Alert archive / Alabama / Mesoscale Discussions in 2012

Mesoscale Discussion 75

January 26, 201230 counties in Alabama; 5 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Jan 26, 2012, 9:34 AM CST for 30 counties in Alabama; 5 counties in Florida. It was in force for 86 min.

The area

The outline as issued.

The facts

Issued
Jan 26, 2012, 9:34 AM CST (15:34 UTC)
Expired
Jan 26, 2012, 11:00 AM CST
In force
86 min
Issued by
the Storm Prediction Center
All 35 counties

Autauga County, AL, Baldwin County, AL, Barbour County, AL, Bullock County, AL, Butler County, AL, Calhoun County, AL, Chambers County, AL, Chilton County, AL, Clay County, AL, Cleburne County, AL, Coffee County, AL, Conecuh County, AL, Coosa County, AL, Covington County, AL, Crenshaw County, AL, Dale County, AL, Dallas County, AL, Elmore County, AL, Escambia County, AL, Geneva County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Monroe County, AL, Montgomery County, AL, Pike County, AL, Randolph County, AL, Talladega County, AL, Tallapoosa County, AL, Wilcox County, AL, Escambia County, FL, Holmes County, FL, Okaloosa County, FL, Santa Rosa County, FL, Walton County, FL

The radar

The Eglin Afb radar (KEVX), 126 km from the middle of the area, began a volume at 15:34 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 watches that followed

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

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 3.6 hours before the alert went out and 202 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 2012-01-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 274 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 2012-01-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 126 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
274 J/kg
Mixed-layer CIN
-8 J/kg
Mixed-layer LCL
478 m above ground
0-6 km bulk shear
58 kt
0-1 km storm-relative helicity
126 m²/s²
0-3 km storm-relative helicity
127 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.0

Open this sounding in Storm Lab

The text

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

333 
ACUS11 KWNS 261534
SWOMCD
SPC MCD 261534 COR
ALZ000-FLZ000-261700-

MESOSCALE DISCUSSION 0075
NWS STORM PREDICTION CENTER NORMAN OK
0934 AM CST THU JAN 26 2012

AREAS AFFECTED...AL...WRN FL PNHDL

CONCERNING...TORNADO WATCH 17...

VALID 261534Z - 261700Z

CORRECTED SPELLING OF GADSDEN

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 17 CONTINUES.

AN ADDITIONAL WW PROBABLY WILL BE NEEDED ACROSS MUCH OF CENTRAL AND
SOUTHERN ALABAMA...AND PARTS OF THE FLORIDA PANHANDLE... TOWARD
17-18Z.

THICK CLOUD COVER IS SLOWING THE DESTABILIZATION OF THE BOUNDARY
AHEAD OF THE SQUALL LINE NOW ADVANCING ACROSS THE SOUTHERN
MISSISSIPPI/ALABAMA BORDER AREA.  AND...WITH LAPSE RATES ONLY WEAKLY
UNSTABLE THROUGH MUCH OF THE LOWER/MID TROPOSPHERE...CAPE SHOULD
REMAIN RATHER LOW...DESPITE THE PRESENCE OF SEASONABLY HIGH MOISTURE
CONTENT AIR.  HOWEVER...WITH TIME...A GRADUAL DESTABILIZATION WITH
FILTERED INSOLATION PROBABLY WILL BECOME SUFFICIENT TO SUPPORT
INTENSIFICATION OF THE ONGOING LINE...BOTH EASTWARD AND
NORTHEASTWARD...ACROSS MUCH OF CENTRAL AND SOUTHERN ALABAMA BY THE
18-21Z TIME FRAME.  THIS WILL BE AIDED BY FORCING ASSOCIATED WITH
CONSOLIDATING UPSTREAM SHORT WAVE TROUGHS WHICH WILL SLOWLY ADVANCE
THROUGH THE MID AND LOWER MISSISSIPPI VALLEY LATE THIS AFTERNOON AND
EVENING.

AN INITIAL CONVECTIVE OUTFLOW BOUNDARY ALONG AND SOUTHEAST OF THE
I-59 CORRIDOR PROBABLY WILL NOT RETREAT MUCH...BUT THE SEVERE THREAT
MAY INCREASE AS FAR NORTH AS THE BIRMINGHAM AREA...AND MORE LIKELY
THE ANNISTON/GADSDEN AREAS EASTWARD TO THE GEORGIA BORDER BY EARLY
AFTERNOON.  LOW-LEVEL FLOW FIELDS AND SHEAR ARE STILL SOMEWHAT
MODEST...BUT THEY ARE PROGGED TO STRENGTHEN ACROSS MUCH OF THE
WESTERN FLORIDA PANHANDLE AND CENTRAL/SOUTHERN ALABAMA DURING THE
NEXT FEW HOURS...CONTRIBUTING TO THE RISK FOR TORNADOES IN ISOLATED
SUPERCELLS.  OTHERWISE...LOCALLY DAMAGING WIND GUSTS WILL REMAIN
POSSIBLE...WITH THE LARGE HAIL THREAT MUCH MORE MARGINAL.

..KERR.. 01/26/2012

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

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

LAT...LON   30408806 31088794 31838777 32438763 32838681 33518633
            33878608 34048551 33138537 32088522 31408539 30208617
            29168629 28048770 28928809 29938807 30408806

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 26, 2:05 AM CSTMesoscale DiscussionSPCMobile, Washington2 hr
Jan 26, 4:18 AM CSTTornado WatchSPCBaldwin, Choctaw, Clarke, Conecuh, Escambia, Mobile and 3 more7 hr
Jan 26, 7:29 AM CSTMesoscale DiscussionSPCBaldwin, Choctaw, Clarke, Conecuh, Escambia, Mobile and 3 more91 min
Jan 26, 9:55 AM CSTTornado WatchSPCAutauga, Baldwin, Barbour, Bibb, Bullock, Butler and 34 more7 hr
Jan 26, 2:16 PM CSTMesoscale DiscussionSPCBarbour, Dale, Henry, Houston, Lee, Russell119 min
Jan 26, 5:35 PM CSTMesoscale DiscussionSPCColbert, Fayette, Franklin, Lamar, Lauderdale, Lawrence and 5 more55 min
Jan 26, 3:30 PM CSTTornado WatchSPCDixie, Franklin, Gadsden, Jefferson, Lafayette, Leon and 4 more6 hr

Nearby

Mesoscale Discussions in Alabama, 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; radar from the NEXRAD Level II archive.