Mesoscale Discussion 2202

Issued

Dec 24, 2012, 11:46 AM CST (17:46 UTC)

Expired

Dec 24, 2012, 1:15 PM CST

In force

89 min

Issued by

the Storm Prediction Center

Chance of a watch

5%

The Eglin Afb radar (KEVX), 37 km from the middle of the area, began a volume at 17:48 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.

399 
ACUS11 KWNS 241746
SWOMCD
SPC MCD 241746 
FLZ000-GAZ000-ALZ000-241915-

MESOSCALE DISCUSSION 2202
NWS STORM PREDICTION CENTER NORMAN OK
1146 AM CST MON DEC 24 2012

AREAS AFFECTED...SERN AL/FL PANHANDLE/FAR SWRN GA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 241746Z - 241915Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...A FEW STRONGER TO SEVERE STORMS ARE POSSIBLE THIS
AFTERNOON ACROSS SERN AL...MUCH OF THE FL PANHANDLE INTO FAR SWRN
GA.  OVERALL EXPECTED THREAT COVERAGE IS FORECAST TO REMAIN TOO
LIMITED TO SUPPORT A WW ISSUANCE.

DISCUSSION...TRENDS IN MID-LATE MORNING OBSERVATIONS AND VERTICAL
WIND PROFILES SHOWED A WARM SECTOR HAD MOVED INLAND ACROSS MUCH OF
THE FL PANHANDLE AND INTO PARTS OF FAR SOUTH-CENTRAL AND SERN
AL...AND EVENTUALLY WILL DO SO INTO FAR SWRN GA. LOW LEVEL
MOISTENING/WARM AIR ADVECTION PER A SWLY STRENGTHENING JET /35-40
KT/ EXTENDING INTO FAR SERN AL WAS RESULTING IN AT LEAST WEAK
INSTABILITY /SBCAPE 250-500 J PER KG/.  THIS COMBINED WITH EFFECTIVE
BULK SHEAR OF 50-60 KT PER A WLY MIDLEVEL JET EXCEEDING 50
KT...WITHIN THE BASE OF A PROGRESSIVE SRN APPALACHIANS SHORTWAVE
TROUGH...WILL MAINTAIN THE POTENTIAL FOR STORM ORGANIZATION THIS
AFTERNOON.  

AT 1730Z...REGIONAL RADAR IMAGERY/LIGHTNING DATA SHOWED A BROKEN
LINE OF TSTMS /PRIMARILY SFC-BASED ACROSS THE DISCUSSION AREA/
EXTENDING FROM THE NORTH CENTRAL GULF OF MEXICO THROUGH THE FAR WRN
FL PANHANDLE INTO SERN AL.  THE NERN EXTENT OF THESE STORMS WERE
LIKELY ELEVATED NNE OF THE WARM FRONT WHICH EXTENDED SEWD FROM NEAR
KMGM TO W OF KTLH.  THE STRONGEST STORMS /WITH SUSTAINED UPDRAFTS
PER CAPPI DATA/ WERE DETECTED MOVING INTO SERN AL AND ADJACENT SWRN
GA...WITH THE POTENTIAL FOR SUPERCELLS GIVEN THE STRONGER SHEAR. 
SFC-1 KM SHEAR OF 20-30 KT SUGGESTS LOW LEVEL ROTATION IS POSSIBLE. 
THUS...IN ADDITION TO LOCALLY STRONGER WIND GUSTS...A BRIEF TORNADO
THREAT CANNOT BE RULED OUT.

THE EWD MOVEMENT OF THE LINE /WHICH LIKELY DELINEATED THE SRN-SWRN
EXTENT OF THE PROGRESSIVE SHORTWAVE TROUGH/ IS EXPECTED TO REACH
SWRN GA BETWEEN 20-21Z. THIS TIMING SUGGESTS IT SHOULD BE MOVING
FARTHER AWAY FROM THE NERN EXTENT OF GREATER INSTABILITY EXTENDING
INTO SERN AL AND CENTRAL PARTS OF THE FL PANHANDLE.

..PETERS/EDWARDS.. 12/24/2012

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

ATTN...WFO...TAE...BMX...MOB...

LAT...LON   31818469 30008429 29478501 29858569 30168649 30248732
            30688683 31598589 31968514 31818469

Mesoscale Discussions in Florida, 2012Mesoscale Discussions in Georgia, 2012Mesoscale Discussions in Alabama, 2012Every mesoscale discussion in 2012

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.