Alert archive / Alabama / Mesoscale Discussions in 2011

Mesoscale Discussion 981

May 26, 20115 states

The Storm Prediction Center issued this mesoscale discussion at May 26, 2011, 12:22 PM CDT for 5 states. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued
May 26, 2011, 12:22 PM CDT (17:22 UTC)
Expired
May 26, 2011, 1:45 PM CDT
In force
83 min
Issued by
the Storm Prediction Center
All 73 counties

Autauga County, AL, Bibb County, AL, Blount County, AL, Bullock County, AL, Butler County, AL, Calhoun County, AL, Cherokee County, AL, Chilton County, AL, Choctaw County, AL, Clarke County, AL, Clay County, AL, Cleburne County, AL, Coosa County, AL, Cullman County, AL, Dallas County, AL, DeKalb County, AL, Elmore County, AL, Etowah County, AL, Greene County, AL, Hale County, AL, Jackson County, AL, Jefferson County, AL, Lowndes County, AL, Macon County, AL, Marengo County, AL, Marshall County, AL, Monroe County, AL, Montgomery County, AL, Perry County, AL, Randolph County, AL, Shelby County, AL, St. Clair County, AL, Sumter County, AL, Talladega County, AL, Tallapoosa County, AL, Tuscaloosa County, AL, Walker County, AL, Washington County, AL, Wilcox County, AL, Bartow County, GA, Catoosa County, GA, Chattooga County, GA, Dade County, GA, Fannin County, GA, Floyd County, GA, Gilmer County, GA, Gordon County, GA, Haralson County, GA, Murray County, GA, Polk County, GA, Walker County, GA, Whitfield County, GA, Clarke County, MS, Covington County, MS, Forrest County, MS, George County, MS, Greene County, MS, Jasper County, MS, Jones County, MS, Lamar County, MS, Lauderdale County, MS, Perry County, MS, Stone County, MS, Wayne County, MS, Cherokee County, NC, Graham County, NC, Bradley County, TN, Hamilton County, TN, Marion County, TN, McMinn County, TN, Meigs County, TN, Monroe County, TN, Polk County, TN

The radar

The Birmingham radar (KBMX), 41 km from the middle of the area, began a volume at 17:22 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, 5.4 hours before the alert went out and 42 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 2011-05-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2103 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 2011-05-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 165 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
2103 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
485 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
165 m²/s²
0-3 km storm-relative helicity
143 m²/s²
Significant tornado parameter
1.8
Supercell composite
7.7

Open this sounding in Storm Lab

The text

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

276 
ACUS11 KWNS 261723
SWOMCD
SPC MCD 261722
NCZ000-TNZ000-GAZ000-ALZ000-MSZ000-261845-

MESOSCALE DISCUSSION 0981
NWS STORM PREDICTION CENTER NORMAN OK
1222 PM CDT THU MAY 26 2011

AREAS AFFECTED...SERN TN...NWRN GA...MOST OF AL...SERN MS

CONCERNING...SEVERE THUNDERSTORM WATCH 379...

VALID 261722Z - 261845Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 379
CONTINUES.

IN THE WAKE OF A STRONG TO LOCALLY SEVERE TSTM CLUSTER PROGRESSING
ACROSS ERN TN...NUMEROUS TSTM CLUSTERS APPEAR TO BE FORMING SWWD TO
THE CNTRL GULF COAST. DESPITE THIS INCREASE IN TSTM COVERAGE...THE
NEED FOR A SEVERE TSTM WATCH S/SW OF WW 379 IS UNCLEAR ATTM WITH
SPORADIC THREATS OF MARGINALLY SEVERE DAMAGING WINDS AND HAIL.

17Z SUBJECTIVE SURFACE ANALYSIS PLACED A SW TO NE ORIENTED
TROUGH/CONFLUENCE AXIS FROM JUST 20 S HSV TO 30 S JAN. TSTMS HAVE
RECENTLY INCREASED ALONG AND AHEAD OF THIS AXIS IN ASSOCIATION WITH
A WEAK UPPER IMPULSE OVER SERN MS EMBEDDED WITHIN THE BASE OF THE
LARGER-SCALE TROUGH. EFFECTIVE SHEAR OF 25 TO 35 KT WILL LIKELY PEAK
IN THE NEAR-TERM WITH SHORT-TERM MODEL GUIDANCE SUGGESTING
LOW/MID-LEVEL FLOW WILL WEAKEN THROUGH THE AFTERNOON AS THE HEIGHT
GRADIENT RELAXES. DESPITE A MODERATELY UNSTABLE AIR MASS...OVERALL
SETUP SHOULD YIELD SPORADIC REPORTS OF DAMAGING WIND AND MARGINALLY
SEVERE HAIL. AN ADDITIONAL WW TO THE S MAY NOT BE NECESSARY UNLESS A
MORE ORGANIZED MCS/QLCS EVOLVES LATER THIS AFTERNOON.

..GRAMS.. 05/26/2011

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

ATTN...WFO...GSP...MRX...FFC...BMX...HUN...MOB...JAN...LIX...

LAT...LON   32488891 33668760 35048590 35748467 35698408 35418374
            35118385 33608534 32168553 31908571 31638701 31398785
            30608848 30388896 30608945 31218966 31958947 32488891

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 25, 8:33 PM CDTTornado WatchSPCBibb, Colbert, Cullman, Fayette, Franklin, Jefferson and 12 more7 hr
May 25, 10:27 PM CDTMesoscale DiscussionSPCColbert, Fayette, Franklin, Lamar, Lawrence, Marion and 2 more2 hr
May 26, 7:56 AM CDTMesoscale DiscussionSPCBibb, Blount, Calhoun, Cherokee, Chilton, Clay and 22 more94 min
May 26, 9:15 AM CDTSevere Thunderstorm WatchSPCAutauga, Barbour, Bibb, Blount, Bullock, Calhoun and 38 more9 hr
May 26, 10:39 AM CDTMesoscale DiscussionSPCBaldwin, Coffee, Conecuh, Covington, Dale, Escambia and 3 more96 min
May 26, 2:32 PM CDTMesoscale DiscussionSPCCherokee58 min
May 26, 2:44 PM CDTSevere Thunderstorm WatchSPCHenry6 hr
May 26, 3:36 PM CDTMesoscale DiscussionSPCCalhoun, Chambers, Cherokee, Clay, Cleburne, Etowah and 6 more84 min
May 26, 4:10 PM CDTSevere Thunderstorm WatchSPCElbert, Franklin, Habersham, Hart, Rabun, Stephens7 hr
May 26, 6:12 PM CDTMesoscale DiscussionSPCColumbia, Lincoln, McDuffie93 min
May 25, 7:22 PM CDTMesoscale DiscussionSPCAlcorn, Benton, Bolivar, Coahoma, DeSoto, Lafayette and 11 more53 min
May 25, 9:43 PM CDTTornado WatchSPCAdams, Attala, Carroll, Choctaw, Claiborne, Clay and 33 more5 hr
May 26, 2:05 AM CDTMesoscale DiscussionSPCAmite, Forrest, Greene, Hancock, Harrison, Jones and 8 more85 min
May 26, 5:18 PM CDTMesoscale DiscussionSPCGeorge, Hancock, Harrison, Jackson, Pearl River, Stone57 min
May 26, 12:42 PM CDTSevere Thunderstorm WatchSPCAlleghany, Ashe, Surry, Watauga, Wilkes, Yadkin11 hr
May 26, 2:09 PM CDTMesoscale DiscussionSPCClay, Fentress, Jackson, Overton, Pickett, Scott and 1 more96 min

Nearby

Mesoscale Discussions in Alabama, 2011Mesoscale Discussions in Georgia, 2011Mesoscale Discussions in Mississippi, 2011Every mesoscale discussion in 2011

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.