Thursday, July 18, 2013

Scattered T-Storms into the Weekend

By Jay Grymes & Steve Caparotta

Showers and storms moved across the northern half of the WAFB viewing area during the morning and mid-day hours.  Those rains were courtesy of a southwest-bound outflow boundary that developed out of a thunderstorm cluster which had originated near the central Alabama/Mississippi border early in the morning.  Throughout the morning we watched as a band of storms tracked from NE to SW, reaching McComb at around 9AM, Hammond and Clinton close to 10AM, metro Baton Rouge, Gonzales and Reserve close to 11AM, and continued west and southwest into the mid-afternoon.

As of 3PM, most of the activity had subsided, with what was left of the storms located over  Acadiana.  That line of storms took much of the potential storm energy out of the atmosphere, leaving most WAFB communities with fair to partly cloudy skies and a less-humid air mass.  While a pop-up shower or storm remains possible through the late afternoon and early evening, most of us are done with the rains for today.

Skies will remain fair to partly cloudy overnight with sunrise temps on Friday in the low 70°s.  After a “dry” start to the day, the Storm Team forecast for Friday afternoon and early evening calls for a 30% to 40% chance of showers and t-storms but not before most neighborhoods see temps back in the 90°s.

The weekend shapes up much the same: mainly dry for Saturday and Sunday mornings with sun-up temps in the low 70°s, afternoon highs returning to the low 90°s, and scattered mainly afternoon and early evening showers and t-storms.  We’re setting rain chances for both days at about 40% or so.  A non-tropical area of low pressure in the eastern Gulf today will continue to move to the west and possibly northwest into the weekend, providing a little extra lift for afternoon rains for the already warm, moist and unstable Gulf air.

On the other hand, we’re adjusting our thinking regarding the forecast for next week.  Rather than a continuation of the “scattered rains” forecast that develops over the weekend, we are now getting some guidance that suggests a “drier” pattern over the central Gulf Coast, especially towards mid-week.

An upper-air ridge that is expected to build over the western U.S. this weekend is forecasted to expand eastward as the week progresses.  That should limit -- but not entirely block -- afternoon shower development over the central Gulf Coast by or before mid-week.  Of course, ridging also means “warming” and our forecast calls for highs in the mid 90°s while the rain chances fall into the “isolated” category.

And ... so far so good in the tropics.

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