Alert archive / Georgia / Mesoscale Discussions in 2012

Mesoscale Discussion 1121

June 11, 2012Geneva County, Henry County, Houston County, Alabama; 9 counties in Florida; 21 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Jun 11, 2012, 12:22 PM CDT for Geneva County, Henry County, Houston County, Alabama; 9 counties in Florida; 21 counties in Georgia. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued: Jun 11, 2012, 12:22 PM CDT (17:22 UTC)
Expired: Jun 11, 2012, 1:15 PM CDT
In force: 53 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 33 counties

Geneva County, AL, Henry County, AL, Houston County, AL, Calhoun County, FL, Gadsden County, FL, Holmes County, FL, Jackson County, FL, Jefferson County, FL, Leon County, FL, Liberty County, FL, Walton County, FL, Washington County, FL, Baker County, GA, Berrien County, GA, Brooks County, GA, Calhoun County, GA, Clay County, GA, Colquitt County, GA, Cook County, GA, Decatur County, GA, Dougherty County, GA, Early County, GA, Grady County, GA, Lanier County, GA, Lowndes County, GA, Miller County, GA, Mitchell County, GA, Randolph County, GA, Seminole County, GA, Terrell County, GA, Thomas County, GA, Tift County, GA, Worth County, GA

The radar

The Tallahassee radar (KTLH), 77 km from the middle of the area, began a volume at 17:23 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 5.4 hours before the alert went out and 77 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: 1839 J/kg
Mixed-layer CIN: -20 J/kg
Mixed-layer LCL: 713 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 145 m²/s²
0-3 km storm-relative helicity: 194 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.6

Open this sounding in Storm Lab

The text

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

919 
ACUS11 KWNS 111722
SWOMCD
SPC MCD 111722 
GAZ000-FLZ000-ALZ000-111815-

MESOSCALE DISCUSSION 1121
NWS STORM PREDICTION CENTER NORMAN OK
1222 PM CDT MON JUN 11 2012

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

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 111722Z - 111815Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...A THREAT FOR ISOLATED DMGG WIND GUSTS MAY DEVELOP THIS
AFTERNOON...BUT EXPECTED COVERAGE SHOULD PRECLUDE THE NEED FOR A WW.

DISCUSSION...VISIBLE SATELLITE AND RADAR LOOPS SHOW A MCV SLOWLY
TRACKING EWD ACROSS THE WRN FL PANHANDLE...WHILE A LARGER-SCALE
SHORTWAVE UPPER TROUGH PROGRESSES EWD ACROSS THE CNTRL GULF COAST.
CONVECTION HAS RECENTLY INTENSIFIED WITHIN THE PAST 1-2 HRS AS
STRONG HEATING HAS RESULTED IN MLCAPE VALUES EXCEEDING 2000 J/KG. AN
ADDITIONAL BAND OF PERSISTENT/REGENERATING TSTMS IS ORIENTED SW-NE
ALONG A WEAK BAROCLINIC ZONE. RICH BOUNDARY LAYER MOISTURE IS
CONTRIBUTING TO PW VALUES NEAR 1.7-2 INCHES /PER REGIONAL 12Z
SOUNDINGS/...AND WILL SUPPORT THE POTENTIAL FOR A FEW DMGG WIND
GUSTS VIA PRECIPITATION LOADING GIVEN THE DEGREE OF INSTABILITY
PRESENT AND STEEP LOW-LEVEL LAPSE RATES. 20-30 KTS OF DEEP-LAYER
SWLY FLOW WILL BE FAVORABLE FOR SOME ORGANIZED MULTICELL CLUSTERS
PROPAGATING ACROSS THE FL PANHANDLE AND ACROSS FAR SRN GA. CURRENT
EXPECTATION IS THAT THE DMGG WIND THREAT WILL REMAIN TOO ISOLATED TO
WARRANT WW ISSUANCE...BUT CONVECTIVE TRENDS WILL CONTINUE TO BE
MONITORED.

..ROGERS/MEAD.. 06/11/2012

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

ATTN...WFO...TAE...MOB...

LAT...LON   31068304 30318377 30068492 30498621 30928629 31638530
            31858449 31758406 31708336 31068304

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 11, 1:12 PM CDT	Mesoscale Discussion	SPC	Colbert, Franklin, Lauderdale, Limestone	93 min
Jun 11, 1:28 PM CDT	Severe Thunderstorm Watch	SPC	Colbert, Cullman, Franklin, Lauderdale, Lawrence	7 hr
Jun 11, 3:29 PM CDT	Mesoscale Discussion	SPC	Colbert, Franklin, Lauderdale	2 hr
Jun 11, 5:05 PM CDT	Mesoscale Discussion	SPC	Colbert, Franklin, Lauderdale, Lawrence	55 min
Jun 11, 5:17 PM CDT	Severe Thunderstorm Watch	SPC	Autauga, Bibb, Blount, Calhoun, Chambers, Chilton and 28 more	6 hr

Nearby

Mesoscale Discussions in Georgia, 2012 Mesoscale Discussions in Florida, 2012 Mesoscale Discussions in Alabama, 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; radar from the NEXRAD Level II archive.