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.
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