499  
FXUS62 KKEY 251846  
AFDKEY  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE KEY WEST FL  
246 PM EDT SAT MAR 25 2017  
   
DISCUSSION
 
IN THE MIDDLE TO UPPER LEVEL(700-200 MB), LATEST  
AVAILABLE MODEL STREAMLINE ANALYSIS OVERLAID ON TOP OF SATELITTE  
IMAGERY AS OF 200 PM, DEPICT A WELL DEFINED COLD CORE CYCLONE  
OVER CENTRAL MISSOURI. THIS SYSTEM SEPARATES A STRONG NORTHERN AND  
SOUTHERN STREAM JET, WITH A 75 TO 100 KNOT JET AT 250 MB ROUNDING  
THE BASE OF THIS SYSTEM ACROSS THE NORTH CENTRAL GULF OF MEXICO,  
THEN ARCING NORTHEASTWARDS TO NORTH CAROLINA. DOWNSTREAM OF THAT,  
THE AXIS OF A REGIONAL SCALE WARM MIDDLE AND UPPER RIDGE POKES  
NORTHEASTWARD TO NEAR 34 NORTH 73 WEST FROM WESTERN CUBA. AND EAST  
OF THAT, THERE IS A WELL DEFINED MIDDLE AND UPPER LEVEL TROUGH  
WITH ITS AXIS FROM NEAR 32 NORTH 68 WEST SOUTHWEST TO NEAR THE  
WINDWARD PASSAGE.  
 
AT THE SURFACE AND IN THE LOWER TO MIDDLE LEVELS(SURFACE TO 700  
MB), LATEST SATELITTE IMAGERY OVERLAID WITH MARINE AND LAND  
SURFACE OBSERVATIONS AND ANALYSIS AS OF 200 PM, DETAILS THE  
CENTER OF A 1030 MB ANTICYCLONE IS NEAR 34 NORTH AND 65 WEST WITH  
THE WESTERN PERIPHERY OF THIS SURFACE RIDGE ACROSS SOUTH CAROLINA.  
THE FLORIDA KEYS ARE BENEATH THE SOUTHWESTERN PERIPHERY OF THIS  
RIDGING, WITH MODERATE TO FRESH EAST WINDS CONTINUING TO BLOW  
ACROSS THE ISLANDS AND SURROUNDING WATERS THIS AFTERNOON.  
   
CURRENTLY
 
AS OF 200 PM, SKIES ARE MOSTLY SUNNY ACROSS THE  
ISLANDS AND ADJOINING WATERS. TEMPERATURES ACROSS THE ISLANDS ARE  
IN THE LOWER 80S WITH DEWPOINTS IN THE MIDDLE 60S. KEY WEST AND  
MIAMI RADARS DO NOT DETECTS ANY ECHOES ATTM. C-MAN STATIONS ALONG  
THE FLORIDA REEF ARE REGISTERING EAST WINDS AT 15 TO 20 KNOTS AND  
GUSTY, NEAR 15 KNOTS IN FLORIDA BAY AND AT SMITH SHOAL LIGHT.  
   
SHORT TERM
 
TONIGHT THRU MONDAY NIGHT, A FAIRLY TYPICAL BENIGN  
WEATHER PATTERN IS IN STORE FOR US AS WE FINISH THE LAST WEEK OF  
MARCH. STRONGER RIDGING OUT OVER THE WEST CENTRAL ATLANTIC  
EXTENDING INTO THE SOUTHEASTERN UNITED STATES WILL GRADUALLY  
WEAKEN TONIGHT THROUGH MONDAY NIGHT. THE AFOREMENTIONED MIDDLE AND  
UPPER TROUGH NOW LOCATED NORTH OF HISPANIOLA IN COMBINATION WITH  
A STALLING FRONTAL BOUNDARY WILL ALLOW FOR DEVELOPMENT OF A GALE  
CENTER/STRONG NON TROPICAL LOW TONIGHT THROUGH SUNDAY NIGHT, THEN  
MOVING ABOUT 500 NM NORTH OF PUERTO RICO BY MONDAY NIGHT. AS A  
RESULT, MODERATE TO FRESH BREEZES AGAIN TONIGHT, WILL SLACKEN TO  
GENTLE TO MODERATE BREEZES SUNDAY THRU MONDAY NIGHT, GIVEN THE  
LOOSENING OF THE MSLP GRADIENT. AFTER A VERY SLIGHT CHANCE OF  
SHOWERS AGAIN TONIGHT, ANY CHANCE FOR REMAIN HAS BEEN REMOVED FROM  
THE GRIDS THEREAFTER. HIGHS IN THE LOWER TO MIDDLE 80S WITH LOWS  
NEAR 70.  
 

 
   
LONG TERM
 
TUESDAY THRU SATURDAY, A WEAK BROAD HIGH IS PROGGED  
TO SET UP OVER THE FLORIDA PENINSULA DURING TUESDAY AND TUESDAY  
NIGHT. THE SYSTEM STRENGTHENS ONLY SLIGHTLY FOR WEDNESDAY THROUGH  
LATE IN THE WEEK. LITTLE MOISTURE IS AVAILABLE FOR THE CHANCE FOR  
RAIN FOR TUESDAY THROUGH THURSDAY NIGHT, WITH HIGHS IN THE MID 80S  
AND LOWS NEAR 70. ANOTHER SYSTEM IS PROGGED TO MOVE THROUGH THE  
TENNESSEE VALLEY FOR FRIDAY THRU THE WEEKEND, WHICH WILL INCREASE  
LOCAL WINDS GIVEN CONVERGENCE AND INCREASE LOWER TO MIDDLE LEVEL  
MOISTURE. FOR NOW JUST HAVE ISOLATED SHOWERS, A DIME POP FOR JUST  
SHOWERS ATTM FOR FRIDAY THRU SATURDAY, BUT A COLD MIDDLE LEVEL  
SYSTEM ALSO IN TANDEM WITH THIS LOW AT 500 MB AT THIS PARTICULAR  
TRACK USUALLY INTRODUCES SUFFICIENT DYNAMICS FOR AT LEAST  
ISOLATED THUNDERSTORMS GIVEN CHILLING OF MID LEVELS AND ASSOCIATED  
INSTABILITY. WILL WAIT AND SEE IF THESE INDICATIONS CONTINUE.  
HIGH IN THE MID 80S AND LOWS IN THE LOWER TO MID 70S.  
 

 
   
MARINE
 
SCA WILL CONTINUE ACROSS THE FLORIDA STRAITS THRU THE  
EVENING, WITH SCEC CONDITIONS ACROSS THE REST OF THE WATERS,  
EXCEPT MAYBE FLORIDA BAY AND NEARSHORE WATERS NORTH OF THE MIDDLE  
AND LOWER KEYS. WINDS AND SEAS SHOULD BE BELOW HEADLINE OR  
ADVISORY CRITERIA FOR SUNDAY THROUGH THURSDAY NIGHT.  
 

 
   
AVIATION
 
VFR CONDITIONS WILL PREVAIL AT THE ISLAND TERMINALS TONIGHT. SURFACE  
WINDS WILL BE OUT OF THE EAST AT 10 TO 15 KNOTS AND GUSTY, RELAXING  
LATER IN THE AFTERNOON AND EVENING.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
KEY WEST 73 83 72 83 / 10 - - -  
MARATHON 72 83 71 84 / 10 - - -  
 

 
   
KEY WATCHES/WARNINGS/ADVISORIES
 
 
FL...NONE.  
GM...SMALL CRAFT ADVISORY THRU THIS EVENING FOR GMZ052>055-  
072>075.  
 

 
 

 
 
PUBLIC/MARINE...FUTTERMAN  
AVIATION/NOWCASTS....11  
DATA COLLECTION......VICKERY  
 
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