Marginal Severe Weather Threat

April 11, 2005, 2:04 pm
Posted by James Spann in Severe Weather
Rating: 4.8/5   Votes : 9
The Monday afternoon web video is on the server:

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

I am not convinced we will have a big problem with severe weather in Alabama tonight.

Having said that, the SPC maintains a high risk of severe storms over southwest Mississippi and parts of Louisiana. And, a moderate risk to the Alabama/Mississippi line. And, a slight risk over much of Alabama.

BUT...

It is hard to get worked up about a severe weather threat with a surface dewpoint of only 49 at Montgomery! The 60 degree dewpoint line runs from about Greenville, MS to Meridian to Atmore. There is no surface based instability here, and it sure looks like we won't get much at all during the night. Even in Mississippi CAPE values are pretty low.

This has been the problem with the severe weather threats this season, the poor instability values. We have had a very hard time getting maritime tropical air in here.

The strongest parameter in our opinion is the diffluence at 300 mb... but many other parameters are just not in place for a big event.

A line of storms should pass through the state from about 9:00 p.m. through 6:00 a.m. The WRF has the storms southeast of Birmingham at 6:00 a.m., so the bulk of the day tomorrow could very well be rain-free. A few instability showers might show up tomorrow afternoon over the Tennessee Valley as colder air aloft moves in from the west.

We will mention scattered showers and storms on Wednesday due to the upper low, and some small hail might be involved.

We still expect great weather by Friday and the weekend with ample sunshine and afternoon temperatures in the 70s.

We will keep an eye to the sky and J.B. will be posting updates here through the evening...
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Posted by Drew  
on April 11, 2005, 2:29 pm
<i>This has been the problem with the severe weather threats this season, the poor instability values. We have had a very hard time getting maritime tropical air in here.</i>

You almost sound dissapointed with the lack of severe weather.

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Posted by  
on April 11, 2005, 2:38 pm
Well you almost sound as if you were pointing out every little (what you would call) mistake that someone says when that certain person could be spending time doing other things than providing weather information for you. You have your right to an opinion, yes-- but I also have a right to mine and that is that you should just keep comments like that off of the blog. This blog is for weather chat. James and the crew, you have done an excellent job and I will be keeping an eye on the sky here in T-Town as storms develop and move through my area.

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Posted by   www
on April 11, 2005, 2:42 pm
It seems the NWS has put out a lot more "moderate" risks this year than in previous years, yet the severe weather events have fallen below expectations. Have they downgraded the criteria they are using to issue "moderate" and "high risk" outlooks? I remember in past years if you got a "moderate" risk outlooked you had better by watching out, and if you got a "high" risk you were almost certain to get a major disaster. This year it seems they have been very liberal with their "moderate" outlooks. Comments?

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Posted by  
on April 11, 2005, 2:42 pm
I agree with you Chase!!!!!

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Posted by  
on April 11, 2005, 2:48 pm
Interesting comment dragonking but I can't say I agree. I remember many many times over the past years when even a high risk would turn out to be nothing. I doubt they've lowered their criteria and to be honest, I still feel the worst is yet to come tonight.

But I could be wrong. Hopefully I am.

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Posted by  
on April 11, 2005, 2:53 pm
I live in a mobile home so every time there is a moderate risk I know for sure I am going to stay with someone else. I know the it hasn't been too bad the last couple of times. I still play it safe. I hope my thinking is right for tonight I am going stay home.

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Posted by  
on April 11, 2005, 3:01 pm
Hey I agree with James the dewpoints are just to low for anything, And I for one am glad I hope it will stay that way.

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Posted by  
on April 11, 2005, 3:05 pm
I do the same thing AJ. I live a mobile home also and my husband and I always stay at my dads when its supposed to get stormy. He, of course, wants to stay at home, but I usually win that debate :o)
I was wondering if I could stay at home tonight or if I should stay at my dads just to be on the safe side.

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Posted by   www
on April 11, 2005, 3:06 pm
Just an observation here, looks like everyone is mis-timing this. The squal line looks like it's just west of Tupelo, if it's moving at that rate no way it's in here after midnight, looks like WAY before then. Again, I'm not a weatherman so listen to James, just an observation looking at the latest radars.

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Posted by  
on April 11, 2005, 3:09 pm
I was just looking at the radars a minute ago and that's what I thought. Does anyone else have any opinions on this?

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Posted by  
on April 11, 2005, 3:14 pm
My thoughts exactly, dragonking which will hopefully not allow the dewpoints to recover. (Remember the juicy air is JUST west of Alabama. It wouldn't take much for Tuscaloosa's dpt to climb to near 60 in just a few hours.

But like you said, dragon, I don't think we have much time. Based purely on radar I'd say west alabama between 7 and 10pm instead of after midnight.

But again, I'm just an amateur having some fun trying to play weatherman.. LISTEN TO JAMES!!!

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Posted by   www
on April 11, 2005, 3:15 pm
I just looked at the NWS website too and they have dropped the high risk area now, though the moderate risk is still in the same area, right up to the state line.

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Posted by  
on April 11, 2005, 3:19 pm
I would much rather it be here early than late. Just in case the air here in T-Town gets "juicy" maybe I will hang out at my parents for a couple of hours this afternoon and watch Mr. Spann. I'll see what he thinks. Thanks for the input

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Posted by  
on April 11, 2005, 3:21 pm
Wow, I feel like such a fool. I had NO IDEA Base velocity and storm relative velocity NexRad imagery was available realtime for free!! that is SOOO COOL!!

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Posted by  
on April 11, 2005, 3:25 pm
Well I just looked at the radar and it looks like the storms might be here around 9 or 10 tonight, But they might fall apart before they get here.

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Posted by   www
on April 11, 2005, 3:25 pm
They are wearing out the moderate risk area this year. Once again, when you keep telling people moderate over and over and over and nothing happens, people who are not as interested in weather as we are will start to overlook it when they heard it which is dangerous to me. They used a high risk for a few hours and evidentally dropped it. Even James said it was marginally ripe for severe weather in Miss where it is all Moderate or High risk on his afternoon video. James and co do a good job at relaying the info they are given from NWS but even they are strarting to wear thin on this risk areas where nothing is happening. Once again I am more worried about conditioning people who see the weather once a day to ignore the moderate risk when they hear it when system after system passes with no severe weather. Even the slight risk gets used constantly. Good job James and Co.

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Posted by jamie  
on April 11, 2005, 3:30 pm
If you have looked at the radar all day, that rain band has been in east MISS most of the day... BUt the line may come thru here earlier, but the main dynamics are further to the south, which is what will pass thru here after midnight... James did say showers this evening, well there they are in east MISS... Not too much worry except for straight line winds... but as we all know, that can cause serious damage as well... later backseat weather men...

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Posted by  
on April 11, 2005, 3:32 pm
It appears Tuscaloosa's dwpt bottomed out at 52 b/c of a "dry slot" feature across alabama. However, it has resumed its climb and is at 53 now. If it can get to 57-60 range before the storms get here, I just don't seem them weakening that much...at least not b/c of too low a dpt. However, those storms closest to Alabama in North Miss don't look to dangerous...

..but that could change fast and I still suspect that what they're really concerned about just hasn't quite gotten going yet. I'm a little worried about SouthWest Alabama actually. Montgomery's dwpt is very low but Mobile's is 64!!! Yikes!!

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Posted by   www
on April 11, 2005, 3:35 pm
Chris, I can't help but agree with you that NWS is way overdoing these convective outlooks this year. I might be wrong, but I'm almost certain there have been FAR more moderate risk outlooks issued this year than in the past. I also seems like "slight" outlook simply means "rain" this year. It often seems like they are looking at completely different data than everyone else???

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Posted by   www
on April 11, 2005, 3:41 pm
I agree. You take the last say 5 events. Almost all of them had moderate risks here or very close by and we have not had one tornado warning and the severe thunderstorm warnings have been few and far between. Worst weather had been heavy rain and some small hail. The wind damage downtown came an hour after the front went through. I am not complaining about not having bad weather, just the fact NWS is using the risks, and higher ones at that, on a very regular basis. I mean the dewpoint in Montgomery is in the 40's!!!

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Posted by   www
on April 11, 2005, 3:42 pm
Also that rain looks like it should be here before midnight. They are saying well after midnight but it appears to be moving right along. Of course with the air being so dry it may dry up coming east till after midnight?!

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Posted by  
on April 11, 2005, 3:47 pm
I think the Slight/Moderate/High risk areas are based on synoptic "large scale" dynamics but even the simplest of mesoscale feature can (a locally stronger cap, an unforecasted dry slot of air, etc.) totally ruin your chance of severe weather. Eventually when we have more powerful models we'll be able to see this but the SPC is dealing with DAILY severe weather threats and they must issue those based on guidance that just can't yet handle mesoscale features.

They want to do better..technology just doesn't allow it yet

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Posted by  
on April 11, 2005, 3:55 pm
Does any of you think that this will be a big lightning event? I have a softball game at 8:15 in Northport, and I dont want to be holding a lightning rod out there.

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Posted by  
on April 11, 2005, 3:58 pm
Donnie: According to the weather channel's lightning detection system.. there is quite a bit all over Miss. I don't forsee any reason that would change before the storms get here.

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Posted by Patrick  
on April 11, 2005, 4:05 pm
Just curious, does anyone know what the SPC forecasted for Mississippi last week when they had the tornado outbreak? Were they under a moderate or high risk? I agree with Chris T, seems like the so called "experts" have really been off their game this year. When it comes down to it, I rely on the opinions of James and the guys. They do a good job of passing along the word from the NWS and SPC but also interjecting their views on what is reported.

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Posted by Carol in Rainbow City  
on April 11, 2005, 4:45 pm
Andy, where do you get Nexrad Imagery stuff for free? Thanks,

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Posted by   www
on April 11, 2005, 4:56 pm
The Mississippi storms came under and mix of slight and moderate. What was weird was on James morning video that day he made mention how they were weakening and then after that the grew stronger fast and the rest is history. Then we had the one lone storm that rotated in west alabama during the day and then the Pickens F0 that evening. I don't have sympathy for the people who miss TV shows because of weather but I just won't want people to start ignoring weather when they are constantly being warned and nothing but rain happening.

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Posted by   www
on April 11, 2005, 5:00 pm
It says above the storm will move through from 9PM to 6AM but they are already crossing the border into Alabama so your softball game at 8:15 may not make it to the 1st inning at this rate.

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Posted by  
on April 11, 2005, 5:01 pm
Andy, the lightning will die down. The line is weaking as it is coming into stable air. I don't expect many warnings in bama. 1 or 2 is not out of the question though.

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Posted by  
on April 11, 2005, 5:15 pm
Justin,

Yeah, for a few minutes it looked like the bow-echo feature in NE Miss was trying to get better organized but now even that area is weakening.

Carol: http://www.srh.noaa.gov/ridge/bmx_n0r.html

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Posted by   www
on April 11, 2005, 5:27 pm
Any word on how that high risk and moderate risj played out today in Miss???? They are in a rain shield now so it is over for them. I take back what I said about the softball game. At the rate the storms are weakening it may not even rain!!! What is going on at SPC and NWS??? James has been all over how weak the parameters were all day even into Miss. Then they went high risk!!! Now we cannot even get heavier rain to make it to Tuscaloosa before getting lighter. Someone there is missing the boat on this severe weather. Something they are using to forecast it is throwing them off. I hope it does not make them predict nothing one time and then a huge outbreak, worse tham the Miss one, happens.

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