Mesoscale Discussion 2168

Issued

Dec 17, 2012, 4:16 AM CST (10:16 UTC)

Expired

Dec 17, 2012, 6:15 AM CST

In force

119 min

Issued by

the Storm Prediction Center

Chance of a watch

40%

Counties Baldwin County, AL, Escambia County, AL, Mobile County, AL, Escambia County, FL, Okaloosa County, FL, Santa Rosa County, FL, George County, MS, Jackson County, MS

The Mobile radar (KMOB), 54 km from the middle of the area, began a volume at 10:15 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.

788 
ACUS11 KWNS 171017
SWOMCD
SPC MCD 171016
FLZ000-ALZ000-MSZ000-LAZ000-171215-

MESOSCALE DISCUSSION 2168
NWS STORM PREDICTION CENTER NORMAN OK
0416 AM CST MON DEC 17 2012

AREAS AFFECTED...FAR SERN MS/SWRN-SOUTH CENTRAL AL/WRN FL PANHANDLE

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 171016Z - 171215Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...A SEVERE WEATHER THREAT /DAMAGING WINDS AND/OR A TORNADO/
MAY BE DEVELOPING EARLY THIS MORNING ALONG THE COASTAL AREAS OF SERN
MS...SWRN AL AND THE WRN FL PANHANDLE...WITH POTENTIAL TO MOVE A
LITTLE FARTHER INLAND OVER SWRN AL/WRN FL PANHANDLE.  WW ISSUANCE IS
AT 40 PERCENT SINCE UNCERTAINTY REMAINS IN THE OVERALL STORM
COVERAGE INTO THE MORNING.

DISCUSSION...TRENDS DURING THE OVERNIGHT/EARLY THIS MORNING SHOWED A
PORTION OF THE CONVECTIVE OUTFLOW BOUNDARY THAT HAD MOVED INTO THE
NRN GULF OF MEXICO HAS RETURNED NWD...AND WAS IMPINGING UPON THE
COASTAL AREAS OF FAR SERN MS/SWRN AL /DAUPHIN ISLAND VICINITY/.
REGIONAL RADAR IMAGERY SHOWED CONVECTIVE CELLS MOVING INTO SRN
MOBILE COUNTY FROM OFFSHORE...WITH LIGHTNING ALSO DETECTED FARTHER
SSW OVER THE CHANDELEUR ISLANDS...WHERE A TRAILING PORTION OF THE
OUTFLOW BOUNDARY HAD BECOME ORIENTED NNE-SSW ALONG AND OFFSHORE OF
SERN LA.

SWLY MIDLEVEL WINDS OVER THE LOWER MS VALLEY-CENTRAL GULF COAST
STATES WILL CONTINUE TO STRENGTHEN THIS MORNING AS A PROGRESSIVE
SHORTWAVE TROUGH...CURRENTLY MOVING EWD ACROSS THE OZARKS-ARKLATEX
REGION PER MOISTURE CHANNEL IMAGERY...BECOMES NEGATIVELY TILTED.
THESE WINDS AND 30-35 KT SSWLY LLJ SUPPORT BULK SHEAR OF 40-55 KT
FOR ORGANIZED STORMS...WHILE EFFECTIVE SRH OF 100-200 M2/S2 INVOF
THE NWD MOVING BOUNDARY INTO THE DISCUSSION AREA WILL SUPPORT THE
POTENTIAL FOR LOW LEVEL ROTATION/AT LEAST A BRIEF TORNADO.  MUCAPE
OF 200-400 J/KG N OF THE RETREATING BOUNDARY AND AOA 500 J/KG IN THE
WARM SECTOR SHOULD REMAIN MEAGER THROUGH THE MORNING AND WILL BE THE
MAIN LIMITING FACTOR FOR GREATER TSTM/SVR COVERAGE.  AN ADDITIONAL
THREAT FOR AT LEAST A FEW STRONG TO SEVERE STORMS COULD DEVELOP
ALONG THE TRAILING EXTENT OF OVERNIGHT ELEVATED CONVECTION THAT
SHOULD MOVE INTO SWRN AL BETWEEN 11-12Z.

..PETERS/EDWARDS.. 12/17/2012

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

ATTN...WFO...TAE...MOB...LIX...

LAT...LON   29638923 30718891 31328798 31258688 30858631 30138664
            30068723 29768820 29458862 29638923

Mesoscale Discussions in Alabama, 2012Mesoscale Discussions in Florida, 2012Mesoscale Discussions in Mississippi, 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.