Afternoon Highs in the 90's... Humid Air Arriving Tomorrow

Currently temperatures at 10 p.m. are ranging from the upper 70's in Northeast Indiana to the lower 80's in Northwest Ohio.  In Antwerp, the temperature has fallen to 82, after an afternoon high of at least 93 degrees in most areas.  Dew points today have been very low, ranging mostly in the upper 40's and lower 50's, allowing for a hot, but comfortably humid set up.  Overnight lows will fall into the lower to middle 60's, under mostly clear skies.  Even though temperatures will fall rapidly, dew points will actually rise tonight, into the lower and middle 60's by early Sunday morning, allowing the possibility of fog to come into the forecast.  Temperatures will then rapidly rise into the lower to middle 90's, with dew points rising into the upper 60's, in the vicinity of an approaching warm front.  The moderately high dew point values will cause heat index temperatures in the middle to upper 90's.  The same warm front will approach during the overnight hours, bringing the possibility of showers and thunderstorms late Sunday Night, with the greatest threat and coverage over Northwest Indiana and Illinois.  Monday, even hotter temperatures in the middle 90's, along with dew point temperatures in the mid 70's, will cause heat indices to rise into the range of 102 to 105, which meets Heat Advisory Criteria.  According to the National Weather Service, they are not sure at this time whether to issue a heat advisory, mainly because of the possibility of thunderstorms that could really limit daytime heating in some areas, especially in Northwest Indiana and Illinois.  Maximum heating will take place in extreme eastern Indiana and Northwest Ohio due to clear skies and dry soil conditions.  Hopefully thunderstorms form on Monday Afternoon, which could cause rainfall amounts of over two inches in scattered areas (hopefully in the Fort Wayne area, because we need it really bad!!)  For the rest of the week, temperatures will remain around 92 on Tuesday after a cold front moves through, but the humidity will definitely drop.  Wednesday and Thursday, temperatures will rise into the upper 80's, before another heat wave begins to hit our area on Friday.  According to the Climate Prediction Center and Accuweather, this same heat wave will likely last through the next week in many areas, before the ridge begins to retrograde westward.

Very Warm Temperatures this Morning...

Currently temperatures across Northwest Ohio and Northeast Indiana are ranging from the upper 70's to the lower 80's as of 10 a.m.  At Antwerp, temperatures are currently at 81 degrees while Fort Wayne they are at 80 degrees.  Other cities temperatures include:

Angola, IN: 79 degrees
Auburn, IN: 79 degrees
Defiance, OH: 79 degrees
Napoleon, OH: 81 degrees
Toledo, OH: 85 degrees
Sandusky, OH: 76 degrees
Paulding, OH: 79 degrees

By four this afternoon, temperatures in most of the area should be in the lower 90's, with the exception of Toledo and adjacent towns, who should be in the middle 90's this afternoon.  Tonight, temperatures will drop into the middle and upper 60's, much warmer than last night.  By  tomorrow, temperatures should rise to the lower to middle 90's and with much higher humidity, we will have heat indices in the upper 90's.  Some areas tomorrow, such as Toledo and adjacent areas, will see highs in the upper 90's.  Monday, will bring back the chance for showers and thunderstorms to the area, but convection will have more of an isolated nature.  Any storms that do form will have the potential to produce heavy rain and maybe gusty winds.  According to Accuweather and the Climate Prediction Center, an intense heat wave may be on the horizon for the Central and Eastern United States, due to higher than normal heights in the 500 hpa layer of the atmosphere.  Our area could even approach one hundred degrees by next Sunday.  Stay tuned for later updates.

Anniversary of Heat Wave of 1936; Somewhat Wetter this Week, But Still Hot

Yesterday and Today, (depending on what city you were in) marks the beginning of the infamous July 1936 North American Heat Wave, which caused extreme drought over a good chunk of North America.  Record high average temperatures were set in many states, along with record daily highs every day of the heat wave in many cities across the Midwest.  At Fort Wayne International Airport, daily record highs were recorded every day from the 8th of July to the 14th.  These temperatures were: 104 on the 8th; 102 on the 9th; 102 on the 10th; 98 on the 11th; 103 on the 12th; 104 on the 13th; and the hottest temperature of 106 (also Fort Wayne's all-time hottest temperature on record) occurred on the 14th.  These temperatures coincided with an extreme drought at Fort Wayne (the next drought of the proportions of 1936 was in 1988). 
      Now as for the weather patterns for the next several weeks, the pattern, according to the Climate Prediction Center, will feature a strong longwave trough in the West, which will continue to cause a strong ridge to form over the Central and Eastern United States.  This strong ridge will aid the hot temperatures around, more than likely to cause our temperatures to hover near the lower 90's for most of the summer, which is much warmer than normal.  This longwave ridge pattern could even several intense heat waves to form from now through the beginning of August.  This week, though, three or four days starting today and lasting through Tuesday, will be in the 90's, which qualifies as a heat wave in the definition of a heat wave as given by the National Weather Service in Northern Indiana.  On Monday and Tuesday, thunderstorms are a possibility as more humid air arrives in the region, causing high heat indices.   The thunderstorms will be mainly isolated to scattered and will be more of a pulse storm nature instead of in organized bands, much like the same pattern of the last month.  By Friday, thunderstorms could bring heavy rainfall again but to isolated, because again they will be more of a pulse storm nature.  I really don't see any organized thunderstorm formation unless the ridge that is over the Eastern United States, breaks down and allows several shortwave impulses to impact the area with organized severe thunderstorm events.  Other than that, if the ridge does not break down, then expect warm to hot temperatures over the next several weeks.

Very Warm for July

All of this week, temperatures have been warm to hot, as temperatures have hovered around the lower 90's all week long.  This pattern will continue as an upper level ridge builds into the region tomorrow into Sunday.  Saturday and Sunday will both be in the lower 90's, not only hot temperatures but higher humidity as well.  By Monday, thunderstorms will be back in the forecast, with even more humid and hotter conditions, with temperatures in the middle 90's.  Also the possibility of strong thunderstorms comes into play Monday through Friday next week, with heavy rain being the primary threat, which is good news for our parched ground.  According the National Weather Service, a much wetter pattern will come into play over the next week, with hopefully several inches coming for the Fort Wayne area.  All of next week temperatures will range from the middle 80's to the lower 90's.  Tomorrow, I will have a longer blog post about the rest of the summer and the upcoming pattern.

Warm Temperatures once again this afternoon... Last blog post until Friday evening

After an extremely hot, humid day yesterday, a cold front moved through last night bringing with it showers and thunderstorms, with most of the activity to the south and west of Fort Wayne.  Today, temperatures have risen quite a bit into the upper 80's as of 1 p.m. across most of the area.  Over the next week or so, temperatures will stay steady in the mid to upper 80's, with the possibility of another heat wave coming by week's end.  This is also the last blog post until Friday early evening, when I will get back from summer camp.  Well, for now, see you then.

Hot, Humid Weather Has Overspread the Region; Severe Thunderstorm Watch in effect.

    After mostly cloudy skies this morning, skies have become mostly sunny, allowing temperatures to rise into the middle 90's this afternoon.  As of 2:45, Antwerp's current temperature stands at a toasty 95 degrees, while dew points are very high, in the low to middle 70's.  Other current temperatures, dew points, and heat indices include:

Fort Wayne, Ind:  93 degrees/DP 73/ Heat Index: 103
Defiance, OH: 92 degrees/ DP 72/ Heat Index: 101
Auburn, Ind: 94 degrees/ DP 72/ Heat Index: 102
Angola, Ind: 93 degrees/ DP 74/Heat Index: 104
Paulding, OH: 94 degrees/ DP 70/ Heat Index: 101
Ottawa, OH: 91 degrees/ DP 68/ Heat Index: 96
Lima, OH: 86 degrees/ DP 69/ Heat Index: 91
Napoleon, OH: 94 degrees/ DP 71/ Heat Index: 101

   With the hot temperatures and high humidity, extreme instability has been allowed to build over the area, with CAPE (Convective Available Potential Energy, a measure of instability in the atmosphere) values ranging 4500 in far Northwestern Ohio to 6500 in western Indiana.  When values reach these levels, they are classified in the extreme category.  This has caused the Storm Prediction Center to issue a high end Severe Thunderstorm Watch until 11 pm tonight.  In one of their Mesoscale Discussions, the SPC said that severe storm potential in the lower Great Lakes is greater than 70%, which means that severe thunderstorms are likely across the area later this afternoon.  Temperatures will likely continue rising to the mid to upper 90's with increasing dew point values as the cold front nears.  Dew point values could actually increase to near 76 or 77 before the cold front passes through around midnight.  Tonight's lows will drop into the lower 70's and a few isolated areas into the upper 60's.  Tomorrow's highs will range from the mid 80's near the Michigan/Ohio/Indiana border to the upper 80's and lower 90's around Fort Wayne and Lima.

Humid Air Overspreading the Region; Heavy Thunderstorms Developing to Our West

This morning temperatures are very warm with most places currently in the lower 70's.  In Antwerp, the current temperature is 73, while Fort Wayne is currently at 72.  Not only is it very warm, but it is becoming much more humid over the next several hours.  Dew points at Antwerp, are in the lower 60's and in most other parts of Northwest Ohio and Northeast Indiana, while areas in Western Indiana and Eastern Illinois have dew points in the 70's.  Because of the high dew points in western Indiana, large and dangerous thunderstorms have formed over Lake Michigan and have been producing flash flooding over adjacent counties as the storms move southward.  These storms pose no threat to our area, mainly because they are riding the edge of the ridge in the plains southward. 
    If temperatures rise quickly, then highs could hit the lower 90's or even mid 90's with much higher heat indices.  This would most likely happen in far eastern Indiana and Northwest Ohio, because these areas have no cloud cover.  This afternoon, an isolated heavy thunderstorm or two can not be ruled as the upper level ridge shifts eastward and flattens.  Lows tonight will drop into the lower 70's, bringing highs with it tomorrow in the middle 90's and heat indices over one hundred degrees.  After a cold front moves through Sunday, temperatures will drop into the upper 80's, while dew points drop to the mid 60's.

Much Warmer Temperatures Today

This morning ended up colder than was expected, with lows falling into the mid and upper 50's in most areas.  Even though it was a little colder this morning, temperatures have skyrocketed into the lower 80's.  As of 10:30 a.m., the temperature in Antwerp was 81 degrees which is much higher than yesterday's temperature at the same time.  Some other temperatures include:

Fort Wayne, Ind: 79 degrees; mostly sunny

Current Temperatures

Angola, IN: 77 degrees; sunny
Defiance, OH: 79 degrees; sunny
Napoleon, OH: 81 degrees; sunny

Hicksville, OH: 78 degrees; sunny
Paulding, OH: 81 degrees; sunny
Ottawa, OH: 82 degrees; sunny

I expect temperatures to climb from the lower 80's right now, to around 85 or 86, with some places hitting 87 or 88.  Tonight's lows will drop into the mid 60's with increasing clouds and the chance of a thunderstorm.  Tomorrow, as I said in yesterday's last blog post, the NWS (National Weather Service) has dropped highs from 93 down to 88, to account for possible thunderstorms.  If the storms do not develop temperatures could 93 or 94 tomorrow, with isolated areas hitting 96.  If the MCS (Mesoscale Convective System), a cluster of heavy thunderstorms, develops, then expect heavy rainfall, frequent lightning, and possibly high winds early tomorrow morning.  By Saturday temperatures will be hitting 93 to 95 and possibly higher if there are no thunderstorms.  On Saturday, extremely humid conditions will cause heat indices of one hundred degrees or more.

Very Warm This Afternoon... Changes to Heat Wave forecast

Temperatures have warmed several degrees since my last post.  Area wide, temperatures are in the lower to middle 80's, with temperatures at Antwerp being the highest at 84 degrees.  At Fort Wayne and Defiance temperatures are still in the lower 80's

 

    Temperatures again tonight will drop into the lower 60's and possibly middle 60's if we get enough cloud cover, but that isn't likely.  Tomorrow, temperatures will be a bit warmer than today, mainly because meteorologists are expecting the winds to veer from the northwest today and tonight to the southwest tomorrow.  Highs in the mid-80's will prevail tomorrow, with tomorrow night's lows dropping only down to the middle to upper 60's with a humid air mass moving in overnight.  For the weather on Friday, the National Weather Service was discussing the possibility of thunderstorms Friday morning, which would greatly reduce Friday's highs into the upper 80's and lower 90's instead of the mid-90's.  But from my instincts, I don't think that any storms will hit us on Friday, keeping Friday's highs in the mid-90's.  If any storms do form, they will most likely hit far northern sections of the CWA in Northern Indiana.  Temperatures on Saturday are still on schedule to hit the lower to middle 90's with extremely humid air keeping heat indices at or above 100 degrees.

Nice Weather, Seasonably Warm Temperatures Before Major Heat Wave

   

As of 1:00 p.m. this afternoon, temperatures are very warm in the area, ranging from the upper 70's to the lower 80's in Northeast Indiana and Northwest Ohio.  Right here in Antwerp, the temperature is currently 80 degrees Fahrenheit under mostly sunny skies.

Fort Wayne - 77 degrees
Defiance - 77 degrees
Auburn - 77 degrees
Napoleon - 79 degrees
Paulding - 79 degrees

At the rate temperatures have been rising, I believe that temperatures could reach around 84 this afternoon in many areas, while some areas will only hit 82.  Tonight, lows will fall into the lower 60's area wide, with some towns and cities only dropping into the mid 60's.  Tomorrow, highs will reach the mid-80's with some isolated areas reaching temperatures around 87 or 88 degrees, as our winds shift from the northwest to the south-southwest by tomorrow which will pump very humid air into the region.  Lows Thursday Night will drop into the mid to upper 60's under partly cloudy skies with the possibility of a thunderstorm very early Friday morning due to a strong warm front ahead of this heat wave.  Temperatures on Friday will soar to near 94 degrees with extremely humid conditions.  Thunderstorm activity will be very little Friday afternoon, as a strong cap from the ridge will prevent any storms from forming.  Friday Night lows will be in the low to mid 70's with dew points near 71, bringing the possibility of fog.  On Saturday, temperatures will again approach 94 with even higher humidity values possible, bringing heat index temperatures over 100 degrees, which bring about the issuance of a Heat Advisory and possibly an Excessive Heat Warning.  On Saturday Night, thunderstorms will arrive in waves or clusters, which could cause flash flooding across the area. By Sunday, temperatures will drop from the 90's to the upper 80's, with the chance of thunderstorms, bringing a risk of flash flooding with them.  Independence Day could see temperatures near 90 again with a chance for thunderstorms due to the humid air.

Forecast Discussion

Saturday's Warm Temperatures

Variations in Climate Part II: The Subtropics

    In the last article, I talked about how the intense heating of the sun in the tropics causes not only warm temperatures, but heavy thunderstorms, which is why the tropics are associated with very wet weather.  This week,  I am going to talk about how the circulation in the tropics (i.e. Hadley Cell), causes the weather in the subtropics.
    The region of the the subtropical climates are usually located in between latitudes of 25 and 35 degrees north and south latitude.  Many of the world's largest deserts are located here.  These deserts include the Sahara desert, the Atacama Desert, the American Southwest (technically this is not a true desert and I will explain why later.), and many others.  These deserts usually are the hottest places in the world, mainly because they rarely receive rain or any kind precipitation for that matter.  The strange thing about many of the deserts, is that when they do receive rainfall, which is about once every couple of years, it comes in the form of intense downpours, and usually leads to catastrophic flash flooding.  Not only are the world's driest places located within this region but also some of the world's wettest places.  With this in mind, why is it that some locations within the subtropics are extremely dry and some are extremely wet?  Or more importantly why is it that some of these places are extremely hot, but can also be wet too?  The next several paragraphs should answer these puzzling questions.
     The circulation within the subtropical region is mostly influenced by the Hadley Cell, and the Intertropical Convergence Zone, which means that this region usually sees the most hurricanes of any other region in the world.  Because the Intertropical Convergence Zone shifts with the seasons, many places in the Subtropical region see an extremely wet and dry season, especially in Southern Asia, where the Intertropical Convergence Zone shifts the most.  As we learned in the last article, the Hadley cell begins when the equator is intensely heated by the sun.  Since most areas surrounding the equator, is ocean, the heated air, rises and condenses forming huge, towering thunderstorms, that produce torrential rainfall.  As the rising air nears the tropopause, it spreads laterally toward the poles.  Due to radiational cooling and convergence of the air, the layer of air causes strong areas of sinking air or subsidence, near latitudes of about 25 to 30 degrees north and south latitude.  Since earth's surface is not uniform, these high pressure ridges form not in bands, but in several cells that stretch around the world.  These cells also change position and actually move differently due to the differentiation of earth's surface and the seasons.  The areas that are generally under the influence of these high pressure ridges, are usually where the deserts are.  These strong areas of high pressure cause large areas of subsidence and compression.  When the air mass compresses, it dries the air mass out, causing few clouds and clear conditions.  The compression also causes a warming of the air mass, which partially explains the heat over the deserts.  Clear skies during the day signal intense surface heating from the high angle sun, causing even hotter conditions and it becomes a cycle of becoming hotter and hotter until the high pressure cell retreats or shifts.
     These high pressure cells are usually called semi-permanent, because they can be stationary for very long periods of time, causing intense heat waves over the deserts.  Areas that are near the oceans, such as the east coast of Saudi Arabia and the Southeastern United States, usually have very high dew points, which combined with the incredible heat, make working outside unbearable.  Other areas, such as the west coasts of continents, are usually influenced by cold ocean currents.  These cold currents cool the intensely heated surface, causing dense fog and a stratus deck of clouds.  This limits the amount of daytime heating along the west coasts of continents.  This also causes deserts to form along west coasts that aren't hot at all, but very dry because the stable air mass along with the subtropical highs would cause subsidence, fog, stratus clouds, and no precipitation.  Even the driest desert in the world, the Atacama, has daily fog and drizzle, but very little, if any, rainfall.  There are some deserts that are really not true deserts because even though they are in the subtropical region, the subtropical high is only part of the reason for these deserts.  These deserts are called rainshadow deserts, and are some of the driest in the world.  They form very short distances away from extremely wet areas.  One such place is the American Southwest, where storm systems may occasionally bring heavy rainfall, mainly during the winter and sometimes summer, but most of the time the storm systems that do make it over the mountains, usually produce little precipitation.  This desert in the Southwest forms because as moist air is lifted over a mountain by a strong low pressure system, it causes heavy and intense rainfall for days on the windward side of the mountain.  As it starts to descend the mountain, it is now dry because it used very large portion of its moisture on the windward side of the mountain.  The air descends and warms by compression at the dry adiabatic rate of 10 degrees celsius for every 1000 meters.  Since the air on the windward side was saturated it cools at a lower rate than when it warms on the leeward side of a mountain.  This causes extremely hot temperatures in the leeward valley (such as Death Valley), along with dry conditions.
     The high pressure cells that cause the heat waves and fog, shift from winter into summer.  In the winter, the subtropical highs tend to be along the west coasts of continents, causing the most fog and the least precipitation to be in the winter.  In the summer, the subtropical highs are usually located closer to the east coasts of continents but still sitting close to the centers of the oceans.  When the subtropical highs sit near the east coasts of continents, they cause warm, humid to be pumped onto the continents, usually the precursor to intense heat waves in the middle-latitudes.  Also when the ridges shift north and eastward, the ITCZ also makes a shift northward, which usually means the beginning of hurricane season.  When the high is oriented such that the ITCZ is just to the south of it, then expect several hurricanes to form and traipse eastward.
    Many people wonder why, if there are so many deserts located in these regions, why are there extremely wet areas around the world that are in the subtropical regions.  One reason that there are extremely wet area is because of the ITCZ.  In areas around the world where the ITCZ extends farther northward than in other areas, they have a wet and dry season.  During the winter in their dry season, these locations usually see very hot temperatures, all the way into late spring.  Then as soon as monsoon season hits in late May, these areas see extremely heavy rainfall, sometimes amounting to 200 inches for their average annual precipitation.  When the wet monsoon hits, the average temperatures drop where they would normally rise to even hotter levels.  This can seen in a climate graph of Calcutta, India.  Another reason that some areas in the Subtropics are extremely wet is because when the subtropical highs move toward the east coasts of continents, the high produces an onshore flow of very humid, air which heats intensely from the sun when it moves on land.  This causes the air mass to become extremely unstable, and because the air mass is very moist, it will rise, condense, and produce towering thunderstorms similar to that of the ITCZ.  This effect can be seen in a graph of Orlando, Florida precipitation which usually receives over 55 inches of rain every year.  You can also see from their climate graph, that they have wintertime minimum and summertime maximum precipitation.  Farther north, in Georgia and Alabama, locations around there are wet all year, mainly because they are hit by numerous low pressure systems during the wintertime, while receiving heavy summertime thunderstorms.
       In my next article, we will be focusing on the mid-latitude circulations and climates.  Middle latitude climates are much more complicated mainly because our weather is controlled by the jet stream.  As we all know the jet stream is variable and can change rapidly, causing rapidly changing surface conditions.  Even as our understanding of the atmosphere has increased, we still do not fully understand the processes that control the climates of the world.

Much Cooler temperatures this morning... Season's First Tropical Storm in Caribbean

Current Northeast Temperatures

Even though yesterday's high temperatures were in the lower 80's, subsidence and strong radiational cooling overnight caused temperatures to drop into the mid 50's area wide.  Currently, in Antwerp, we have a temperature of 55 while Fort Wayne is recording a temperature of 56.  Here are some other cities and their current temperatures

Defiance: 54 degrees - Defiance Forecast and Weather Conditions
Ottawa: 57 degrees - Ottawa Forecast and Weather Conditions
Napoleon: 56 degrees - Napoleon Forecast and Weather Conditions
Hicksville: 55 degrees - Hicksville Forecast and Weather Conditions
Paulding: 54 degrees - Paulding Forecast and Weather Conditions
Continental: 55 degrees - Continental Forecast and Weather Conditions

Thursday's high temperatures

Temperatures should rise this afternoon into the lower 80's once again, around 82.  Tonight's lows will only drop into the lower 60's, causing Thursday's afternoon highs to rise into the mid 80's, around 85.  By Friday, temperatures should skyrocket to the lower-middle 90's and possibly higher, especially in Northwest Ohio.  Lows Friday Night and Saturday Night will be very warm and muggy, with temperatures only dropping into the middle 70's.  Our first wave of showers and thunderstorms should arrive on Saturday accompanied by very high humidity.  By Sunday, several waves of Mesoscale Convective Systems could hit the area with heavy rain, large hail, and high winds.  For Independence Day, I expect still warm and humid conditions with temperatures in the upper 80's, around 88.  After that, meteorologists are still unsure as to whether another cold front will move through on Tuesday, or if the ridge will be allowed to expand northward again which would result in another heat wave.
           As for the Tropical Atlantic, the first tropical storm of the season has formed, with storm being named Arlene.  The storm is currently located in the Bay of Campeche, has sustained winds of 40 mph, and is moving to the west-northwest.  Meteorologists at the National Hurricane Center are expecting the storm to make landfall in the next several days over northern Mexico as a tropical storm with winds of 60 mph.

IR imagery of Tropical Storm Arlene

Warm Temperatures to End the Day and Mid-Week Outlook.

Current temperatures

After a unseasonably warm morning, (even though we have had temperatures this warm in the mornings many times this year.) temperatures rose to very comfortable seasonable temperatures in the lower 80's.  The air is not very moist this afternoon with dew points area wide being in the low-to mid fifties, creating a very comfortable afternoon.  Tomorrow should be about the same, maybe even a little warmer, with temperatures rising to around 82 after morning lows that will be much colder than this morning's low, with temperatures being around 59 at 6:00 a.m. tomorrow morning.  Thursday will bring much of the same thing, but the humidity will be increasing as we progress into Friday.  Temperatures on Thursday will remain around 83, while nighttime lows will be much warmer, in the mid-60's.

Wednesday's and Thursday's High temperatures

Heat Wave Possibility is Becoming More Likely

Before the heat wave, we will have several days of tranquil weather with temperatures in the lower 80's and less humid conditions.  But by Friday, temperatures will be at least to the lower to middle 90's, and since we have been much drier than what was originally forecasted, I believe that temperatures could end up in the upper 90's if everything works out right.  On Saturday, temperatures will be a bit cooler, but more humid, then on Friday, because of thunderstorms brought in by a weak cold front that is slicing southward out of Canada.  This should allow for cooler and drier air to move in for the Fourth of July, even though it will still be in the mid-80's according to the National Weather Service: NWS forecast for Antwerp, OH .  According to Chad Evan's blog from the WLFI TV station in Lafayette, IN, if it weren't for the wet soil, we would have temperatures close to 110 degrees.  He's forecasting temperatures in the middle 90's for his area.  For Northwest Ohio, our soils are a bit drier because we haven't as much rainfall as Lafayette had, so I expect temperatures to approach one hundred if everything goes the way it is supposed to. NOAA temperature forecast

Tropical Cyclone Formation

Hurricane Katrina, as it was about to make landfall in 2005

   We are almost done with our first month of hurricane season in the Tropical Atlantic, and nothing has formed yet.  In the past 5 years, since 2005, every year has seen a tropical storm, depression, or hurricane form in June or earlier, except in 2009.  One of the earliest was in 2007, when Subtropical Storm Andrea formed on May 6, and pounded the Southeast Coast with high waves and strong winds.  This year there has been several systems that have been monitored, but none have actually organized into a cyclone.  Due to this some people were wondering why some tropical waves become organized and others do not.  To answer this question, I will describe the process in which a hurricane forms.  Then I will update you on potential hurricane development in the next few days
     Before a hurricane can become several things must happen.  First, there needs to be a preexisting area of convection, such as a weakening mid-latitude cyclone or a tropical wave from Africa.  For this system to become organized, it needs to interact with the ITCZ, when the ITCZ is located between 10 and 30 degrees north latitude.  As explained in the last article, when the ITCZ moves this far north, the Coriolis effect acts on the converging winds, turning the southeast trade winds on the south side of the boundary, to southwest winds.  When the northeast and southwest converge along the boundary, cyclonic rotation and a higher relative vorticity of the air is possible.  When a region of low air pressure has cyclonic rotation and high relative vorticity, it begins to rotate.  When the tropical wave or front interacts with this area of strong vorticity, its air pressure lowers, causing a greater rush of converging winds.  The converging winds move toward the center of lowest air pressure in the region, and with the Coriolis effect, causes the disorganized bands of heavy thunderstorms to rotate around the center of low pressure.  Soon the system becomes organized into a full-blown hurricane.  Second, there needs to be a source of energy.  This source of energy comes from warm water temperatures in the region where most hurricanes form (central and northern Caribbean eastward toward Western Africa).  The National Hurricane Center has made one of the factors of hurricane development, water temperatures of at least 80 degrees Fahrenheit.  When a tropical wave enters a region of relatively warm water, the converging winds within the tropical wave cause the warm, moist air to rise, cool, and condense into thunderstorms.  As the air within the thunderstorms cools and condenses, it releases heat to its environment, which encourages the warm, moist air to rise even more vigorously, producing more thunderstorms.  The warm, moist air also lowers the air pressure within the center of the now-organized tropical wave, causing air to move faster toward the center of the low, causing surface convergence and further lowering of the air pressure, which causes thunderstorm development and so on and so on.  The third factor is the upper level winds surrounding the tropical wave.  In order for a tropical cyclone to develop into a strong hurricane or to sustain hurricane strength, their cannot be strong wind shear in the atmosphere.  If winds in the environment surrounding the hurricane change direction with height, then its central circulation will be ripped apart because it does not encourage organized rotation.  But if winds are light at every level of the atmosphere and do not change direction with height, the tropical cyclone can strengthen and become a hurricane.  Finally, last factor deals with a hurricane position relative to land.  If a hurricane is close to land, winds in the outer bands that are affecting land will be reduced by friction, causing a reduction in convergence at the center and a rising atmospheric pressure.  If the hurricane interacts with land along the western coast of a continent, not only does friction with land weaken the hurricane, but almost always there is a cold current along the west coasts of continents, which will cut the hurricane off from its source of energy.

A simplified model of a hurricane

      Using these factors, I will give an example of how a hypothetical hurricane could form in these conditions.  Suppose a tropical wave moves off of the west coast of Africa, along the Intertropical Convergence Zone.  As the tropical wave moves along the ITCZ, the convergence zone begins to shift northward and the Coriolis effect comes into play.  Then the tropical wave, as it nears the Canary Islands in the Western Atlantic, begins to interact with this area of increased convergence and vorticity, causing a drop in central pressure and increasing thunderstorm activity.  As this process gets going, the system unexpectedly weakens as it passes over the Canary Islands.  When meteorologists examine why this system weakened, they know it was not because of the islands that it weakened (the Canary Islands are way too small to weaken a tropical wave.), they realize that the cold Canaries current weakened the storm.  The process then starts back up again as soon as the tropical wave moves into the much warmer waters of the Central Atlantic.  Very quickly, the system develops into a tropical depression and then within a few hours a tropical storm.  Then as thunderstorm activity picks up, the heat released from condensation warms the air causing a drop in central pressure.  This creates a tighter pressure gradient, which causes stronger winds.  The stronger winds whip up the ocean into huge waves, increasing evaporation.  The evaporation of the warm waters bring about added moisture to the air, which decreases air density, causing stronger rising air thermals, which further creates more thunderstorms starting the process all over again.  Soon this mess of thunderstorms begins to rotate around the low pressure center.  As the process described continues, the thunderstorm bands become even more organized and rotate around an eye-like feature.  Once the highest sustained winds within a tropical cyclone become greater than 74 miles per hour, and an eye feature is observed (which is sometimes obscured from satellites by upper level clouds) it becomes an official hurricane.  As the system intensifies, so does the process that was described earlier, causing even more intensification.  The intensification rate then slows down and even stops, due to four factors.  One:  upper level winds may have become unfavorable for greater development within the hurricane. Two: dry air may have become entangled with the system.  Three: It is to close to land.  Four: the system is at its highest level of strength possible.  This can happen when the storm uses so much energy that its energy intake equals the level of energy it puts out.  Without this, hurricanes would die after a few days.

An example of a trough and ridge

     As the hurricane approaches land (in the case of the Atlantic, the United States), meteorologists begin forecast its path and its intensity.  The main factor that controls hurricane movement is the position of the highs and lows across the Atlantic and over the United States.  If the there is an upper level ridge over the Central and Eastern United States, then the hurricane will more than likely move more westerly than northerly and hit Mexico or South Texas.  When a hurricane approaches a trough, it tends to be steered north and eastward away from the United States.  But troughs can also allow hurricanes to hit the United States.  If a trough is sitting over the Central Plains and a ridge is stagnant over the East Coast, a hurricane in the Atlantic will not be allowed to turn northward, and it will keep moving westward until hits the Gulf of Mexico where it will turn northward, and depending on the position of the trough and ridge, it could hit anywhere from Florida to the Texas Coast.
After many weeks of waiting for a tropical disturbance to form, a tropical disturbance has finally arrived and is located just to the southeast of the Yucatan Peninsula.  According to Accuweather and the NHC (National Hurricane Center), this strong tropical disturbance will move across the Yucatan Peninsula and into the Bay of Campeche, where it will interact with water that has temperatures of 82 to 86 degrees which is perfect for hurricane formation.  The curved shape of the coast in the Bay of Campeche, provides the necessary cyclonic vorticity for the storm to become organized into a tropical storm or hurricane.  Once it does become a tropical storm or hurricane, it will be called Arlene.  As to whether it will make landfall in the United States, meteorologists are currently thinking that the storm will make landfall in northern Mexico, because of a large ridge of high pressure in the central plains that is expected to develop later this week.  But, still if you are making plans to go vacationing in the Gulf Coast region, particularly along the Texas Coast, be on the look out for shower and thunderstorm activity.

Variation in Climate Part One: The Tropics

Usually, when we go on a vacation to a place we have never been before, we find out what the climate is like first before we start packing. Finding out the climate before we go on vacation helps us to know what kind of clothes to pack, whether to bring umbrellas or not, whether to bring tents or tarps, and so much more.    But what exactly IS a climate?  Climate is the average weather of any given location, including how much precipitation it usually has during a given period of time, and what kind of extremes to expect at this location.

As most of you know, the sun controls the weather, therefore it also controls the climate of a location. For example: the farther north you travel (or if you live south of the equator, the farther south you travel) the less the sun angle is. When the sun angle is more acute to the ground (a lesser sun angle), it is usually colder than a place that has a higher sun angle. With this in mind, the higher the latitude, the colder it gets. But why then, is a city such as Eureka, California, that is at the same latitude as New York City, warmer then New York during the winter and colder in the summer, or why is a southern city such as Tampa Bay, Florida warmer then some cities at the equator, which has a higher sun angle than Tampa Bay? In the next few paragraphs, I will attempt to answer these questions as best as I can, seeing as that some of the climate questions are still puzzling meteorologists and climatologists alike.

The first climate we will start with is the Tropics. Usually climatologists think of the Tropics as the climate that controls the rest of the climates around the world. One of the main proponents in a tropical climate is the intensity of the sunlight hitting the earth. The intense sunlight causes intense heating of the surface and warm water temperatures. The intense heat from the surface rises, cools and condenses producing towering thunderstorms that produce heavy rainfall in a band that stretches around the world, called the Intertropical Convergence Zone (ITCZ). Thus, since maximum surface heating occurs where the most intense sunlight radiates the earth, the ITCZ moves with the sun and the seasons. When the heated air rises, expands, and condenses, it causes upper level divergence of the air, and as I stated in my last article, upper level divergence encourages surface convergence which further aids the development of thunderstorms. This is an example of a thermal low, one that is produced by heat and not by the jet stream. These are usually much weaker than storm systems in the middle latitudes. Usually the ITCZ, is located over or just south of the equator during January and is usually located around 23-25 degrees north during July, but extends much farther north over Asia during the summer. The reason for this is because land is heated more intensely than water and since Asia is the biggest continent it absorbs much more sunlight than in the western hemisphere at the same latitude and causes the air mass over this area to be very hot, humid and unstable. Because of this, there is a very large difference in the position of the ITCZ over Asia from the summer to the winter season, and is the main reason for the wet and dry season over southeast Asia, or the monsoonal seasons. Where the Intertropical Convergence Zone is located, is where the most rainfall will occur. (usually over the rainforests of South America, the Caribbean, Africa, and Southeast Asia) Also where most of the rainfall occurs, the summertime temperatures are usually colder then at a location that is located in the subtropical zones or even at a location in the middle latitudes. Not only does the ITCZ affect the weather in the tropics, but it also affects the weather of the subtropics and middle latitudes. When the ITCZ extends in between latitudes of 15 and 25 degrees north, the Coriolis force is now enough to turn the normally southeast winds on the south side of the boundary, when it is at the equator, to southwesterly winds. When the northeast winds on the north side of the boundary converge with the southwesterly winds on the south side of the boundary, they produce cyclonic rotation and vorticity, and when a tropical wave interacts with the area of vorticity, the tropical wave becomes organized and could develop into a hurricane if wind shear and dry air are not involved. The organized tropical wave then travels along the ITCZ until a subtropical high begins to steer the system northward into the United States.

This is a model that simplifies the basic climate variations in the world.

When sailors from the Old World first sailed in this region of the world (to get to the tropics they used the trade winds, the northeast and southeast winds that converge along the ITCZ) they called the area around the ITCZ the doldrums, because of the light winds and violent thunderstorms that were not reliable for wind power. This is because within the tropics, there is very little difference in sea level pressure. Without much wind, sea breezes and land breezes are much more noticeable in the tropics than in the rest of the world.
The circulation of the tropics is  involved with a circulation cell in the atmosphere, which is why I mentioned before that it is the driving force of most of the other climates of the world. This circulation cell is called a Hadley Cell, named after Sir George Hadley, who was using his theory to explain world circulation patterns in 1735, such as the trade winds.  His idea is today used as an idealistic model in tropical atmospheric circulation.
This is the model that is used today: the hot air mass over the tropics rises and condenses producing heavy thunderstorms over the ITCZ.  When this air hits the tropopause it spreads laterally. One: because the stratosphere (the layer above the troposphere) is stable, and because there is so much upward motion in this humid air mass, it spreads laterally toward the poles; and two: the pressure gradient force between the poles and the tropics causes air to move towards the poles. This air then begins to cool due to radiation and it begins to sink at about 30 degrees latitude on both sides of the equator, causing large high pressure cells to dominate the climate of the subtropics, which I will continue to explain in next week’s article.
Next week, I will talk about how the air flow in the tropics influences the climate of the subtropics, which is where the world’s largest deserts are located such as the Sahara Desert and the Atacama Desert in Chile—the driest desert in the world. Back to the weather around here, temperatures will definitely start to warm to a hotter drier pattern over the next several days, as the monsoonal trough develops over the American Southwest deserts. When this trough develops, a large subtropical high will move over the central plains, causing a major and intense heat wave to develop over the Midwest and East. According to long range forecasts, this heat wave could last to Independence Day or longer, before a cold front moves through temporarily ending the heat, only to return again after a few days.  The recent heat and the heat that is forecasted to come has lead me to change my own summer forecast to a very warm one. Other than that, have a great week!

Warm temperatures this Morning

Temperatures this morning across Northwest Ohio and Northeast Indiana are very warm in the low seventies and upper 60's, slightly warmer than what was expected.  Here are a list of cities and their current temperatures:


Fort Wayne, IN: 69 degrees Fort Wayne Current Conditions and Forecast
Antwerp, OH: 71 degrees Antwerp Current Conditions and Forecast
Defiance, OH: 69 degrees Defiance Current Conditions and Forecast
Paulding, OH: 70 degrees Paulding Current Conditions and Forecast
Ottawa, OH: 70 degrees Ottawa Current Conditions and Forecast
Napoleon, OH: 70 degrees  Napoleon, OH Current Conditions/Forecast


Current conditions and forecasts can be found for these towns and cities through their respective links. 
According to the NWS, temperatures will hit the low to middle 90's on Friday and possibly even Saturday (depending on if the storms hit).  To read more click on this link to their forecast discussion.

Forecast Discussion

Storm Potential For Tonight and Warmer Temperatures by Week's End.

As of 5:00 p.m., the severe potential for tonight has diminished as the highest instability has been held to the south of us.  It's looking like there will be a line of showers and storms in the evening hours around 9 or 10 p.m.  According to the SPC (Storm Prediction Center), the severe storm potential has moved into northern Wisconsin and into the mid-South.  The storms that are still supposed to form in our area will develop in the next couple of hours and move through with an isolated wind threat and large hail threat.  Clouds will clear out after midnight when the cold front passes through.  Tomorrow will be slightly cooler and less humid with highs in the lower eighties. Temperatures will slowly moderate throughout the week and by Friday we should have temperatures in the 90's and higher humidity levels. 
www.noaa.gov