Alert archive / Alabama / Mesoscale Discussions in 2011
Mesoscale Discussion 977
The Storm Prediction Center issued this mesoscale discussion at May 26, 2011, 7:56 AM CDT for 4 states. It was in force for 94 min.
The area
The outline as issued.
The facts
- Issued
- May 26, 2011, 7:56 AM CDT (12:56 UTC)
- Expired
- May 26, 2011, 9:30 AM CDT
- In force
- 94 min
- Issued by
- the Storm Prediction Center
All 51 counties
Bibb County, AL, Blount County, AL, Calhoun County, AL, Cherokee County, AL, Chilton County, AL, Clay County, AL, Cleburne County, AL, Coosa County, AL, Cullman County, AL, DeKalb County, AL, Etowah County, AL, Fayette County, AL, Jackson County, AL, Jefferson County, AL, Lamar County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marion County, AL, Marshall County, AL, Morgan County, AL, Pickens County, AL, Shelby County, AL, St. Clair County, AL, Talladega County, AL, Tuscaloosa County, AL, Walker County, AL, Winston County, AL, Catoosa County, GA, Chattooga County, GA, Dade County, GA, Floyd County, GA, Gordon County, GA, Murray County, GA, Walker County, GA, Whitfield County, GA, Lowndes County, MS, Bledsoe County, TN, Bradley County, TN, Franklin County, TN, Grundy County, TN, Hamilton County, TN, Lincoln County, TN, Marion County, TN, McMinn County, TN, Meigs County, TN, Moore County, TN, Polk County, TN, Rhea County, TN, Sequatchie County, TN, Van Buren County, TN
The radar
The Northeast Alabama radar (KHTX), 100 km from the middle of the area, began a volume at 12:56 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, 0.9 hours before the alert went out and 116 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.
- 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
The text
As transmitted, in the capitals the NWS used until 2016.
037 ACUS11 KWNS 261257 SWOMCD SPC MCD 261256 NCZ000-TNZ000-GAZ000-ALZ000-MSZ000-261430- MESOSCALE DISCUSSION 0977 NWS STORM PREDICTION CENTER NORMAN OK 0756 AM CDT THU MAY 26 2011 AREAS AFFECTED...EXTREME EASTERN MS AND NORTHERN AL/SOUTHEAST TN/NORTHWEST GA CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 261256Z - 261430Z A SEVERE THREAT...INCLUDING THE POSSIBILITY OF A TORNADO AND DAMAGING WINDS...MAY INCREASE EARLY TODAY ACROSS PORTIONS OF EXTREME EASTERN MS INTO MUCH OF NORTHERN AL/NORTHWEST GA AND SOUTHEAST TN. CLOSELY MONITORING CONVECTIVE TRENDS FOR THE POSSIBILITY OF A WATCH. WITHIN A BAND OF PRE-FRONTAL CONFLUENCE...A PERSISTENT CORRIDOR OF TSTMS FROM FAR NORTHEAST MS INTO NORTHERN AL/EAST-CENTRAL TN HAS SHOWN SOME SIGNS OF INCREASE OVER THE PAST HOUR OR SO. CONTINUED GRADUAL HEIGHT FALLS/JET ENTRANCE REGION ALOFT...COUPLED WITH A HEATING/DESTABILIZING BOUNDARY LAYER...SHOULD ONLY CONTRIBUTE TO A SPATIAL/INTENSITY INCREASE OF DEEP CONVECTION THROUGH THE MORNING ACROSS PORTIONS OF AL INTO GA/EASTERN TN. THE 12Z BIRMINGHAM OBSERVED RAOB WAS INDICATIVE OF A VERY UNSTABLE/WEAKLY CAPPED AIRMASS /2200 J PER KG MLCAPE/ THAT EXISTS ACROSS MUCH OF THE REGION...WITH THE RESIDUAL INFLUENCE OF CONVECTIVE OUTFLOW ACROSS NORTHERN AL INTO TN EXPECTED TO MODIFY/DESTABILIZE WITH TIME. ALTHOUGH WINDS WITHIN THE LOWEST FEW KM ARE EXPECTED TO GRADUALLY VEER/WEAKEN WITH TIME INTO MIDDAY...STRONG DEEP LAYER SOUTHWESTERLY FLOW COUPLED WITH INITIALLY AMPLE LOW LEVEL SRH WILL SUPPORT A BOW ECHO/SUPERCELL THREAT WITH ASSOCIATED TORNADO POTENTIAL IN ADDITION TO DAMAGING WINDS AND SOME SEVERE HAIL. ..GUYER.. 05/26/2011 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...MRX...FFC...OHX...BMX...HUN...MEG...JAN... LAT...LON 33258877 34928733 35868524 35328412 32728630 33258877
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 25, 8:33 PM CDT | Tornado Watch | SPC | Bibb, Colbert, Cullman, Fayette, Franklin, Jefferson and 12 more | 7 hr |
| May 25, 10:27 PM CDT | Mesoscale Discussion | SPC | Colbert, Fayette, Franklin, Lamar, Lawrence, Marion and 2 more | 2 hr |
| May 26, 9:15 AM CDT | Severe Thunderstorm Watch | SPC | Autauga, Barbour, Bibb, Blount, Bullock, Calhoun and 38 more | 9 hr |
| May 26, 10:39 AM CDT | Mesoscale Discussion | SPC | Baldwin, Coffee, Conecuh, Covington, Dale, Escambia and 3 more | 96 min |
| May 26, 12:22 PM CDT | Mesoscale Discussion | SPC | Autauga, Bibb, Blount, Bullock, Butler, Calhoun and 33 more | 83 min |
| May 26, 2:32 PM CDT | Mesoscale Discussion | SPC | Cherokee | 58 min |
| May 26, 2:44 PM CDT | Severe Thunderstorm Watch | SPC | Henry | 6 hr |
| May 26, 3:36 PM CDT | Mesoscale Discussion | SPC | Calhoun, Chambers, Cherokee, Clay, Cleburne, Etowah and 6 more | 84 min |
| May 26, 4:10 PM CDT | Severe Thunderstorm Watch | SPC | Elbert, Franklin, Habersham, Hart, Rabun, Stephens | 7 hr |
| May 26, 6:12 PM CDT | Mesoscale Discussion | SPC | Columbia, Lincoln, McDuffie | 93 min |
| May 25, 7:22 PM CDT | Mesoscale Discussion | SPC | Alcorn, Benton, Bolivar, Coahoma, DeSoto, Lafayette and 11 more | 53 min |
| May 25, 9:43 PM CDT | Tornado Watch | SPC | Adams, Attala, Carroll, Choctaw, Claiborne, Clay and 33 more | 5 hr |
| May 26, 2:05 AM CDT | Mesoscale Discussion | SPC | Amite, Forrest, Greene, Hancock, Harrison, Jones and 8 more | 85 min |
| May 26, 5:18 PM CDT | Mesoscale Discussion | SPC | George, Hancock, Harrison, Jackson, Pearl River, Stone | 57 min |
| May 26, 2:09 PM CDT | Mesoscale Discussion | SPC | Clay, Fentress, Jackson, Overton, Pickett, Scott and 1 more | 96 min |
Nearby
Mesoscale Discussions in Alabama, 2011Mesoscale Discussions in Tennessee, 2011Mesoscale Discussions in Georgia, 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.