• Welcome to TalkWeather!
    We would love for you to become a part of our community.
    Take a moment to look around and join the discussion.
    CLICK HERE TO JOIN TALKWEATHER

Archive Severe threat April 26-27, 2011 (1 Viewer)


TW Archive

Member
Staff member
Don't Feed The Bots
Messages
2,028
tennessee storm chaser
Posted 22 April 2011 - 08:58 PM

yep, forbes is really concerned about tornadoes with that 2nd system next week. people in the midsouth, tennesee valleys. deep south need to be on their toes next week.
 

TW Archive

Member
Staff member
Don't Feed The Bots
Messages
2,028
TimHSV
Posted 22 April 2011 - 10:39 PM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
ISSUED 352 PM CDT FRI APR 22 2011

Edited for specifics:


DISCUSSION...FORECAST FOCUS ON SEVERE POTENTIAL TONIGHT...THEN ON
TWO SYSTEMS NEXT WEEK THAT COULD BRING SIGNIFICANT RAINFALL AND
SEVERE WEATHER.


THE FRONT WILL MORE OR LESS REMAIN STATIONARY UNTIL LATE THIS
WEEKEND AS A PRETTY POTENT SYSTEM FORMS IN THE SOUTHERN PLAINS
AND FORCES THE FRONT FURTHER NORTH. SEVERAL MCS/S WILL DEVELOP
ALONG THE FRONT BETWEEN NOW AND SUNDAY NIGHT...PRODUCING
POTENTIALLY CATASTROPHIC AMOUNTS OF RAINFALL /8+ INCHES/ OVER
MISSOURI INTO SOUTHERN ILLINOIS. THE MIDSOUTH WILL BE ON THE FAR
SOUTHERN FRINGES OF THIS ACTIVITY...SO POPS WILL GENERALLY BE LOW
FOR THE REMAINDER OF THIS PERIOD. CONSULT THE LONG TERM DISCUSSION
FOR CONSEQUENCES OF THIS HEAVY RAINFALL FOR THE MIDSOUTH RIVERS.

.LONG TERM...MONDAY THROUGH NEXT FRIDAY.

EARLY PORTIONS OF NEXT WEEK WILL HAVE TO DEAL WITH MULTIPLE SEVERE
WEATHER EVENTS AND HEAVY RAIN/FLASH FLOODING...FOLLOWED BY LONG
DURATION AND SIGNIFICANT RIVER FLOODING POSSIBLE
AS THE WATER FROM
UPSTREAM WORKS DOWN THE MISSISSIPPI LATER NEXT WEEK.
Edited by TimHSV, 22 April 2011 - 10:47 PM.

 

TW Archive

Member
Staff member
Don't Feed The Bots
Messages
2,028
trency911
Posted 22 April 2011 - 10:44 PM

TimHSV, on 22 April 2011 - 10:39 PM, said:

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
ISSUED 352 PM CDT FRI APR 22 2011

Edited for specifics:



Yea flooding is going to be a great concern.


p120i00.gif

 

TW Archive

Member
Staff member
Don't Feed The Bots
Messages
2,028
skywatcher22
Posted 22 April 2011 - 11:25 PM

Tuesday's severe threat has the potential to be exceptionally bad with a similar jet structure to the 4/15 event. I would not be surprised to see a High Risk across NE TX, SE OK, and much of AR near a warm front.
Edited by Matt Grantham, 22 April 2011 - 11:26 PM.

 

TW Archive

Member
Staff member
Don't Feed The Bots
Messages
2,028
TimHSV
Posted 22 April 2011 - 11:32 PM

Matt Grantham, on 22 April 2011 - 11:25 PM, said:

Tuesday's severe threat has the potential to be exceptionally bad with a similar jet structure to the 4/15 event. I would not be surprised to see a High Risk across NE TX, SE OK, and much of AR near a warm front.



Yea Matt I just had time to look at the 12Z ECMWF and it really is cranking the 850mb Jet near 65-70knts across E.AR/ W TN /N MS.along with a 95knt 500mb jet coming in out of the SW by 12Z Wed., and the 500mb trof it shows coming acorss OK is really deep and powerful it looks at this time.
Edited by TimHSV, 22 April 2011 - 11:38 PM.

 

TW Archive

Member
Staff member
Don't Feed The Bots
Messages
2,028
tennessee storm chaser
Posted 22 April 2011 - 11:38 PM

TimHSV, on 22 April 2011 - 11:32 PM, said:

Yea Matt I just had time to look at the 12Z ECMWF and it really is cranking the 850mb Jet near 65-70knts across E.AR/W TN/N MS. by 12Z Wed., and the 500mb trof it shows coming acorss OK is really deep and powerful it looks at this time.

yeah, yall the 0zgfs is quite frighting. the 114 hour looks to be super cells hammering east ar. and west tn. very nice strong ll jet cranking that late tuesday evening
 

TW Archive

Member
Staff member
Don't Feed The Bots
Messages
2,028
ARCC
Posted 22 April 2011 - 11:52 PM

Scary look for MS,AL,Ga and TN. All that really can be said.
 

TW Archive

Member
Staff member
Don't Feed The Bots
Messages
2,028
TimHSV
Posted 22 April 2011 - 11:55 PM

tennessee storm chaser, on 22 April 2011 - 11:38 PM, said:

yeah, yall the 0zgfs is quite frighting. the 114 hour looks to be super cells hammering east ar. and west tn. very nice strong ll jet cranking that late tuesday evening



10-4 there...
 

TW Archive

Member
Staff member
Don't Feed The Bots
Messages
2,028
skywatcher22
Posted 22 April 2011 - 11:55 PM

I've drawn the surface features (dryline and warm front) on top of the 300 mb map. What really scares me is the jet nosing in just south and parallel to the warm front as depicted. That could lead to strong backing of the surface winds as the surface low deepens and the pressure trough along the warm front sharpens. This same forcing traditionally leads the development of explosive convection.
picture1rgz.png

 
  • Like
Reactions: KoD

TW Archive

Member
Staff member
Don't Feed The Bots
Messages
2,028
TimHSV
Posted 22 April 2011 - 11:58 PM

ARCC, on 22 April 2011 - 11:52 PM, said:

Scary look for MS,AL,Ga and TN. All that really can be said.


I'll say. Bounadary layer looks ripe and jet structure's looks very well defined, with SRH averages around 450-550m^2/s^2, and EHI's average 4-6.
Edited by TimHSV, 22 April 2011 - 11:59 PM.

 

TW Archive

Member
Staff member
Don't Feed The Bots
Messages
2,028
TimHSV
Posted 23 April 2011 - 12:03 AM

Matt Grantham, on 22 April 2011 - 11:55 PM, said:

I've drawn the surface features (dryline and warm front) on top of the 300 mb map. What really scares me is the jet nosing in just south and parallel to the warm front as depicted. That could lead to strong backing of the surface winds as the surface low deepens and the pressure trough along the warm front sharpens. This same forcing traditionally leads the development of explosive convection.


Wow, 120knts. AR/ Western TN/ Northern MS. just looks very dangerous at this point.
Edited by TimHSV, 23 April 2011 - 12:04 AM.

 

TW Archive

Member
Staff member
Don't Feed The Bots
Messages
2,028
ARCC
Posted 23 April 2011 - 12:04 AM

TimHSV, on 22 April 2011 - 11:58 PM, said:

I'll say. Bounadary layer looks ripe and jet structure's looks very well defined, with SRH averages around 450-550m^2/s^2, and EHI's average 4-6.



Lift would be incredible over AL,MS and GA in this setup. Add in a decent cap and dry air at 700mb to hold off the junk convection. Add in subtle forcing and good helicity. You then have a perfect setup for explosive supercells and long tracked tornadoes. What a setup. Deep ridge over the Atlantic gives me the idea that the GFS could be under doing moisture and instability as well.
Edited by ARCC, 23 April 2011 - 12:04 AM.

 

TW Archive

Member
Staff member
Don't Feed The Bots
Messages
2,028
TimHSV
Posted 23 April 2011 - 12:05 AM

ARCC, on 23 April 2011 - 12:04 AM, said:

Lift would be incredible over AL,MS and GA in this setup. Add in a decent cap and dry air at 700mb to hold off the junk convection. Add in subtle forcing and good helicity. You then have a perfect setup for explosive supercells and long tracked tornadoes. What a setup. Deep ridge over the Atlantic gives me the idea that the GFS could be under doing moisture and instability as well.

Yea ARCC, I was gonna type did you see that 700mb dry punch
 

TW Archive

Member
Staff member
Don't Feed The Bots
Messages
2,028
storm5
Posted 23 April 2011 - 12:08 AM

What are the chances this trends away from being such an explosive event??
 

TW Archive

Member
Staff member
Don't Feed The Bots
Messages
2,028
mwbwhorton
Posted 23 April 2011 - 12:09 AM

i can only imagine the SPC's thinking on this with these latest models given what's already happened tonight and over the last week or so....
Edited by mwbwhorton, 23 April 2011 - 12:09 AM.

 

TW Archive

Member
Staff member
Don't Feed The Bots
Messages
2,028
skywatcher22
Posted 23 April 2011 - 12:12 AM

ARCC, on 23 April 2011 - 12:04 AM, said:

Lift would be incredible over AL,MS and GA in this setup. Add in a decent cap and dry air at 700mb to hold off the junk convection. Add in subtle forcing and good helicity. You then have a perfect setup for explosive supercells and long tracked tornadoes. What a setup. Deep ridge over the Atlantic gives me the idea that the GFS could be under doing moisture and instability as well.


What do you mean by incredible lift, but subtle forcing?

IMO it looks like the forcing is quite strong and linear by 114-120 hours. Mainly a big squall line with maybe a few cells out ahead.
 

TW Archive

Member
Staff member
Don't Feed The Bots
Messages
2,028
ARCC
Posted 23 April 2011 - 12:12 AM
storm5, on 23 April 2011 - 12:08 AM, said:

What are the chances this trends away from being such an explosive event??



The chances are there of course, after all it happened a few weeks ago. However, with both GFS and Euro showing a nasty event, you have to think it holds a pretty good shot at happening.
 

TW Archive

Member
Staff member
Don't Feed The Bots
Messages
2,028
skywatcher22
Posted 23 April 2011 - 12:38 AM

storm5, on 23 April 2011 - 12:08 AM, said:

What are the chances this trends away from being such an explosive event??

It honestly doesn't look all that explosive for Alabama, although there still will be severe weather. Tuesday looks like the worst day from SE OK/NE TX into AR and western TN/KY.
Edited by Matt Grantham, 23 April 2011 - 12:40 AM.

 

TW Archive

Member
Staff member
Don't Feed The Bots
Messages
2,028
tennessee storm chaser
Posted 23 April 2011 - 12:59 AM

the 0z euro has the sl a tad more north. that would get the warm sector farther north. that could lead to higher dews. mid 60s to upper 60s across much of the region. painting a severe weather event to say the least.
 

TW Archive

Member
Staff member
Don't Feed The Bots
Messages
2,028
weatherguy
Posted 23 April 2011 - 03:56 AM

SUBSTANTIAL SEVERE WEATHER POTENTIAL IS EXPECTED TO SHIFT SLOWLY EWD
ACROSS THE ERN U.S. DAYS 4-6 /TUE. 4-26 THROUGH THU. 4-28/...AS A
LARGE UPPER TROUGH PROGRESSES FROM THE CENTRAL U.S. DAY 4 ACROSS THE
MS VALLEY DAY 5...AND THEN ON EWD THROUGH DAYS 6/7. MODEL
DIFFERENCES WITH RESPECT TO TIMING OF THIS FEATURE BEGIN TO EMERGE
DAY 5...BUT BECOME INCREASINGLY PRONOUNCED THROUGH DAYS 6 AND 7 AS
THE TROUGH APPROACHES THE E COAST STATES/ERN ATLANTIC.

THE THREAT SHOULD SHIFT E OF THE MS VALLEY INTO THE MID
SOUTH/SOUTHEAST DAY 5...AS THE SHORT-WAVE FEATURE TAKES ON A NEUTRAL
TO EVEN NEGATIVE TILT AS IT CROSSES THIS REGION. AGAIN -- AMPLY
UNSTABLE AIRMASS COMBINED WITH THE STRENGTH OF THE UPPER SYSTEM AND
ASSOCIATED FLOW FIELD SUGGESTS WIDESPREAD SEVERE WEATHER CAN BE
EXPECTED...INCLUDING THE POTENTIAL FOR TORNADOES.
day48prob201104231200.gif
 
Top