*Possible Widespread Severe 23rd/24th*

by **Toot** 2012-02-21, 10:32 pm

Larry Cosgrove on the coming setup

After the debacle that was this year's "non winter", I was kind of gearing up for severe weather season anyway. There is a certain charge in the air in Texas during March, as we await the first "particularly dangerous situation" watch box and series of severe thunderstorm and tornado warnings. Well, lo and behold, it would appear that we will not have to wait for calendar spring to be concerned with the potential for intense convection. Threats for inclement weather will abound not only in Texas but also much of the Old South during the next two weeks. Starting with Thursday night.

The flow of warm and humid air off of the Gulf of Mexico will be impinged upon by an advancing 500MB shortwave from the Rocky Mountains, another closed upper impulse in Mexico as well as approaching cPk and cTw air masses. This is the familiar "stew" of air mass convergence and synoptic parameters which leads to important severe weather events, and it appears that thunderstorms will start to fire ahead of surface cyclogenesis in the Texas Panhandle and Red River Valley on Thursday evening. The two systems aloft will merge and drive pressure falls toward the Tennessee Valley on Friday, then up along the Atlantic Coastal Plain into southern New England by Saturday morning. This is, of course, a formula for intense hail, high wind and tornado production, along with the threat of flooding rainfall (we still have about 2 - 3 inches of rain needed in the Houston metro to completely eliminate the drought). I am confident that other localities will have it far worse than Houston (the Mid-South and lower Mid-Atlantic will be hit hardest by the storms). That said, the potential exists to come into some rather turbulent conditions in the hours before sunrise on Friday.

SPC Convective outlook

*Possible Widespread Severe 23rd/24th* Day3otlk_0830

by **Eric** 2012-02-21, 10:33 pm

Damaging winds and hail I'll buy, but "tornado production"? I don't see it.....

by **tennessee storm09** 2012-02-21, 10:42 pm

Eric wrote:Damaging winds and hail I'll buy, but "tornado production"? I don't see it.....

+ one

by **Toot** 2012-02-21, 10:56 pm

SPC

...SERN STATES...

POTENTIAL FOR SIGNIFICANT SEVERE WEATHER WILL EXIST THURSDAY EVENING
AND OVERNIGHT.

STRENGTHENING SWLY BOUNDARY LAYER WINDS WILL CONTRIBUTE TO NEWD
TRANSPORT OF MODIFYING GULF AIR WITH DEWPOINTS FROM THE UPPER 60S
OVER SRN AND ERN TX INTO THE GULF COASTAL STATES TO NEAR 50 OVER SRN
PORTIONS OF THE OH VALLEY. GREATEST INSTABILITY WILL LIKELY DEVELOP
OVER THE LOWER MS VALLEY REGION JUST AHEAD OF THE FRONT WHERE PLUME
OF STEEPER LAPSE RATES WILL ADVECT EWD AND OVERTAKE THE WRN EDGE OF
THE MOIST AXIS. MLCAPE IN THIS REGION COULD RANGE FROM 1000-1500
J/KG. HOWEVER...THE RETURNING LOW LEVEL MOISTURE MIGHT CONTRIBUTE TO
THE DEVELOPMENT OF CLOUDS OVER A PORTION OF THIS REGION...AND THE
ATMOSPHERE WILL LIKELY REMAIN CAPPED TO SURFACE BASED CONVECTION
MUCH OF THE DAY. MODEL CONSENSUS IS THAT STORMS WILL DEVELOP BY
EARLY EVENING IN ZONE OF HEIGHT FALLS AND INCREASING FRONTAL
CONVERGENCE ASSOCIATED WITH THE AMPLIFYING WAVE AND STRENGTHENING
LLJ. ACTIVITY WILL EXIST WITHIN A STRONG KINEMATIC ENVIRONMENT AS
LLJ INCREASES TO IN EXCESS OF 50 KT WITH STRONG DEEP LAYER WINDS AND
VERTICAL SHEAR. THIS ENVIRONMENT WILL SUPPORT ORGANIZED STORMS
INCLUDING SUPERCELLS AND BOWING STRUCTURES WITH UPSCALE GROWTH
LIKELY OVERNIGHT. LARGE HAIL...DAMAGING WIND AND A FEW TORNADOES
WILL BE POSSIBLE AS STORMS DEVELOP EWD.

*Possible Widespread Severe 23rd/24th* Day3prob_0830

It may be threadworthy even if it dont produce any naders

by **Eric** 2012-02-21, 10:59 pm

Toot wrote:SPC

...SERN STATES...

POTENTIAL FOR SIGNIFICANT SEVERE WEATHER WILL EXIST THURSDAY EVENING
AND OVERNIGHT.

STRENGTHENING SWLY BOUNDARY LAYER WINDS WILL CONTRIBUTE TO NEWD
TRANSPORT OF MODIFYING GULF AIR WITH DEWPOINTS FROM THE UPPER 60S
OVER SRN AND ERN TX INTO THE GULF COASTAL STATES TO NEAR 50 OVER SRN
PORTIONS OF THE OH VALLEY. GREATEST INSTABILITY WILL LIKELY DEVELOP
OVER THE LOWER MS VALLEY REGION JUST AHEAD OF THE FRONT WHERE PLUME
OF STEEPER LAPSE RATES WILL ADVECT EWD AND OVERTAKE THE WRN EDGE OF
THE MOIST AXIS. MLCAPE IN THIS REGION COULD RANGE FROM 1000-1500
J/KG. HOWEVER...THE RETURNING LOW LEVEL MOISTURE MIGHT CONTRIBUTE TO
THE DEVELOPMENT OF CLOUDS OVER A PORTION OF THIS REGION...AND THE
ATMOSPHERE WILL LIKELY REMAIN CAPPED TO SURFACE BASED CONVECTION
MUCH OF THE DAY. MODEL CONSENSUS IS THAT STORMS WILL DEVELOP BY
EARLY EVENING IN ZONE OF HEIGHT FALLS AND INCREASING FRONTAL
CONVERGENCE ASSOCIATED WITH THE AMPLIFYING WAVE AND STRENGTHENING
LLJ. ACTIVITY WILL EXIST WITHIN A STRONG KINEMATIC ENVIRONMENT AS
LLJ INCREASES TO IN EXCESS OF 50 KT WITH STRONG DEEP LAYER WINDS AND
VERTICAL SHEAR. THIS ENVIRONMENT WILL SUPPORT ORGANIZED STORMS
INCLUDING SUPERCELLS AND BOWING STRUCTURES WITH UPSCALE GROWTH
LIKELY OVERNIGHT. LARGE HAIL...DAMAGING WIND AND A FEW TORNADOES
WILL BE POSSIBLE AS STORMS DEVELOP EWD.

It may be threadworthy even if it dont produce any naders

Like to clarify my earlier statement...I was speaking specifically for TN. It should be understood that the chances would be greater to the south due to greater moisture return, in addition to the other factors. popcorn

by **Dyersburg Weather** 2012-02-22, 1:39 am

Just saw Dr Forbes has Eastern Arkansas , West Tennessee and Mississippi a 3 on the Torcon . Mississippi maybe but I tend to agree with Eric as far as Tennessee's chances for tornadoes.

by **tennessee storm09** 2012-02-22, 5:49 am

Dyersburg Weather wrote:Just saw Dr Forbes has Eastern Arkansas , West Tennessee and Mississippi a 3 on the Torcon . Mississippi maybe but I tend to agree with Eric as far as Tennessee's chances for tornadoes.

yea, if only we could the deeper moisture return up to tennessee this would turn into a more significant event... that being said, it is a really potent cold front coming into warm environment with decent dew points... winds loook directional so this should be in a linear form of fashion, with damaging winds main threat over hail... spc has us again more in the slight risk cat. they have been all over the place with this... they seem to be struggling just a bit with this system. yak

by **tennessee storm09** 2012-02-22, 6:01 am

the nws has issed a statement this morning for some strong storms with pea size hail just north of memphis, titon county. fayette co.

by **Toot** 2012-02-22, 8:12 am

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MORRISTOWN TN
404 AM EST WED FEB 22 2012

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-
005-006-008-222100-
CHEROKEE-CLAY-SCOTT TN-CAMPBELL-CLAIBORNE-HANCOCK-HAWKINS-
SULLIVAN-JOHNSON-MORGAN-ANDERSON-UNION-GRAINGER-HAMBLEN-
NORTHWEST COCKE-COCKE SMOKY MOUNTAINS-NORTHWEST GREENE-
SOUTHEAST GREENE-WASHINGTON TN-UNICOI-NORTHWEST CARTER-
SOUTHEAST CARTER-ROANE-LOUDON-KNOX-JEFFERSON-NW BLOUNT-
BLOUNT SMOKY MOUNTAINS-NORTH SEVIER-SEVIER SMOKY MOUNTAINS-
SEQUATCHIE-BLEDSOE-RHEA-MEIGS-MCMINN-NORTHWEST MONROE-
SOUTHEAST MONROE-MARION-HAMILTON-BRADLEY-WEST POLK-EAST POLK-LEE-
WISE-SCOTT-RUSSELL-WASHINGTON-
INCLUDING THE CITIES OF...MURPHY...HAYESVILLE...ONEIDA...
LA FOLLETTE...TAZEWELL...SNEEDVILLE...ROGERSVILLE...KINGSPORT...
BRISTOL...MOUNTAIN CITY...WARTBURG...CLINTON...OAK RIDGE...
MAYNARDVILLE...RUTLEDGE...MORRISTOWN...NEWPORT...COSBY...
GREENEVILLE...CEDAR CREEK...JOHNSON CITY...ERWIN...ELIZABETHTON...
ROAN MOUNTAIN...KINGSTON...LENOIR CITY...KNOXVILLE...DANDRIDGE...
MARYVILLE...CADES COVE...SEVIERVILLE...GATLINBURG...DUNLAP...
PIKEVILLE...DAYTON...DECATUR...ATHENS...MADISONVILLE...
COKER CREEK...JASPER...CHATTANOOGA...CLEVELAND...BENTON...
DUCKTOWN...JONESVILLE...WISE...NORTON...GATE CITY...LEBANON...
ABINGDON
404 AM EST WED FEB 22 2012 /304 AM CST WED FEB 22 2012/

...SEVERE THUNDERSTORMS POSSIBLE THIS AFTERNOON AND THURSDAY
NIGHT...

A GREATER POTENTIAL FOR SEVERE STORMS WILL ARRIVE THURSDAY NIGHT
AHEAD OF A STRONG COLD FRONT. AS LOW PRESSURE CROSSES THE OHIO
VALLEY...A STRONG SOUTH WIND WILL DEVELOP THURSDAY AFTERNOON...AND
TEMPERATURES WILL RISE INTO THE 70S IN THE TENNESSEE VALLEY. THE
WARM MOIST AIR AND GUSTY SOUTH WINDS WILL GENERATE STRONG TO
SEVERE THUNDERSTORMS AFTER SUNSET THURSDAY EVENING...MOVING EAST
ACROSS THE AREA THROUGH MIDNIGHT. DAMAGING STRAIGHT LINE WINDS ARE
EXPECTED TO BE THE MAIN THREAT...WITH A POTENTIAL FOR SOME
TORNADOES AS WELL.

SINCE THE MAIN THREAT OF SEVERE WEATHER IS EXPECTED TO ARRIVE
AFTER DARK THURSDAY NIGHT...RESIDENTS OF EAST TENNESSEE AND
SOUTHWEST VIRGINIA ARE URGED TO MAINTAIN A HIGH LEVEL OF
AWARENESS. STAY TUNED TO NOAA WEATHER RADIO AND OTHER LOCAL MEDIA
FOR FURTHER DETAILS OR UPDATES.

$$

by **Eric** 2012-02-22, 12:54 pm

Not much has changed concerning my thoughts for tomorrow's FROPA. Upper-level wind fields are still disjointed (12 NAM, 12z GFS, 09z SREF, 0z Euro back this up), so as of right now, a widespread, organized severe weather event doesn't look like a real possibility, but an isolated severe thunderstorm or two cannot be ruled out. Instability is sorely lacking with both the 12z NAM and GFS spitting out ~750 j/kg statewide.

Thermodynamically speaking, it's going to be unseasonably warm tomorrow and you will feel "it" - that feeling you get when its 70F+ in February. GFS MOS paints a high of ~75F at several locations, however, dew points are only progged to be between 55-60F. If those values are 1) being underdone, or 2) were any higher, we could be looking at a more robust event.

Considering the remarkable consensus we have with the numericals (especially after last weekend's debacle), there is an item that I personally want to revisit. The 0z Euro puts a 996mb SLP over PAH tomorrow, putting the greatest amount of divergence over central areas of MS and AL. If for any reason, the SLP doesn't swing as far south as the 0z says, the threat area could then migrate northward towards the TN Valley. Do I think that's going to happen...quite honestly, no, and if the 12z Euro is in line with the 0z then, IMO, the solution is rock-solid.

So, my best guess for tomorrow -DISCLAIMER: this is not an official forecast, only my interpretation of data as I see it. Always heed any and all warnings that are/will be issued by the NWS. : a squall line/QLCS with a damaging wind threat, hail threat, and maybe a few QLCS-type tornado spinups (given the amount of wind shear that will be present).

UPDATE: 12z Euro placed the SLP over central IL, which is a bit further north, but synoptically should have a negligible effect on the end solution.

by **Reb** 2012-02-22, 5:54 pm

some nice storms breaking out now in middle tn and ky

by **Reb** 2012-02-22, 6:04 pm

severe thunderstorm warning issued by MRX

by **Math/Met** 2012-02-22, 6:04 pm

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MORRISTOWN TN
555 PM EST WED FEB 22 2012

THE NATIONAL WEATHER SERVICE IN MORRISTOWN HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
ANDERSON COUNTY IN EAST TENNESSEE...
BLEDSOE COUNTY IN EAST TENNESSEE...
BLOUNT COUNTY IN EAST TENNESSEE...
NORTHERN BRADLEY COUNTY IN EAST TENNESSEE...
SOUTHERN CAMPBELL COUNTY IN EAST TENNESSEE...
CARTER COUNTY IN EAST TENNESSEE...
CLAIBORNE COUNTY IN EAST TENNESSEE...
COCKE COUNTY IN EAST TENNESSEE...
GRAINGER COUNTY IN EAST TENNESSEE...
GREENE COUNTY IN EAST TENNESSEE...
HAMBLEN COUNTY IN EAST TENNESSEE...
HAMILTON COUNTY IN EAST TENNESSEE...
HANCOCK COUNTY IN EAST TENNESSEE...
HAWKINS COUNTY IN EAST TENNESSEE...
JEFFERSON COUNTY IN EAST TENNESSEE...
KNOX COUNTY IN EAST TENNESSEE...
LOUDON COUNTY IN EAST TENNESSEE...
MCMINN COUNTY IN EAST TENNESSEE...
MEIGS COUNTY IN EAST TENNESSEE...
MONROE COUNTY IN EAST TENNESSEE...
MORGAN COUNTY IN EAST TENNESSEE...
RHEA COUNTY IN EAST TENNESSEE...
ROANE COUNTY IN EAST TENNESSEE...
EXTREME SOUTHERN SCOTT COUNTY IN EAST TENNESSEE...
SEQUATCHIE COUNTY IN EAST TENNESSEE...
SEVIER COUNTY IN EAST TENNESSEE...
EXTREME WESTERN SULLIVAN COUNTY IN EAST TENNESSEE...
UNICOI COUNTY IN EAST TENNESSEE...
UNION COUNTY IN EAST TENNESSEE...
WASHINGTON COUNTY IN EAST TENNESSEE...

* UNTIL 645 PM EST/545 PM CST/

* AT 546 PM EST/446 PM CST/...NATIONAL WEATHER SERVICE DOPPLER RADAR
INDICATED A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING GOLF
BALL SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH. THESE
STORMS WERE LOCATED ALONG A LINE EXTENDING FROM 7 MILES NORTHEAST
OF SNEEDVILLE TO 8 MILES NORTH OF MCMINNVILLE...AND MOVING EAST AT
65 MPH.

* LOCATIONS IN THE WARNING INCLUDE...
MAYNARDVILLE...RUTLEDGE...ROGERSVILLE...CLINTON...ROCKWOOD...OAK
RIDGE...MORRISTOWN...KINGSTON...JEFFERSON CITY...PIKEVILLE...
KNOXVILLE...JOHNSON CITY...LENOIR CITY...DANDRIDGE...DAYTON...
LOUDON...GREENEVILLE...ELIZABETHTON...ALCOA AND SEVIERVILLE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...CONTINUOUS CLOUD TO
GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS
IMMEDIATELY! LIGHTNING IS ONE OF NATURES NUMBER ONE KILLERS.
REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE
STRUCK BY LIGHTNING.

That is a huge Severe Thunderstorm Warning.

by **Toot** 2012-02-22, 6:10 pm

Blanket SVR warning out from MRX and they mention golfballs....HAIL YESSSS!! rock on

by **Reb** 2012-02-22, 6:20 pm

PUMPED!

by **Toot** 2012-02-22, 6:54 pm

Rotaion must have been detected over toward Vanns way..hope all is well over there

TORNADO WARNING
TNC035-175-177-185-230045-
/O.NEW.KOHX.TO.W.0011.120222T2347Z-120223T0045Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE NASHVILLE TN
547 PM CST WED FEB 22 2012

THE NATIONAL WEATHER SERVICE IN NASHVILLE HAS ISSUED A

* TORNADO WARNING FOR...
SOUTHERN CUMBERLAND COUNTY IN MIDDLE TENNESSEE...
NORTHERN VAN BUREN COUNTY IN MIDDLE TENNESSEE...
NORTHEASTERN WARREN COUNTY IN MIDDLE TENNESSEE...
SOUTHERN WHITE COUNTY IN MIDDLE TENNESSEE...

* UNTIL 645 PM CST

* AT 541 PM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS
STORM WAS LOCATED NEAR MCMINNVILLE...AND MOVING EAST AT 55 MPH.

* LOCATIONS IMPACTED INCLUDE...
SPENCER...CROSSVILLE AND CRAB ORCHARD.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 3584 8477 3577 8491 3576 8523 3575 8526
3571 8575 3579 8577 3603 8475 3591 8470
TIME...MOT...LOC 2347Z 257DEG 46KT 3576 8564

$$

19

Meso discussion
*Possible Widespread Severe 23rd/24th* Mcd0143

by Vanster67 2012-02-22, 7:15 pm

Wow!! Tornado warning just to my South. Did not expect that. No hail, but the lightning and wind, with the buckets of heavy, heavy rain was unreal. I had rain coming down the chimney ya'll. The wind was unreal here, but not really sustained for any amount of time just 3-5 really powerful gust. Never went severe warned here. With a temp of 53, dewpoint of 51 I can only wonder what tomorrow/ tomorrow yikes

night will bring. Stay safe to the east of me.

by **Stovepipe** 2012-02-22, 7:18 pm

Thanks for the update Van.

rock on

by **Toot** 2012-02-22, 7:46 pm

MRX Multimedia briefing for tonight and tomorrow

http://www.srh.noaa.gov/rtimages/mrx/presentations/Feb22_2012_SevereWxPotential.wmv

*Possible Widespread Severe 23rd/24th* Image7

*Possible Widespread Severe 23rd/24th* Image7

by **Math/Met** 2012-02-22, 7:52 pm

Maybe I’ve just missed it in the past, but that is the first time I’ve seen them do that. Thanks for posting.

by **Toot** 2012-02-22, 7:58 pm

Math/Met wrote:Maybe I’ve just missed it in the past, but that is the first time I’ve seen them do that. Thanks for posting.

To my knowledge it is the first time they have did that. They mentioned possible discrete activity out ahead of the cold front too...Not something one wants to hear unless you actively chase lmao

by **Jed33** 2012-02-22, 10:19 pm

Wow I just got home, but on the way, I ran into a small hailstorm. Better late
than never tonight I guess. Looks like that's the last intense cell on radar for tonight.
There for a min. it was coming down. Pea and Marble sizd hail. Sounds like tomorrow could be the real deal for hail though

by **Eric** 2012-02-22, 10:43 pm

I think the tornado risk is being a smidge overblown by MRX (granted I'm not sure how they usually react...I hope they reign in the overexuberance that was shown tonight, however), but things do look a bit more robust tonight for you guys than they did last night. Still primarily a wind/hail threat, but cannot rule out a rogue isolated tornado.

by Vanster67 2012-02-23, 7:35 am

FWIW I have an Accu-Weather weather alarm with a 75% chance thunderstorms tonight, strong winds and isolated tornadoes. FWIW Very Happy

Gimmee a BREAK. I needed to type something!!![u] facepalm

by **Stovepipe** 2012-02-23, 8:31 am

Vanster67 wrote:FWIW I have an Accu-Weather weather alarm with a 75% chance thunderstorms tonight, strong winds and isolated tornadoes. FWIW

Gimmee a BREAK. I needed to type something!!![u]