Alert archive / Georgia / Mesoscale Discussions in 2012

Mesoscale Discussion 2195

December 20, 20127 counties in Alabama; 13 counties in Florida; 19 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Dec 20, 2012, 1:31 PM CST for 7 counties in Alabama; 13 counties in Florida; 19 counties in Georgia. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued
Dec 20, 2012, 1:31 PM CST (19:31 UTC)
Expired
Dec 20, 2012, 2:30 PM CST
In force
59 min
Issued by
the Storm Prediction Center
All 39 counties

Barbour County, AL, Coffee County, AL, Dale County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Pike County, AL, Bay County, FL, Calhoun County, FL, Franklin County, FL, Gadsden County, FL, Gulf County, FL, Holmes County, FL, Jackson County, FL, Leon County, FL, Liberty County, FL, Okaloosa County, FL, Wakulla County, FL, Walton County, FL, Washington County, FL, Baker County, GA, Calhoun County, GA, Clay County, GA, Colquitt County, GA, Decatur County, GA, Dougherty County, GA, Early County, GA, Grady County, GA, Lee County, GA, Miller County, GA, Mitchell County, GA, Quitman County, GA, Randolph County, GA, Seminole County, GA, Terrell County, GA, Thomas County, GA, Tift County, GA, Turner County, GA, Worth County, GA

The nearest sounding before it

Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 7.5 hours before the alert went out and 125 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Tallahassee Rgnl, FL at 12:00Z on 2012-12-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Tallahassee Rgnl, FL at 12:00Z on 2012-12-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 200 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2063 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
200 m²/s²
0-3 km storm-relative helicity
202 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

803 
ACUS11 KWNS 201931
SWOMCD
SPC MCD 201931 
GAZ000-FLZ000-ALZ000-202030-

MESOSCALE DISCUSSION 2195
NWS STORM PREDICTION CENTER NORMAN OK
0131 PM CST THU DEC 20 2012

AREAS AFFECTED...FL PANHANDLE...SERN AL...SWRN GA

CONCERNING...TORNADO WATCH 690...

VALID 201931Z - 202030Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 690 CONTINUES.

SUMMARY...CONVECTION HAS GRADUALLY WEAKENED ACROSS MUCH OF NRN/CNTRL
PORTIONS OF TORNADO WATCH.  SEVERE THREAT APPEARS TO BE FOCUSING
NEAR THE COAST.

DISCUSSION...MAJORITY OF UPDRAFTS WITHIN CONVECTIVE CORRIDOR THAT
EXTENDS INLAND FROM THE NRN FL PANHANDLE INTO CNTRL GA APPEAR TO BE
GRADUALLY WEAKENING.  LIGHTNING OVER LAND HAS ALL BUT DISSIPATED
THOUGH PRE-FRONTAL SQUALL LINE REMAINS FAIRLY ORGANIZED AS IT
PROGRESSES INTO WCNTRL GA.  MORE BUOYANT AIRMASS CURRENTLY RESIDES
OVER THE NERN GOM AND 18Z SOUNDING FROM TLH EXHIBITS MEAGER
INSTABILITY AND POOR LAPSE RATES.  FOR THIS REASON IT APPEARS THE
GREATEST SEVERE RISK WILL BE NOTED WITH NEAR COASTAL SUPERCELL
STRUCTURES THAT MOVE OFF THE WARMER WATERS BEFORE WEAKENING.

WITH TIME ADDITIONAL WEAK DESTABILIZATION IS EXPECTED AHEAD OF CLOUD
CANOPY OVER NERN FL.  LOW LEVEL LAPSE RATES ARE SLOWLY STEEPENING
BUT UNTIL BOUNDARY LAYER MOISTURE INCREASES ACROSS THIS REGION THE
PROSPECT FOR ROBUST ORGANIZED SEVERE UPDRAFTS WILL BE DELAYED.

..DARROW.. 12/20/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...FFC...TAE...BMX...MOB...

LAT...LON   31878598 31888326 29618462 29598730 31878598

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 20, 4:08 AM CSTMesoscale DiscussionSPCChoctaw, Colbert, Fayette, Franklin, Greene, Lamar and 5 more67 min
Dec 20, 4:23 AM CSTTornado WatchSPCAutauga, Baldwin, Barbour, Bibb, Bullock, Butler and 34 more9 hr
Dec 20, 7:09 AM CSTMesoscale DiscussionSPCAutauga, Baldwin, Bibb, Butler, Chilton, Choctaw and 22 more96 min
Dec 20, 8:49 AM CSTMesoscale DiscussionSPCDale, Geneva, Henry, Houston56 min
Dec 20, 9:19 AM CSTTornado WatchSPCCoffee, Dale, Geneva, Henry, Houston9 hr
Dec 20, 9:56 AM CSTMesoscale DiscussionSPCAutauga, Baldwin, Bibb, Butler, Chambers, Chilton and 22 more64 min
Dec 20, 5:22 PM CSTMesoscale DiscussionSPCAlachua, Baker, Bradford, Clay, Columbia, Dixie and 7 more53 min
Dec 20, 11:24 AM CSTMesoscale DiscussionSPCBaldwin, Bibb, Bleckley, Butts, Chattahoochee, Coweta and 36 more66 min

Nearby

Mesoscale Discussions in Georgia, 2012Mesoscale Discussions in Florida, 2012Mesoscale Discussions in Alabama, 2012Every mesoscale discussion in 2012

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive.