Challenging Forecast

The Friday morning web video is on the server:

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

This is becoming a difficult forecast with some model differences showing up.

SPC maintains a moderate risk of severe storms later today across southeast Arkansas, north Mississippi, southwest Tennessee, and the northwest corner of Alabama. A slight risk surrounds the moderate risk and covers much of Alabama.

Here are some points to consider:

*Models are weaker with the 500 mb short wave.

*Models have moved the surface low more to the south in the latest runs. A blend of model output puts the surface low closer to Nashville during the pre-dawn hours.

*NAM wants to slow down the overall system a bit.

With the surface low position closer to us, that might mean some rotating storms over northwest Alabama late tonight. We still believe the storms will merge into a long squall line, passing through the state sometime during the pre-dawn hours tomorrow. Very strong wind fields mean the possibility of damaging winds along the line.

With some respect for the slower NAM model, we will now project the greatest risk of severe weather between 2:00 and 9:00 a.m. The overall threat will come from about midnight to noon. The model differences have made for a lower confidence on the specific timing.

It is interesting to note the NAM runs the surface dewpoint up to 69 at midday tomorrow with a surface based CAPE of over 3000! But, the dynamics will be mostly gone by then. The GFS has a drier airmass in place by then, however.

If the NAM is correct, there could be a few showers or storms into early tomorrow afternoon over east Alabama. For now we still think the rain will be over for the race tomorrow at the Talladega Superspeedway.

Sunday will be a beautiful day with ample sunshine and afternoon temperatures in the 70s.

Will be very interested to watch the 12Z models come in a little later this morning. I will be speaking at Chalkville Elementary today and back in the office after that for the afternoon update...
Posted by  
on April 29, 2005, 5:24 am
I know that Nascar is the greatest thing since sliced bread..<ahem>, but us DoDahDayers wonder if we will have good weather Saturday. The parade starts at 1101a.m.
Can you help us out and tell us about the city of Birmingham as well as Talladega?

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Posted by  
on April 29, 2005, 6:37 am
Hey Goldwing I think the best thing to do is wait and see, just like James said the forecast is a challange.

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Posted by Kim  
on April 29, 2005, 6:47 am
hey guys i switched computers and lost all of my websites for tracking storms and the national weather service warning map can someone please give me a link please please please

thank you
kim

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Posted by Kim  
on April 29, 2005, 7:25 am
thank you wdb

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Posted by  
on April 29, 2005, 10:57 am
Thanks again James got putting things into perspective for us and keeping the public up to date on the potenial for severe weather. Just thought I'd take the time to personally thnk you for such a wonderful job you do for all of the peoplethat are able to tune into your weather alerts. Let's pray that we won't have to deal with torndoes and straight line winds. My bible tells me where 2 or more are gathered in my name I will be there . May God bless and keep each and every person in our state and otheres states from harm. God Bless

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Posted by  
on April 29, 2005, 11:07 am
Guys, I've been looking at this model data and I'm REALLY worried this could be a historical day (and I DONT mean that in the good way) over parts of North MS. I'm still holding to my forecast that the line will weaken and be basically thundershowers with gusty winds (20-35mph) by the time it gets to Central AL. However, MS will likely not be so lucky.

Anyway... what do you guys think (those who look at models)? Moisture convergence, LIs, Veering winds, RH, temps all look just about perfect across N MS for later this evening based on what I'm seeing.

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Posted by Rusty Pitts  
on April 29, 2005, 11:20 am
Andy , I have noticed that they have added a good portion of North Al into the nmoderate risk are for the Day ,

http://www.skywarn.org/


But I am not finding anything but marginal INstability values for N. miss.

Where are you getting your info ??

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Posted by  
on April 29, 2005, 11:36 am
Rusty: You may have more updated info than I do (this is likely the case)

I was looking at ETA data for 7pm tonight and it showed LIs about -4 ..not impressive..but right over N MS it showed strong veering winds from surface to 500mb...good moisture convergence...high RH values and approaching cold front. The wind fields actually bothered me more than anything...seems like tornados will have little trouble forming in that region.

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Posted by  
on April 29, 2005, 11:43 am
Actually, Rusty...I just went back and reviewed those images. I think what concerns me is not so much the actual forecast values for 7pm tonight but what could so EASILY evolve from these values between 7 and midnight..if that makes any sense.

But I have only looked at these forecast values:

-temp
-dwpt
-Wind speed/dir surface thru 300mb
-Moisture convergence
-LI
-RH

Haven't looked at CAPE or SIG TOR or anything like that...so, you probably have much better info than me.

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Posted by Rusty Pitts  
on April 29, 2005, 12:19 pm
Here is your sig Tor values .... There is becomming more of an increase in the values over N ala than N. Miss... But I am an Amature... Wish james would give us an update ... Maybe JB./....


http://www.spc.noaa.gov/exper/mesoanalysis/s3/index2.html

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