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PDS (Particularly Dangerous Situation) tornado watches remain in effect for parts of Texas, Arkansas, and Louisiana this afternoon, and we will be dealing with a band of storms tomorrow morning.
Not much change in our thinking based on the 12Z model runs… although the instability values have come in a little higher (but still relatively low for a spring severe weather event), and the wind fields are screaming. Here are some parameters for Birmingham tomorrow morning (from the 12Z NAM):
Surface based CAPE: 221 j/kg
0 to 3 km helicity: 598.1 m2/s2
2M dewpoint: 61.7 (F)
SWEAT Index: 419.4
850 mb wind speed: 68 knots
500 mb wind speed: 102 knots
All of that mumbo jumbo means excellent dynamics, somewhat marginal thermodynamics. We expect a low topped line of storms tomorrow morning, with the prime threat coming from damaging straight line winds, but a few isolated tornadoes are certainly possible considering the shear.
TIMING: The storms should enter West Alabama in the 5:00 to 6:00 a.m. time frame… moving into the Birmingham metro around 8:00 or 9:00, and then exiting our state into Georgia around 1:00 p.m.
You know the drill… everyone will need to be close to a source of weather information so you can hear warnings if they are needed.
The good news is that beneficial rain is likely; with most spots seeing one inch, and isolated totals to two inches.
DRIER AIR RETURNS: We will be dry Thursday and Friday with mild days and cool nights.
EASTER WEEKEND: The 12Z GFS is trending cooler and drier for the weekend. A surface low will pass north of Alabama Saturday, turning the winds around to the north. This will bring cooler air into the state on Saturday, and by Sunday the air will be cool and dry. The upper impulse that moves just north of Alabama Sunday won’t have much moisture to work with, and this run suggests there will be no rain at all on Sunday, with a high in the cool 50s. If this trend keeps up, we can remove all mention of showers on Sunday.
LONG RANGE: The GFS has backed off a bit on the strength of the March 28 system… but that is all voodoo at this point.
WEATHER BRAINS: Don’t forget you can listen to our weekly 30 minute netcast anytime on the web, or on iTunes. This is the show all about weather featuring many familiar voices, including our meteorologists here at ABC 33/40. You can even listen here on the blog; look for the player on the top left.
J.B. will keep the blog updated through tomorrow with this next severe weather threat… stay tuned. I will try to get a Weather Xtreme video posted by 7:00 a.m. tomorrow, but if the weather is too active the next one will be up by tomorrow afternoon!
