Good morning, folks! Our weather story hasn’t changed much this past week. We’re still under the influence of a potent mid-level ridge responsible for persistent above-average temperatures and muggy air.
The above image shows the current 500mb heights, where the higher heights indicate the position of an upper-level high pressure system, centered over southern Arkansas. Much like last week, this feature will continue to hang around, however, it does appear that it will drift about and fluctuate in intensity.
The first adjustment that this high pressure will make is a slight drift westward. Global models are in agreement that a strengthening upper-level low off the coast of the Mid-Atlantic will push the center of the ridge from Arkansas to the Texas/Oklahoma border by Thursday morning. This upper-level low, as well as an additional negative height anomaly over California, will give the pesky ridge a run for its money, even weakening it somewhat by Thursday evening.
So now that we’re on the periphery of the ridge, what does that mean for us? Much like this past Sunday, a prolonged northerly flow will help to force some drier air into the region late Thursday evening into Friday.
In fact, by Friday afternoon, the surge of drier air will bring dew points well below average into the 50s for most locations! This drier weather will stick around into Saturday, and will cut down the chances of an afternoon storm across the area.
What this drier air doesn’t bring, however, is cooler temperatures. As drier air is easier to heat up, it may actually be hotter on Friday and Saturday than any other day this week. It is worth noting, though, that there are some significant disagreements between the American GFS model and the European ECMWF model.
While both the GFS and ECMWF produce temperatures well into the 100s for both Friday and Saturday, its the ECMWF that is showing some really eye-popping values upwards of 110 F for Saturday! For Friday, the GFS shows relatively cooler temperatures, with the southern halves of Mississippi and Alabama being the warmest – while the ECMWF shows a rather uniform scorching-hot day.
For Saturday, there is more agreement with the distribution of the heat, but the GFS still runs a tad cooler. While it needs to be said that both these models are likely overdoing the high temperatures toward the end of the week, it goes without saying that both Friday and Saturday will feature dangerously hot temperatures likely exceeding 100 F.
Luckily, this wave of extreme heat appears to be short-lived thanks to an increased risk of showers and thunderstorms Sunday through the middle of next week.
As the weekend closes out, the likelihood of synoptic-scale lift courtesy of a trough to the north and enhanced moisture return from the Gulf of Mexico will increase our chances for rain through Wednesday. The GEFS shows around 0.1″ falling Sunday night through Monday afternoon, followed by around 0.25″ Monday night into Tuesday afternoon.
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Day to Day Forecast
Wednesday
Partly cloudy with a 30-percent chance of an afternoon storm. Highs in the mid-to-upper 90s, with heat index values around 100F.
Thursday
Partly cloudy with a 30-percent chance of an afternoon storm. Highs in the mid-to-upper 90s, with heat index values around 100F.
Friday
Mostly sunny skies with highs in the upper-90s to around 100F, heat index values exceeding 100F are likely.
Saturday
Mostly sunny skies with highs in around 100F. Heat index values exceeding 105F are likely.
Sunday
Partly cloudy skies early followed by a 60-percent chance of showers or thunderstorms developing by the afternoon. Highs in the mid-to-upper 90s, with heat index values approaching 100F.
Monday
Mostly cloudy with a 70-percent chance of an afternoon thunderstorm. Highs in the low-to-mid-90s, with heat index values approaching 100F.
Tuesday
Mostly cloudy with a 60-percent chance of an afternoon thunderstorm. Highs in the low-to-mid-90s, with heat index values approaching 100F.
