Coastal Flood in Florida, September 26 to 27, 2015

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
352 PM EDT SAT SEP 26 2015

.CURRENTLY...ISOLD TO SCT SHOWERS OVER THE FORECAST AREA MAINLY IN
NE FL SLOWLY PUSHING WWD TO NW. NOT WHOLE LOT OF INSTABILITY SO
FAR WITH SBCAPE MAXIMIZED AT ABOUT 2000-2500 J/KG...BUT AIRMASS
IS FAIRLY TROPICAL WITH 500 MB TEMPS OF ABOUT -6 AND NARROW CAPE
ALOFT. ANTICIPATE AN UPTICK IN CONVECTION REST OF THE AFTN MAINLY
INLAND WITH MAIN CONCERN LIGHTNING AND LOCALLY HEAVY
DOWNPOURS...MAINLY IN NE FL.

.SHORT TERM...
TONIGHT...ISOLD TO SCT SHOWERS AND A FEW STORMS IN THE EVENING
WILL GRADUALLY FADE WITH COASTAL TROUGH SET UP AGAIN TO PRODUCE
SOME OVERNIGHT MARINE SHOWERS AND PERHAPS A TSTMS IN CONVERGENT
LOW LEVEL NE FLOW. A FEW SHOWERS CANNOT BE RULED OUT FOR THE
COASTAL ZONES AGAIN LATE TONIGHT AND EARLY SUNDAY COMING IN OFF
THE ATLC. SIMILAR TO LAST NIGHT...LOW STRATUS AND PATCHY DENSE
FOG IS LIKELY TONIGHT. RAP AND SREF SHOW A VERY MOIST LAYER AROUND
500-1000 FT WITH SREF LOW CIGS PROBABILITIES BETTER THAN 70%. LOWS
TONIGHT MAINLY IN THE LOWER 70S.

SUNDAY...AFTER AREAS OF MORNING LOW CLOUDS/FOG EXPECT SCATTERED
MORNING COASTAL SHOWERS TO SHIFT INLAND WITH ISOLATED AFTERNOON
THUNDERSTORMS POSSIBLE. A NE LOW LEVEL FLOW WILL PERSIST WITH
STRONG HIGH PRESSURE CENTER MOVING OFF THE NEW ENGLAND COAST AND
A WEAK SURFACE LOW DRIFTING INTO THE GULF...NORTH OF THE YUCATAN
PENINSULA. HIGH CLOUDINESS WILL INCREASE WHICH WILL LIKELY RESULT
IN HIGH TEMPERATURES A COUPLE OF DEGREES LOWER THAN TODAYS. HIGH
SHOULD BE MOSTLY IN THE LOW TO MID 80S. MODELS SHOW SURGE OF
TROPICAL MOISTURE STARTING TO MOVE INTO THE FL PANHANDLE AND
SUWANNEE VALLEY SUNDAY NIGHT. THUS POPS WILL BE HIGHER OVER OUR
WESTERN COUNTIES.

MONDAY AND TUESDAY...MODELS CONTINUE TO SHOW DEEP TROPICAL
MOISTURE SPREADING ACROSS THE AREA MONDAY AND TUESDAY. BOTH GFS
AND ECMWF SHOW PWATS REACHING NEAR 2.5" WHICH IS MUCH ABOVE
NORMAL. THIS WILL LIKELY PRODUCE AREAS OF HEAVY RAINFALL ENHANCED
BY UPPER IMPULSES IN SW FLOW ALOFT. UNCERTAINTY STILL EVIDENT IN
TRACK OF SURFACE LOW WITH GFS/GFS ENSEMBLE MOVING LOW INTO THE FL
PANHANDLE ON TUESDAY AND THEN ACROSS S GA TUESDAY NIGHT. ECMWF
SHOWS A TRACK FURTHER SOUTH...WITH THE LOW MOVING ACROSS NE FL
WITH HIGHER QPF VALUES FOR NE FL.

.LONG TERM...WEDNESDAY THROUGH SATURDAY...UPPER LOW OVER THE
WESTERN GULF WEAKENS AND OPENS UP AS IT PHASES WITH A NORTHERN
STREAM TROUGH ON WEDNESDAY. DRIER AIR IN THE MID AND UPPER LEVELS
WILL SPREAD INTO THE AREA DECREASING THE HEAVY RAINFALL CHANCES.
ANOTHER STRONG SURFACE HIGH WILL BUILD DOWN THE EAST COAST FRIDAY
AND SATURDAY WITH INCREASING ONSHORE WINDS AND A CONTINUING
CHANCE OF SHOWERS. TEMPERATURES WILL BE AT OR SLIGHTLY BELOW
AVERAGE WITH RAIN CHANCES RETURNING TO NEAR NORMAL.

&&

.AVIATION...OCNL MVFR CIGS EXPECTED THROUGH THE AFTN WITH A FEW
SHOWERS POSSIBLE. VFR EXPECTED THIS EVENING ...WITH LOW CIGS
EXPECTED LATE TONIGHT. CIGS EXPECTED TO LOWER INTO IFR AND
POSSIBLY INTO LIFR CATEGORY AFTER 06Z...WITH HIGHEST PROBABILITIES
AROUND THE 09Z-13Z TIME FRAME. CIGS SHOULD LIFT TO MVFR BY
14Z/15Z SUNDAY.

&&

.MARINE...E TO NE WINDS AOB 15 KT EXPECTED THROUGH SUNDAY WITH
SEAS GENERALLY IN THE 3-4 FT RANGE. WINDS WILL SLACKEN THROUGH
BY MONDAY AS PRES GRADIENT RELAXES. WIND DIRECTION VEERS MONDAY
AND TUESDAY AS THE WEDGE BEGINS TO SHIFT EAST AND LOW PRESSURE
FORMS IN THE GULF OF MEXICO.

RIP CURRENTS: MODERATE RISK THROUGH SUNDAY DUE TO ONSHORE WINDS
AND SURF AROUND THE 3 FT RANGE.

COASTAL IMPACTS: ISSUING A COASTAL FLOOD ADVISORY FOR THIS
EVENING HIGH TIDE AND ONSHORE WINDS. BASED ON GUIDANCE...WE SHOULD
JUST TOUCH MINOR FLOODING CRITERIA. WE HAVE DECIDED TO EXTEND
THIS ADVISORY THROUGH LATE SUNDAY DUE TO UPCOMING FULL MOON AND
PERSISTENT ONSHORE WINDS.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  69  84  70  83 /  30  40  20  60
SSI  72  79  72  79 /  30  30  30  50
JAX  72  82  73  83 /  30  40  20  60
SGJ  75  81  73  82 /  30  40  30  50
GNV  71  85  71  84 /  30  50  30  60
OCF  72  87  72  86 /  40  50  40  60

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...COASTAL FLOOD ADVISORY UNTIL 2 AM EDT MONDAY FOR COASTAL DUVAL-
     COASTAL NASSAU-FLAGLER-INLAND DUVAL-INLAND NASSAU-ST. JOHNS.

GA...COASTAL FLOOD ADVISORY UNTIL 2 AM EDT MONDAY FOR COASTAL CAMDEN-
     COASTAL GLYNN-INLAND CAMDEN-INLAND GLYNN.

AM...NONE.

&&

SHASHY/ZIBURA/GUILLET

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE JACKSONVILLE FL
436 PM EDT SAT SEP 26 2015

AMZ450-452-454-470-472-474-FLZ020>025-030>033-035>038-040-124-125-
GAZ132>136-149>154-162>166-272030-
COASTAL WATERS FROM ALTAMAHA SOUND TO FERNANDINA BEACH FL OUT
20 NM-
COASTAL WATERS FROM FERNANDINA BEACH TO ST. AUGUSTINE FL OUT
20 NM-
COASTAL WATERS FROM ST. AUGUSTINE TO FLAGLER BEACH FL OUT 20 NM-
WATERS FROM ALTAMAHA SOUND GA TO FERNANDINA BEACH FL FROM 20 TO
60 NM-
WATERS FROM FERNANDINA BEACH TO ST. AUGUSTINE FL FROM 20 TO 60 NM-
WATERS FROM ST. AUGUSTINE TO FLAGLER BEACH FL FROM 20 TO 60 NM-
HAMILTON-SUWANNEE-COLUMBIA-BAKER-INLAND NASSAU-INLAND DUVAL-UNION-
BRADFORD-CLAY-ST. JOHNS-GILCHRIST-ALACHUA-PUTNAM-FLAGLER-MARION-
COASTAL NASSAU-COASTAL DUVAL-COFFEE-JEFF DAVIS-BACON-APPLING-
WAYNE-ATKINSON-WARE-PIERCE-BRANTLEY-INLAND GLYNN-COASTAL GLYNN-
ECHOLS-CLINCH-CHARLTON-INLAND CAMDEN-COASTAL CAMDEN-
436 PM EDT SAT SEP 26 2015

...COASTAL FLOOD ADVISORY THROUGH SUNDAY NIGHT...

...MODERATE RISK OF RIP CURRENTS CONTINUES THROUGH THE WEEKEND...

...HEAVY RAINFALL POSSIBLE NEXT WEEK...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST FLORIDA...
SOUTHEAST GEORGIA AND THE ADJACENT COASTAL WATERS.

.DAY ONE...REST OF TODAY AND TONIGHT...

SCATTERED AFTERNOON AND EARLY EVENING SHOWERS WITH ISOLATED
THUNDERSTORMS ARE EXPECTED MAINLY ACROSS THE INLAND AREAS TOWARDS
I-75.

MINOR COASTAL FLOODING IS POSSIBLE DURING THE HIGH TIDE CYCLES THIS
WEEKEND WITH ELEVATED WATER LEVELS ALSO ALONG THE SAINT JOHNS RIVER
AND ITS TRIBUTARIES. MINOR FLOODING WILL BE POSSIBLE ALONG NORMALLY
FLOOD PRONE AREAS ALONG THE SAINT JOHNS RIVER AND THE INTRACOASTAL
WATERWAY.

A MODERATE RISK OF RIP CURRENTS CONTINUES AT AREA BEACHES DUE TO A
LONG PERIOD OCEAN SWELL AND ONSHORE WINDS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY...

ELEVATED WATER LEVELS WILL PERSIST THROUGH EARLY NEXT WEEK...WITH
MINOR COASTAL FLOODING POSSIBLE DURING TIMES OF HIGH TIDE AS
ASTRONOMICAL TIDES PEAK ON SUNDAY AND MONDAY.

A MODERATE RISK OF RIP CURRENTS WILL CONTINUE AT AREA BEACHES.

LOW PRESSURE WILL MOVE INTO THE SOUTHERN GULF OF MEXICO BY LATE
SUNDAY. THIS SYSTEM COULD ORGANIZE FURTHER AS IT MOVES NORTHWARD
TOWARDS THE FLORIDA PANHANDLE COAST EARLY NEXT WEEK. A DEEP FEED
OF TROPICAL MOISTURE MAY IMPACT THE SUWANNEE VALLEY AND INLAND
SOUTHEAST GEORGIA BY LATE MONDAY...CREATING NUMEROUS HEAVY SHOWERS
AND EMBEDDED THUNDERSTORMS. DEPENDING ON THE STRENGTH AND MOVEMENT
OF THIS SYSTEM...WIDESPREAD HEAVY RAINFALL MAY PUSH INTO THE REST OF
OUR AREA ON TUESDAY. THERE IS A RISK FOR FLOODING DEPENDING ON THE
EVOLUTION OF THIS SYSTEM.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED THROUGH TONIGHT.

FOR ADDITIONAL INFORMATION...VISIT THE NATIONAL WEATHER SERVICE
IN JACKSONVILLE WEBSITE ON THE INTERNET AT WEATHER.GOV/JAX.