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000
ACUS11 KWNS 061548
SWOMCD
SPC MCD 061548
FLZ000-061715-

MESOSCALE DISCUSSION 0171
NWS STORM PREDICTION CENTER NORMAN OK
0948 AM CST THU MAR 06 2014

AREAS AFFECTED...CENTRAL AND SOUTHERN FLORIDA...INCLUDING THE KEYS

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 061548Z - 061715Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...A LARGE CLUSTER OF STORMS IS EXPECTED TO BEGIN TO
OVERSPREAD MUCH OF THE CENTRAL/SOUTHERN FLORIDA PENINSULA DURING THE
17-18Z TIME FRAME...WITH ADDITIONAL STORM DEVELOPMENT POSSIBLE AHEAD
OF IT...ACROSS ATLANTIC COASTAL AREAS...DURING THE EARLY TO MID
AFTERNOON.  TRENDS ARE BEING MONITORED FOR A SEVERE WEATHER
WATCH...WHICH PROBABLY WILL BE NEEDED ACROSS AS LEAST THE SOUTHERN
PENINSULA.

DISCUSSION...IN ADVANCE OF A MORE SIGNIFICANT UPPER TROUGH/MID-LEVEL
CLOSED LOW CURRENTLY DIGGING INTO THE CENTRAL GULF COAST
REGION...SATELLITE IMAGERY AND MODEL FORECAST OUTPUT SUGGEST THAT A
SHORT WAVE TROUGH WILL CONTINUE TO MIGRATE EAST NORTHEASTWARD FROM
THE EASTERN GULF OF MEXICO THROUGH MUCH OF NORTHERN AND CENTRAL
FLORIDA BY 20-21Z.  THIS WILL BE ACCOMPANIED BY A LARGE CLUSTER OF
THUNDERSTORM ACTIVITY WHICH COINCIDES WITH A BELT OF 30-50 KT
SOUTHWESTERLY DEEP LAYER MEAN FLOW.

IN ASSOCIATION WITH THE STRONG SHEAR...HIGHER LEVEL CLOUD COVER AND
RAINFALL BLOWING OFF/ADVECTING DOWNSTREAM OF STRONGEST THUNDERSTORM
ACTIVITY HAS ALREADY OVERSPREAD MUCH OF THE NORTHERN AND CENTRAL
FLORIDA PENINSULA...CONTRIBUTING TO SOME UNCERTAINTY CONCERNING
SUBSEQUENT BOUNDARY LAYER DESTABILIZATION.  BUT THE CORE OF STRONGER
LOWER/MID TROPOSPHERIC FLOW FIELDS IS FORECAST TO NOSE INLAND
ROUGHLY ALONG THE INTERSTATE 4 CORRIDOR.

ACROSS THE SOUTHERN TIER OF THE PENINSULA...INCLUDING THE MIAMI
METRO...AND THE KEYS...DEEP LAYER FLOW/SHEAR WILL BE MORE MODEST
...BUT SUBSTANTIVE BOUNDARY LAYER DESTABILIZATION PRIOR TO THE
ARRIVAL OF THE MORE SIGNIFICANT LARGE-SCALE FORCING AND CONVECTIVE
LINE IS MORE CERTAIN.

EVEN WITH THE UNCERTAINTIES...THUNDERSTORMS APPEAR LIKELY TO
OVERSPREAD MUCH OF THE CENTRAL AND SOUTHERN PENINSULA MID DAY
THROUGH LATE AFTERNOON...WITH AT LEAST SOME RISK FOR DAMAGING WIND
GUSTS...PERHAPS ISOLATED TORNADOES.  HIGH RESOLUTION MODEL OUTPUT
SUGGESTS ADDITIONAL STORM DEVELOPMENT IS POSSIBLE IN ADVANCE OF THIS
ACTIVITY...ALONG ATLANTIC COASTAL AREAS...BUT LOW-LEVEL CONVERGENCE
STILL APPEARS WEAK ACROSS THIS AREA AT THE PRESENT TIME.

..KERR/MEAD.. 03/06/2014

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

ATTN...WFO...MFL...MLB...KEY...TBW...

LAT...LON   27608233 28708123 28978074 27987969 25897946 24488042
            24718143 26188209 26758226 27608233