Alert archive / Alabama / Mesoscale Discussions in 2012

Mesoscale Discussion 2013

October 1, 201226 counties in Alabama; 7 counties in Florida; 11 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Oct 1, 2012, 5:51 AM CDT for 26 counties in Alabama; 7 counties in Florida; 11 counties in Georgia. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued
Oct 1, 2012, 5:51 AM CDT (10:51 UTC)
Expired
Oct 1, 2012, 7:45 AM CDT
In force
114 min
Issued by
the Storm Prediction Center
Chance of a watch
40%
All 44 counties

Barbour County, AL, Bullock County, AL, Calhoun County, AL, Chambers County, AL, Clay County, AL, Cleburne County, AL, Coffee County, AL, Coosa County, AL, Covington County, AL, Crenshaw County, AL, Dale County, AL, Elmore County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Jefferson County, AL, Lee County, AL, Macon County, AL, Montgomery County, AL, Pike County, AL, Randolph County, AL, Russell County, AL, Shelby County, AL, St. Clair County, AL, Talladega County, AL, Tallapoosa County, AL, Bay County, FL, Calhoun County, FL, Holmes County, FL, Jackson County, FL, Okaloosa County, FL, Walton County, FL, Washington County, FL, Carroll County, GA, Chattahoochee County, GA, Clay County, GA, Coweta County, GA, Harris County, GA, Heard County, GA, Meriwether County, GA, Muscogee County, GA, Quitman County, GA, Stewart County, GA, Troup County, GA

The nearest sounding before it

Birmingham, AL (KBMX), launched 00:00Z, 10.9 hours before the alert went out and 163 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, Birmingham, AL at 00:00Z on 2012-10-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 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, Birmingham, AL at 00:00Z on 2012-10-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 159 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
1 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
569 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
159 m²/s²
0-3 km storm-relative helicity
179 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.

317 
ACUS11 KWNS 011052
SWOMCD
SPC MCD 011051
GAZ000-FLZ000-ALZ000-011245-

MESOSCALE DISCUSSION 2013
NWS STORM PREDICTION CENTER NORMAN OK
0551 AM CDT MON OCT 01 2012

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

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 011051Z - 011245Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...A MARGINAL SITUATION FOR BRIEF WEAK TORNADOES EXISTS BUT
THE NEED FOR A WATCH IS UNCLEAR.

DISCUSSION...SURFACE ANALYSIS CONTINUES TO SHOW A GRADUAL INCREASE
IN LOW LEVEL THETA-E FROM THE WRN FL PANHANDLE INTO ERN AL NWD TO A
DIFFUSE WARM FRONT FROM NERN AL INTO NWRN GA. INSTABILITY REMAINS
WEAK WITH LITTLE LIGHTNING ACTIVITY...BUT DEWPOINTS IN THE LOWER 70S
ARE HELPING TO MAXIMIZE LOW LEVEL BUOYANCY.

VWPS INDICATE SHEAR IS SUFFICIENT FOR A FEW ROTATION STORMS. RECENT
RADAR TRENDS HAVE SHOWN BRIEF AREAS OF WEAK ROTATION AT TIMES...BUT
OBSERVED VELOCITIES HAVE NOT BEEN MUCH STRONGER THAN THE AMBIENT
FLOW JUST OFF THE SURFACE.

LITTLE OVERALL CHANGE IN THE ENVIRONMENT IS EXPECTED THROUGH MORNING
AS THE SYSTEM PROGRESSES SLOWLY EWD. SMALL AMOUNTS OF HEATING FROM
SWRN GA INTO NRN FL WHICH MAY AID STORMS LATER THIS MORNING.

..JEWELL/THOMPSON.. 10/01/2012

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

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

LAT...LON   30158701 31078678 32148660 32798656 33258667 33648698
            33968692 33988618 33898547 33618493 33258460 32768464
            31688484 30808502 30178516 29908539 29938570 30248617
            30298661 30158701

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 30, 9:48 PM CDTMesoscale DiscussionSPCBaldwin, Choctaw, Clarke, Conecuh, Escambia, Mobile and 3 more87 min
Oct 1, 1:45 AM CDTMesoscale DiscussionSPCBaldwin, Coffee, Conecuh, Covington, Dale, Escambia and 5 more2 hr
Oct 1, 12:52 PM CDTMesoscale DiscussionSPCBarbour, Blount, Calhoun, Chambers, Cherokee, Clay and 13 more53 min
Oct 1, 1:16 PM CDTTornado WatchSPCBlount, Bullock, Calhoun, Chambers, Cherokee, Clay and 19 more7 hr
Oct 1, 3:00 PM CDTMesoscale DiscussionSPCBlount, Calhoun, Chambers, Cherokee, Clay, Cleburne and 12 more2 hr
Oct 1, 5:40 PM CDTMesoscale DiscussionSPCChambers, Cherokee, Cleburne, Lee, Randolph95 min

Nearby

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