Alert archive / Alabama / Mesoscale Discussions in 2016

Mesoscale Discussion 503

April 29, 201622 counties in Alabama; Lowndes County, Noxubee County, Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 29, 2016, 4:29 PM CDT for 22 counties in Alabama; Lowndes County, Noxubee County, Mississippi. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued
Apr 29, 2016, 4:29 PM CDT (21:29 UTC)
Expired
Apr 29, 2016, 6:00 PM CDT
In force
91 min
Issued by
the Storm Prediction Center
Chance of a watch
20%
All 24 counties

Bibb County, AL, Blount County, AL, Calhoun County, AL, Chilton County, AL, Cullman County, AL, Etowah County, AL, Fayette County, AL, Greene County, AL, Hale County, AL, Jefferson County, AL, Lamar County, AL, Lawrence 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, Lowndes County, MS, Noxubee County, MS

The radar

The Columbus AFB radar (KGWX), 83 km from the middle of the area, began a volume at 21:30 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 nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 9.5 hours before the alert went out and 84 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 2016-04-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 481 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 2016-04-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -23 square meters per square second.193958Sfc1 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
481 J/kg
Mixed-layer CIN
-167 J/kg
Mixed-layer LCL
1110 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
-23 m²/s²
0-3 km storm-relative helicity
72 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

973 
ACUS11 KWNS 292129
SWOMCD
SPC MCD 292129 
ALZ000-MSZ000-292300-

MESOSCALE DISCUSSION 0503
NWS STORM PREDICTION CENTER NORMAN OK
0429 PM CDT FRI APR 29 2016

AREAS AFFECTED...PORTIONS OF FAR EASTERN MS AND NORTHERN/CENTRAL AL

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 292129Z - 292300Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...A CLUSTER OF STORMS WILL CONTINUE TO POSE A THREAT FOR A
FEW STRONG WIND GUSTS AND A LARGE HAIL REPORT OR TWO. HOWEVER...THE
LIMITED NATURE OF THE THREAT PRECLUDES WATCH ISSUANCE.

DISCUSSION...A QUASI-LINEAR COMPLEX OF STRONG TO OCCASIONALLY SEVERE
STORMS CONTINUES EAST/SOUTHEASTWARD ACROSS FAR EASTERN MS AND
NORTHERN/CENTRAL AL. THESE STORMS SHOULD GENERALLY FOLLOW AN
INSTABILITY AXIS TO THEIR EAST/SOUTHEAST...WHERE PRIOR SFC HEATING
HAS PROMOTED STEEPENED LOW-LEVEL LAPSE RATES AND AN ENVIRONMENT
FAVORABLE FOR STRONG WIND GUSTS. ADDITIONALLY...ADVECTION OF
WARM/MOIST AIR IS FAVORING PROPAGATION ALONG THE SOUTHERN END OF THE
COMPLEX. MERGING COLD POOLS AND ANY EMBEDDED ROTATING ELEMENTS WILL
FAVOR POCKETS OF GUSTY WINDS OVER THE NEXT FEW HOURS. HOWEVER...THE
THREAT SHOULD SLOWLY DIMINISH AS BOUNDARY-LAYER STABILIZATION OCCURS
AND CELLS BECOME MORE OUTFLOW-DOMINANT THIS EVENING.

..PICCA/HART.. 04/29/2016

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

ATTN...WFO...BMX...HUN...MEG...JAN...

LAT...LON   33558867 34368772 34778725 34608620 34348588 33488576
            32758674 32708804 32898857 33298872 33558867

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 29, 9:46 AM CDTMesoscale DiscussionSPCBolivar, Coahoma, Washington89 min
Apr 29, 12:37 PM CDTMesoscale DiscussionSPCAttala, Benton, Calhoun, Carroll, Chickasaw, Choctaw and 34 more83 min

Nearby

Mesoscale Discussions in Alabama, 2016Mesoscale Discussions in Mississippi, 2016Every mesoscale discussion in 2016

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.