Warm, Humid this morning

After an overcast morning, the skies have cleared partially, allowing for rapidly warming temperatures along with increasing humidity levels.  In fact, most areas now are seeing temperatures in the mid 80's with dew points in the mid 60's, making it very uncomfortable.  The reason for the warm temperatures and high humidity is because of the fact that the cold front has slowed down significantly and has almost stalled.  Current short range model forecasts are still showing the front move through by noon, only bringing lower humidity not cooler conditions.  For this reason I am going to raise high temperatures for today into the lower 90's, especially south of Route 6.  Dew points will decrease considerably during the afternoon (below 50 to be exact), leading to much more comfortable conditions even with 90 degree temperatures.  By tonight, the same stalling front will surge back north as a warm front, bringing extremely humid conditions along with even warmer temperatures.  A few showers and thunderstorms may accompany the frontal passage, but it is likely that upper level ridging will hamper much thunderstorm activity, with areas west of Fort Wayne the most likely to see any kind of showers and thunderstorms.  For tomorrow, expect temperatures to surge into the low to mid 90's with dew points in the upper 60's.  Not every place in Northwest Ohio will see this kind of warmth and humidity, especially north of Route 6, where periodic showers and storms will possible in the morning north of the warm front.  By Saturday Night, a nice, warm and humid night is in store, with most places not dropping below 71 or 72.  On Sunday, a very hot, humid and oppressive day is in store, with high temperatures soaring to the upper 90's and some areas might even see 100.  It will be one of the hottest days ever recorded in May and one of the earliest 95+ temperatures on record.  By Monday, temperatures will not be as warm as on Sunday, but it will still be hot and humid, with high temperatures approaching the low to mid 90's once again.  By nightfall, storms will be possible as a frontal system approaches the area.  This will front that ends it all, with temperatures plummeting back into the lower 80's on Tuesday, and the lower 70's by Wednesday and Thursday.  After that, it seems as if we will be seeing cooler for a few more days before returning back to the 90's.  Enjoy the nice summer weather!

Drought Advancing

I said I would post an article on the drought and so I will.  For "official" measurements, visit www.crh.noaa.gov/iwx.  So far this May, most of the area has seen less than an inch of rain (excluding areas north of Route 6 and east of Defiance, with the epicenter of this rainfall deficit centered between Fort Wayne and Antwerp (including the two places).  In fact, it has been so dry that in the last 14-20 days, most areas have not seen rain, which is extremely rare in a spring month.  This has created a rainfall deficit of nearly 2-3 inches since the start of May, and an inch and a half rainfall deficit for the month of April.  Most of you probably have noticed that your yard does not look like it was May, but rather August.  WE really have a serious situation on our hands which will continue to impact our weather throughout the summer and into the fall.  My bet is that we end May with little more rainfall than we have right now, given the fact that most of the rainfall from the next two storm systems will bypass the area well to the north, I do not expect much if any rainfall when this heat wave comes to an end.  As I have talked about before in past blogposts, rainfall deficits lead to dry ground, and dry ground is able to heat up faster and to higher temperatures than wet ground.  Obviously, this is probably one of the most pronounced affects of the drought, with the sun causing warmer temperatures, which may lead to a hotter summer than originally forecast.  One less obvious effect of the drought, is the fact that it will lead to a positive feedback process (a process in which one variable "positively" influences another variable, leading to an enhancement in the process).  I am expecting that this drought will lead to more drought, due to the fact that quite a few storms that form during the summer depend on soil moisture for them to grow.  With less moisture for the storms to feed off of, there will be less rainfall, ultimately making the drought worse.  My theory on what is causing this drought is a combination of the extremely warm winter (even though we had near normal snowfall, the water did not stay in the ground very long because it never froze for more than a couple of days.), the "hot" weather we had in March, and a virtually rainless spring.  There are some other long-term factors, such as the changing positions of the ocean currents during the El Nino phase of the Southern Oscillation, and the changing ocean temperatures, but they likely have less effect than the other factors involved.  Due to the persistence in the heat this spring, I am expecting yet another hot summer across the area, as upper level ridges have seemed to dominate the weather across the East and Central U.S. for large portions of the spring.  This will all lead into next winter's weather, which could once again feature above normal temperatures, but below normal precipitation.  That is too far out to accurately predict so I will not say anything else.
As for this week's weather, temperatures will likely soar into the lower 90's across the area, especially in the aforementioned dry areas.  Even with strong mixing in the boundary layer, southeast winds will transport 60+ degree dew points into the area, giving the air quite a humid feel compared to recent days.  By tomorrow, the front that I mentioned in yesterday's post will cross into the area, causing temperatures to cool slightly (probably to near 88-89 with less humidity).  I am not expecting thunderstorm development with this front (even with the instability in place), due to the fact that the "cap" in the mid-levels is quite strong, which limit any thunderstorm development.  Second, much of the upper level lift will exist to far north of the area to even break the cap for the storms.  By Saturday, that same front will surge back northward, causing temperatures to jump to near 93, along with dew points approaching the mid to upper 60's, making for very humid weather.  On Sunday, temperatures will reach their highest, with some areas (especially areas near extreme eastern Indiana and western Ohio, including Antwerp and Fort Wayne) reaching from 96-98 from time to time.  This will also occur along with humid conditions, so don't be surprised if the National Weather Service issues a heat advisory.  During this same time period, low temperatures will become very warm, with lows in the upper 60's and lower 70's.

This chart shows how far behind in rainfall we are for the year to date

Hot weather on the rise

Most of you will notice that temperatures will take a hike today, with highs being almost 10 degrees warmer than yesterday.  This will lead to increasing wind speeds (greater lapse rates and deeper mixing within the boundary layer) today, making for a rather comfortable day.  Tomorrow, moisture return flow (strong and deeper winds originating from the Gulf of Mexico which transport tropical air masses northward) will increase, causing even warmer temperatures and a significantly more moist air mass.  With this, I am expecting highs tomorrow approaching 90, probably leveling off in between 88-90 (depending on the depth of the mixing within the boundary layer).  By Friday, several computer models are persistent in driving a "cold" front into the area, bringing showers and thunderstorms to the area, along with cooler temperatures.  I do not believe this, even though the National Weather Service has started to accept this idea.  I do not believe this will be the case mainly because strengthening upper level ridging will act to push the front farther north and weaken it.  In my opinion, I do not expect much if any thunderstorm activity in the area, and if there is any, it will likely be west of Fort Wayne due to strong capping and weak subsidence over the area (though that shortwave may cause some upward motion over the area, leading to the possibility of destabilization of the atmosphere and thunderstorms.)  If the low levels are moist enough (short-range models are indicating that dew points are going to be in the low to mid 60's), an isolated shower or storm can not be ruled out.  As for highs on Friday, this will be a bit tricky, as some of the computer models are indicating temperatures dropping into the upper 70's (such as the GFS).  More than likely, it is showing this bias due to the fact that it may be over aggressive with the shortwave that will be passing to the northwest of the area, especially because the same shortwave is not very well-defined over the Intermountain West, embedded in the main trough.  I would forecast a less amplified shortwave than what the GFS and some other models are forecasting, and with upper level ridging, I expect that the surface front will quickly weaken, stall, and race back northward as the strong upper level ridge builds into the region, generally around the time frame of Friday Night.  I would expect Friday high temperatures near 90 if the front fails to stall in the area by late afternoon, with dew points surging to near 60 (this dew point surge may be a bit overdone, as the models tend to be too strong with moisture return flow, meaning that dew points are probably going to be a bit lower.)  By Saturday, there are some differences in regards to timing of the front pushing back northward, with the GFS being the slowest.  In my opinion, a faster push northward is the best option right now, especially given the strength of the upper level ridging that will be in place by Saturday.  With 850 millibar temperatures nearing 15-20 degrees Celsius, expect highs to reach the lower 90's (unless the front does not lift through the area until afternoon), with even more humid conditions present across the area (dew points reaching into the mid and upper 60's), which will make the air mass very uncomfortable (unlike last weekend, which featured a very dry air mass).  On Sunday, 850 millibar temperatures could reach from 22-25 degrees, indicating surface temperatures at least into the mid 90's (94-96) if not near 97 or even 98 in isolated areas.  This combined with dew points right near 70 throughout the day, will cause extreme instability and a very hot and humid day.  In fact, it could be so hot and humid that the National Weather Service is considering issuing a heat advisory on Sunday, and possibly into Monday.  On Monday, temperatures will be a bit cooler, with temperatures making it into the lower 90's under mostly sunny skies.  With mid-level temperatures cooling, we have a greater likelihood for thunderstorms, especially as the upper level trough passes to the northwest of the area, but I am not expecting much.  Tuesday, though, may be the day that brings us much-needed rain, as the upper level ridge breaks down, and gives way to much more zonal flow, which will allow for warm temperatures (low to mid 80's), but not to the extremes that we will see this weekend.