Friday, June 12, 2015

Staying Soggy This Weekend

By Jay Grymes & Steve Caparotta

June 11th WAFB First Alert Quickcast:

- rain likely through the weekend

As expected, the showers and storms were rather numerous for our area today.  It took a little time for the action to really get going and fair to partly-cloudy morning skies for many WAFB neighborhoods allowed the sun to drive temperatures up to near 90° by or even before lunchtime.  However, Doppler radar became quite active into the afternoon and the rains knocked temperatures down into the 70°s and 80°s for many communities by mid-afternoon. 

Fortunately, there were no ‘severe’ storms in our area today but a few storms did become rather strong … and a few neighborhoods did receive a pretty good soaking.

In the meantime, satellite imagery continues to show a consistent counter-clockwise spin over the northern Gulf, located just off the Louisiana coast.  This mid/upper-air low/trough was the key factor in today’s wet pattern and it will remain a factor for Saturday and probably Sunday too.  

The circulation around the low/trough will strengthen our typical summertime inbound flow of Gulf moisture over the next two days.  Indeed, water vapor imagery shows a very moist plume of air on the eastern flank of the westward-traveling trough.  In addition, somewhat cooler air aloft associated with the trough creates a steepened vertical temperature gradient (cool aloft and warm near the surface), and an increased temperature difference means enhanced instability (greater lift).  All of these ingredients will likely yield elevated rain chances through the weekend.

Just like today, we aren’t expecting all-day rains for Saturday and Sunday.  However, everyone should be prepared for the potential for multiple rounds of passing showers and storms on both days.

Given the consistent flow off the Gulf, you already know that the days will remain humid, with dew points staying in the 70°s through next week.  And remember, the morning low can’t drop below the dew point temperature -- so expect muggy morning starts in the low to mid 70°s through the weekend and through most or all of the coming work week.

The rains on Saturday and Sunday should mean that highs for most WAFB communities should top-out in the mid to upper 80°s for both days, although a few areas may sneak up into the 90°s.

As we head into next week, the influence of the west-bound trough should slowly wane.  At the same time, high-pressure -- the Bermuda High -- will expand into the area from the east.  We’re still expecting scattered, mainly-afternoon rains for Monday (50% chance), but by Tuesday and Wednesday, the Bermuda High should begin to knock back our local rain chances even with our muggy, Gulf air mass.  For the time being, we’ll call for rain chances at around 40% for Tuesday and then around 20% to 30% for Wednesday and Thursday.  However, less rain (and less cloud cover) will come with a return to the 90°s for most WAFB neighborhoods.

So enjoy your weekend .. and good luck dodging those rains this weekend!

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