The Wednesday afternoon web video is on the server:
http://beta.abc3340.com/weather/video.hrb
We will take this discussion to go over the expected event here late Friday night into early Saturday morning. We will be in great shape through the daytime Friday, with upper 70s tomorrow and low 80s on Friday.
I still think the greatest risk of severe storms here will come from 10:00 p.m. Friday through 10:00 a.m. Saturday. Especially in the midnight to 5:00 a.m. time frame.
Severe thunderstorms should form Friday afternoon to the west, over Mississippi, Arkansas, and west Tennessee. Those storms could produce a few damaging tornadoes along with very large hail. Ultimately, all of that should evolve into a long squall line that will race through Alabama late Friday night into the pre-dawn hours Saturday. Therefore, our greatest threat here will come from damaging straight line winds. But, the wind damage could be widespread. Look at these parameters valid for midnight Friday night (from the NAM extraction):
SB CAPE 505
Lifted Index -2.7
0 to 3 km Helicity 429
SWEAT Index 393
2m AGL Dewpoint: 66
850 mb wind speed: 60 knots (wow)
500 mb wind speed: 72 knots
The wind fields will be screaming late Friday night. The instability looks a little low, but if surface dewpoints are in the mid 60s as suggested, CAPE values should be well over 1500 instead of 505 as the extraction calculates.
So... my main concern is for a widespread damaging wind event from a fast moving squall line sometime between 10:00 p.m. Friday and 10:00 a.m. Saturday. Any storms that form ahead of the main line could produce a tornado.
I am a little worried about the fact that tens of thousands of people will be in RVs and campers at the Talladega Superspeedway Friday night; I know there are sirens around the track and hopefully they will be enough to wake people up if warnings are needed. The biggest problem is getting them to a safe place.. as you know the crowds are huge over there on race weekends.
But, the good news for NASCAR fans is that the rain should be over by midday Saturday, and Sunday promises to be a very nice day with ample sunshine and temperatures in the 70s during the race. Not bad at all.
NEXT WEEK: The 12Z GFS has gone wet again for the middle and end of next week... but we will deal with that after Friday night's event!
http://beta.abc3340.com/weather/video.hrb
We will take this discussion to go over the expected event here late Friday night into early Saturday morning. We will be in great shape through the daytime Friday, with upper 70s tomorrow and low 80s on Friday.
I still think the greatest risk of severe storms here will come from 10:00 p.m. Friday through 10:00 a.m. Saturday. Especially in the midnight to 5:00 a.m. time frame.
Severe thunderstorms should form Friday afternoon to the west, over Mississippi, Arkansas, and west Tennessee. Those storms could produce a few damaging tornadoes along with very large hail. Ultimately, all of that should evolve into a long squall line that will race through Alabama late Friday night into the pre-dawn hours Saturday. Therefore, our greatest threat here will come from damaging straight line winds. But, the wind damage could be widespread. Look at these parameters valid for midnight Friday night (from the NAM extraction):
SB CAPE 505
Lifted Index -2.7
0 to 3 km Helicity 429
SWEAT Index 393
2m AGL Dewpoint: 66
850 mb wind speed: 60 knots (wow)
500 mb wind speed: 72 knots
The wind fields will be screaming late Friday night. The instability looks a little low, but if surface dewpoints are in the mid 60s as suggested, CAPE values should be well over 1500 instead of 505 as the extraction calculates.
So... my main concern is for a widespread damaging wind event from a fast moving squall line sometime between 10:00 p.m. Friday and 10:00 a.m. Saturday. Any storms that form ahead of the main line could produce a tornado.
I am a little worried about the fact that tens of thousands of people will be in RVs and campers at the Talladega Superspeedway Friday night; I know there are sirens around the track and hopefully they will be enough to wake people up if warnings are needed. The biggest problem is getting them to a safe place.. as you know the crowds are huge over there on race weekends.
But, the good news for NASCAR fans is that the rain should be over by midday Saturday, and Sunday promises to be a very nice day with ample sunshine and temperatures in the 70s during the race. Not bad at all.
NEXT WEEK: The 12Z GFS has gone wet again for the middle and end of next week... but we will deal with that after Friday night's event!
on April 27, 2005, 1:39 pm
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