Alert archive / Alabama / Mesoscale Discussions in 2012

Mesoscale Discussion 337

March 23, 201216 counties in Alabama; Carroll County, Haralson County, Heard County, Georgia

The Storm Prediction Center issued this mesoscale discussion at Mar 23, 2012, 4:03 PM CDT for 16 counties in Alabama; Carroll County, Haralson County, Heard County, Georgia. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued
Mar 23, 2012, 4:03 PM CDT (21:03 UTC)
Expired
Mar 23, 2012, 5:30 PM CDT
In force
87 min
Issued by
the Storm Prediction Center

Counties Autauga County, AL, Calhoun County, AL, Chambers County, AL, Cherokee County, AL, Chilton County, AL, Clay County, AL, Cleburne County, AL, Coosa County, AL, Elmore County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Montgomery County, AL, Randolph County, AL, Talladega County, AL, Tallapoosa County, AL, Carroll County, GA, Haralson County, GA, Heard County, GA

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 9.1 hours before the alert went out and 82 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 12:00Z on 2012-03-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 490 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 12:00Z on 2012-03-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 176 square meters per square second.19395878Sfc1 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
490 J/kg
Mixed-layer CIN
-7 J/kg
Mixed-layer LCL
500 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
176 m²/s²
0-3 km storm-relative helicity
225 m²/s²
Significant tornado parameter
0.4
Supercell composite
3.1

Open this sounding in Storm Lab

The text

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

136 
ACUS11 KWNS 232104
SWOMCD
SPC MCD 232103
GAZ000-ALZ000-232230-

MESOSCALE DISCUSSION 0337
NWS STORM PREDICTION CENTER NORMAN OK
0403 PM CDT FRI MAR 23 2012

AREAS AFFECTED...EASTERN AL INTO FAR WESTERN GA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 232103Z - 232230Z

A SUPERCELL/BRIEF TORNADO THREAT MAY EXIST THROUGH LATE AFTERNOON
INTO EARLY/MID EVENING ESPECIALLY ACROSS EAST-CENTRAL PORTIONS OF
AL/PERHAPS FAR WESTERN GA. CURRENT EXPECTATIONS ARE FOR THE OVERALL
THREAT TO REMAIN MARGINAL/ISOLATED...BUT CONVECTIVE TRENDS WILL
CONTINUE TO BE MONITORED.

SHOWERS AND SOME TSTMS HAVE BEEN OCCURRING ACROSS OVER THE PAST FEW
HOURS ACROSS EASTERN AL/NORTHWEST GA WITHIN A ZONE OF DIFFERENTIAL
HEATING/LOW LEVEL CONFLUENCE. IN THE WAKE OF EARLY DAY CLOUD
COVER/SCATTERED PRECIPITATION...THE AIRMASS HAS BECOME MODERATELY
UNSTABLE AS SURFACE DEWPOINTS REMAIN IN THE MIDDLE/UPPER 60S F.
WHILE CONVERGENCE/FLOW JUST ABOVE THE SURFACE IS EXPECTED TO SLOWLY
ABATE INTO THIS EVENING...LATEST WSR-88D VWP DATA FROM MAXWELL AIR
FORCE BASE IS INDICATIVE OF 0-1 KM SRH AROUND 150 M2/S2 WHEN
ADJUSTED FOR THE WEAK SOUTH-SOUTHEASTERLY WINDS THAT CURRENTLY EXIST
ACROSS EAST-CENTRAL AL. THUS...A SUPERCELL/BRIEF TORNADO THREAT
CANNOT BE RULED OUT OVER THE NEXT FEW HOURS...ALTHOUGH THE OVERALL
THREAT SHOULD REMAIN RELATIVELY MARGINAL/ISOLATED.

..GUYER.. 03/23/2012

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

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

LAT...LON   31788681 32548713 34278556 33638492 32208547 31788681

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 23, 10:19 AM CDTMesoscale DiscussionSPCBarbour, Bullock, Coffee, Dale, Geneva, Henry and 2 more56 min

Nearby

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