Tornado Watch

[Andrew Khan]

No storm/tornado reports yet, however, I would say tommorow there will be many, but that will be peoples least worries.

 

[Andrew Khan]

5000 J/KG

 

[Scott Olson]

Originally posted by Andrew Khan
5000 J/KG

Which area are you speaking of?

 

[HAltschule]

A. Actually, it is very common for tornado warnings to be issued when the eye wall of a significant hurricane moves onshore. This is owed in part to the massive angular momentum and spin in the individual thunderstorms within the eye wall.

B. The reason they are so short lived is because the thunderstorms themselves are unorganized and do not really last too long (unlike spring time storms in the plains). As a result, it is hard to have much lead time for warnings. A long lived tornado during a tropical storm or hurricane is not common at all.

C. Many of the verifications are made by eyewitness accounts and damage reports. If one area has maximized wind damage (and not the other areas nearby), then it most likely would have been a tornado that caused that damage since hurricane winds would have a more widespread damage pattern. Tornado damage will be very localized in most cases. As far as determining tornado damage vs. hurricane damage in an eye wall, good luck....pretty much impossible.

 

[Robert Dewey]

Originally posted by Jason_Politte+--><div class='quotetop'>QUOTE(Jason_Politte)</div>

<!--QuoteBegin-Guest

The local weather guys on WWL-TV in New Orleans have been saying that the NWS is going to issue tornado warnings that parallel the path of the eyewall due to the intense speed of the storm. I've never heard of this before. Anyone know what this is about?

Many offices that have had to deal with hurricanes in recent years have been doing this basically because there is no such warning to actually warn for the eyewall. I doubt if issuing tornado warnings for the eyewall has much effect though or does any good considering that many won't have access to the warning or will already be taking shelter because of the hurricane strength winds already ongoing.

Edit: I'll also add that because this storm will be making landfall quite a bit earlier than originally expected, this technique may actually have some use during this event . . . if those affected can receive the warning.

Jason[/b]

Yeah, it's usually something like this: http://www.srh.noaa.gov/mlb/charley/TOR/TO....0408132250.txt

That was issued for Charley...

 

[Scott Olson]

Originally posted by HAltschule
A. Actually, it is very common for tornado warnings to be issued when the eye wall of a significant hurricane moves onshore. This is owed in part to the massive angular momentum and spin in the individual thunderstorms within the eye wall.

B. The reason they are so short lived is because the thunderstorms themselves are unorganized and do not really last too long (unlike spring time storms in the plains). As a result, it is hard to have much lead time for warnings. A long lived tornado during a tropical storm or hurricane is not common at all.

C. Many of the verifications are made by eyewitness accounts and damage reports. If one area has maximized wind damage (and not the other areas nearby), then it most likely would have been a tornado that caused that damage since hurricane winds would have a more widespread damage pattern. Tornado damage will be very localized in most cases. As far as determining tornado damage vs. hurricane damage in an eye wall, good luck....pretty much impossible.

If anyone needs further proof of how hard it is to survey tornado damage in a Hurricane look at the records for tropical tornadoes and look under F-rating. Most often then not you will get 'UNK'

They issued a tornado warning for the eyewall of Dennis and that turned out to be a high end CAT 2 <3. I think its just another way of getting the attention of those people who wait till the last minute or maybe have become to used to Hurricanes. Im not sure I agree with always issuing it as I've seen they have already issued many many warnings, advisories of all types and just need to be clear. I think in this case anything they can do is okay.

 

[HAltschule]

Notice the band coming onshore now south of Mobile, AL and Biloxi, MS. This is in a prime area for supercells and tornadoes to form within these spiral bands. Since the timing is right and the thermodynamic setup is still favorable, we may see some tornadoes forming shortly as they move onshore.

PS: When I did my reserch project years ago on TS Beryl and the tornado outbreaks that occurred, I found that the drag force that developed as the storms reached land actually increased the relative shear...thus increasing the tornado threat. Will watch and see....

 

[HAltschule]

* TORNADO WARNING FOR...

BALDWIN COUNTY IN SOUTHWEST ALABAMA
MOBILE COUNTY IN SOUTHWEST ALABAMA

* UNTIL 715 PM CDT

 

[Scott Olson]

Nice 35kts low level rotational velocity heading towards Fort Morgan. A second questionable area south of Dauphin, Island.

 

[Andrew Khan]

Originally posted by HAltschule
* TORNADO WARNING FOR...

BALDWIN COUNTY IN SOUTHWEST ALABAMA
MOBILE COUNTY IN SOUTHWEST ALABAMA

* UNTIL 715 PM CDT

I can see a pretty bad formed hook echo.

I see a TVS that has a depth of 19700 FT it's size is 0.25".

 

[Andrew Khan]

Originally posted by Scott Olson+--><div class='quotetop'>QUOTE(Scott Olson)</div>

<!--QuoteBegin-Andrew Khan

5000 J/KG

Which area are you speaking of?[/b]

South of Eastern LA.

 

[nickgrillo]

Pretty good looking supercell just to the south of Mobile. Very favorable envirement for tornadoes across southern AL/MS - with CAPEs >3000J/KG and very strong low-level shear / SRH >350 invof of this band of storms moving inland. Any of these storms could quickly produce tornadoes...

 

[Scott Olson]

Im anxious to see the soundings. Usually there isn't a lot of instability avaliable because of cloud cover/rain cooled air. At least enough instability in proportion to some incredible shear. I think thats why the tropical depressions can sometimes become prolific tornado producers as there becomes enough breaks in the clouds to create enough instability vs good but not so extremely sheared out cells. My hats off to the forecasters at KMOB and KLIX who have an enormous challenge ahead of them.

 

[HAltschule]

think thats why the tropical depressions can sometimes become prolific tornado producers as there becomes enough breaks in the clouds to create enough instability vs good but not so extremely sheared out cells.

EXACTLY. You do not need much instability at all b/c the shear is so sufficient....even in Tropical Depressions. This setup is good.. Right along the coast CAPE's are as high as 3500 and 0-3km SRH is as high as 250-300. Certainly sufficient for isolated tornadoes.

PS: There looks to be a nice supercell south of the FL/AL state boarder....offshore. It has been persistent for awhile now.[/quote]

 

[Anonymous]

It looks more like a Squall line than a supercell. It's got a defined area of rotation about, 1.2 nm. What evidence do you have that it's a supercell? Scott, are you saying that their NEVER is enough instability since your near water?