Alert archive / Georgia / Mesoscale Discussions in 2012

Mesoscale Discussion 13

January 10, 201216 counties in Alabama; 5 counties in Florida; 17 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Jan 10, 2012, 11:39 PM CST for 16 counties in Alabama; 5 counties in Florida; 17 counties in Georgia. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jan 10, 2012, 11:39 PM CST (05:39 UTC)
Expired: Jan 11, 2012, 1:45 AM CST
In force: 2 hr
Issued by: the Storm Prediction Center

All 38 counties

Barbour County, AL, Bullock County, AL, Chambers County, AL, Coffee County, AL, Crenshaw County, AL, Dale County, AL, Elmore County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Lee County, AL, Macon County, AL, Montgomery County, AL, Pike County, AL, Russell County, AL, Tallapoosa County, AL, Calhoun County, FL, Gadsden County, FL, Holmes County, FL, Jackson County, FL, Washington County, FL, Baker County, GA, Calhoun County, GA, Chattahoochee County, GA, Clay County, GA, Decatur County, GA, Early County, GA, Harris County, GA, Marion County, GA, Miller County, GA, Muscogee County, GA, Quitman County, GA, Randolph County, GA, Seminole County, GA, Stewart County, GA, Terrell County, GA, Troup County, GA, Webster County, GA

The nearest sounding before it

Tallahassee Rgnl, FL (KTLH), launched 00:00Z, 5.7 hours before the alert went out and 180 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 13 J/kg
Mixed-layer CIN: -30 J/kg
Mixed-layer LCL: 654 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 70 m²/s²
0-3 km storm-relative helicity: 83 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.

802 
ACUS11 KWNS 110540
SWOMCD
SPC MCD 110539
GAZ000-FLZ000-ALZ000-110745-

MESOSCALE DISCUSSION 0013
NWS STORM PREDICTION CENTER NORMAN OK
1139 PM CST TUE JAN 10 2012

AREAS AFFECTED...PARTS OF SERN AL AND SWRN GA...AND THE FL PANHANDLE

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 110539Z - 110745Z

IT IS NOT YET CERTAIN THAT A SEVERE WEATHER WATCH WILL BE NEEDED
OVERNIGHT.  BUT TRENDS ARE BEING CLOSELY MONITORED FOR THE
DEVELOPMENT OF CONDITIONS THAT COULD BECOME MORE CONDUCIVE OF SEVERE
STORM FORMATION...INCLUDING SUPERCELLS CAPABLE OF PRODUCING
TORNADOES...PERHAPS BY 08-09Z.

AN UPPER TROUGH IS TAKING ON AN INCREASING NEGATIVE TILT ORIENTATION
ACROSS THE LOWER MISSISSIPPI VALLEY AND NORTH CENTRAL GULF OF
MEXICO...AS A SHORT WAVE IMPULSE PIVOTS AROUND A DEEPENING MID-LEVEL
LOW NOW SHIFTING FROM EASTERN TEXAS INTO NORTHERN LOUISIANA.  AS THE
MID-LEVEL LOW CONTINUES ACROSS THE LOWER MISSISSIPPI VALLEY
OVERNIGHT...MODELS INDICATE SUBSTANTIAL DEEPENING OF AN ASSOCIATED
SURFACE LOW WILL OCCUR ACROSS NORTHERN MISSISSIPPI INTO WESTERN
PORTIONS OF MIDDLE TENNESSEE.  LATEST RUC GUIDANCE SUGGESTS THAT
THIS WILL BE ACCOMPANIED BY STRENGTHENING SOUTHERLY 850 MB FLOW /ON
THE ORDER OF 40-50+ KT/ IN A CORRIDOR ACROSS THE FLORIDA PANHANDLE
INTO THE VICINITY OF THE CENTRAL/SOUTHERN ALABAMA AND GEORGIA BORDER
BY 08-10Z.  AND THIS MAY COINCIDE WITH AN INFLUX OF INCREASINGLY
MOIST BOUNDARY LAYER AIR OFF THE NORTHEAST GULF OF MEXICO...AS A
WARM FRONT LIFTS NORTHWARD ACROSS SOUTHEAST ALABAMA AND SOUTHERN
GEORGIA...AHEAD OF A COLD FRONT SURGING EAST OF THE LOWER
MISSISSIPPI VALLEY.

INCREASINGLY LARGE CLOCKWISE CURVED LOW-LEVEL HODOGRAPHS...AND THE
DEVELOPMENT OF AT LEAST WEAK SURFACE OR NEAR SURFACE BASED
INSTABILITY...IN THE PRESENCE OF STRONG DEEP LAYER SHEAR AND
INCREASINGLY DIFLUENT/DIVERGENT UPPER FLOW SEEM TO SUPPORT POTENTIAL
FOR AN INCREASING SEVERE THREAT OVERNIGHT.  THIS INCLUDES THE RISK
FOR DISCRETE SUPERCELLS CAPABLE OF PRODUCING TORNADOES...IN ADDITION
TO CONVECTION WITH POTENTIALLY DAMAGING WIND GUSTS AND HAIL.

..KERR.. 01/11/2012

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

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

LAT...LON   30808603 31808644 32318644 32878626 33278533 32998483
            31978432 31018422 30458455 30318551 30808603

Nearby

Mesoscale Discussions in Georgia, 2012 Mesoscale Discussions in Alabama, 2012 Mesoscale Discussions in Florida, 2012 Every 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.