Warmth Continues...

As of  4 p.m. this afternoon, the official high temperature at Fort Wayne International Airport was 88 degrees (note: this will likely change as temperatures continued rising after 4 p.m.).  It is very likely that across the area, mainly west of Defiance, that many areas reached or exceeded 90.  In fact, most of the warmer temperatures were west of here, with some areas, such as Chicago, reaching into the lower 90's.  The reason for this well above normal warmth, is because of the incredibly dry ground.  In fact, it has been almost two weeks since some areas in the region even saw rain.  Dry ground combined with completely clear skies lead to large diurnal temperature swings, with low temperatures this morning near 50, and high temperatures in the upper 80's and lower 90's.  Also, a strong upper level ridge is currently located over us, which is basically a large bubble of relatively warm air in the upper atmosphere.  This "warm bubble" is causing downward motion over the area, which is causing the warm temperatures aloft to be carried to the surface, plus the added subsidence is causing adiabatic warming which also warms the surface.  With warmer lows tonight near 60, expect even warmer temperatures for tomorrow afternoon, with highs possibly reaching well into the 90's (91-93) in some localized areas.  With increasing moisture into the area, high temperatures may not reach that high tomorrow.  By Monday, a dying upper level system will reach the area, causing scattered showers and thunderstorms.  Because of the weak forcing associated with the system, and meager moisture in the lower atmosphere, do not expect much shower and thunderstorm activity in the area.  Because the cold front will be moving through, temperatures will be quite a bit cooler on Monday then on Sunday, with highs only reaching the lower 80's.  On Tuesday, the core of the upper level low will move over the area, bringing the chance for an isolated shower, but this is highly unlikely.  The cold core of the upper level low will cause much cooler temperatures on Tuesday, with a high near 73.  By Wednesday, the next upper level ridge will build into the region with yet another warming trend for Memorial Day weekend.  Wednesday's highs will peak in the upper 70's under partly cloudy skies.  By Thursday, temperatures will approach the mid 80's yet again, under sunny skies.  On Friday, Saturday, and Sunday, I am expecting temperatures to rise into the upper 80's and lower 90's, with temperatures possibly peaking in the mid 90's on Sunday and Monday.  This will have to be monitored in the future because this could be a sign the season's first heat wave could hit the area.

Fair weather through the weekend

With temperatures approaching the low to mid 70's this afternoon (west of Defiance anyway), along with plentiful sunshine, it has been one beautiful day.  The cold front that I was predicting on Tuesday did more "damage" than I thought it would, as brought temperatures tumbling down to the upper 60's yesterday, and the same anticyclone is bringing cooler weather to the area today.  Tonight, temperatures probably will not be as cool as last night, mainly because high and mid level clouds from a weak shortwave crossing the upper Mississippi Valley will keep temperatures from dropping nearly as fast.  Also, veering low level winds from the southeast and weak warm air advection will also be a caveat to lower temperatures.  By tomorrow, plentiful sunshine (possibly some puffy cumulus in the afternoon), upper level ridging and weak return flow, will cause temperatures to jump about 10 degrees from today, with temperatures ranging from the mid 70's near Toledo, to the lower 80's near Antwerp and Fort Wayne.  By Saturday, in response to a major trough entering the west coast, upper level height rises and ridging will allow for warmer 850 millibar temperatures, stronger mixing throughout the low levels, and thus even warmer temperatures.  In fact, I would not be surprised for some areas on Saturday to see temperatures as high as 87 or 88, especially west of Fort Wayne.  Saturday night lows will be much warmer than previous nights, with temperatures dropping only to near 60.  I expect pretty much the same on Sunday, with temperatures easily approaching the 90's under mostly sunny skies.  By Monday and Tuesday, a shortwave will approach from the plains, possibly bringing the chance for showers and thunderstorms, mainly on Tuesday.  Temperatures on both days look to range in the upper 70's and 80's.  In the long-range, there is a lot of discrepancy, but the ECMWF, which has been pretty consistent with its solutions of a ridge over most of the United States, is forecasting a rather strong upper level ridge to form over the Eastern and Central United States, and persist for several days.  It is forecasting 850 millibar temperatures to be in excess of 20 degrees Celsius by next Thursday (it is a week away so a lot can change by then!), which translates to surface temperatures in the 90's, which could mean our first heat wave may be on the way.  We'll just to have to wait and see, but it is a good bet that we see some hot weather in the near future, as the ground is incredibly dry and the pattern is very conducive to warm spells (as we have seen all winter long!).  Enjoy the nice weather!

Slighty Cooler Tomorrow

After such a beautiful day today, with temperatures near 85 (an impressive diurnal temperature range, 49 this morning to 85 in the afternoon) and incredibly low humidity, a weak cold front from Canada will invade the area, bringing the possibility of weak scattered showers, but more importantly temperatures back into the 70's for a few days.  This cold front diving southward in response to a high amplitude trough sitting in southeastern Canada.  This will send a bit of a reality check to the region, with temperatures only reaching the mid 70's tomorrow.  I am not expecting really any rain except for the possibility of a few sprinkles, as moisture return from the Gulf of Mexico is incredibly meager and any significant upper level forcing is too far north of here to produce anything of consequence.  This will likely mean a partly cloudy rather warm night with temperatures dropping into the mid 50's.  By tomorrow, cooler temperatures with make their way into the area with highs dropping near 73 or 74.  Much cooler temperatures tomorrow night could mean lows in the mid 40's, quite a bit cooler than in recent nights.  By Thursday, temperatures will begin making their recovery with highs back into the upper 70's underneath a very dry air mass.  For the rest of the weekend and the beginning of next week, strong upper level ridging will cause much warmer temperatures, with highs as warm as the upper 80's and lower 90's.  A lot of the models are tend to under do warm events like these, mainly because they cannot account for soil moisture very well.  When soils are incredibly dry and the air mass is also dry, temperatures tend to rise much faster and to higher temperatures as well.  Temperatures also tend to drop considerably at night, making for large diurnal temperatures ranges.  This means very hot temperatures for the weekend under mostly sunny skies as ridging continues to build.  After this, the forecast gets a little out of hand.  The GFS has a small amplitude wave moving through the Midwest on Monday and Tuesday, with ridging building back into the region after that.  To me, this seems like the most logical conclusion, as a rather strong trough will build onto the West Coast, causing an amplification of the Central and Eastern ridge.   After a couple of days of being in the upper 70's on Monday and Tuesday, expect temperatures to warm back into the mid to upper 80's, with continuing warmth possible.

Warm, dry weather pattern

For all the people who love summer-like weather, there is yet another batch of much above normal temperatures coming, with highs by the end of this week reaching into the 80's.  This will come on the heels of a long dry spell, which will likely last through the next week or so.  So far this month, we have only received 0.8 inches of rain, and with little or no rain in the next week and a half, this could end up as the second month in a row with below normal rainfall.  With the below normal rainfall and record warmth over the past several months, drought will likely ensue, with parts of the area already in the first category of drought status.  This could have huge implications for this summer's weather, with widespread dry ground over the Midwest leading to hotter daytime temperatures (dry ground heats up faster and longer than wet ground does).  As late spring and summer progresses, the large amount of heat radiated from the ground level will cause a deep layer of warm air to form, making it nearly impossible for cold fronts from Canada to penetrate into the Midwest.  Not only will this occur, but building warm air will cause higher pressure aloft, causing greater subsidence, clear skies, more sunshine, no rain, and higher temperatures which will all continue to cause warmer temperatures throughout the summer.  Obviously, this is an idealized process, with many complications which will act to counteract the warmer temperatures, such as isolated summer thunderstorms.  What I'm trying to say is that the warm and dry weather pattern of this spring will likely continue through the summer.  According to Accuweather, they are expecting a much different pattern.  They believe that this summer will hold above normal storms and rainfall for the area but normal temperatures.  Unless there is some kind of major pattern reversal, I do not see this happening in the near future, as blocking is characteristic of an El Nino pattern, which we are entering into.  Also I have found correlations with other years that had warm winters, warm and dry springs, and they have also had very warm and dry summers (the summer of 1955, one of Fort Wayne's hottest summers).  Otherwise, over the next week, due to dry soils and relatively little moist air entering the region, I do not see much rain nor cooler weather.  In fact, each day will see large diurnal temperature swings, which could mean lows in the lower 50's during the morning but temperatures in the mid to upper 80's and lower 90's by afternoon.  It is entirely possible that temperatures reach into the 90's by the beginning of next week.  Though, it is very hard to tell, as the long-range is very difficult to forecast.  If computer model forecasts are correct, then 850 millibar temperatures could approach the lower 20's degrees Celsius, which translates to surface temperatures in the lower 90's.  This pattern won't last forever, but it will likely last quite a while.  My forecast is that this type of pattern will continue throughout the summer months, bringing our area quickly into drought.  Before we hit the 80's though, expect temperatures in the upper 70's through Thursday, before they rise into the 80's.  Enjoy the beautiful weather this week!