Wednesday, May 1, 2013

Flash Flood Watch Continues into Thursday

By Jay Grymes & Steve Caparotta

We’re seeing quite a range in rain totals through Wednesday afternoon: some neighborhoods are reporting little if any rain today while Doppler radar shows some 1” to 2” inch totals, mainly to the south of metro Baton Rouge.  Indeed, Doppler was indicating some 2” to 3”+ bull’s eyes closer to the coast.

While you’ve possibly seen some sun this afternoon, you can be sure that the rains aren’t over yet.  A FLASH FLOOD WATCH remains in effect for the entire viewing area until 7:00pm Thursday . . . that watch could be extended into Friday depending on how the weather shapes up in the next 24 hours.

The upper-level low we’ve shown the last couple of days has now moved over north-central Louisiana, with the forecast calling for it to move to the southeast -- passing over metro BR -- and then semi-stalling again over the southeastern parishes for much of Thursday.  Meanwhile the low-level air mass in place remains relatively warm and moist. 
Today’s late morning and afternoon showers and t-storms appear to have temporarily “stabilized” the atmosphere somewhat for much of the WAFB viewing area, but as those rains come to an end, it won’t take much for the moist air mass to destabilize again, especially as the upper low draws closer tonight.
So whether you stayed mainly-dry or happened to be under one of those pockets of heavier rains today, we all still can expect more rain tonight into Thursday -- and into Friday too.
The upper-low will slip out over the Gulf late Thursday, but that does not mean an immediate end to the rain.  We’re still expecting a Canadian cold front to move across the state late Thursday into Friday, with that front serving as a second focus for showers and storms.   The front appears like it could be a slow-mover, which means scattered rains could extend into the middle of the afternoon on Friday, especially for those living in the eastern portions of our viewing area.
We think the rains end by, or even before, Friday late afternoon, but it may still take a while for the clouds to clear.  But you will definitely notice the change in air mass by late Friday into early Saturday, with temps dropping into the low to mid 40°s by Saturday’s sunrise!

Even with “almost chilly” starts (by May standards) for Saturday and Sunday -- morning lows in the 40°s -- the weekend afternoons look like they will be real May beauties!

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