Wednesday, August 22, 2012

Returning Humidity & Watching Isaac

By Jay Grymes & Steve Caparotta

Just like yesterday, most of us stayed dry, but several of the coastal parishes dealt with showers and t-storms as a weak, quasi-stationary front continues to hug the coast.  In fact, the NWS posted a Tornado Warning for areas near Grand Isle during the afternoon as a severe storm showed indications of rotation! While there were no confirmed reports of a waterspout or tornado, a 53 mph wind gust was measured on Grand Isle.

With the front lingering along the coast into Thursday,  we could see a couple of showers continue there well into the evening.  But for most of us, it should be a fairly nice evening and a mild night ahead.
Many along and north of the I-10/12 will wake-up to the upper 60°s on Thursday as we enjoy one more day of slightly-lower humidity before more typical August weather returns.  But the coastal front will dissipate during the day, winds will swing around to the southeast bringing in Gulf moisture and we’ll say goodbye to the run of slightly drier air.  But the air won’t “moisten” all that rapidly, so we’re calling for only isolated afternoon showers on Thursday under otherwise partly cloudy skies, with highs in the low 90°s.
Set rain chances at 40% for Friday, then back them down to 30% for Saturday and only 20% for Sunday.  Sunrise temps will be near 70° to the low 70°s with highs in the low 90°s for all three days.   Our forecast remains mostly-dry for the first part of next week as well.
Meanwhile, more and more attention turns to the tropics. 
Tropical Storm Isaac is rolling through the Lesser Antilles this afternoon and is headed into the warm Caribbean.   While Isaac is a fairly large system, it is not especially well-developed as yet.  The model forecast consensus and the NHC 5-day projection still keeps Isaac heading towards Florida, although there should be some significant interaction with the Greater Antilles (mainly Hispaniola & Cuba) to slow any intensification.  

A threat to the eastern Gulf certainly can’t be ruled out and we are far from ready to sound the “All Clear” for Louisiana.  But for us, it is too early to get too concerned up about Isaac.  Still, be aware that there is a fairly good chance that Isaac gets into the SE Gulf by Monday.
And east of Isaac, the NHC upgraded the next tropical system to T.D. #10 earlier today.  Thankfully, early indications are that T.D. #10 does not appear to be a Gulf threat.  However, the 5-day outlook for #10 does suggest that the U.S. East Coast needs to remain vigilant with that system as well as Isaac!

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