565  
FOUS30 KWBC 171600  
QPFERD  
 
EXCESSIVE RAINFALL DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1100 AM EST TUE DEC 17 2024  
 
DAY 1  
VALID 16Z TUE DEC 17 2024 - 12Z WED DEC 18 2024  
 
...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ALONG PORTIONS OF  
THE EAST CENTRAL TO SOUTHEAST COAST OF FLORIDA...  
   
..16Z UPDATE
 
 
12Z SOUNDINGS FROM MFL AND KEY SHOWED PW VALUES OF 1.5 AND 1.7  
INCHES, RESPECTIVELY, OR NEAR THE 90TH PERCENTILE FOR MID-  
DECEMBER. LOW LEVEL EASTERLY FLOW IS EXPECTED TO SUPPORT  
SHOWERS/THUNDERSTORMS MOVING INLAND DURING THE DAY TODAY WITH AN  
INCREASING THREAT FOR SLOW MOVING/STALLED CELLS LATE TODAY AND  
OVERNIGHT ALONG AN EXPECTED COASTAL/NEAR-COASTAL CONVERGENCE AXIS.  
 
925-850 MB WINDS OF 15 TO 20+ KT ARE FORECAST BY THE LATEST  
GUIDANCE WITH A SHIFT TOWARD MORE OF A SOUTHEASTERLY DIRECTION  
LATER TONIGHT. THE 12Z HREF INDICATED NEIGHBORHOOD PROBABILITES  
FOR 5 INCHES IN 24 HOURS (ENDING 12Z WEDNESDAY) OF 50-60 PERCENT  
AND WHILE THESE PROBABLITIES HAVE COME DOWN AND ARE LARGELY DRIVEN  
BY THE MORE BULLISH 12Z NAM_NEST AND ARW2, A LOW END THREAT FOR  
LOCALIZED FLASH FLOODING WILL REMAIN THROUGH 12Z WEDNESDAY FOR THE  
EASTERN AND SOUTHEASTERN FL PENINSULA.  
 
OTTO  
   
..PREVIOUS DISCUSSION FOLLOWS
 
 
MODEL CONSENSUS IS FOR INCREASINGLY ACTIVE SHOWERS LATE TUESDAY  
AFTERNOON INTO TUESDAY NIGHT/EARLY WEDNESDAY ALONG THE EAST CENTRAL  
TO SOUTHEAST COAST OF FLORIDA. LOW LEVEL EASTERLY TO SOUTHEASTERLY  
FLOW IN AN AXIS OF PW VALUES 1.5 TO 2+ STANDARD DEVIATIONS ABOVE  
THE MEAN EXPECTED TO PERSIST INTO THE EAST CENTRAL TO SOUTHEAST  
FLORIDA COAST, WITH MODELS SHOWING AN AXIS OF DEFINED BOUNDARY  
LAYER CONVERGENCE IN THIS LOW LEVEL INFLOW AXIS PARALLEL TO THE  
EAST CENTRAL TO SOUTHEAST COAST. THERE WILL BE POTENTIAL FOR VERY  
SLOW MOVING CELLS ALONG THE COASTAL REGIONS, SUPPORTING LOCALLY  
VERY HEAVY RAINFALL AMOUNTS AND AN URBAN FLASH FLOOD THREAT. HREF  
NEIGHBORHOOD PROBABILITIES ARE HIGH (50-90%) FOR 3"+ AMOUNTS FROM  
CAPE CANAVERAL, SOUTH TO MIAMI, WHILE THE 5"+ NEIGHBORHOOD  
PROBABILITIES ARE HIGH (60-90%) FROM NEAR WEST PALM BEACH, SOUTH TO  
MIAMI. THE BEST HI RES OVERLAP, EVIDENT IN THE GREATEST EAS  
PROBABILITIES FOR 2"+ AMOUNTS, IS FROM NEAR WEST PALM, SOUTH TO  
JUST NORTH OF MIAMI.  
 
ORAVEC  
 
DAY 2  
VALID 12Z WED DEC 18 2024 - 12Z THU DEC 19 2024  
 
THE PROBABILITY OF RAINFALL EXCEEDING FLASH FLOOD GUIDANCE IS LESS  
THAN 5 PERCENT.  
 
ORAVEC  
 
DAY 3  
VALID 12Z THU DEC 19 2024 - 12Z FRI DEC 20 2024  
 
THE PROBABILITY OF RAINFALL EXCEEDING FLASH FLOOD GUIDANCE IS LESS  
THAN 5 PERCENT.  
 
ORAVEC  
 
DAY 1 THREAT AREA: HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/94EPOINTS.TXT  
DAY 2 THREAT AREA: HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/98EPOINTS.TXT  
DAY 3 THREAT AREA: HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/99EPOINTS.TXT  
 
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