I figured I need to expand my thoughts on the watch and warning system I started here yesterday. I wrote about too many tornado warnings that don’t verify, too many severe thunderstorm warningss, and too many “moderate” and “high” risk severe weather outlooks that are busts.

It is easy to sit here in a TV weather office and be critical; here are some suggestions:

Like I wrote here yesterday, I think a “tornado emergency” messages needs to be formalized. Used only when a tornado is down and has caused damage. This is NOT to replace tornado warnings, but simply to add urgency when there is an immediate known threat to human life. Many NWS offices and TV stations use the term “tornado emergency” in such a situation; I think it needs to be included in the official warning list. We used the term "tornado emergency" during events like the Tuscaloosa F4 tornado on December 16, 2000, and the long track tornadoes across north Alabama on November 10, 2002.

I think the bar needs to be raised on severe thunderstorm criteria. Few people pay attention to severe thunderstorm warnings now with current criteria (58 mph winds or greater, or hail 3/4" in diameter or larger). I suggest defining a severe storm as one that has winds of 65 mph or higher, or hail 1” in diameter or larger. This will cut back on the number of warnings, and hopefully lead to better public awareness of their importance.

I also suggest we junk the “slight, moderate, and high” risk levels as defined by the Storm Prediction Center. When people hear “slight”, most folks think there is little chance of severe weather. That is actually the standard term used prior to most severe weather outbreaks now. Maybe a color code, like green (no severe weather), yellow (severe storms are possible), orange (a significant outbreak of severe weather is likely), and red (multiple long track, damaging tornadoes are expected). People tend to understand color schemes much better, and they also tend to remember them more easily. It works nicely with air quality forecasts.

Hopefully these kind of ideas will get some traction and some positive changes can be made in the watch/warning process in the coming years....

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!

The Wednesday morning web video is on the server:

http://beta.abc3340.com/weather/video.hrb

I should also mention I posted the Storm Alert 2005 TV special on that video page last night.... so if you missed it, or live out of market, you can watch it online now. It includes some good stories on Hurricane Ivan, Bill Murray's Great Plains tornado adventure, and more.

Nice spring weather with a warming trend headlines our forecast through tomorrow; most of the attention will be focused on the next storm event late Friday night and early Saturday morning...

Sure looks like a potent severe weather setup for parts of the deep south. For Alabama, the greatest chance of severe weather will come from about 10:00 p.m. Friday through 10:00 a.m. Saturday. I get the idea most of the storms will be over by 6:00 a.m. Saturday. This is great news for everyone planning on enjoying the races at Talladega this weekend.

Late Friday, a deepening surface low will move from near Tulsa to southern Indiana, while high surface dewpoints will surge northward over the southern U.S. In the upper levels, a strong trough will go negative tilt to some degree as it passes north of us, and wind fields at all levels will be very strong.

Severe storms with damaging wind, large hail, and a few tornadoes will likely form over Mississippi, Arkansas, and west Tennessee Friday afternoon. If model parameters are correct, a few strong, long track tornadoes will be possible in this region. All of this should evolve into a long squall line which will race through Alabama late Friday night and during the pre-dawn hours Saturday morning. This would suggest our greatest threat would be from damaging winds with the squall line. But, this early in the game, you can't rule out a few isolated supercell storms in advance of the line that could produce a tornado or two.

We have had so many moderate risk busts this season I hope folks won't ignore this one; looks like the most potent threat of the season in general.

REST OF THE WEEKEND: We will be rain-free Saturday afternoon through Sunday. Afternoon highs on both days will be in the 70s.

NEXT WEEK: The GFS has backed off on the amount of rain expected during the middle of next week, leaving a lower confidence forecast out there. Lets get through the Friday night event and we can concentrate on it over the weekend...