Wednesday, August 21, 2013

Typical Summertime T-Storms Persist

By Jay Grymes & Steve Caparotta

For the trivia buffs ... note that today’s “Normal Low” is 73°, the first 73° normal low since July 2nd.  “Climatologically,” we’ve arrived at the time of year when we begin the slow cool down into autumn.  (But don’t start cheering just yet -- it’s not likely to feel noticeably cooler for a another several weeks!)
As expected, scattered showers and t-storms developed over the WAFB viewing area this afternoon ... and you’ll want to keep the umbrella nearby for the next several days.  We still anticipate mainly-afternoon scattered showers and storms for Thursday, Friday and the weekend.  Our “normal” August weather pattern looks to be locked-in right into next week:  daytime heating will enhance afternoon instability and take advantage of abundant Gulf moisture to get things going each afternoon.
The quasi-stationary front that has been plaguing much of the Southeast U.S. with daily rains appears to be finally fizzling out, but it likely gets replaced by sea-breeze set-ups each day that will fuel daily scattered rains through the weekend and into next week.
Our forecast through the coming days calls for morning minimums in the low to mid 70°s for metro Baton Rouge.  During the afternoons, temps will reach the 90°s for most WAFB neighborhoods before the rains arrive.  As is typical for summer, we don’t anticipate any severe-weather outbreaks in the coming days but one or two storms could be on the strong side.

We’re expecting rain chances to run in the 30% to 40% range through the weekend.
Remember, this percentage represents the amount of the WAFB area expected to receive “measureable” rainfall (meaning rains of 0.01” or more) each day.  In other words, not everyone gets wet every day.  In fact, there is a chance -- albeit a slight chance -- that a couple of WAFB areas could remain essentially rain-free right through the weekend.  But over the course of the next four days (Thursday thru Sunday), simple statistics tell us that there is a very good chance -- better than an 80% chance -- that you’ll see at least some rain.
Also, remember that the rain forecast "percentage” does not tell us “how much rain?”  True, in the summer, higher rain chances are often associated with more active weather and can result in larger daily totals, but there are no guarantees.  The truth is, forecasting rain amounts during the “summer shower season” is much more difficult than trying to predict storm totals during the cooler months when most of our rain is frontal.
No better example of that then what we’ve seen the past couple of days:  many of us have had only modest amounts of rain so far this week, yet some communities experienced localized downpours of 1” to 3” in short periods of time!  Yep, say “hello!” to summer weather in the Bayou State!
In the meantime, while we dodge the afternoon rains, let’s enjoy the “quiet” time in the tropics.  Although we are watching a few tropical waves in the basin, none are currently showing any imminent threats for development.

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