FXUS62 KMLB 281343 AFDMLB AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 943 AM EDT WED AUG 28 2013 UPDATE...CONVGT BAND AND ATTENDANT CONVECTIVE CELLS WHICH PRODUCED MARINE VORTICES ALONG/OFFSHORE THE TREASURE COAST FOR THE SECOND CONSECUTIVE DAY (AND THIRD IN SIX DAYS) HAS WEAKENED A BIT SINCE EARLIER THIS MORNING. SUBSIDENCE ZONE ASCD WITH DEVELOPING ECSB CIRC NEAR SHORE WILL LIKELY CONTINUE THIS TREND THROUGH LATE MORNING AND EARLY AFTERNOON...DECREASING THREAT FOR SPOUT TYPE VORTICES. ELSEWHERE...SUNNY TO MOSUNNY SKIES PREVAIL. GPS AND RAOB DATA SHOW A FAIRLY SIGNIFICANT N-S DISPARITY IN PWATS EXISTS AGAIN TODAY...WITH 1.2" ACROSS THE FAR NORTH...1.4" TO 1.5" OVER THE CENTRAL...AND 1.6" TO 1.7" SOUTHERN CWA. THE LAKE OKEE/TREASURE COAST REGION ALSO REMAINS UNDER WEAKLY DIVERGENT FLOW ASCD WITH THE MID TO UPPER LEVEL LOW CENTERED OVER THE FL KEYS. ALL IN ALL...THIS FAVORS THE CURRENT CONFIGURATION OF HIGHEST POPS TO THE SOUTH...WITH NIL TO MINIMAL RAIN CHANCE FARTHER NORTH. MAY TWEAK GRIDS TO SHOW RAIN CHANCES MOVING WEST AND OUT OF THE COASTAL COUNTIES BY LATE AFTERNOON. ASIDE FROM THAT POTENTIAL TWEAK...THE FORECAST LOOKS FINE. && .AVIATION...MINIMAL RAIN CHANCES TODAY. MUCH LIKE TUE...THE BEST CHANCE WILL BE THROUGH ABOUT 18Z @ KVRB-KFPR-KSUA. && .MARINE...LOCAL PGRAD HAS SIGNIFICANTLY WEAKENED THAT PAST TWO DAYS AND AS A RESULT...SO HAS THE WIND CHOP. SEA STATE OVER THE MAOR IS COMPRISED ALMOST ENTIRELY OF 8-9SEC PD NE-ENE GROUNDSWELL OF 2-3FT. CURRENT GRIDS/CWF HAVE THIS WELL IN HAND. NO CHGS NEEDED. && FORECAST/AVIATION...CRISTALDI IMPACT WX...WIMMER && .PREV DISCUSSION... /ISSUED 313 AM EDT WED AUG 28 2013/ TODAY...THE UPPER LOW NEAR THE KEYS WILL DRIFT SLOWLY NORTH BRINGING THE CHANCE FOR SHOWERS AND LIGHTNING STORMS TO MAINLY SRN SECTIONS THIS AFTERNOON. AT THE SFC...A WEAK HIGH PRESSURE CENTER NE OF THE AREA WILL PROVIDE A LIGHT ONSHORE FLOW. THE DRIER AIRMASS THAT SETTLED IN ACROSS NRN AND CENTRAL PORTIONS OF THE FORECAST AREA YESTERDAY SHOULD LINGER WITH SOME DEWPOINTS INTO THE 60S AND NEARLY NIL RAIN CHANCES FOR N CSTL SECTIONS WITH MUCH LOWER THAN NORMAL PRECIPITABLE WATER VALUES LESS THAN 1.4 INCHES AND A WEAK E COAST SEA BREEZE MOVING INLAND THIS AFTERNOON. WILL INCLUDE A SLGT CHC FOR AN AFTERNOON SHOWER OR TSTM ACROSS WELL INTERIOR SECTIONS INCLUDING LAKE COUNTY AS THE EAST COAST SEA BREEZE PUSHES INLAND LATE IN THE AFTERNOON. HIGHS WILL BE IN THE UPPER 80S COAST TO LOWER 90S INTERIOR. TONIGHT...MID/UPR LOW WILL DRIFT NW JUST OFF THE SW FL COAST WITH LOW LVL SE FLOW VEERING THROUGH THE NIGHT. WILL KEEP A LOW POP FOR SRN COASTAL SECTIONS WHERE ISOLD SHOWERS MAY MOVE ONSHORE MAINLY BEFORE MIDNIGHT. LOWS WILL BE PLEASANT FOR LATE AUGUST IN THE UPPER 60S TO LOWER 70S. THU-SUN...MODELS CONTINUE TO SHOW THE UPPER LEVEL LOW NEAR THE SOUTHWEST FLORIDA COAST FORECAST TO LIFT NORTH-NORTHWESTWARD ALONG THE WEST FLORIDA COAST AND WEAKEN THROUGH THE WEEKEND. AS THIS OCCURS MID LEVEL HIGH PRESSURE WILL BUILD BACK INTO THE AREA FROM THE SOUTH AND EAST. AT THE SURFACE...HIGH PRESSURE RIDGING WILL BUILD BACK INTO THE SOUTH-CENTRAL PENINSULA. THE PRESSURE GRADIENT WILL REMAIN WEAK WITH LIGHT WINDS WITH DAILY EAST COAST SEA BREEZE FORMATION AND LIKELY INLAND MOVEMENT. HOWEVER...DEEPEST PRECIPITABLE WATER VALUES WILL REMAIN BOTH NORTH AND SOUTH OF EAST CENTRAL FLORIDA AS DRIER AIR WILL LIE OVER THE AREA. WILL CONTINUE WITH UNSEASONABLY LOWER PRECIPITATION CHANCES WITH 20 TO 30 PERCENT FOR THE PERIOD. STILL FEEL MAV MOS TEMPERATURES ARE TOO HIGH FOR AFTERNOON MAXES AND WILL REMAIN BELOW GUIDANCE IN THE FORECAST. OVERALL HIGHS AND LOWS SHOULD BE NEAR CLIMO. MON-TUE...AN UPPER TROUGH OVER THE GREAT LAKES EARLY IN THE PERIOD WILL MOVE TOWARDS THE EASTERN SEABOARD AND BEAT BACK DOWN A BIT THE MID-LEVEL HIGH PRESSURE RIDGING ACROSS THE REGION. THIS WILL ACT TO DRIVE A WEAK SURFACE BOUNDARY INTO THE DEEP SOUTH. DEEPER MOISTURE WILL POOL ACROSS THE FLORIDA PENINSULA AHEAD OF THIS FEATURE. THE PRESSURE GRADIENT REMAINS WEAK WITH A DAILY EAST COAST SEA BREEZE BOUNDARY EXPECTED TO MOVE INLAND EACH AFTERNOON. WILL KEEP INHERITED 30 POPS FOR NOW BUT AN INCREASE TO 40 PERCENT MAY BE POSSIBLE BY FUTURE FORECAST SHIFTS AS WE HEAD TOWARD TUE. && .AVIATION...MAINLY VFR. ISOLD SHOWERS FOR THE KVRB-KSUA CORRIDOR INTO EARLY AFTERNOON BEFORE EAST COAST SEA BREEZE PUSHES CONVECTION INLAND. SOME ISOLD SHRA/TSRA ACTIVITY MAY ALSO DEVELOP ACROSS THE INTERIOR 20Z-24Z BUT CONFIDENCE LOWER NORTH OF KISM WHERE DRIER AIR LINGERS. && .MARINE...LIGHT ONSHORE FLOW WILL VEER FROM SE TO S/SW LATE TONIGHT. SEAS 2 FT NEAR THE COAST TO AROUND 3 FT OFFSHORE. SOME SHOWERS AND POSSIBILITY AN ISOLATED TSTM MAINLY SOUTH OF MELBOURNE BEACH TODAY AND TONIGHT. THU-SUN...LOW-LEVEL RIDGING HOLDING STEADY OVER THE SOUTH-CENTRAL PENINSULA WITH A WEAK PRESSURE GRADIENT IN PLACE. EAST COAST SEA BREEZE FORMATION IS EXPECTED EACH AFTERNOON. WHILE AN ONSHORE COMPONENT OF WIND WILL DEVELOP EACH AFTERNOON...EXPECT A LIGHT SW-W COMPONENT TO DEVELOP EACH NIGHT/MORNING. WIND SPEEDS AOB 15 KTS THRU THE PERIOD. SEAS MAINLY 2-3 FT. && .FIRE WEATHER...SHORT RANGE MOS GUIDANCE INDICATES SFC DEWPOINTS SHOULD DROP INTO THE MID 60S ACROSS NRN INTERIOR SECTIONS WITH MIN RHS DROPPING TO AROUND 40 PCT THIS AFTERNOON. EAST WINDS TO 5 TO 10 MPH AND LOW ERC VALUES ACROSS THE INTERIOR WILL NOT MEET CRITICAL FIRE WEATHER CRITERIA. && .CLIMATE...VERO BEACH RECORDED 0.49 INCHES OF RAIN YESTERDAY WHICH BRINGS THEIR MONTHLY TOTAL TO 1.31 INCHES. THIS IS CURRENTLY THE SECOND ALL-TIME DRIEST AUGUST AT VERO BEACH WITH FOUR DAYS LEFT IN THE MONTH. DRIEST IS 1.22 INCHES IN 1980 AND THIRD DRIEST IS 1.73 INCHES IN 1996. && .PRELIMINARY POINT TEMPS/POPS... DAB 88 71 91 74 / 10 10 20 20 MCO 91 71 92 73 / 20 10 20 20 MLB 88 71 88 74 / 20 10 20 20 VRB 88 69 90 73 / 30 20 20 20 LEE 92 73 93 75 / 20 10 20 20 SFB 91 72 93 75 / 10 10 20 20 ORL 91 73 92 76 / 20 10 20 20 FPR 88 69 88 72 / 30 20 20 20 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM/AVIATION...VOLKMER LONG TERM....SEDLOCK PALMBAYWEATHER.info
Posted on: Wed, 28 Aug 2013 13:43:48 +0000