocean currents and other large scale factors, favored ridging over the area, which means that high pressure is above the area. Higher pressure (pressure rises or more politically correct “height” rises) usually correspond to subsidence in the lower atmosphere (downward motion), and downward motion results in warming by compression, causing a rise in low and mid level temperatures and clear, sunny skies. This further hindered rainfall development during most of April and May. By May, we had two official heat waves (which normally does not occur), with temperatures in the first heat wave reaching the lower 90's, and temperatures during the second heat wave breaking all-time records for two days straight. This is when drought conditions developed across Northeast Indiana, while Northwest Ohio experienced abnormally dry (D0) conditions. With the same synoptic scale patterns that had started during the late winter, the high pressure area or upper level ridge continued to move back into the region after cooler periods of weather. Even in the cooler periods of weather, dryness continued intensifying the drought. By mid-June, a classic heat wave set up across the United States, with records broken in quite a few places. Here, temperatures were in the middle to upper 90's for 4 or 5 days in a row, until the heat broke on June 21 with a violent thunderstorm in some spots. At Fort Wayne International Airport, precipitation for that day was a mere 0.19 inches, while just north and west of Antwerp, Doppler Radar estimated that almost 2 inches of rain fell, right along the state line (my rain gauge recording 0.25 inches of rain from that storm in Antwerp). With continued dry conditions, the next heat wave set up in about a week's time, with the following week reaching well into the 100's, highs officially at Fort Wayne International Airport tied the all-time record high at 106, while Defiance Memorial Airport hit a record of 107 on the same day. During the next several days into July, upper level ridging built back into the area after the incredibly violent storm moved through. The heat wave culimnated by the middle of the week of the Fourth of July, with temperatures 101 and above for each and every day until Sunday. This was an unprecedented event, having four consecutive days above 100 degrees. This has never happened in the history of Fort Wayne with the next closest run of 100 degree temperatures occurring back in July of 1988, with only three consecutive days. With continued heat throughout the rest of the month, I expect that this July will become the hottest July on record, breaking last year's record. (This post will be updated as more information comes in.)

Most of the past heat waves of this year were rather dry with humidity levels not having much influence on the heat index. In the heat wave we had in the last week though, relatively wet soils from the violent thunderstorms and the maturing corn canopy contributed to excessive humidity, with dew points in the low to mid 70's occurring during the hottest part of the heat wave. This contributed to the heat indices that were over 110 at times. Also, favorable flow from the Gulf of Mexico, plus a series of upper level disturbances enhanced moist flow into the region. In theory, this should have produced multiple rounds of thunderstorms to help mitigate (which it did at times) the heat, but so far it has failed to do this because of a lack of strong lifting mechanisms, and strong capping (warm mid level temperatures) has thus far prevented widespread thunderstorm activity.

This heat wave's effects have also been exaggerated by the fact that the powerful derecho that slammed into the region, caused millions of power outages from Indiana to Washington, D.C. As of this writing (Friday, July 6, 2012), nearly 1.5 million are still without power in the areas affected by this storm in Ohio, West Virginia, and Virginia. Many people are without air conditioning during one of the worst heat waves in many years.

For what I think will happen in the long run, given no significant rainfall in the near future, drought conditions will continue, contributing to above normal temperatures, and exacerbating heat waves that plague the area. This will likely continue into August and even September before the changing climatic variables and ENSO phases within the Pacific affect the long-range patterns.

Extended Heat Wave Possible.

Even as the post-clean up process from Friday's storms is underway, another heat wave is on the horizon. Except this one will last an entire week. In fact, the National Weather Service has issued an Excessive Heat Warning for the area. The National Weather Service said that they are expecting a period of heat which will feature temperatures in the upper 90's to the lower 100's and heat indices well above that. This heat wave will be characterized by high humidity and maximum sunshine, which only make it worse for the many thousands of people who still need power. Even the heat does not exactly fit criteria for the excessive heat warning, it was issued because of its duration and impact. This heat wave is caused by a building heat dome or upper level ridge moving in from the west. This will allow for several days of quiet weather. By next weekend though, temperatures will reach their maximum on Saturday, near or over 100. Then a cold front will be forced through the area, cooling temperatures back into the lower 90's and upper 80's.

The Mechanics of Heat Waves. Updated Forecast.

When forecasting heat waves, there are many variables that are needed to be considered. Some of these include soil conditions, cloud cover, vegetation cover, climate region, low level temperatures, upper level wind flow, and low level wind flow. These are only a few of the many factors that meteorologists take into account when forecasting periods of extremely high temperatures. To start, the definition of a heat wave for the southern Great Lakes region is a period of three days with temperatures of 90 degrees or higher. The standard definition of a heat wave is a period of three days or longer with much above normal temperatures (10 degrees above normal or more). This would make the March warm spell that we had a heat wave, because temperatures were almost 40 degrees above average. The onset of a heat wave comes as an upper level ridge builds into a region. According to the hypsometric equation, upper level ridges (or regions of high pressure) must be associated with a warm column of air. That means, the stronger the ridge, the hotter it has to be at the surface. Not only does the ridge bring a wave of warmer air, but subsidence also brings warmer air into the region. At the far eastern edge of a ridge, subsidence is strongest due to upper level height rises, usually low level cold air advection (because of a passing cold front from the last storm system), and NVA, which is negative vorticity advection increasing with height. All of this leads to subsidence, which warms the low level air mass through time. As the surface high moves east of a region, warm air advection increases into a region, allowing for even warmer low level temperatures. For a temperature forecast, you have to take into account how long the ridge was over a specific region such as a dry region. The current ridge was located over the West for over a week, located right over the Intermountain West and American Southwest desert, which will strengthen the ridge. Since the surface temperatures over the West are actually the low and mid level temperatures when they advect into our area, mixing of these hot temperatures in the presence of solar heating will lead to even hotter temperatures. Soil conditions and type are an enormous factor in summer heat waves. If soils are wet and a clay-type mixture (such as what is usual in our area), then dew points will be quite high during heat waves (75 or higher) while temperatures are usually cooler. If soils are incredibly dry and of a sandy texture (which is what is happening now, our soils have become so dry that some of the soil has turned into a sandy texture), temperatures are quite a bit hotter. I've already talked about the upper level flow, but what may be more important it the low level flow. If low level flow is from the Gulf of Mexico, then a very warm and moist air mass will become present over the area, making outside conditions very uncomfortable. Even in drought conditions, moist flow can bring higher dew points from the Gulf of Mexico, its just that a moist air mass will cause haze in the sky and clouds to form, limiting daytime heating, which is one reason why higher dew points leads to lower temperatures. You also have to take into account cloud cover. This means that you need to thoroughly analyze the jet stream for shortwaves which could induce cloud cover and thunderstorms.

As for the updated forecast, the National Weather Service has just issued an Excessive Heat Warning for temperatures 104-107 tomorrow. Heat indices will approach 110, especially if dew points are higher than expected. Tomorrow night, there will not be much relief with temperatures only falling to near 76 or 77 (which would break records). On Friday, expect yet another dry day as temperatures will soar into the upper 90's, but with slightly cooler low level temperatures. Some meteorologists are predicting rain for tomorrow, but it is highly unlikely due to the fact that the area is moisture deprived and far removed from upper level dynamics. Plus, the storms would have to break through the incredibly strong cap, which is not entirely likely. In fact, expect dry weather for the next week at least. Enjoy the hot days!

Near Record High Temperatures Possible

It may not seem like it now, with the polar air mass over the area, causing temperatures to drop just slightly below normal into the lower 80's and upper 70's, but by the end of the week, we may be seeing record highs shattered, and maybe even a few all-time record highs shattered. Before I explain Thursday's and Friday's weather, I will explain how the current weather will allow for the warmer weather later in the week. First off, if it wasn't for Tropical Storm Debbie, many areas would have seen thunderstorms during the afternoon yesterday. This is because the tropical storm blocked the main synoptic scale flow from the Gulf of Mexico. If there were no tropical storm in the Gulf, southerly flow into our area would have brought a deep and moist tropical air mass that was highly unstable. This coupled with some upper level forcing would have caused the development of numerous thunderstorms. This is what has been happening ever since March. A large thunderstorm complex or system in the Gulf states blocks the flow of moisture northward into the Midwest, not allowing for storm systems to strengthen. In reality, if this natural flow of air northward would not have been blocked, we could've have had quite a bit more snow this winter. Instead, that is not how it happened. This is one of the first and most prominent signs of the transition to an El Nino phase in the atmosphere. When the El Nino begins to show its ugly face, the southern part of the jet stream becomes more active. This is why many of the systems that hit the area this winter came up from the southwest and south, bringing warmer air northward and rain with it. Any northern stream that hit the region was moisture starved and produced little more than clouds and a few snowflakes. This may have been one of the reasons for the development of the drought across the region. Back to what I was saying before, the thunderstorms, if they would have developed, would have saturated the soil, allowing it to be cooler but more moist. The drier weather is allowing temperatures today and tomorrow to climb into the lower 80's. As the low level southerly flow causes a nose of incredibly warm and dry air to move into the Upper Midwest, upper level heights will build across the region, especially as the upper level low over New England weakens. This will likely happen starting on Tuesday night and continue through Wednesday. By Wednesday, strong warm air advection and subsidence will cause clear skies once again, but this time with highs approaching 90. By Thursday, upper level ridging will cause subsidence and a nose of hot, dry to move into the area, allowing temperatures to soar to near record levels. The hot, dry nose of air from the west combined with near desert and drought conditions in our will allow temperatures to rise into the 100's for Thursday, and possibly again for Friday. If we reach 102 or higher for Thursday, we could tie or break the record set in the 1930's. On Friday, though, depending on the timing of a weak front, temperatures will likely only make it into upper 90's. Humidity levels will significantly increase for Friday though, allowing the atmosphere to feel very uncomfortable. Don't get too excited about this frontal boundary though, thunderstorms aren't likely even with the highly unstable atmosphere, because of mid level capping and subsidence across the region. Even after Friday, the frontal boundary will do little more than cool temperatures into the middle 90's. By next week, yet another surge of hot air will occur, allowing temperatures to rise back into the upper 90's and lower 100's. This is still way out, so take this forecast with a grain of salt. With no tropical storm to block flow from the Gulf of Mexico, expect much more humid conditions for next week.

Technological Improvements: Radiosonde Part III

       Last week, I talked about how long the radiosonde flight lasts, how data is screened, and how wind direction and speed was determined from the flight path of the radiosonde. This week, as I mentioned in the previous article, I will talk about some of the improvements in the data collection process has improved forecasting.

       

      Due to government spending, budget cuts, and a limited money supply, the NWS is forced to slowly cut down on its work force and the amount of money it spends on forecasting and saving lives. If no changes were made to this, all kinds of weather would kill thousands more than already are killed. One of the ways that the National Weather Service can make up for this, is through researching more modern and advanced technology in use for forecasting. Right now, radiosondes are sent up only a twice a day to receive upper air conditions and many other useful products for weather forecasting. The problem with this extremely inefficient system is that the atmosphere changes so quickly, that many factors can be missed. Take for instance on the day of a severe weather outbreak. Usually, the morning sounding will show almost no instability, due to the fact that the surface has not had time to heat from the sun. This will lead to extremely inaccurate calculations when trying to determine when the severe thunderstorms, which could end up meaning the difference between several hundred to over a million lives at stake (depending on the area). During the 1990's, to obtain meaningful wind measurements at all times of the day, the National Weather Service and the National Severe Storms Laboratory set up network of wind instruments called wind profilers across the Central Plains. These wind profilers are similar to Doppler Radars, except the fact that their parabolic dishes which sent out the microwaves are mounted vertically. As long as the microwaves which are sent out into the vertical can be scattered from dust particles or other particulate matter (including water vapor), wind speed and direction can be determined at many different levels of the atmosphere. Three other dishes are mounted at different angles to help determine the wind speed and direction. The NWS thought that this would give a much greater advantage to severe storm forecasters, as it allowed them to accurately determine wind shear throughout the low levels of the atmosphere. Then, in 2004, the wind profilers were cut out of the National Weather Service budget, and now they are funded by other means. The data is available online at several websites. Its data has other uses to, some of which have been described by other meteorologists. They claim that it may be possible to calculate the upper level wind, pressure, and temperature patterns just by knowing the wind speed and direction at a certain height. This could give a great advantage to many meteorologists, as long as these profilers are not shut down. There have been several cases where profiler data has made a huge difference in the forecast, one of which happened during the infamous May 3, 1999 tornado outbreak near Oklahoma City. Because of the profiler in central New Mexico, forecasters determined that there was a jet streak that missed by the radiosondes. Jet streaks are known to cause strong upward motion and destabilization, which would definitely help initiate severe thunderstorms. Also, jet streaks can also strengthen the vertical wind shear, which causes thunderstorms to become more organized.

       There are other ways that upper air data is obtained, and one of them is through a system called AMDAR. AMDAR come from air planes who are flying at specific pressure levels. Usually, these planes are commerical flights as they usually fly in the upper troposphere. The onboard instruments measure temperature, wind, pressure and humidity. The data is then relayed to the World Meteorological Organization, which collects and disperses the data. This data is especially useful in Africa and the Middle East, where the countries have Weather Services that are not funded by the government, or the country is so poor, there is no weather service. Another way data is collected is through weather satellites. Not only can they detect wind speed and direction and most levels (through tracking cloud movement), but through their radiation detection systems, they can determine temperature and dew point levels throughout all levels of the atmosphere. This system was implemented with the Terra series of satellites in 1999. In October of 2011, NOAA's next generation of earth monitoring satellites, called Suomi NPP, were sent up into space. This new generation of satellites have much more advanced equipment, which could eventually make them more accurate then radiosondes themselves. Plus, atmospheric soundings and wind profiles can be computed for any airport location in the world, and at each and every hour. The one problem with GOES soundings (their proper name) is that they have really coarse resolution, which affects certain small scale features. This being resolved with the NPP satellites which not only have better resolution, but they can also determine data in the presence of clouds. This will greatly improve forecasting within the next 10 or even 20 years.

      Next week, I am going to write about my trip to the National Weather Service on June 12, 2012, and then the following week's article is going to be about the history of the National Weather Service and its future plans. Have a great week!

Drought Conditions and Medium Range forecast

Many of you probably have heard by now, but a large portion of Northwest Ohio and Northeast Indiana have been updated by the Drought Monitor and put in the severe drought category.  Included with the upgrade was the possibility that this may end up as a long term drought, which is one that lasts longer than six months.  This may very well happen, as I have described before, atmospheric blocking has been rather strong for the past two months, and when blocking patterns come into place, drier weather and more extreme weather is usually the result.  This is one of the main reasons for the drought.  Other reasons include but are not limited to developing El Nino conditions around the globe causing a shift in the jet stream patterns, very warm winter and very warm and dry spring, and changing long-term climate variables. These factors have all combined to create the worst drought in the area since 2007 and possibly since 1988.  In fact, just to get back to normal, we need about 7 to 8 inches of rain in a short amount of time and we need 9-12 inches of rain to get out of the drought! That does not look like its going to happen very soon. Remember, the worse the drought the hotter it gets, and the hotter it gets the worse the drought gets.
As for the general medium range pattern that will persist across the area, by tonight and tomorrow and strong upper level shortwave will clear the area, forcing the cold front through the area, and dropping temperatures into the low to mid 80's under sunny skies for tomorrow. By Saturday and Sunday, a rather large longwave trough will build itself into the area, as an arctic cold front moves into the main wave over Northern Canada.  This will cause the entire longwave to shift southward into New England and Eastern Canada.  Compared to previous model runs, the entire pattern looks to settle farther east than originally expected so I would expect temperatures to remain a few degrees warmer than the upper 70's. By the very end of June and beginning of July, the ridge will finally begin to build into the area, allowing temperatures once again to soar into the 90's.

Facebook site

Don't forget to like Northwest Ohio Storm Prediction Center on facebook! It is much easier to update on facebook than it is on the blogsite.

Article from the West Bend News

This article is from this week's issue of the West Bend News.

Last week, we talked about how weather variables in the upper atmosphere are measured, such as temperature, humidity, and pressure. This week, I will talk about how the data is screened, and how wind throughout all levels of the atmosphere is measured.

Usually the radiosonde is sent off by balloon on two separate occasions each and every day. These times are 12 UTC and 00 UTC. For everyone who does not know what UTC means, it stands for Universal Coordinated Time, or Zulu time. It is not the same as military time, as it does not vary with time zone. For instance, if it is 12 z (or UTC) in New York, it is also 12 z in Los Angeles. This Universal Coordinated Time is the same as Greenwich Mean Time (GMT), accept for the fact that it does not change with Daylight Savings Time. If you want to know what the UTC time is right now (depending on your time zone), just subtract five hours from the current military time to obtain the UTC time, if you live in the Eastern Standard Time, while under daylight savings time just subtract four hours. Right now, 8 a.m. Is at 12 z and 8 p.m. is at 00z. The balloon which is sent off is filled with either helium or hydrogen.

During a normal flight, it will take in between 37 and 40 minutes for the balloon to reach its maximum height (usually about 15 kilometers), before bursting and descending through the atmosphere. The weather conditions at the time of lift off will determine whether the balloon will go up or not. For example, usually weather balloons will not be sent up in or near a thunderstorm (unless it is conducted for research purposes), because this will cause noise in the data when sent to the National Centers for Environmental Prediction. Usually, the temperature, humidity and wind profile of a thunderstorm is characterized by by a moist adiabatic lapse rate (temperatures decreasing with height at about 6 degrees Celsius/ kilometer), with 100% relative humidity throughout the entire atmosphere, and chaotic wind patterns due to turbulence, mesocyclones, tornadoes, and other small scale circulations within the thunderstorm. Since the grid-spacing of most models is too large for thunderstorms, if this data was placed into the model's analysis grid, to fit with physical equations that govern model, it would have to generate quite a bit of convective precipitation and latent heat to keep the atmospheric conditions accurate. This can cause quite a problem because the model will either 1.) have to assume that the storm is at least the size of its grid spacing (this will cause problems with global models, such as the GFS, ECMWF, and the GEM), or 2.) it will have to smooth out the latent heating throughout several grid spaces, especially for convective complexes. Latent heating has an enormous impact on our weather (a topic saved for another article), and since model physics are fairly close to the real world (not quite though), they will have to account for this incredible area of heating. Then, the models, when run, will disperse the enormous amount of heating, destabilizing the atmosphere even further, which will generate something called a convective or “QPF” bomb, which is basically a giant land hurricane on the model's grid, as a result of the latent heating, which can completely offset all accuracy of forecasting. This is why the data has to be screened for accuracy. Until the day at which models can actually physically create thunderstorms on their grids, this will be a problem. Other noise problems are also taken care of such as inaccurate data due to broken instruments, or elevation problems. Areas such as the Rocky mountains can not measure variables at levels such as the 850 and 925 millibar levels, so after the data is decoded and sent to the NCEP for use in model grids, the pre-processing that the model does before it runs the data uses the hypsometric equation, which relates atmospheric thickness to the average temperature. Using the atmospheric standard lapse rate, (which is rarely the case in a mountainous and dry region), it calculates data for levels that do not exist in the mountains so that the model can run properly. This why model forecasts of mountain conditions are rarely correct.

I never talked about how radiosondes measure wind speed and direction last week, but now I will. In reality, wind is not actually measured by radiosonde, as they do not mount an anemometer to the side of the radiosonde. What they actually do is use a radar tracking device to measure the angle of elevation, the balloon's displacement from its original position, and calculate the wind vectors from the balloon's movement. By doing this though, it leaves a rather large margin of error for the calculation of wind vectors (wind direction and speed) throughout all levels of the troposphere. When put into the archives, this wind information is put into the format of degrees of direction and wind speed in knots. In meteorology, the scale used for direction is: 0 degrees for a north wind, 90 degrees for an east wind, 180 degrees for a south wind, and 270 degrees for a west wind. This wind information is then plotted on atmospheric soundings, called skew-T charts, and hodographs, on which wind information is the only thing plotted. A hodograph is a chart on which many weather variables can be evaluated, such as total shear, bulk shear, and storm-relative winds. These are very important in determining the severity of storms and their structures.

Next, week we will talk more about improvements in the current technologies that are used in obtaining the weather information (I was trying to get to that this week!).

New Forecast Developments

Over the past few days, some areas in Northeast Indiana and Northwest Ohio received beneficial rain.  Though, it wasn't nearly enough to vanquish the drought, the plants and grass are just a tad bit greener, making everything seem more beautiful.  I don't about any of you who live around here, but in the town of Antwerp, I have estimated that there was about a quarter of an inch that fell within the town.  With the rain came quite a bit of lightning also, which was really neat since we haven't had any real thunderstorms since the beginning of May.
As for the weather pattern over the next few days, expect near record high temperatures for today, and tomorrow.  It is possible that Thursday we see highs in the low to mid 90's, but it also depends on the amount of cloud cover and how fast the cold front moves through the region.  Right now, I would expect highs on Thursday to reach near 90, given our dry soils and warm low level temperatures. For today, the 500 millibar ridge will amplify considerably, with 500 millibar heights already approaching 590 dekameters.  This amplification will cause strong subsidence (also coupled with subsidence from the right exit region of the jet streak located over Northern Minnesota) over the region, allowing for completely clear skies by afternoon, and combined with nearly maximum insolation from the sun (remember tomorrow is the longest day of the year), will cause temperatures to jump to near 100 yet again.  The good news is that this extreme heat will cause strong mixing within the planetary boundary layer, mixing dry air aloft to the surface, reducing humidity and dew point values, making the heat more bearable. It is possible that subsidence is so strong that it will not allow for the mixing of drier air to the surface, but this is not a good possibility.  As the ridge axis shifts off to the east, I am expecting that a more humid and moist air mass will move into the region for tomorrow afternoon and evening, making it feel quite a bit more uncomfortable.  By tomorrow, the ridge will reach maximum strength, with 500 millibar heights approaching 594 dekameters.   This will cause temperatures to be very similar to today's, with highs tomorrow probably a few degrees cooler into the mid 90's.  The 00z ECMWF is showing an expansive area of 20 degrees Celsius temperatures at the 850 millibar level over the area by tomorrow afternoon, which would allow for warmer temperatures than what I am forecasting. On Thursday, the cold front will approach the area, causing moisture pooling (a term which refers to the fact that dew points tend to increase ahead of a front.) and a more humid air mass. By the time we get to afternoon, depending on the speed of the cold front, temperatures will likely reach the lower 90's.  As the cold front approaches and passes through the region, expect only a few showers, as upper level forcing and low level convergence will be lacking.  By Friday, temperatures will moderate into middle 80's with mostly sunny skies. 

By next week, things get very interesting with a large closed low system over eastern Canada and New England, which may be stuck in that position for a while. With atmospheric blocking continuing across the Atlantic, the trough that will eject out of the plains and into Canada will not be allowed to progress (all of this depends on the actual strength of blocking over Canada, in fact blocking is expected to weaken considerably over the next week or so, leaving this forecast completely invalid.).  Here is where models are all over the place.  The ECMWF has an incredibly strong closed low retrograding with the pattern into New England, and even south into the Appalachian Mountains.  At this point, it seems very unreasonable for this to happen, as the degree of atmospheric is not that strong, and it doesn't look to get stronger with time. Also, the ECMWF has a tendency to be too strong on cool air invasions, especially during the summer time, so even if this trough were to progress south and westward, our high temperatures would still reach the low to middle 80's, especially given the drought conditions (usually troughs of low pressure bring periods of heavy rain to areas, but given the dry air mass out of Canada, we'll be lucky if we even get a few clouds out of it.).  Depending on the extent of the atmospheric blocking, the trough will begin to weaken by early to mid next week, and shift out of the region, according to the GFS, which has had a good handle on the weather patterns lately.  This will allow the entire pattern to shift, with the ridge over the Central Plains eventually shifting into our area, bringing us yet another heat wave by the beginning of July.  Have a great day!

New and Interesting Developments

As I said yesterday, the forecast was incredibly likely to change, and it has! Over the past several model runs, the models have trended to a much more amplified ridge developing over the area, which seems likely, given the strength of the jet streak which will amplify the Northern Plains trough, introducing what I like to call the "teeter totter" effect.  What happens is that when a jet streak or a strong trough moves into the West, usually strong height falls (equivalent to falling pressure over time) accompany them, causing a deepening of the trough.  This strong trough then progresses eastward, "squeezing" the ridge, eventually causing it to amplify.  The reason I call it the "Teeter Totter" effect, is because usually when there are height falls in the west, there are usually height rises occurring in the East, kind of like a kid sitting on the end of a teeter totter, causing the other end to go up.  Even with the ridge developing, I do expect that a weakening shortwave will move north of the area into Canada.  This will cause a cold front to approach to the area, but not pass through.  The good news about this front is that it COULD produce rain (even if it does it will probably occur west of here), given enough moisture and lift, which will not be in good supply over the area.  If any of you ever happen to look at recent model runs, you will notice that these models are forecasting that dew points into the lower 70's by Sunday afternoon. Do not believe this for one minute, because most models have well known moisture biases, which can cause major problems with convective feedback.  When models forecast more moisture than there actually will be, and since instability is related to the low level moisture profile, this will create a bias towards higher instability and thus more widespread thunderstorm activity.  In actuality, the models are having a problem with this insane drought, due to the fact that they are overestimating evapo-transpiration from crops such as corn, soybeans, and wheat.  The ground is so dry and the plants are so dry right now, that the models moisture parameterization schemes implement this into the  model, causing an extreme overestimation in moisture.  Therefore, I do not believe that thunderstorm activity will be very widespread, if there are thunderstorms that develop.  My second reason for not anticipating thunderstorms, is the fact that a strong cap will still be located over the region (even though it could be effectively reduced depending on where the shortwave tracks).  This will effectively block most thunderstorm activity.  If there is widespread thunderstorm activity it will be to the northwest of here in Illinois and Wisconsin on Sunday afternoon and evening.  The third reason is for the fact that over the past few weeks and months, models have consistently overdone convective potential.  There are a multitude of other reasons, but those are based on my opinions on how the situation is going to develop, not on actual facts. For these reasons, I don't think we will have as much cloud cover on Sunday, allowing temperatures to reach the lower 90's
     As for most of next week, the ridge appears to be stronger than what I thought yesterday.  Ridging will begin to build back in by Monday, sending temperatures back into the low to mid 90's.  On Tuesday through at least Thursday, temperatures could soar into the middle 90's to near 96 (according to the HPC and other guidance) with nighttime lows in the lower 70's. By Friday, the ridge will break with the approach of an upper level trough, as blocking breaks down in the Atlantic. After a few cooler days in the 80's looks likely, with highs returning to the 90's soon after.