Alert archive / Alabama / Mesoscale Discussions in 2012

Mesoscale Discussion 59

January 23, 20125 states

The Storm Prediction Center issued this mesoscale discussion at Jan 23, 2012, 6:38 AM CST for 5 states. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued
Jan 23, 2012, 6:38 AM CST (12:38 UTC)
Expired
Jan 23, 2012, 8:15 AM CST
In force
97 min
Issued by
the Storm Prediction Center
All 65 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, Clarke 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, Lee County, AL, Lowndes County, AL, Macon County, AL, Mobile County, AL, Monroe County, AL, Montgomery County, AL, Pike County, AL, Randolph County, AL, Russell County, AL, Talladega County, AL, Tallapoosa County, AL, Washington County, AL, Wilcox County, AL, Escambia County, FL, Santa Rosa County, FL, Carroll County, GA, Coweta County, GA, Douglas County, GA, Floyd County, GA, Haralson County, GA, Harris County, GA, Heard County, GA, Meriwether County, GA, Muscogee County, GA, Paulding County, GA, Polk County, GA, Quitman County, GA, Troup County, GA, Jefferson Parish, LA, Lafourche Parish, LA, Orleans Parish, LA, Saint Charles Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Tammany Parish, LA, Terrebonne Parish, LA, Forrest County, MS, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Pearl River County, MS, Perry County, MS, Stone County, MS

The radar

The Mobile radar (KMOB), 63 km from the middle of the area, began a volume at 12:39 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

Slidell Radar S, LA (KSIL), launched 12:00Z, 0.6 hours before the alert went out and 193 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, Slidell Radar S, LA at 12:00Z on 2012-01-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1319 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, Slidell Radar S, LA at 12:00Z on 2012-01-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 179 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
1319 J/kg
Mixed-layer CIN
-7 J/kg
Mixed-layer LCL
563 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
179 m²/s²
0-3 km storm-relative helicity
134 m²/s²
Significant tornado parameter
1.1
Supercell composite
5.9

Open this sounding in Storm Lab

The text

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

691 
ACUS11 KWNS 231239
SWOMCD
SPC MCD 231238
GAZ000-ALZ000-FLZ000-MSZ000-LAZ000-231415-

MESOSCALE DISCUSSION 0059
NWS STORM PREDICTION CENTER NORMAN OK
0638 AM CST MON JAN 23 2012

AREAS AFFECTED...PORTIONS ERN/SRN AL...WRN GA...SERN MS...SERN LA.

CONCERNING...TORNADO WATCH 11...

VALID 231238Z - 231415Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 11 CONTINUES.

ALTHOUGH MOST FAVORABLE PORTION OF WARM SECTOR IS SHRINKING OVER
E-CENTRAL THROUGH SWRN AL...TORNADO THREAT CONTINUES ALONG AND W OF
WARM FRONT...AND ALONG AND E OF MAIN TSTM BAND.  WW MAY BE CLEARED
BEHIND THAT BAND.  AREAS OF SRN/ERN AL AND PERHAPS WRN GA AHEAD OF
PRESENT WW WILL BE MONITORED FOR POSSIBILITY OF ADDITIONAL WW
ISSUANCE.

AS OF 12Z...WARM FRONT WAS DRAWN FROM FL PANHANDLE BETWEEN
CEW-MAI...NWD ACROSS ERN AL JUST W OF DHN-AUO LINE.  THIS BOUNDARY
MAY REACH GA BORDER REGION BEFORE BEING OVERTAKEN BY PRIMARY
CONVECTIVE BAND...WHICH WAS EVIDENT AT 12Z FROM NEAR ANB SWWD ACROSS
SWRN MS TO NEAR PTN IN LA.  CORRIDOR OF 250-800 J/KG MLCAPE REMAINS
OVER WARM SECTOR FROM E-CENTRAL AL SWWD ACROSS SERN LA.  50-60 KT
EFFECTIVE SHEAR MAGNITUDES AND 400-700 J/KG EFFECTIVE SRH REMAIN
COMMON IN AL WARM SECTOR IN SUPPORT OF SUPERCELL POTENTIAL...AND
SIMILAR VALUES SHOULD BE MAINTAINED THROUGH AT LEAST 15Z AHEAD OF
MAIN BAND.

LOW-LEVEL SRH...DEEP-LAYER SHEAR AND LOW-LEVEL CONVERGENCE EACH
WEAKEN CONSIDERABLY FROM NEAR MS/AL BORDER SWWD BECAUSE OF
RELATIVELY VEERED SFC FLOW.  HOWEVER...AS CONFLUENCE LINE CONTINUES
MOVING INTO FAVORABLY MOIST AIR MASS ALONG MS/AL GULF
COAST...CONDITIONAL THREAT WILL LINGER FOR SVR IN THAT AREA...MAINLY
IN FORM OF DAMAGING GUSTS.

..EDWARDS.. 01/23/2012

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

ATTN...WFO...FFC...TAE...BMX...MOB...JAN...LIX...LCH...

LAT...LON   30798991 33048661 34518511 34068473 32898463 31738501
            30538686 30318847 30358911 29928934 29239038 29299098
            29609132 30798991

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 22, 9:47 PM CSTMesoscale DiscussionSPCColbert, Franklin, Lamar, Lauderdale, Marion58 min
Jan 22, 10:59 PM CSTTornado WatchSPCBlount, Colbert, Cullman, DeKalb, Fayette, Franklin and 17 more7 hr
Jan 23, 1:25 AM CSTMesoscale DiscussionSPCAutauga, Bibb, Blount, Calhoun, Cherokee, Chilton and 31 more2 hr
Jan 23, 2:44 AM CSTTornado WatchSPCAutauga, Barbour, Bibb, Blount, Bullock, Butler and 37 more9 hr
Jan 23, 4:02 AM CSTMesoscale DiscussionSPCAutauga, Bibb, Blount, Butler, Calhoun, Chambers and 32 more118 min
Jan 23, 11:30 AM CSTMesoscale DiscussionSPCBarbour, Bullock, Coffee, Crenshaw, Pike, Russell2 hr
Jan 23, 7:49 AM CSTTornado WatchSPCBibb, Carroll, Chattahoochee, Coweta, Crawford, Crisp and 24 more5 hr
Jan 22, 7:59 PM CSTMesoscale DiscussionSPCBienville, Bossier, Caddo, Claiborne, De Soto, Jackson and 6 more91 min
Jan 22, 8:37 PM CSTMesoscale DiscussionSPCBolivar, Coahoma, DeSoto, Panola, Quitman, Sunflower and 4 more83 min

Nearby

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