MESOSCALE PRECIPITATION DISCUSSION 0645
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
330 AM EST MON NOV 09 2015
 
AREAS AFFECTED...FLORIDA PANHANDLE 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 090829Z - 091200Z
 
SUMMARY...A SHORT TERM LOCALIZED FLASH FLOOD THREAT MAY BE
DEVELOPING ACROSS PORTIONS OF THE FLORIDA PANHANDLE AS AN AREA OF
LOW PRESSURE NUDGES TOWARDS THE COAST.

DISCUSSION...LATEST SURFACE OBS CONTINUE TO SHOW NORTHEASTERLY
WINDS ALONG THE COAST SUGGESTING THE FRONT REMAINS OFFSHORE.
HOWEVER VAD WIND PROFILES SHOW A STRONGLY VEERING LOW LEVEL
FLOW...AND RECENT RAP RUNS SHOW INCREASING BOUNDARY LAYER
CONVERGENCE ACROSS THE FLORIDA PANHANDLE COAST.

ONE HEAVY RAINFALL BAND HAS BEEN NEARLY STATIONARY FROM NEAR
PANAMA CITY TO WEWAHITCHKA TO NEAR SMITH CREEK...LIKELY ANCHORED
IN AN AREA OF ENHANCED CONVERGENCE ON A BOUNDARY JUST ELEVATED
ABOVE THE SURFACE. OBSERVATIONS AND DUAL POL RADAR ESTIMATES
SUGGEST RAINFALL IN PORTIONS OF THIS BAND ARE APPROACHING 2" AN
HOUR. MEANWHILE A CLUSTER OF EMBEDDED THUNDERSTORMS IS BEGINNING
TO MOVE ONSHORE OFF THE GULF OF MEXICO...WITH RAINFALL RATES UP TO
AROUND 1.5" AN HOUR WITH THIS ACTIVITY.

MOST OF THE INSTABILITY REMAINS OFFSHORE SOUTH OF THE SURFACE
BOUNDARY. HOWEVER LIKELY SEEING A MARGINAL AMOUNT OF ELEVATED
INSTABILITY JUST INLAND HELPING TO SUPPORT THESE HIGHER RATES. NOT
SEEING MANY SIGNS THAT SUGGESTS THIS INSTABILITY IS ABLE TO MOVE
FURTHER INLAND...THUS THINKING THE HEAVY RAINFALL RATES WILL MOST
LIKELY NOT MOVE MUCH FURTHER NORTH THAN WHERE THEY CURRENTLY ARE.
THE CONTINUED INFLOW UP AND OVER STATIONARY BOUNDARY SHOULD ALLOW
FOR CONTINUED POCKETS OF HEAVY RAINFALL. 

PRECIPITABLE WATER VALUES AND WET BULB ZERO HEIGHTS ARE NEAR
RECORD LEVELS FOR NOVEMBER...SUGGESTING EFFICIENT RAINFALL WILL
CONTINUE WHERE INSTABILITY IS REALIZED. MODEL FORECASTS SHOW THE
BETTER INFLOW BEGINS TO WEAKEN AS WE APPROACH 12Z...SUGGESTING WE
SHOULD SEE A WEAKENING OF ACTIVITY. NONE OF THE HIGH RES GUIDANCE
ARE REALLY DOING A GOOD JOB WITH THIS ACTIVITY. THE 0Z GEM
REGIONAL LOOKS BEST...JUST DISPLACED A BIT WEST. CURRENTLY
THINKING RAINFALL TOTALS OF 1-4" WILL BE POSSIBLE IN THE CIRCLED
REGION...WHICH MAY POSE A MARGINAL FLASH FLOOD RISK...ESPECIALLY
IN ANY MORE URBAN AREAS.

CHENARD

ATTN...WFO...TAE...

ATTN...RFC...SERFC...

LAT...LON   29488565 29488565 
30478567 30418515 30448476 30458446 30238423 
            29848419 29628433 29608434 29408472 29408520 
            29548573 29668618 29668618 29868658 29898658 
            30278610