Stormy Start To The Weekend

The Thursday afternoon web video is on the server:

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

Check out that amazing wall cloud picture on the video today... amazing stuff.

We have seen a few echoes on radar over north Alabama today, but nothing has reached the ground as far as we know. We will leave the forecast dry and tonight and tomorrow. Winds will really pick up tomorrow out of the south, gusting to 30 mph at times. We will have a few intervals of sunshine, and temperatures should reach the low 80s tomorrow afternoon.

STORM SITUATION: Not much change in our thinking on the next storm event. A long squall line should race through Alabama sometime between midnight tomorrow night and 6:00 a.m. Saturday with the potential for widespread wind damage. If we happen to get a few discrete cell ahead of the line, a few isolated tornadoes are not out of the question, especially over northwest Alabama. SPC has now placed much of north Mississippi, western Tennessee, and northeast Louisiana under a moderate risk of severe storms for tomorrow evening and tomorrow night. This is where a few damaging tornadoes will be possible.

Here are the latest severe weather parameters for us as they peak between midnight and 6:00 a.m. Saturday:

SB CAPE 945
Lifted Index -2.4
0 to 3 km Helicity 427
2M AGL Dewpoint: 66
SWEAT Index: 360
850 mb winds: 59 knots
500 mb winds: 53 knots

Not much change in our thinking. Severe storms and isolated tornadoes will form to the west late tomorrow, with the thunderstorms evolving into a squall line that will race through Alabama. It won't take much to get those 850 mb winds (around 5,000 feet off the surface) down to the surface, and a number of segments within the line could produce winds to 70 mph or greater.

Everyone will need to have a good way of hearing severe weather warnings during the pre-dawn hours on Saturday.

Interesting to note how the forecast rain totals keep coming down; the NAM now only showing about one-third of an inch of rain with the storms early Saturday morning. The storms will simply be moving so quickly we won't see all that much rain. We might even get in the little league baseball games on Saturday!

REST OF THE WEEKEND: The storms will end early Saturday morning, with the sky becoming partly sunny. We have lowered afternoon forecast temperatures into the 60s. The day will also feature a brisk northwest wind from 12 to 22 mph.

Sunday should be a very nice day with ample sunshine and high temperatures in the 70s.

NEXT WEEK: Looks wet at times Tuesday through Thursday. Will fine tune this as we get closer...

Enjoyed speaking to a big group of retired physicians at St. Vincent's Hospital today...
Posted by  
on April 28, 2005, 2:20 pm
James,we had a brief shower in Boldo,just northwest of Jasper-thats B-o-w-l-d-o-e,not B-a-l-l-d-o.LOL

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Posted by Clay  
on April 28, 2005, 2:26 pm
james,

what kind of cape number signifies severe weather...and what does that particular number represent?

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Posted by  
on April 28, 2005, 2:34 pm
James, I will be one of the thousands at the Talladega Speedway this weekend. I live in KY and have been reading your forecast for a week now, I really appreciate how you are keeping the fans up to date on the severe weather potential. I really am concerened about spending the night there Fri Night in a camper because there will be no where to go. Please keep us informed!! Thanks JPS

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Posted by AC  
on April 28, 2005, 3:01 pm
Interesting Paul...I live in Cullman County and I was just thinking that it looked like rain!

AC

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Posted by Rusty Pitts  
on April 28, 2005, 3:31 pm
Clay Cape is Defined as a measurement of the amout of energy available for convection. Thus the Name CAPE ( COnvective Available Potential Energy) , well there are different cape values , but here you go ... The NCAPE (Normalized CAPE) is CAPE that is divided by the depth of the buoyancy layer (units of m s**-2). Values near or less than .1 suggest a "tall, skinny" CAPE profile with relatively weak parcel accelerations, while values closer to .3 to .4 suggest a "fat" CAPE profile with large parcel accelerations possible. Normalized CAPE and lifed indicies are similar measures of instability.And you also have the Downdraft Cape which can be used to estimate the potential strength of rain-cooled downdrafts within thunderstorm convection, and is similar to CAPE. Larger DCAPE values are associated with stronger downdrafts.



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Posted by Rusty Pitts  
on April 28, 2005, 3:42 pm
Clay , Here is a Breakdown of the Cape Values and what they mean in the way of Instability....


CAPE value Convective potential
0 Stable
0-1000 Marginally Unstable
1000-2500 Moderately Unstable
2500-3500 Very Unstable
3500 + Extremely Unstable


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Posted by  
on April 28, 2005, 6:54 pm
I'm the weather watcher in my family and they depend on me to call them when it is going to "get bad". I am leary of calling them because of the last few "bust", I know James and the guys can't predict a reality of bad weather, only the statistics, but should I make my call or not for tomorrow night?

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Posted by Josh  
on April 28, 2005, 7:02 pm
We had some light rain showers in NW Alabama this afternoon. Some of the storms had a little lightning and cool looking wave like cloud formations all across the sky, it looked like the ocean.

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Posted by Jason  
on April 28, 2005, 7:06 pm
The NWS confirmed two F0 tornadoes touched down back on April 22nd here in Cherokee County. That storm definetly looked impressive when James showed it on the Hytop radar.

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Posted by  
on April 28, 2005, 8:08 pm
Susan...
If I were you, I would go ahead and call your family just to give them a "heads up" for late Friday night/earlySaturday morning. It's far enough away that no immediate attention is needed except for planning purposes.

Still looks like a line of strong to severe thunderstorms late Friday night--possibly even past midnight.

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Posted by  
on April 28, 2005, 8:20 pm
I'm still concerned about the timing in western tn, and north ms since my daughter will be traveling home from college in those areas. Can you tell me the expected time for severe weather in those areas? Thanks

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Posted by  
on April 28, 2005, 8:57 pm
Carole...
Don't know the exact location your daughter will be departing from, but I think the earlier the better. Strong thunderstorms may be ongoing early Friday morning in parts of Arkansas and around Tulsa.

The Memphis area will be subject to thunderstorms during the day also. But the highest risk of severe weather should be Friday afternoon and evening Memphis area and North Mississippi.

In places like Columbus/Starkville/Tupelo the worst may be after nightfall...reaching NW Alabama toward midnight. Remember, I said the worst of the bad weather. This does not mean those areas will not have a threat earlier than that.

For Central Alabama...Birmingham/Gadsden/Cullman/Anniston...main threat will be a ling of strong to severe thunderstorms after midnight Friday night.

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