TS Lee Tornadic Threat

[andyhb]

Seeing as the most significant threats with Lee besides the rainfall are likely to be tornado-based, decided to start this.

Here's the current watch:

URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 830

NWS STORM PREDICTION CENTER NORMAN OK

945 PM CDT SAT SEP 3 2011

THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF

EXTREME SOUTHERN ALABAMA

THE WESTERN FLORIDA PANHANDLE

SOUTH CENTRAL AND SOUTHEAST LOUISIANA

SOUTHERN MISSISSIPPI

COASTAL WATERS

EFFECTIVE THIS SATURDAY NIGHT AND SUNDAY MORNING FROM 945 PM

UNTIL 700 AM CDT.

TORNADOES...HAIL TO 0.5 INCH IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 70 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 45 MILES SOUTHWEST OF BATON

ROUGE LOUISIANA TO 35 MILES EAST OF PENSACOLA FLORIDA. FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU0).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR

TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH

AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR

THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS

AND POSSIBLE WARNINGS.

OTHER WATCH INFORMATION...THIS TORNADO WATCH REPLACES TORNADO

WATCH NUMBER 828. WATCH NUMBER 828 WILL NOT BE IN EFFECT AFTER

945 PM CDT. CONTINUE...WW 829...

DISCUSSION...TS LEE IS LOCATED NEAR THE S CENTRAL LA COAST AND IS

EXPECTED TO MOVE LITTLE THE NEXT SEVERAL HOURS. DISCRETE CELLS WILL

CONTINUE TO FORM ON THE NOSE OF THE MIDLEVEL DRY SLOT ACROSS THE LA

DELTA EWD TO THE AL COAST...WHERE LOW-LEVEL MOISTURE/BUOYANCY/SHEAR

ARE STRONGEST. THE TORNADO RISK WILL PERSIST WITH STORMS CROSSING

THE COAST THROUGH THE OVERNIGHT HOURS. THE TORNADO RISK IS A LITTLE

LESS FARTHER INLAND ACROSS SRN MS...AND CLOSER TO THE CENTER IN S

CENTRAL LA...BUT LOW-TOPPED SUPERCELL DEVELOPMENT CANNOT BE RULED

OUT IN THESE AREAS A LITTLE LATER TONIGHT.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

500. MEAN STORM MOTION VECTOR 18030.

...THOMPSON

[andyhb]

Tornado

Location: 2 SSW BELLEFONTAINE

Local Date: 09/04/2011

Local Time: 1:02 AM CDT

County: MOBILE

State: AL

Source: FIRE DEPT/RESCUE

Magnitude:

Comments: HOME DAMAGED WITH SEVERAL TREES DOWN ALONG PIONEER ROAD AND FOWL RIVER ROAD. POSSIBLE TORNADO.

[on_wx]

I couldn't imagine being under a tornado watch for three days. Some of them counties have been under 10 to 15+ tornado warnings so far.

[ScottL]

There was a tornado in Rainbow City, AL today associated with Lee. No injuries reported.

From James Spann's Alabamawx blog:

http://www.alabamawx.com/?p=52470

and a follow-up

http://www.alabamawx.com/?p=52479

Scott

[andyhb]

10 tornado reports so far today. 4 warnings currently in place. One of them is for one of the areas affected on April 27th (Raleigh, MS).

[andyhb]

Rather substantial 10% tor probs. in new day 1 outlook.

...GULF COAST/SOUTHEAST STATES...

CURRENT TROPICAL DEPRESSION LEE /REFERENCE NHC FORECASTS FOR THE

LATEST INFORMATION/ IS EXPECTED TO GRADUALLY BECOME MORE

EAST-NORTHEASTWARD PROGRESSIVE /ESPECIALLY LATER TODAY INTO TONIGHT/

AS IT UNDERGOES AN EXTRATROPICAL TRANSITION THROUGH THE PERIOD. AN

ENHANCED SOUTHERLY LOW-LEVEL WIND FIELD MAY ACTUALLY STRENGTHEN TO A

DEGREE AS IT BECOMES EXTRATROPICAL/INTERACTS WITH THE EASTERN CONUS

LONGWAVE TROUGH...WITH THE LIKELIHOOD OF 50+ KT WINDS WITHIN THE

LOWEST 1-2 KM /EG 850 MB/ TRANSLATING EASTWARD ACROSS THE SOUTHERN

HALF OF AL AND THE FL PANHANDLE INTO GA...AND PERHAPS SC LATER

TONIGHT.

ASIDE FROM A DEGREE OF SPREAD REGARDING THE EXACT TIMING/PLACEMENT

AND UNCERTAIN ACCELERATION OF LEE REMNANTS...THE SPECIFIC DEGREE OF

DESTABILIZATION INLAND REMAINS A KEY UNCERTAINTY. BUT EVEN MODEST

DESTABILIZATION /ESPECIALLY DURING THE DAYLIGHT HOURS/ SHOULD BOOST

TORNADO POTENTIAL WITHIN A HEIGHTENED SHEAR/SRH AND MOISTURE-RICH

ENVIRONMENT. ADDITIONALLY...WITH DRY AIR BECOMING A BIT MORE

PREVALENT ON THE WESTERN PERIPHERY OF LEE EARLY IN THE

OVERNIGHT...IT APPEARS THAT A MID-LEVEL DRY SLOT /PER LATEST

GUIDANCE/ COULD EMERGE/SPREAD EAST-NORTHEASTWARD BY AFTERNOON...OR

MORE CERTAINLY THE EVENING. THIS COULD BE A FACTOR FOR A MORE

CONSEQUENTIAL DESTABILIZATION ESPECIALLY IF IT INDEED BEGINS TO

OVERSPREAD TO THE LEE-REMNANT EASTERLY ENVELOPE MOIST AXIS PRE-DARK.

WHILE THE MAIN TORNADO THREAT WILL LIKELY BE ACROSS THE WARM SECTOR

TO THE IMMEDIATE EAST OF REMNANT LEE...AN INTERACTION WILL CONTINUE

TO OCCUR WITH THE SOUTHWARD-SAGGING SOUTHWEST-NORTHEAST ORIENTED

FRONT ACROSS THE NORTHERN PORTIONS OF AL/MS TO THE SOUTHERN

APPALACHIANS. THIS FRONTAL ZONE WILL SERVE AS THE NORTHWARD

DEMARCATION OF TORNADO POTENTIAL...BUT COULD BECOME A QUASI-FOCUS

FOR TORNADO POTENTIAL /ASIDE FROM THE BROAD WARM SECTOR/ SHOULD

SUFFICIENT DESTABILIZATION OCCUR ON THE SOUTHERN FRINGE OF THE MORE

PERSISTENT/CONCENTRATED RAIN-COOLED AIR.

OVERALL...THE POTENTIAL WILL EXIST FOR LOW-TOPPED SUPERCELLS CAPABLE

OF TORNADOES THROUGHOUT THE PERIOD...ESPECIALLY ACROSS PORTIONS OF

AL/FL PANHANDLE/GA.

[andyhb]

MESOSCALE DISCUSSION 2129

NWS STORM PREDICTION CENTER NORMAN OK

0426 AM CDT MON SEP 05 2011

AREAS AFFECTED...EXTREME SERN LA...SERN AND ECNTRL MS...SRN AND

CNTRL AL...WRN GA AND THE FL PANHANDLE

CONCERNING...TORNADO WATCH 837...

VALID 050926Z - 051100Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 837 CONTINUES.

TORNADO WATCH 837 WILL NEED TO BE REPLACED BY ANOTHER TORNADO WATCH

BEFORE 11Z THAT WILL EXTEND FARTHER NORTH AND EAST THROUGH CNTRL AND

ERN AL AND POSSIBLY INTO EXTREME SWRN GA...REMAINING VALID THROUGH

AFTERNOON. IT APPEARS LOW LEVEL SHEAR/INSTABILITY PARAMETER SPACE

MAY BECOME MORE FAVORABLE FOR TORNADOES THAN PREVIOUS DAYS ACROSS A

PORTION OF CNTRL AND SRN AL INTO WRN GA. AREA IS BEING CONSIDERED

FOR A POSSIBLE UPGRADE TO MODERATE RISK.

TROPICAL DEPRESSION LEE OVER SERN LA IS BECOMING INFLUENCED BY A

HIGH AMPLITUDE UPPER TROUGH AMPLIFYING SEWD THROUGH THE GREAT LAKES

AND OH VALLEYS. AS A RESULT...LEE IS FORECAST TO EJECT IN A

GENERALLY NEWD DIRECTION WHILE GRADUALLY TRANSITIONING TO EXTRA

TROPICAL. SEE LATEST DISCUSSION FROM NHC FOR FURTHER INFORMATION.

SURFACE ANALYSIS SHOWS A COLD FRONT FROM WRN TN SWWD THROUGH NRN MS

INTO SERN TX. PRE-FRONTAL BOUNDARY EXTENDS FROM THE CENTER OF LEE

NEWD THROUGH E-CNTRL MS INTO N-CNTRL AL. FARTHER SOUTH A COASTAL

FRONT EXTENDS FROM THE CENTER OF LEE EWD INTO THE FL PANHANDLE. THE

COASTAL FRONT SHOULD LIFT SLOWLY NWD TODAY AS LEE EJECTS

NEWD...ALLOWING MID-UPPER 70S DEWPOINTS TO ADVECT FARTHER INTO THE

WARM SECTOR. MID-UPPER DRY AIR CONTINUES TO BE ENTRAINED INTO THE

CIRCULATION. AS HEATING OF THE MOIST BOUNDARY LAYER

COMMENCES...POTENTIAL WILL EXIST FOR 500-1000 J/KG MUCAPE IN

VICINITY OF THE COASTAL BOUNDARY DURING THE AFTERNOON WHICH SHOULD

BECOME CO-LOCATED WITH 50 KT LLJ AXIS EAST OF THE CYCLONE CENTER.

THIS SUGGESTS GREATEST TORNADO THREAT MAY EVOLVE ACROSS A PORTION OF

SRN AND CNTRL AL THROUGH SWRN AND W-CNTRL GA BY LATE MORNING INTO

THE AFTERNOON.

..DIAL.. 09/05/2011

[Stebo]

Nice cell/rotation NW of Lucedale MS currently. Tight couplet there G2G.

[NavarreDon]

Mention made about this in the GSP AFD. This would pertain to Extreme NE GA, Upstate SC, & the Western Piedmont (Gen. Charlotte area) of NC.

Here is a portion of the AFD:

A BIGGER THREAT INITIALLY MIGHT BE SEVERE THUNDERSTORMS/LOW

TOPPED MINI-SUPERCELLS MOVING IN FROM GEORGIA THIS AFTERNOON AND

EARLY THIS EVENING. AS IS THE CASE WITH MOST TROPICAL CYCLONE

REMNANTS...THERE WILL BE AN AREA WITH SUFFICIENT SHEAR AND LOW LCL

HEIGHT ON THE E AND NE PART OF THE SYSTEM TO FAVOR TORNADOES AND

WIND DAMAGE IF WE CAN GET ENOUGH INSTABILITY. IF FOR WHATEVER REASON

SOME BREAKS IN THE OVERCAST DEVELOP INTO NE GEORGIA AND THE UPSTATE

OF SC...WATCH OUT.

[Ian]

Mod risk Al/Ga. Big 15% torn area now.

[TheWeatherPimp]

MESOSCALE DISCUSSION 2131

NWS STORM PREDICTION CENTER NORMAN OK

1101 AM CDT MON SEP 05 2011

AREAS AFFECTED...SERN-EAST CENTRAL MS/SRN AND CENTRAL AL/FL

PANHANDLE/PARTS OF WRN AND CENTRAL GA

CONCERNING...TORNADO WATCH 838...

VALID 051601Z - 051630Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 838 CONTINUES.

A NEW TORNADO WATCH WILL BE COORDINATED SOON FOR PARTS OF WRN AND

CENTRAL GA...AS THE ONGOING TORNADO THREAT ACROSS VALID PARTS OF WW

838 DEVELOPS/EXPANDS ENEWD THIS AFTERNOON.

15Z MESOSCALE ANALYSIS AND SATELLITE/RADAR IMAGERY SHOWED THE

REMNANT CENTER OF LEE LOCATED OVER SERN MS...WITH A SECOND AREA OF

LOW PRESSURE OVER SWRN-W CENTRAL AL. THIS LATTER LOW WAS LOCATED

ALONG A BAROCLINIC ZONE WHICH EXTENDED NEWD FROM THE SERN LOW CENTER

THROUGH WRN TO NERN AL...INTO FAR NWRN GA TO ALONG THE TN/NC

BORDER...AND FARTHER NEWD INTO WRN VA. DIABATIC HEATING IS

SUPPORTING SUFFICIENT DESTABILIZATION INTO THE AFTERNOON FROM WW 838

INTO PARTS OF WRN/CENTRAL GA AND PARTS OF NWRN FL. AS THE SERN MS

LOW TRACKS NEWD TODAY...50 KT SLY LLJ WILL TRANSLATE EWD RESULTING

IN AN INCREASE IN LOW LEVEL SHEAR/SRH FOR AN ENHANCED TORNADO

THREAT.

MEANWHILE...EXTENSIVE CLOUDS N OF THE REMNANT LOW IN MUCH OF ERN MS

AND N OF THE BAROCLINIC ZONE INTO NRN AL WILL LIMIT THE SEVERE

WEATHER THREAT ACROSS THESE AREAS...AND AS SUCH AFFECTED COUNTIES

HAVE BEEN REMOVED FROM WW 838.

[Cheeznado]

The 15% here in north GA is overdone IMO, too many clouds. too little instability. Farther south perhaps where some heating is going on, but overall I think that this system is moving a bit too slowly with the dry intrusion not really punching in like in the really classic ex-TC tornado outbreaks. We shall see but so far this has been somewhat underwhelming tornado-wise.

[andyhb]

SEVERE WEATHER STATEMENT

NATIONAL WEATHER SERVICE PEACHTREE CITY GA

320 PM EDT MON SEP 5 2011

GAC057-051930-

/O.CON.KFFC.TO.W.0070.000000T0000Z-110905T1930Z/

CHEROKEE GA-

320 PM EDT MON SEP 5 2011

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 330 PM EDT FOR CHEROKEE

COUNTY...

AT 313 PM EDT...LOCAL LAW ENFORCEMENT REPORTED A TORNADO. THIS

TORNADO IS LOCATED NORTH OF LEBANON...MOVING NORTHEAST AT 30 MPH.

OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO

CANTON...BUFFINGTON...BALL GROUND...WALESKA AND REAVIS MOUNTAIN.

TROPICAL ENVIRONMENTS LIKE WE HAVE TODAY CAN PRODUCE TORNADOES THAT

DEVELOP RAPIDLY AND GIVE LITTLE TIME FOR WARNING. SUCH TORNADOES

ALSO FORM WITH LITTLE OR NO LIGHTNING ACTIVITY. TAKE PRECAUTIONS NOW

TO RESPOND QUICKLY IN THE EVENT A WARNING IS ISSUED OR A TORNADO IS

SPOTTED IN YOUR AREA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU SEE WIND DAMAGE...LARGE HAIL OR SIGNIFICANT FLOODING...WAIT

UNTIL AFTER THE STORM HAS PASSED...AND THEN CALL THE NATIONAL WEATHER

SERVICE TOLL FREE AT 1 8 6 6 7 6 3 4 4 6 6.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 800 PM EDT MONDAY EVENING FOR

NORTHWESTERN GEORGIA.

[phil882]

Mention made about this in the GSP AFD. This would pertain to Extreme NE GA, Upstate SC, & the Western Piedmont (Gen. Charlotte area) of NC.

Here is a portion of the AFD:

A BIGGER THREAT INITIALLY MIGHT BE SEVERE THUNDERSTORMS/LOW

TOPPED MINI-SUPERCELLS MOVING IN FROM GEORGIA THIS AFTERNOON AND

EARLY THIS EVENING. AS IS THE CASE WITH MOST TROPICAL CYCLONE

REMNANTS...THERE WILL BE AN AREA WITH SUFFICIENT SHEAR AND LOW LCL

HEIGHT ON THE E AND NE PART OF THE SYSTEM TO FAVOR TORNADOES AND

WIND DAMAGE IF WE CAN GET ENOUGH INSTABILITY. IF FOR WHATEVER REASON

SOME BREAKS IN THE OVERCAST DEVELOP INTO NE GEORGIA AND THE UPSTATE

OF SC...WATCH OUT.

Uh oh.

[Ian]

Quite a few active warnings now.

[andyhb]

Jesus...

FFC staff taking shelter. BMX taking over warning responsibilities.

[Ian]

Jesus...

Right over the radar

[TheWeatherPimp]

Reports are coming out of the Woodstock, Georgia area of a significant tornado touchdown. The Sheriff's Office is reporting over 100 houses either damage or destroyed.

[andyhb]

Reports are coming out of the Woodstock, Georgia area of a significant tornado touchdown. The Sheriff's Office is reporting over 100 houses either damage or destroyed.

[CandymanColumbusGA]

Reports are coming out of the Woodstock, Georgia area of a significant tornado touchdown. The Sheriff's Office is reporting over 100 houses either damage or destroyed.

Wow... Hadn't seen that one yet! I have relatives up that way. I'll try to get in contact with them and see what's going on.... On a side note: Had a tornado warning right over the station and had a nice wall cloud and a funnel, but no tornado.... It will be interesting to see how many tornadoes are confirmed in my area. Only reason I say this: My station cut-in for 20 mins COMBINED. The other station, about an hour each 3 different times...

[phil882]

Right over the radar

Warnings are starting to go up across SC/NC where there is a little more instability. As the surface low chugs to the NE, I think some of the more discrete cells will be able to tap into the higher bulk shear this evening and have more rotation. First it will be east Georgia, but should quickly spread into central SC and NC by 00z.

[SluggerWx]

From Twitter (DougTurnbull) For those that haven't heard, a tornado did damage Dixie Speedway in Woodstock. Main building okay, but some smaller ones hit.

using Tapatalk

[phil882]

Pair of hook echo's heading towards Charlotte Metro. low level shear might not be quite high enough near the surface to allow for tornado genesis, but with low LCL's its certainly not out of the question.

[tornadotony]

Incredible circulation in Stanly County.