Short Term Forecast

Over the last few hours, the atmosphere has destabilized over the last few hours, with rather high instability building over parts of the area.  Current RUC analysis images from 3 p.m., show the axis of highest instability located in Northeast Indiana, along with parts of extreme western Ohio. (note: areas west of Defiance are relatively stable, and not near as warm as areas east of Defiance, due to morning rain and thunderstorms.)  CAPE values or instability values are over 3000 J/kg which indicates a strongly unstable environment, conducive for thunderstorms.  According to the latest satellite imagery, convection was developing over western Indiana, with a large cumulus field also located over the area.  Farther south, large areas of widespread severe thunderstorms were occurring in southern Indiana and along the Ohio River.  I expect over the next few hours that thunderstorms will begin to develop especially east of a line from South Bend to Indianapolis.  More organized thunderstorms will be present east of Defiance, due to stronger deep layer wind shear present, even though instability is not as high as around here.  With the rather moist environment that is also present, I expect that these thunderstorms will be capable of producing heavy rainfall, especially in areas where thunderstorms train (meaning that they move over the same areas over and over).  According to the Storm Prediction Center, large hail is the primary threat from any isolated severe thunderstorm, but it is possible that they also produce gusty winds.  The thunderstorm threat will gradually die out by about 11 or 12 tonight.  Tomorrow, a similar situation will occur, but with more available moisture.  In fact, according to computer models, these situations will be very similar each day until Sunday, when the ridge will be too strong to allow thunderstorms to develop.  The ridge will amplify considerably by Tuesday, with even warmer temperatures than what we've been seeing.  As for right now, we are not sure when this warmth will end, primarily due to the fact that computer models keep changing the story.  I will keep you informed about this record-breaking heat over the next several days.

Summer-like Conditions Overspreading the region.

During the overnight hours, due to the high degree of warmth located in the area, an unstable atmosphere has remained overnight, allowing for the development of scattered strong thunderstorms.  It does look like that over the next few hours, these storms will continue popping up, affecting many areas.  These storms will be capable of small hail, frequent lightning, and heavy rainfall.  Be on your guard this morning.  In other news, temperatures will once again soar to record levels by this afternoon, with high temperatures near 80 degrees.  Upper 70's and lower 80's look to be prevalent through at least the middle of next week.  Stay tuned for further updates.

Record Breaking Warmth Overspreading the Nation.

As I have said over the last several days, the wave of warmth overspreading the nation will be record-breaking in many aspects.  Even in our local area it will be unprecedented.  Temperatures will approach record highs for several days this week, and even well into next week.  For example, tomorrow, it is possible that temperatures reach the upper 70's and lower 80's in some areas (depending on how cold it gets tonight, especially if a weak frontal boundary sags farther south than what is expected).  This high is calculated based on using 850 millibar temperatures.  The idea behind it is that during a regular spring or summer day, the wind and solar heating will cause the entire boundary layer (the first several thousand feet from the surface) to mix out, allowing warm air aloft to mix to the surface.  I will show you how I did my math.  If you assume that the warm aloft is brought to surface by the Dry Adiabatic Lapse Rate (the rate at which the temperature of air changes as it is moved up or down.  On Earth, this lapse rate is approximately 10 degrees Celsius/kilometer), and if you can determine how far above the earth the 850 millibar layer is, you can find the surface temperature for that day.  Assuming that the 850 millibar temperature is 12 degrees Celsius and its height was 1530 meters (which is the conditions that will be existent tomorrow across the area), then you would add 15.3 degrees Celsius to 12 degrees ( first divide 1530 by 1000 , multiply that by 10 to get 15.3), yielding a high of 27.3 degrees Celsius or 81 degrees Fahrenheit.  You would not be able to use that number alone because we are above sea level by 200 meters or 720 feet, which would cause the actual high to be a couple of degrees cooler.  Since we are not that far above sea level, it will not make much a difference, considering the fact that even warmer air aloft could be transported to the surface, making this high temperature forecast true.  So after a high somewhere in the upper 70's on Wednesday, expect the development of scattered thunderstorms after midnight in northern areas, mainly in Michigan.  These storms will eventually develop southward, bringing the thunderstorm potential to most of the area by Thursday morning and afternoon.  This type of pattern will continue into Saturday, before large scale height rises in the upper atmosphere, cause an enormous ridge to develop that extends as far north as the Hudson Bay.  This will lead to a widespread surge of tropical moisture and warmth into the area, including temperatures into the upper 70's and lower 80's next week, along with very moist air.  Even most of the severe weather by the middle of next week will be concentrated in Oklahoma and Kansas, by the end of next week, severe weather may move into our area as a potent storm system affects the region.  Enjoy this warmth while it lasts, as this event is very rare and only happens every decade or so.

Important Update

I have been monitoring the latest trends in the storm system, and it looks like the severe threat could extend farther south than what was indicated this morning.  Upper level forcing is expected to move over the area in a few hours, causing the development of strong thunderstorms to our northwest over southwest lower Michigan and Northwest Indiana.  This thunderstorms will more than likely only sideswipe most areas that are south of Route 6, with a much more robust severe weather threat north of Route 6.  The main threats will be damaging winds and large hail, but tornadoes are also beginning to look like a possibility especially just north of the Michigan border.  Instability is on the increase west of us, and should soon develop in our area, as the area of clearing moves in.  Temperatures have warmed very nicely despite cloud cover.  As soon as clouds move out, I expect temperatures to jump several degrees, possibly just shy of 70.  Tonight, thunderstorms will impact the area after about 7 or 8 p.m.  These thunderstorms could be severe, but mainly north of Route 6.  Tomorrow will be a very nice day with temperatures in the upper 60's and lower 70's as upper level ridging builds into the region.  Light winds and a dry air mass will promote intense cooling Tuesday night, with temperatures falling into the mid 40's, instead of the mid 50's.  Despite this, temperatures on Wednesday will soar to near record levels, with most regions in the area hitting the middle 70's, under sunny skies.  By Wednesday Night, a stalling frontal boundary will approach the region, causing the development of scattered thunderstorms.  These storms probably will not be severe, but they could cause locally heavy rainfall in some areas, due to the highly moist air mass expected to arrive in the area.  Thursday, Friday, Saturday, upper level ridging will only get stronger, even with a series of shortwaves moving around it.  These individual shortwaves will initiate thunderstorms along the frontal boundary in Michigan, which will be a continual threat through Saturday.  These storms could also bring locally heavy rainfall.  At the same time, the rather moist and warm air mass will still remain across the area, keeping temperatures in the lower 70's and nighttime lows above 55.  Just to show how warm this air mass, I will tell you a little fact.  According to the National Weather Service, a nighttime low of 55 or warmer in mid-March has only occurred TWICE in Fort Wayne's 110 years of record keeping.  The forecast for the next week or so is showing at least five days could have lows above 55 degrees (mainly Wednesday, Thursday, Friday, Saturday, and Sunday.).  Next week, the ridge will amplify, causing an even greater surge of tropical air into the region.  In fact, it could get so warm by Monday and Tuesday, some areas could be seeing temperatures as high as 80 degrees!  Many March's in the last 30 years haven't even seen a 70 degree day.  Back in 2008, we were well below average and very snowy.  This  is how extreme the weather pattern has been.  The GFS is showing a quick end to the "heat wave" by the 24th of March, with a potential freeze. It is highly unlikely that this cold wave will last long at the end of March, especially given the current pattern.  Opposite the GFS, the ECMWF model is showing that the ridging will hold, allowing the warmth to continue.  I will continue to monitor this very nice late-spring weather in coming days, as we could see several temperature records broken!

Forecast Updated

The Experimental forecast page has been updated.  Come check it out for a brief long-range forecast and the forecast for this week.

Stormy at First, then Spring

I have good news and some bad news.  For the bad news, current data suggests the potential for thunderstorms tomorrow, mainly south of the Michigan/Indiana border.  If the thunderstorm threat persists longer into the day, then I highly doubt that temperatures will make it much past the lower 60's and upper 50's.  The initial waves of showers look to arrive in late afternoon for areas west of here such as Northern Illinois and possibly even Northwest Indiana, while the initial waves of showers for Indiana and Ohio will not arrive until about 10 p.m. to midnight.  A more solid line of convection will make its way to the Ohio Valley and lower Great Lakes by the early morning hours, with the NAM suggesting these showers and possibly thunderstorms will arrive by 4 or 5 a.m., and the GFS suggesting a much faster solution of arrival around 3 a.m.  Rainfall amounts will likely be near a half inch, with higher amounts of rainfall farther west near Chicago and Illinois.  After the initial warm front passes through the region, temperatures will warm quite nicely from the overnight lows of the mid to upper 40's, into the lower 60's.  If enough diurnal heating takes place tomorrow,  (aka. sunshine) then it is possible that any weak instability that forms do to the heating, will cause the scattered development of thunderstorms, with some taking on severe characteristics, especially with the wind profile that is suggested by the NAM.  This would be supportive of small hail, and a few damaging wind gusts.  Right now, this is only small possibility as the best lifting from the upper level system will have moved out of the region by the time that conditions would be conducive for severe weather.

GFS forecast of the 500 millibar closed low at 5 a.m. tomorrow morning

Conditions will then clear for Monday night, with temperatures dropping into the upper 40's.  Through most of the upcoming week, expect sunny conditions and very warm weather, with highs likely hitting the 70's for several days in a row.  There are some thunderstorm chances coming up, especially Wednesday night into Thursday and next Saturday night, but these rain chances will be rather small, and will not affect temperatures much.  In fact, the latest GFS is forecasting this warmth to last even into the next week, and it really isn't showing much of an end to the warmth even 16 days into the future!  According to the WFO IWX (Northern Indiana's National Weather Service office), they would be not surprised to see the lower 80's by the week after this week, that's how warm this pattern is going to be!  Enjoy!