802  
FXUS62 KMLB 240843  
AFDMLB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MELBOURNE FL  
440 AM EDT SUN JUN 24 2018  
   
DISCUSSION
 
 
CURRENT...  
SURFACE RIDGE LOOKS TO BE JUST SOUTH OF LAKE OKEECHOBEE EARLY THIS  
MORNING. MID LEVEL RIDGE WITH ITS AXIS ACROSS NORTH FLORIDA IS  
BEGINNING TO STRENGTHEN AS FORECAST, WITH ECFL LOCATED ON ITS  
SOUTHERN FLANK IN A SLIGHTLY FRESHENING E-NE H70-H50 FLOW.  
H30-H20 HIGH CENTER REMAINS ANCHORED OVER NFL/ECFL. DISSIPATING HIGH  
CLOUDS OVERHEAD WITH SOME SCATTERED TO BROKEN STRATOCUMULUS BELOW.  
LOCAL RADARS SHOW A BIT MORE SHOWER ACTIVITY OFFSHORE THE SE COAST  
EARLY THIS MORNING AS ONSHORE FLOW HAS FINALLY STARTED TO CREEP  
NORTHWARD OVER SOUTH FLORIDA AND THE NORTHERN BAHAMAS. SULTRY TEMPS  
IN THE M-U70S AS OF 3AM.  
 
TODAY-TONIGHT...  
LOCAL AIR MASS WILL REMAIN MORE THAN SUFFICIENTLY MOIST FOR  
SCATTERED-NUMEROUS DIURNAL SHOWERS/STORMS ONCE AGAIN TODAY.  
LOW TO MID LEVEL FLOW PATTERN CONTINUES TO BACK, BECOMING MORE S-SE  
AT/NEAR THE SURFACE AND EASTERLY ABOVE. THIS WILL CONTINUE TO SHIFT  
THE HIGHEST RAIN CHANCES (50-60) TO THE INTERIOR, WITH LOWEST POPS  
(30-40) ALONG THE IMMEDIATE COAST. THIS ALSO PORTENDS AN EARLIER  
ONSET/ENDING TIME FOR CONVECTION, ESPECIALLY NEAR THE COAST AS A  
LIGHT EASTERLY SURFACE TO STEERING LAYER FLOW PUSHES ACTIVITY AWAY  
FROM THE COAST AND INTO THE INTERIOR BY MID-LATE AFTERNOON, AND INTO  
THE WESTERN PENINSULA AROUND SUNSET OR A LITTLE THEREAFTER. THIS  
WILL ALSO SHAVE A DEGREE OR TWO FROM MAX TEMPS, WHICH WILL REACH  
U80S TO AROUND 90F AT THE COAST, AND L90S INLAND. LEFT A SMALL EARLY  
EVENING POP FOR THE INTERIOR, BUT WOULDN'T BE SURPRISED IF ACTIVITY  
WAS WEST OF THERE BY 8PM. DEVELOPING LIGHT ONSHORE (SE-E) LOW-MID  
LEVEL MEAN WIND WILL SUPPORT A SMALL CHANCE FOR SHOWERS TO REACH THE  
TREASURE COAST, PERHAPS AS FAR NORTH AS MLB. SULTRY MINS AGAIN IN  
THE M-U70S.  
 
MON-MON NIGHT...  
BERMUDA RIDGE AXIS OVER NORTH FL WILL GENERATE A LIGHT S/SE BREEZE  
THRU THE H100-H70 LYR...BACKING TO E/SE THRU THE H70-H50 LYR. CLOSE  
PROXIMITY OF THE RIDGE AXIS WILL MAINTAIN A WEAK PGRAD ACRS CENTRAL  
FL, LIMITING STEERING WINDS TO ARND 10KTS. THE EASTERLY WINDS WILL  
PROMOTE AN EARLY FORMATION OF THE EAST COAST SEA BREEZE WHILE  
FOCUSING DIURNAL PRECIP OVER THE WEST HALF OF THE PENINSULA. LATEST  
ANALYSIS OF THE SW ATLC SHOWS HIGH MOISTURE ACRS THE THE BAHAMAS...  
BTWN 70-80PCT THRU THE H100-H70 LYR, AND BTWN 60-70PCT THRU THE H85-  
H50 LYR...PWATS ON THE ORDER OF 2.00".  
 
FAIRLY GOOD RAIN CHANCES AREAWIDE AS THE WEAK PGRAD WILL ALLOW BOTH  
EAST AND WEST COAST SEA BREEZES TO DVLP BY EARLY AFTN. SLOW INLAND  
PROGRESS AND WEAK STEERING FLOW, HOWEVER, WILL BE A LIMITING FACTOR  
AS STORM ACTIVITY PROPAGATES INLAND. EARLY FORMATION OF THE EAST  
COAST SEA BREEZE WILL LIMIT PRECIP CHANCES ALONG THE COAST TO 50PCT.  
AREAS ALONG AND NORTH OF THE I-4 MAY EXPERINCE SLIGHTLY STRONGER MID  
LVL THERMAL RIDGING DUE TO THEIR CLOSER PROXIMITY TO THE RIDGE  
AXIS...WILL LIMIT THESE COUNTIES TO 50PCT AS WELL. FURTHER SOUTH,  
OSCEOLA/OKEECHOBEE COUNTIES SHOULD SEE LESS SUPPRESSION, BUMPING  
THIER POPS UP TO 60PCT. TEMPS SLIGHTLY ABV AVG WITH AFTN MAX TEMPS  
U80S/L90S ALONG THE COAST...L/M90S INTERIOR. MRNG MINS IN THE L/M70S.  
 
TUE-TUE NIGHT...  
HIGH PRES BUILDING OVER THE MID ATLC REGION WILL SHUNT A WEAK  
FRONTAL TROF INTO THE DEEP SOUTH, WITH THE ITS WRN EXTENTION  
PINCHING OFF INTO A BROAD H100-H70 CYCLONE OFF THE CAROLINA COAST.  
THIS WILL WEAKEN AND BREAK DOWN THE WRN FLANK OF THE BERMUDA RIDGE,  
SPLITTING IT INTO TWO INDEPENDENT ANTICYCLONES OVER THE DEEP SOUTH  
AND EAST OF THE BAHAMAS, WITH THE FL PENINSULA SANDWICHED IN BETWEEN  
UNDER A DEEP LYR COL. LIGHT/VARIABLE FLOW THRU THE H100-H70 LYR,  
BCMG EAST ARND 5KTS THRU THE H70-H50 LYR. LITTLE CHANGE IN MOISTURE  
LVLS WITH PWAT HOLDING ARND 2.00".  
 
VERY WEAK STEERING FLOW WILL ALLOW BOTH EAST/WEST COAST SEA BREEZES  
TO FORM BY MIDDAY AND PROPAGATE WELL INLAND. DEEP MOISTURE AND  
DIMINISHING SUPPRESSION WILL KEEP PRECIP CHANCES IN THE 50-60PCT  
RANGE, WHILE SLOW STORM MOTION WILL ENHANCE THE POTENTIAL FOR VERY  
HEAVY LOCALIZED RAINFALL. NO SIG CHANGE IN AIRMASS...TEMPS SIMILAR  
TO MON WITH AFTN MAX TEMPS U80S/L90S ALONG THE COAST...L/M90S  
INTERIOR. MRNG MINS IN THE L/M70S.  
 
WED-SAT...  
DEEP LYR (ALBEIT WEAK) TROFFING PATTERN OVER THE ERN SEABOARD AS THE  
CYCLONE OFF THE CAROLINA COAST JOINS WITH A SECOND TROF PASSING OVER  
THE NRN TIER STATES. THIS WILL PREVENT THE BERMUDA RIDGE FROM  
REBUILDING INTO THE FL PENINSULA, WHILE MAINTAINING A WEAK PGRAD  
ACRS THE REGION. POSITION OF THE TROF AXIS WILL DETERMINE DAY-TO-DAY  
PRECIP CHANCES WITH AREAS ON ITS ASCENDING ERN FLANK MORE LIKELY TO  
SEE RAINFALL. DIFFICULT TO PINPOINT WHERE THIS WILL OCCUR,  
ESPECAILLY AS ECMWF AND GFS DIVERGE SIGNIFICANTLY WITH THE TROF  
DEVELOPMENT BY MIDWEEK. WILL NOT GET TOO FANCY WITH THE FCST AND  
STICK WITH 50PCT POPS THRU THE LATTER HALF OF THE WEEK.  
 

 
   
AVIATION
 
 
06Z TAF PACKAGE RAN WITH ABOUT 3 HOURS OF VCTS 18-21Z NEAR THE COAST  
WITH SHORT/2HR TEMPO TS GROUPS FOR THE INTERIOR AERODROMES BEGINNING  
DURING THE 20Z-24Z TIME FRAME.  
 

 
   
MARINE
 
 
TODAY-TONIGHT...VERY WEAK PRESSURE GRADIENT AS RIDGE AXIS LIFTS  
NORTH ACROSS LAKE OKEECHOBEE AND INTO THE SOUTHERN MAOR BY TONIGHT.  
A GENTLE TO LIGHT S-SW BREEZE WILL BACK TO SE WITH THE AFTERNOON SEA  
BREEZE CIRCULATION, THEN LIGHT SE TO SSW FROM SOUTH TO NORTH AROUND  
THE RIDGE AXIS. SEAS 1FT NEAR SHORE, 2FT OFFSHORE.  
MUCH LOWER COVERAGE OF SHOWERS, WITH THE THREAT FOR OFFSHORE MOVING  
STORMS HAVING BECOME NIL.  
 
MON-TUE...WEAK RIDGING OVER NORTH FL WILL GENERATE A LIGHT TO GENTLE  
SRLY BREEZE, SHIFTING BTWN S/SE IN THE AFTN/EVNG HRS AND S/SW IN THE  
OVERNIGHT/MRNG HRS DUE TO THE LAND/SEA BREEZE CIRCULATION. SEAS AOB  
2FT NEARSHORE AND 2-3FT OFFSHORE. CHC TSRAS EACH DAY.  
 
WED-THU...LOW PRES AREA EXPECTED TO DVLP OFF THE CAROLINA COAST BY  
MIDWEEK WITH ITS TROF AXIS EXTENDING BACK INTO NORTH FL. WEAK PGRAD  
WILL CONTINUE TO KEEP WINDS AOB 10KTS, THOUGH PROXIMITY OF THE TROF  
AXIS WILL FORCE WINDS TO VEER MORE TO A MORE WESTERLY COMPONENT WITH  
SEA BREEZE FORMATION LIMITED TO LATE AFTN/EARLY EVNG. SEAS AOB 2FT  
NEARSHORE AND 2-3FT OFFSHORE. CHC TSRAS EACH DAY.  
 

 
   
HYDROLOGY
 
THE SAINT JOHNS RIVER ABOVE LAKE HARNEY/NEAR GENEVA  
WILL REMAIN AT ACTION STAGE FOR THE FORESEEABLE FUTURE. A VERY SLOW  
RISE IS FORECAST THIS WEEK, WITH THE RIVER CURRENTLY FORECAST TO  
REMAIN BELOW FLOOD STAGE. REFER TO THE LATEST RIVER STATEMENTS  
(MIARVSMLB) ISSUED BY THE NWS OFFICE IN MELBOURNE FOR SPECIFIC  
DETAILS AND RIVER STAGE FORECASTS.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
DAB 91 75 89 75 / 30 10 40 20  
MCO 93 75 93 74 / 60 20 50 30  
MLB 89 76 89 74 / 40 10 60 20  
VRB 89 75 89 73 / 40 20 60 20  
LEE 94 76 94 74 / 60 20 50 30  
SFB 93 76 92 74 / 50 10 50 30  
ORL 93 76 93 74 / 60 20 50 30  
FPR 89 74 88 73 / 40 20 70 20  
 

 
   
MLB WATCHES/WARNINGS/ADVISORIES
 
 
FL...NONE.  
AM...NONE.  
 

 
 

 
 
SHORT TERM/AVIATION...CRISTALDI  
LONG TERM/IMPACT WX...BRAGAW  
 
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