Alert archive / Georgia / Mesoscale Discussions in 2007

Mesoscale Discussion 2001

September 21, 200720 counties in Alabama; 15 counties in Florida; 43 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Sep 21, 2007, 4:37 PM CDT for 20 counties in Alabama; 15 counties in Florida; 43 counties in Georgia. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued
Sep 21, 2007, 4:37 PM CDT (21:37 UTC)
Expired
Sep 21, 2007, 5:30 PM CDT
In force
53 min
Issued by
the Storm Prediction Center
All 78 counties

Barbour County, AL, Bullock County, AL, Butler County, AL, Coffee County, AL, Conecuh County, AL, Covington County, AL, Crenshaw County, AL, Dale County, AL, Elmore County, AL, Escambia County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Monroe County, AL, Montgomery County, AL, Pike County, AL, Russell County, AL, Bay County, FL, Calhoun County, FL, Escambia County, FL, Gadsden County, FL, Gulf County, FL, Holmes County, FL, Jackson County, FL, Jefferson County, FL, Leon County, FL, Liberty County, FL, Okaloosa County, FL, Santa Rosa County, FL, Wakulla County, FL, Walton County, FL, Washington County, FL, Baker County, GA, Bleckley County, GA, Calhoun County, GA, Chattahoochee County, GA, Clay County, GA, Colquitt County, GA, Cook County, GA, Crawford County, GA, Crisp County, GA, Decatur County, GA, Dodge County, GA, Dooly County, GA, Dougherty County, GA, Early County, GA, Grady County, GA, Harris County, GA, Houston County, GA, Irwin County, GA, Lee County, GA, Macon County, GA, Marion County, GA, Miller County, GA, Mitchell County, GA, Muscogee County, GA, Peach County, GA, Pulaski County, GA, Quitman County, GA, Randolph County, GA, Schley County, GA, Seminole County, GA, Stewart County, GA, Sumter County, GA, Talbot County, GA, Taylor County, GA, Terrell County, GA, Thomas County, GA, Tift County, GA, Turner County, GA, Twiggs County, GA, Upson County, GA, Webster County, GA, Wilcox 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, 9.6 hours before the alert went out and 151 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 2007-09-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 399 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 2007-09-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 31 square meters per square second.1939Sfc1 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
399 J/kg
Mixed-layer CIN
-15 J/kg
Mixed-layer LCL
507 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
31 m²/s²
0-3 km storm-relative helicity
94 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.6

Open this sounding in Storm Lab

The text

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

000 
ACUS11 KWNS 212137
SWOMCD
SPC MCD 212137 
GAZ000-FLZ000-ALZ000-212230-

MESOSCALE DISCUSSION 2001
NWS STORM PREDICTION CENTER NORMAN OK
0437 PM CDT FRI SEP 21 2007

AREAS AFFECTED...FL PANHANDLE...SRN AL AND SWRN GA

CONCERNING...SEVERE POTENTIAL...WATCH NEEDED SOON 

VALID 212137Z - 212230Z

ENVIRONMENTAL CONDITIONS HAVE BECOME FAVORABLE FOR SEVERE STORMS AND
A WATCH ISSUANCE WILL BE COORDINATED BETWEEN THE SPC AND THE
AFFECTED LOCAL NATIONAL WEATHER SERVICE OFFICES SHORTLY.

PORTIONS OF SWRN GA..SRN AL AND THE FL PANHANDLE ARE BEING MONITORED
FOR A POSSIBLE WW.

TROPICAL DEPRESSION IN THE EXTREME NRN GULF WSW OF PFN IS RESULTING
IN STRONG LOW LEVEL SHEAR ACROSS THE AREA. CONVECTION HAS RECENTLY
STRENGTHENED ON A CONFLUENT BAND LOCATED IN GA FROM NEAR CSG TO 40 S
OF MCN AND ALSO ALONG A NEWLY DEVELOPED BAND IN THE FL PANHANDLE
FROM NEAR CEW TO NEAR MAI. GIVEN THE RECENT INCREASE IN UPDRAFT
STRENGTH...COMBINED WITH THE EXPECTED STRONG LOW/MID LEVEL SHEAR AND
VERY MOIST BOUNDARY LAYER.

..IMY.. 09/21/2007

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

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

30278776 31578753 32528648 32948527 33018420 32628329
32108302 31078343 30138401 29768512

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 21, 4:58 PM CDTTornado WatchSPCBarbour, Bullock, Chambers, Coffee, Covington, Crenshaw and 11 more7 hr
Sep 20, 9:56 PM CDTMesoscale DiscussionSPCAlachua, Baker, Bradford, Citrus, Clay, Columbia and 13 more94 min
Sep 20, 10:19 PM CDTTornado WatchSPCAlachua, Bradford, Columbia, Dixie, Gilchrist, Hamilton and 12 more7 hr
Sep 21, 1:35 AM CDTMesoscale DiscussionSPCAlachua, Baker, Bradford, Columbia, Dixie, Franklin and 13 more115 min
Sep 21, 10:45 AM CDTMesoscale DiscussionSPCBay, Calhoun, Franklin, Gulf, Liberty, Wakulla and 1 more60 min

Nearby

Mesoscale Discussions in Georgia, 2007Mesoscale Discussions in Alabama, 2007Mesoscale Discussions in Florida, 2007Every mesoscale discussion in 2007

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.