Alert archive / Alabama / Mesoscale Discussions in 2011
Mesoscale Discussion 417
The Storm Prediction Center issued this mesoscale discussion at Apr 11, 2011, 5:53 PM CDT for 5 counties in Alabama. It was in force for 97 min.
The area
The outline as issued.
The facts
- Issued
- Apr 11, 2011, 5:53 PM CDT (22:53 UTC)
- Expired
- Apr 11, 2011, 7:30 PM CDT
- In force
- 97 min
- Issued by
- the Storm Prediction Center
Counties Bibb County, AL, Greene County, AL, Jefferson County, AL, Shelby County, AL, Tuscaloosa County, AL
The radar
The Birmingham radar (KBMX), 58 km from the middle of the area, began a volume at 22:55 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, 10.9 hours before the alert went out and 57 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
- 9 J/kg
- Mixed-layer CIN
- -684 J/kg
- Mixed-layer LCL
- 606 m above ground
- 0-6 km bulk shear
- 43 kt
- 0-1 km storm-relative helicity
- 109 m²/s²
- 0-3 km storm-relative helicity
- 179 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
712
ACUS11 KWNS 112255
SWOMCD
SPC MCD 112253
ALZ000-120030-
MESOSCALE DISCUSSION 0417
NWS STORM PREDICTION CENTER NORMAN OK
0553 PM CDT MON APR 11 2011
AREAS AFFECTED...PARTS OF W CNTRL INTO CNTRL AL
CONCERNING...TORNADO WATCH 130...
VALID 112253Z - 120030Z
THE SEVERE WEATHER THREAT FOR TORNADO WATCH 130 CONTINUES.
WITHIN A SLOWLY EVOLVING PRE-FRONTAL SQUALL LINE...A COLD POOL
APPEARS TO BE STRENGTHENING IN ASSOCIATION WITH AN EMBEDDED SMALL
STORM CLUSTER NOW APPROACHING THE TUSCALOOSA AL AREA. ACTIVITY IS
EMBEDDED WITHIN A STRONG SOUTHWESTERLY DEEP LAYER MEAN FLOW FIELD ON
THE ORDER OF 40-50+ KT...WHICH WILL CONTRIBUTE TO FORWARD
PROPAGATION ALONG A CORRIDOR OF STEEP LOW-LEVEL LAPSE RATES INTO
CENTRAL ALABAMA DURING THE NEXT FEW HOURS. RUC GUIDANCE SUGGESTS
MIXED LAYER CAPE IS ON THE ORDER OF 1000-2000 J/KG...WHICH PROBABLY
WILL MAINTAIN VIGOROUS NEW UPDRAFTS...AND A SWATH OF DAMAGING WIND
GUSTS SEEMS LIKELY ACROSS THE TUSCALOOSA AREA BY 2330Z THROUGH THE
BIRMINGHAM VICINITY BETWEEN 00-01Z.
..KERR.. 04/11/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...BMX...
LAT...LON 33348795 33618735 33788697 33598651 33088667 32788750
32848812 33348795SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 11, 8:58 AM CDT | Mesoscale Discussion | SPC | Colbert, Cullman, Fayette, Franklin, Lamar, Lauderdale and 7 more | 62 min |
| Apr 11, 10:41 AM CDT | Mesoscale Discussion | SPC | Colbert, Cullman, Fayette, Franklin, Jackson, Lamar and 9 more | 64 min |
| Apr 11, 3:56 PM CDT | Mesoscale Discussion | SPC | Autauga, Bibb, Blount, Calhoun, Chilton, Choctaw and 32 more | 34 min |
| Apr 11, 4:05 PM CDT | Tornado Watch | SPC | Bibb, Blount, Chilton, Choctaw, Clarke, Dallas and 16 more | 6 hr |
| Apr 11, 5:11 PM CDT | Tornado Watch | SPC | Colbert, Cullman, DeKalb, Franklin, Jackson, Lauderdale and 5 more | 7 hr |
| Apr 11, 6:42 PM CDT | Mesoscale Discussion | SPC | Autauga, Bullock, Calhoun, Chambers, Cherokee, Chilton and 12 more | 33 min |
Nearby
Mesoscale Discussions in Alabama, 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.