Alert archive / Georgia / Mesoscale Discussions in 2011

Mesoscale Discussion 2134

September 5, 201115 counties in Alabama; 15 counties in Florida; 26 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Sep 5, 2011, 3:15 PM CDT for 15 counties in Alabama; 15 counties in Florida; 26 counties in Georgia. It was in force for 30 min.

The area

The outline as issued.

The facts

Issued
Sep 5, 2011, 3:15 PM CDT (20:15 UTC)
Expired
Sep 5, 2011, 3:45 PM CDT
In force
30 min
Issued by
the Storm Prediction Center
All 56 counties

Barbour County, AL, Bullock County, AL, Chambers County, AL, Coffee 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, Bay County, FL, Calhoun County, FL, Gadsden County, FL, Gulf County, FL, Holmes County, FL, Jackson County, FL, Jefferson County, FL, Lafayette County, FL, Leon County, FL, Liberty County, FL, Madison County, FL, Taylor County, FL, Wakulla County, FL, Walton County, FL, Washington County, FL, Baker County, GA, Ben Hill 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, Irwin County, GA, Lanier County, GA, Lee County, GA, Lowndes 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 8.3 hours before the alert went out and 86 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 2011-09-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2763 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 2011-09-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 223 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
2763 J/kg
Mixed-layer CIN
-7 J/kg
Mixed-layer LCL
465 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
223 m²/s²
0-3 km storm-relative helicity
266 m²/s²
Significant tornado parameter
2.6
Supercell composite
17.8

Open this sounding in Storm Lab

The text

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

521 
ACUS11 KWNS 052015
SWOMCD
SPC MCD 052015 
GAZ000-FLZ000-ALZ000-052045-

MESOSCALE DISCUSSION 2134
NWS STORM PREDICTION CENTER NORMAN OK
0315 PM CDT MON SEP 05 2011

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

CONCERNING...TORNADO WATCH 838...

VALID 052015Z - 052045Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 838 CONTINUES.

TORNADO WATCH 838 IS CURRENTLY SCHEDULED TO EXPIRE AT 21Z.  PARTS OF
THIS WATCH OVER ERN AL WILL LIKELY NEED TO BE REPLACED WITH A NEW
TORNADO WATCH...WHILE FARTHER TO THE SE OVER PARTS SERN AL...THE FL
PANHANDLE AND INTO SWRN GA...A SEVERE TSTM WATCH /#841/ HAS BEEN
ISSUED.

...ERN AL...
MID AFTERNOON TRENDS IN RADAR IMAGERY AND SURFACE OBSERVATIONS
SHOWED AN AREA OF LOW PRESSURE SHIFTING ENEWD INTO SOUTH CENTRAL AL
WITH STRONGEST LOW LEVEL FLOW/SHEAR EXTENDING FROM SERN AL INTO
CENTRAL/NRN GA.  GIVEN THESE FACTORS...A NEW TORNADO WATCH WILL
LIKELY BE NEEDED OVER PARTS OF ERN AL AS THE THREAT FOR TORNADOES
AND DAMAGING WINDS WILL PERSIST ALONG AND ENE OF THE TRACK OF THE
SURFACE LOW TOWARD NWRN GA.

...PARTS OF SERN AL...FL PANHANDLE INTO SWRN GA...
A DEEPER MIXED BOUNDARY LAYER AND WEAKER LOW LEVEL SHEAR IS
RESULTING IN A GREATER THREAT FOR DAMAGING WINDS...THAN A TORNADO
THREAT.  STRONG UNI-DIRECTIONAL /SLY/ WIND FIELDS SUPPORTS THIS
THREAT FOR DAMAGING WINDS...AS THE AIR MASS OVER THESE AREAS REMAINS
MODERATELY UNSTABLE AND SUFFICIENTLY SHEARED THROUGH A DEEP LAYER
FOR ORGANIZED LINE SEGMENTS.

..PETERS.. 09/05/2011

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

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

LAT...LON   31908488 31818304 30968301 30218323 29678305 29618336
            30038400 29778480 29688517 30488634 31008622 31558611
            32408629 32908605 33318530 31908488

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 4, 9:42 PM CDTTornado WatchSPCAutauga, Baldwin, Butler, Choctaw, Clarke, Conecuh and 16 more9 hr
Sep 4, 11:35 PM CDTMesoscale DiscussionSPCBaldwin, Choctaw, Clarke, Conecuh, Covington, Escambia and 6 more115 min
Sep 5, 4:26 AM CDTMesoscale DiscussionSPCAutauga, Baldwin, Barbour, Bibb, Bullock, Butler and 41 more94 min
Sep 5, 5:35 AM CDTTornado WatchSPCAutauga, Baldwin, Barbour, Bibb, Blount, Bullock and 50 more10 hr
Sep 5, 7:24 AM CDTMesoscale DiscussionSPCAutauga, Barbour, Bibb, Bullock, Butler, Calhoun and 20 more66 min
Sep 5, 11:01 AM CDTMesoscale DiscussionSPCAutauga, Baldwin, Barbour, Bibb, Blount, Bullock and 41 more29 min
Sep 5, 3:04 PM CDTSevere Thunderstorm WatchSPCCoffee, Dale, Geneva, Henry, Houston6 hr
Sep 5, 3:49 PM CDTTornado WatchSPCAutauga, Barbour, Bullock, Calhoun, Chambers, Chilton and 16 more4 hr
Sep 5, 6:37 PM CDTMesoscale DiscussionSPCBarbour, Bullock, Calhoun, Chambers, Clay, Cleburne and 9 more113 min
Sep 5, 5:24 PM CDTMesoscale DiscussionSPCAlachua, Baker, Columbia, Gilchrist, Hamilton, Levy and 1 more66 min
Sep 5, 11:10 AM CDTTornado WatchSPCBartow, Bibb, Butts, Carroll, Chattahoochee, Chattooga and 46 more4 hr
Sep 5, 12:23 PM CDTMesoscale DiscussionSPCBaldwin, Burke, Columbia, Elbert, Emanuel, Glascock and 17 more67 min
Sep 5, 2:05 PM CDTMesoscale DiscussionSPCBaldwin, Banks, Barrow, Bartow, Bibb, Bleckley and 75 more55 min
Sep 5, 2:42 PM CDTTornado WatchSPCBaldwin, Banks, Barrow, Bartow, Bibb, Bleckley and 81 more7 hr
Sep 5, 4:48 PM CDTMesoscale DiscussionSPCAppling, Bacon, Brantley, Bryan, Bulloch, Camden and 19 more87 min
Sep 5, 5:12 PM CDTSevere Thunderstorm WatchSPCBurke, Richmond4 hr

Nearby

Mesoscale Discussions in Georgia, 2011Mesoscale Discussions in Alabama, 2011Mesoscale Discussions in Florida, 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.