Area Forecast Discussion
Issued by NWS Charleston, SC

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857
FXUS62 KCHS 290938
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
538 AM EDT FRI APR 29 2016

...NEAR RECORD WARMTH THIS AFTERNOON ACROSS SOUTHEAST SOUTH
CAROLINA AND SOUTHEAST GEORGIA...

.SYNOPSIS...
A WEAK COLD FRONT WILL DISSIPATE NEAR THE COAST THIS MORNING. LOW
PRESSURE WILL TRACK TO THE NORTH SUNDAY...BRINGING UNSETTLED
CONDITIONS TO THE AREA. A DEVELOPING LOW WILL PASS OVER OR NEAR
THE AREA DURING THE MIDDLE OF NEXT WEEK...FOLLOWED BY HIGH
PRESSURE BUILDING INTO THE AREA TOWARDS THE END OF THE WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THROUGH SUNRISE...SATELLITE AND SURFACE OBSERVATIONS SHOW STRATUS
AND FOG STEADILY EXPANDING NORTH TOWARDS THE ALTAMAHA RIVER.
REPORTS FROM WFO JACKSONVILLE INDICATE THE FOG REMAINS FAIRLY
SHALLOW...ALTHOUGH THE GOES-EAST FOG CHANNEL SUGGESTS THE FOG IS
THICKENING WITH TIME. HAVE ISSUED AN UPDATE TO INCLUDE AREAS OF
FOG FOR THE ZONES ALONG THE ALTAMAHA RIVER WITH A MENTION OF
PATCHY FOG AS FAR NORTH AS A CLAXTON-RICHMOND HILL LINE. RIGHT
NOW...FOG IS NOT EXPECTED TO BE SIGNIFICANT IN THE SAVANNAH METRO
AREA FOR THE MORNING COMMUTE. THERE IS A CHANCE A DENSE FOG
ADVISORY MAY BE NEEDED ACROSS THE FAR SOUTHERN ZONES PRIOR TO
SUNRISE.

TODAY...29/07Z MESOANALYSIS PLACED THE COLD FRONT ROUGHLY ALONG
THE NORTH CAROLINA-SOUTH CAROLINA BORDER. THE FRONT IS ON TARGET
TO PUSH SOUTH INTO THE FORECAST AREA BY MID-MORNING BEFORE
BECOMING INCREASINGLY DIFFUSE AS IT BECOMES ENTANGLED WITHIN THE
AFTERNOON SEA BREEZE CIRCULATION. INCREASING HEIGHT ALOFT
ASSOCIATED WITH THE BUILDING 850-500 HPA RIDGE COUPLED WITH FULL
INSOLATION AND A WEAK 925-700 HPA DOWNSLOPE COMPONENT WILL SUPPORT
A DOWNRIGHT HOT DAY FOR LATE APRIL WITH HIGHS POISED TO REACH THE
LOWER 90S AWAY FROM THE BEACHES. GENERALLY FAVORED THE HIGHER END
OF THE 29/00Z GUIDANCE, BUT ADDED AN ADDITIONAL 1-2 DEGREES TO
TAKE WEAK DOWNSLOPE PROCESSES INTO ACCOUNT. RECORD HIGHS AT BOTH
THE CHARLESTON AND SAVANNAH AIRPORTS COULD BE CHALLENGED WHILE THE
RECORD IN DOWNTOWN CHARLESTON LOOKS SAFE FOR NOW. THE 925-850 HPA
FLOW IS NOT PARTICULARLY STRONG--GENERALLY 8-15 KT--SO THE SEA
BREEZE CIRCULATION SHOULD MAKE SOME INLAND PROGRESSION, ALTHOUGH
IT WILL BE LIKELY GO NO FURTHER THAN THE HIGHWAY 17 CORRIDOR IN
SOUTHEAST SOUTH CAROLINA AND I-95 IN SOUTHEAST GEORGIA.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
TONIGHT...BENIGN CONDITIONS WILL PERSIST TONIGHT. MODELS SHOW A
WEAK WARM FRONTAL FEATURE DEVELOPING ALONG THE GULF OF COAST
COINCIDENT WITH A STRENGTHENING LOW-LEVEL JET, BUT ANY SHOWER
ACTIVITY ASSOCIATED WITH THIS BOUNDARY WILL REMAIN DISPLACED WELL
TO THE WEST. COULD SEE SOME SHALLOW GROUND FOG DEVELOP JUST BEFORE
SUNRISE SATURDAY, BUT SUSPECT STRONG DRYING TODAY WILL LIKELY
LIMIT ITS POTENTIAL DESPITE SURFACE DEWPOINTS POOLING BACK INTO
THE LOWER 60S. LOWS WILL RANGE FROM THE MID 60S INLAND TO THE
UPPER 60S/NEAR 70 AT THE BEACHES--WARMEST ALONG THE GEORGIA COAST.

SATURDAY...THE RIDGE OVER THE EAST COAST WILL SHIFT EASTWARD AND
WEAKEN DURING THE DAY AS A STRENGTHENING TROUGH MOVES INTO THE
CENTRAL U.S. THE MODELS ARE IN FAIRLY GOOD AGREEMENT SHOWING ENOUGH
MOISTURE AND FORCING AHEAD OF THE APPROACHING TROUGH TO GENERATE
ISOLATED SHOWERS AND THUNDERSTORMS LATE IN THE DAY...ESPECIALLY WEST
OF I-95. HIGHS WILL AGAIN BE IN THE UPPER 80S TO NEAR 90...EXCEPT
COOLER AT THE COAST DUE TO SOUTHERLY FLOW VEERING TO A RESULTANT SEA
BREEZE DURING THE AFTERNOON. MOISTURE AND CLOUDS WILL CONTINUE
INCREASING SATURDAY NIGHT AS THE TROUGH MOVES EASTWARD. MODELS STILL
SHOW SOME WEAK IMPULSES MOVING ACROSS THE REGION OVERNIGHT. BUT THE
LACK OF STRONG FORCING AND LOSS OF HEATING/INSTABILITY WILL BE
ENOUGH TO KEEP LIMIT POPS TO SLIGHT CHANCE ACROSS MOST OF THE AREA
LATE. LOWS ARE AGAIN MILD...IN THE MID TO UPPER 60S...POSSIBLY 70
ALONG THE SE GEORGIA COAST.

SUNDAY...LOOKS TO BE THE MOST UNSETTLED DAY OF THE PERIOD.
SUFFICIENT DEEP LAYER MOISTURE AND CAPE VALUES 1000-1500 J/KG ON THE
SOUTHEAST SIDE OF THE UPPER TROUGH OVER THE OH RIVER VALLEY...SHOULD
TRANSLATE TO SCATTERED SHOWERS AND THUNDERSTORMS. AGAIN...NO STRONG
UPPER FORCING...THUS FEEL BEST CHANCES WILL BE MAINLY AFTERNOON
COINCIDENT WITH MAXIMUM HEATING/INSTABILITY. HIGHS A TAD COOLER THAN
PREVIOUS DAYS DUE TO CLOUD COVER...IN THE MID 80S MOST AREAS.

MONDAY...A TROUGH WILL BE OVER THE NORTHEASTERN STATES WHILE SURFACE
LOW PRESSURE IS TO OUR NORTH. AS THE LOW MOVES OFFSHORE THE COLD
FRONT ASSOCIATED WITH THE LOW WILL MOVE THROUGH OUR REGION IN THE
AFTERNOON. A CHANCE OF SHOWERS AND THUNDERSTORMS WILL PERSIST.
TEMPERATURES WILL REMAIN ABOVE NORMAL...THE MID TO UPPER 80S
INLAND...COOLER ALONG THE COAST.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
THE MODELS START TO DIVERGE MONDAY NIGHT. THE 00Z GFS HAS WEAK HIGH
PRESSURE IN PLACE MONDAY NIGHT INTO TUESDAY...FOLLOWED BY A LOW
DEVELOPING TO OUR SOUTH TUESDAY NIGHT. THE LOW WILL PASS OVER OR
NEAR US WEDNESDAY FOLLOWED BY BUILDING HIGH PRESSURE THURSDAY. THE
00Z ECMWF DOES NOT HAVE HIGH PRESSURE IN PLACE MONDAY NIGHT INTO
TUESDAY...INSTEAD IT HAS UNSETTLED WEATHER OVER OUR
AREA...ORIGINATING IN THE GULF OF MEXICO. A LOW WILL DEVELOP TO OUR
SOUTH TUESDAY. THE LOW WILL PASS OVER OR NEAR US TUESDAY NIGHT
FOLLOWED BY POSSIBLY ANOTHER LOW ON WEDNESDAY. HIGH PRESSURE BUILDS
IN ON THURSDAY. THE 00Z CANADIAN HAS WEAK HIGH PRESSURE IN PLACE
MONDAY NIGHT INTO TUESDAY. A LOW WILL DEVELOP TO OUR SOUTHWEST
TUESDAY...PASSING TO OUR WEST TUESDAY NIGHT. HIGH PRESSURE BUILDS IN
BEHIND THAT. GIVEN ALL THE DIFFERENT SOLUTIONS...OPTED TO GO WITH
SLIGHT CHANCE POPS MONDAY NIGHT FOLLOWED BY CHANCE POPS TUESDAY INTO
WEDNESDAY. WE START DRYING OUT WEDNESDAY NIGHT INTO THURSDAY. WITH A
TROUGH OVER THE EAST COAST DURING THIS TIME FRAME TEMPERATURES WILL
BE BELOW NORMAL WEDNESDAY AND THURSDAY.

&&

.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
VFR. COULD SEE SHALLOW GROUND FOG PRIOR TO SUNRISE...ESPECIALLY
KCHS WHERE RAINS FELL EARLIER. DO NOT ANTICIPATE ANY SIGNIFICANT
REDUCTIONS IN VSBYS UNLESS WINDS GO CALM PRIOR TO DAYBREAK.

EXTENDED AVIATION OUTLOOK...EARLY NEXT WEEK...SCATTERED
SHOWERS AND THUNDERSTORMS ARE LIKELY...WHICH COULD PRODUCE BRIEF
FLIGHT RESTRICTIONS.

&&

.MARINE...
TODAY...SOUTHWEST WINDS WILL BECOME SOUTH THE AFTERNOON AS A
COLD FRONT WEAKENS AS IT INTERACTS WITH A SEA BREEZE CIRCULATION
THIS AFTERNOON. WINDS WILL REMAIN RATHER LIGHT ACROSS THE LOCAL
MARINE AREA WITH WINDS REMAINING 10 KT OR LESS THROUGH THE DAY.
SEAS WILL AVERAGE 1-2 FT.

TONIGHT...LIGHT SOUTHERLY WINDS WILL PERSIST INTO TONIGHT WITH
SPEEDS GENERALLY LESS THAN 10 KT AND SEAS 1-2 FT.

SATURDAY THROUGH WEDNESDAY...TRANQUIL WEATHER CONDITIONS...WIND
SPEEDS ARE EXPECTED TO REMAIN BELOW 15 KT WHILE SEAS ARE 3 FEET OR
LESS. ATLANTIC HIGH PRESSURE WILL BE MORE NOTICEABLE ON SATURDAY.
SUNDAY THROUGH THE MIDDLE OF NEXT WEEK THE PATTERN BECOMES
UNSETTLED AS A TROUGH MOVES WELL NORTH OF THE WATERS. EXPECT
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS THROUGH THIS
PERIOD.

&&

.CLIMATE...
RECORD HIGHS FOR 29 APRIL...
KCHS 92/2002...
KCXM 92/2002...
KSAV 93/2002...

&&

.EQUIPMENT...
THE CHARLESTON HARBOR NOS TIDE GAUGE HAS STOPPED REPORTING ALL
METEOROLOGICAL AND TIDE DATA. THE NATIONAL OCEAN SERVICE IS
INVESTIGATING THE CAUSE OF THE OUTAGE. AN ESTIMATED TIME FOR DATA
RESTORATION IS UNKNOWN AT THIS TIME.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

ST/MS



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