Alert archive / Georgia / Mesoscale Discussions in 2011

Mesoscale Discussion 296

March 27, 201110 counties in Alabama; 25 counties in Florida; 40 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Mar 27, 2011, 6:24 PM CDT for 10 counties in Alabama; 25 counties in Florida; 40 counties in Georgia. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Mar 27, 2011, 6:24 PM CDT (23:24 UTC)
Expired
Mar 27, 2011, 8:30 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 75 counties

Baldwin County, AL, Coffee County, AL, Conecuh County, AL, Covington County, AL, Dale County, AL, Escambia County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Washington County, AL, Baker County, FL, Bay County, FL, Calhoun County, FL, Columbia County, FL, Escambia County, FL, Gadsden County, FL, Gilchrist County, FL, Gulf County, FL, Hamilton County, FL, Holmes County, FL, Jackson County, FL, Jefferson County, FL, Lafayette County, FL, Leon County, FL, Liberty County, FL, Madison County, FL, Nassau County, FL, Okaloosa County, FL, Santa Rosa County, FL, Suwannee County, FL, Taylor County, FL, Union County, FL, Wakulla County, FL, Walton County, FL, Washington County, FL, Appling County, GA, Atkinson County, GA, Bacon County, GA, Baker County, GA, Ben Hill County, GA, Berrien County, GA, Brantley County, GA, Brooks County, GA, Calhoun County, GA, Camden County, GA, Charlton County, GA, Clay County, GA, Clinch County, GA, Coffee County, GA, Colquitt County, GA, Cook County, GA, Decatur County, GA, Dougherty County, GA, Early County, GA, Echols County, GA, Glynn County, GA, Grady County, GA, Irwin County, GA, Lanier County, GA, Lee County, GA, Long County, GA, Lowndes County, GA, McIntosh County, GA, Miller County, GA, Mitchell County, GA, Pierce County, GA, Randolph County, GA, Seminole County, GA, Terrell County, GA, Thomas County, GA, Tift County, GA, Turner County, GA, Ware County, GA, Wayne County, GA, Worth County, GA

The radar

The Tallahassee radar (KTLH), 37 km from the middle of the area, began a volume at 23:28 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, 11.4 hours before the alert went out and 39 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 2011-03-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1068 joules per kilogram.LCLLFCEL10008507005003002001001 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 2011-03-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 174 square meters per square second.1939587897Sfc1 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
1068 J/kg
Mixed-layer CIN
-21 J/kg
Mixed-layer LCL
620 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
174 m²/s²
0-3 km storm-relative helicity
150 m²/s²
Significant tornado parameter
1.1
Supercell composite
6.0

Open this sounding in Storm Lab

The text

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

866 
ACUS11 KWNS 272324
SWOMCD
SPC MCD 272324 
GAZ000-FLZ000-ALZ000-280130-

MESOSCALE DISCUSSION 0296
NWS STORM PREDICTION CENTER NORMAN OK
0624 PM CDT SUN MAR 27 2011

AREAS AFFECTED...EXTREME SRN PORTIONS GA/AL...EXTREME NRN FL...FL
PANHANDLE.

CONCERNING...SEVERE THUNDERSTORM WATCH 69...

VALID 272324Z - 280130Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 69
CONTINUES.

BAND OF CONVECTION IS EXPECTED TO CONTINUE MOVING SLOWLY SEWD ACROSS
ERN PORTIONS WW...WHILE A FEW EMBEDDED SUPERCELLS PRODUCING LARGE
HAIL WILL MOVE ESEWD.  WW MAY BE CLEARED N OF GA PORTION WHERE
GREATER TSTM COVERAGE HAS MORE STRONGLY STABILIZED BOUNDARY LAYER. 
S-CENTRAL AL PORTIONS WW...ADJACENT TO FL BORDER...SHOULD BE
MAINTAINED BECAUSE...
1. AIR MASS THERE HAS NOT BEEN SUBSTANTIALLY STABILIZED BY PRIOR
CONVECTION...WITH 1000-1500 J/KG MLCAPE EVIDENT IN MODIFIED RUC
SOUNDINGS S OF FRONT...AND
2. CONVECTION INCREASING IN COVERAGE N OF MOB DURING PAST HOUR MAY
MOVE IN AND NEAR WW AREA BEFORE SCHEDULED 03Z EXPIRATION.

SFC MESOANALYSIS SHOWS WAVY COLD FRONT...WITH A COUPLE OF
WEAK/ATTACHED MESOLOWS...FROM MIDDLE PORTIONS GA COAST WWD TO NEAR
TOI...TO JUST N GZH...TO NEAR MCB.  WITH FLOW ALOFT BEING NEARLY
PARALLEL TO THIS BOUNDARY...AND NO SUBSTANTIAL PERTURBATIONS BEHIND
WEAK TROUGH PASSING OVER SERN GA...FRONT SHOULD DRIFT SLOWLY SWD
ACROSS SERN GA WHILE BECOMING QUASISTATIONARY ELSEWHERE.  LARGE HAIL
WILL REMAIN DOMINANT SVR THREAT WITH THIS ACTIVITY...MUCH OF WHICH
IS MOVING ATOP SHALLOW OUTFLOW AIR LEFT BY PRIOR CONVECTION. 
HOWEVER...MOST INTENSE CONVECTION MAY PRODUCE A FEW DAMAGING GUSTS
AS WELL AS IT CROSSES AREAS ON EITHER SIDE OF NRN BORDER OF FL. 
AFTER 00Z...COMBINATION OF POSTFRONTAL CAA AND DIABATIC COOLING WILL
REINFORCE STATIC STABILITY OVER S-CENTRAL/SERN GA...AND FROM N-S
ACROSS SRN AL.  MEANWHILE...AVAILABLE BUOYANCY AT AND JUST ABOVE
SFC...AMIDST 45-55 KT EFFECTIVE SHEAR MAGNITUDES...SHOULD SUPPORT
POTENTIAL FOR HAIL-PRODUCING SUPERCELLS.

..EDWARDS.. 03/27/2011

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

ATTN...WFO...CHS...JAX...FFC...TAE...BMX...MOB...

LAT...LON   30688146 30318185 29768261 29508341 29658343 29758358
            29978376 30098407 29588500 29708522 29688539 29908539
            30238592 30388653 30328721 30258772 30678819 31448843
            31588711 31848473 31798106 30688146

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 26, 7:47 PM CDTTornado WatchSPCBibb, Blount, Calhoun, Chambers, Cherokee, Chilton and 17 more7 hr
Mar 26, 11:21 PM CDTMesoscale DiscussionSPCBibb, Blount, Calhoun, Chambers, Cherokee, Chilton and 17 more54 min
Mar 27, 7:33 AM CDTMesoscale DiscussionSPCAutauga, Bibb, Chambers, Chilton, Clay, Coosa and 16 more117 min
Mar 27, 8:55 AM CDTSevere Thunderstorm WatchSPCAutauga, Barbour, Bullock, Butler, Chambers, Chilton and 17 more7 hr
Mar 27, 10:51 AM CDTMesoscale DiscussionSPCBarbour, Coffee, Covington, Crenshaw, Dale, Geneva and 3 more84 min
Mar 27, 2:49 PM CDTMesoscale DiscussionSPCBaldwin, Coffee, Covington, Dale, Geneva, Henry and 1 more56 min
Mar 27, 3:27 PM CDTSevere Thunderstorm WatchSPCCoffee, Covington, Dale, Escambia, Geneva, Henry and 1 more5 hr
Mar 26, 7:55 PM CDTMesoscale DiscussionSPCBanks, Barrow, Bartow, Catoosa, Chattooga, Cherokee and 36 more95 min
Mar 26, 8:19 PM CDTSevere Thunderstorm WatchSPCBanks, Barrow, Bartow, Burke, Catoosa, Chattooga and 39 more8 hr
Mar 26, 10:10 PM CDTMesoscale DiscussionSPCBryan, Bulloch, Candler, Chatham, Effingham, Evans and 3 more65 min
Mar 26, 11:43 PM CDTMesoscale DiscussionSPCBanks, Barrow, Bartow, Burke, Catoosa, Chattooga and 38 more62 min
Mar 27, 2:03 AM CDTMesoscale DiscussionSPCAppling, Atkinson, Bacon, Ben Hill, Bibb, Bleckley and 40 more57 min
Mar 27, 2:25 AM CDTTornado WatchSPCAppling, Baldwin, Bibb, Bleckley, Bryan, Bulloch and 46 more3 hr

Nearby

Mesoscale Discussions in Georgia, 2011Mesoscale Discussions in Florida, 2011Mesoscale Discussions in Alabama, 2011Every mesoscale discussion in 2011

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.