163  
FXUS62 KMFL 230811  
AFDMFL  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MIAMI FL  
411 AM EDT THU MAR 23 2017  
   
DISCUSSION
 
 
TODAY-TONIGHT: WEAKENING FRONTAL BOUNDARY MAKING IT'S WAY SOUTH AND  
WEST ACROSS CENTRAL FLORIDA EARLY THIS MORNING, GENERATING A FEW  
SHOWERS AND STORMS, MAINLY ACROSS THE WATERS. ANALYSIS SHOWS THAT  
THE DEEPER MOISTURE ASSOCIATED WITH THE BOUNDARY IS LAGGING  
BEHIND SLIGHTLY, AND WHILE THE BOUNDARY AND WIND SHIFT ARE LIKELY  
TO ARRIVE INTO SOUTH FLORIDA EARLY MORNING, THE DEEPER MOISTURE  
MAY LAG MORE TOWARDS THIS AFTERNOON.  
 
DESPITE THIS, ENOUGH LOW-LEVEL MOISTURE, ALONG WITH WEAK  
OVERRUNNING/ISENTROPIC LIFT WILL ALLOW SCATTERED SHOWERS TO SPREAD  
FROM NORTHEAST TO SOUTHWEST ACROSS THE REGION THROUGH THE MORNING  
HOURS. THE BEST RAIN CHANCES WILL BE LATE MORNING INTO THIS  
AFTERNOON, WHEN THE DEEPER MOISTURE AND BEST LIFT COMBINE.  
 
UPPER LEVEL VORT MAXES CROSSING THE PENINSULA THIS MORNING HAVE  
BROUGHT IN MUCH COLDER TEMPERATURES ALOFT, WITH RUC ANALYSIS SHOWING  
500MB TEMPS AROUND -14 TO -16C. WITH ANOTHER VORT MAX EXPECTED TO  
COOL TEMPS A DEGREE OR TWO, AND DAYTIME TEMPERATURES STILL EXPECTED  
TO CLIMB INTO THE UPPER 70S AND LOW 80S, MID LEVEL LAPSE RATES WILL  
BE QUITE STEEP TODAY. THIS INSTABILITY MEANS THAT A FEW STORMS CAN'T  
BE RULED OUT, ESPECIALLY ALONG THE EAST COAST AND LAKE OKEECHOBEE  
REGION. IT ALSO SETS UP A FAVORABLE ENVIRONMENT FOR A FEW STRONG  
STORMS WITH HAIL, AND SPC HAS PLACED MOST OF SOUTH FLORIDA UNDER A  
MARGINAL RISK FOR TODAY. OVERALL RAINFALL AMOUNTS ARE EXPECTED TO  
GENERALLY BE LIGHT, BUT A FEW AREAS COULD SEE A NICE SOAKING  
RAINFALL OF AROUND A HALF AN INCH, HELPING THE ONGOING DROUGHT  
SITUATION.  
 
CONDITIONS TO BECOME BREEZY TO WINDY LATE IN THE DAY AS EAST-  
NORTHEAST WIND SURGE ARRIVES BEHIND THE BOUNDARY, WITH THE  
STRONGEST WINDS ALONG THE EAST COAST. OVERNIGHT LOWS WILL BE IN  
THE AROUND 60 OVER THE INTERIOR AND GULF COAST AND MID-UPPER 60S  
FOR THE EAST COAST.  
 
FRIDAY: BOUNDARY MOVES SOUTH OF THE REGION AND WASHES OUT AS STRONG  
HIGH PRESSURE BUILDS TO THE NORTH. THE TIGHT PRESSURE GRADIENT WILL  
LEAD TO AN BREEZY TO WINDY DAY, WITH WIND GUSTS OF 20-30 MPH COMMON  
AT TIMES. LINGERING SHOWERS ALONG THE EAST COAST WILL ALSO  
CONTINUE.  
 
HIGHS ON FRIDAY BEHIND THE FRONT WILL BE SLIGHTLY COOLER, RANGING  
FROM THE MID 70S TO AROUND 80. LOW TEMPERATURES WILL GENERALLY BE IN  
THE 60S, WITH A FEW UPPER 50S READINGS IN THE INTERIOR.  
 
SATURDAY-WEDNESDAY: MODELS HAVE SHIFTED WESTWARDS WITH THE CUT-OFF  
LOW THAT HAD BEEN FORECAST TO MEANDER WELL EAST OF THE BAHAMAS. THIS  
RESULTS IN A WEAKER AND SHORTER LIVED UPPER LEVEL RIDGE MOVING  
ACROSS THE FL PENINSULA ON SATURDAY. THE WEAKER RIDGE IN TURN ALLOWS  
THE NEXT SYSTEM MOVING ACROSS THE TN/MS VALLEY TO DIG A LITTLE  
FURTHER SOUTH BEFORE THE RIDGE REBUILDS MONDAY AND TUESDAY.  
 
GENERALLY EASTERLY FLOW WILL PREVAIL THROUGH THE PERIOD, REMAINING  
BREEZY ON SATURDAY BEFORE THE SURFACE GRADIENT WEAKENS SUNDAY AND  
MONDAY. PERIODIC SHOWERS ARE EXPECTED THROUGH THE PERIOD OFF THE  
ATLANTIC AS EASTERLY FLOW CONTINUES TO BRING IN LOW LEVEL  
MOISTURE. SOME ENHANCEMENT IN COVERAGE IS POSSIBLE DURING THE  
WEEKEND AS VORT MAXES ROTATE THROUGH THE REGION, AND AGAIN ON  
TUESDAY AS ANOTHER WEAK FRONT APPROACHES.  
 
TEMPERATURES WILL BE NEAR TO SLIGHTLY ABOVE NORMAL FOR THE LONG TERM  
PERIOD.  
 

 
   
MARINE
 
BOATING CONDITIONS WILL BEGIN DETERIORATING LATE THIS  
MORNING OVER THE ATLANTIC WATERS, AND INTO THIS EVENING OVER THE  
GULF AS A WEAK FRONTAL BOUNDARY MOVES ACROSS THE REGION. THE  
BOUNDARY WILL ALSO BRING SCATTERED TO NUMEROUS SHOWERS, WITH THE  
POTENTIAL FOR A FEW STORMS, ESPECIALLY OVER THE LOCAL ATLANTIC  
WATERS.  
 
EXPECT EAST-NORTHEAST WINDS 20-25KTS OVER MUCH OF THE LOCAL WATERS,  
INCLUDING BISCAYNE BAY, THROUGH THE OVERNIGHT HOURS WITH SEAS  
BUILDING TO 9-11FT IN THE GULF STREAM. WINDS DIMINISH INTO FRIDAY,  
BUT HAZARDOUS MARINE CONDITIONS FOR THE ATLANTIC WATERS ARE  
EXPECTED TO CONTINUE THROUGH SATURDAY. A SMALL CRAFT ADVISORY IS  
CURRENTLY IN EFFECT FOR THE ATLANTIC WATERS FROM MIDDAY, AND THE  
GULF WATERS STARTING THIS EVENING.  
 

 
   
AVIATION
 
GENERALLY VFR CONDITIONS SHOULD PREVAIL, THOUGH SUB-  
VFR CONDITIONS ARE POSSIBLE WITH OVERNIGHT FOG POSSIBLE AT APF.  
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE TODAY, WITH A FOCUS ON  
THE EAST COAST DURING THE AFTERNOON AND EVENING.  
 

 
   
BEACH FORECAST
 
EAST-NORTHEASTERLY WIND SURGE ARRIVES EARLY THIS  
AFTERNOON WITH FRONTAL BOUNDARY, LEADING TO A RAPID INCREASE IN THE  
RIP CURRENT THREAT ALONG ALL THE ATLANTIC BEACHES. THERE IS A HIGH  
RISK OF RIP CURRENTS FOR ALL THE EAST COAST BEACHES TODAY AND INTO  
THE WEEKEND.  
 

 
   
FIRE WEATHER
 
LIGHT TO MODERATE SHOWERS ARE EXPECTED TO OVERSPREAD  
MUCH OF THE REGION THROUGH THE DAY WITH A FRONTAL BOUNDARY, ALONG  
WITH A THREAT FOR ISOLATED THUNDERSTORMS. A FEW SHOWERS MAY ALSO  
LINGER ALONG THE EAST COAST INTO FRIDAY, WITH RELATIVE HUMIDITY  
VALUES EXPECTED TO REMAIN ABOVE CRITICAL LEVELS THROUGH SATURDAY.  
GUSTY EAST-NORTHEAST WINDS WILL ALSO ARRIVE WITH THE BOUNDARY LATE  
TODAY, LEADING TO VERY GOOD TO EXCELLENT DISPERSIONS ACROSS MUCH OF  
THE REGION INTO SATURDAY.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
WEST PALM BEACH 78 69 78 68 / 60 40 20 10  
FORT LAUDERDALE 79 69 78 70 / 60 50 30 20  
MIAMI 81 68 79 69 / 50 40 40 20  
NAPLES 80 62 82 62 / 40 20 10 0  
 

 
   
MFL WATCHES/WARNINGS/ADVISORIES
 
 
FL...HIGH RIP CURRENT RISK FROM 8 AM EDT THIS MORNING THROUGH FRIDAY  
EVENING FOR FLZ168-172-173.  
 
AM...SMALL CRAFT ADVISORY FROM NOON TODAY TO 8 AM EDT SATURDAY FOR  
AMZ630-650-651-670-671.  
 
GM...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 11 AM EDT FRIDAY  
FOR GMZ656-657-676.  
 

 
 
 
DISCUSSION...88/ALM  
MARINE...88/ALM  
AVIATION...02/RAG  
BEACH FORECAST...88/ALM  
FIRE WEATHER...88/ALM  
 
 
 
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