Area Forecast Discussion
Issued by NWS Charleston, SC

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FXUS62 KCHS 250007
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
707 PM EST WED DEC 24 2014

.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA FROM WEST TO EAST TONIGHT. HIGH
PRESSURE WILL BUILD FROM THE GULF COAST REGION THURSDAY AND
WILL PREVAIL INTO THIS WEEKEND. INCREASING MOISTURE COULD BRING SOME
SHOWERS THIS WEEKEND...AND UNSETTLED WEATHER WILL LINGER INTO THE
MIDDLE OF NEXT WEEK AS A FRONT STALLS NEARBY.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
WEDNESDAY EVENING...THE WARM CONVEYOR BELT AND ASSOCIATED WIDESPREAD
PRECIPITATION WAS SHIFTING OFFSHORE. HOWEVER...THE SURFACE COLD
FRONT REMAINED WEST OF THE REGION...AND DEEP LAYER SOUTH/SOUTHWEST
FLOW WILL CONTINUE TO ADVECT MOISTURE INTO THE REGION AHEAD OF
THIS FEATURE. PER RECENT RADAR TRENDS...FORCING FOR ASCENT WILL
SUPPORT AT LEAST ISOLATED/SCATTERED SHOWERS AHEAD OF COLD FROPA.
THUS...RAISED POPS SOMEWHAT THIS EVENING AND EXTENDED POPS DEEPER
INTO THE OVERNIGHT HOURS. LOCALLY GREATER POPS COULD BE
NEEDED...BUT THE POTENTIAL FOR HEAVY RAIN AND THUNDERSTORMS HAS
PASSED.

THE COLD FRONT WILL CROSS THE REGION LATER THIS EVENING AND
OVERNIGHT...AND GUSTY WEST WINDS WILL PUSH COOLER AND DRIER AIR
INTO THE REGION. BY DAYBREAK...TEMPERATURES WILL FALL INTO THE 40S
INLAND AND 50S NEAR THE COAST...AND ALL PRECIPITATION SHOULD SHIFT
OFF THE COAST.

LAKE WINDS...POST/COLD FRONT PRESSURE RISES AND UPSTREAM
OBSERVATIONS SUGGEST THE POTENTIAL FOR A FEW HOURS OF WESTERLY WIND
GUSTS TO 25 KTS ON LAKE MOULTRIE AS COLD ADVECTION DEVELOPS.
TO ADDRESS THIS SCENARIO...ISSUED A LAKE WIND ADVISORY VALID 10 PM
TO 5 AM.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
THURSDAY...A MUCH DRIER AND COOLER AIR MASS WILL MOVE INTO THE
REGION BEHIND A DEPARTING COLD FRONT. HIGHS WILL BE BACK CLOSER TO
NORMAL /AROUND 60/...PROBABLY A BIT WARMER IN THE LOWER 60S GIVEN
THE DOWNSLOPE FLOW. DECENT RADIATIONAL COOLING CONDITIONS THURSDAY
NIGHT WILL ALLOW TEMPS TO FALL BACK TO NEAR NORMAL IN THE UPPER 30S
INLAND TO LOWER 40S AT THE COAST.

FRIDAY...HIGH PRESSURE WILL SETTLE OVER THE CAROLINAS WITH DRY
CONDITIONS PREVAILING...ALTHOUGH HIGH CLOUDS WILL BE ON THE
INCREASE. HIGHS SHOULD PUSH INTO THE MID 60S MOST PLACES. FRIDAY
NIGHT SHOULD BE DRY TOO ALTHOUGH CLOUDS WILL BE ON THE INCREASE AS
DEEPER MOISTURE MOVES IN FROM THE SOUTH. THIS WILL KEEP TEMPS FROM
DROPPING MUCH...LIKELY ONLY REACHING THE MID 40S INLAND AND LOWER
50S NEAR THE COAST.

SATURDAY...MOISTURE WILL CONTINUE TO INCREASE WITH SOME SHOWERS
LIKELY...ESPECIALLY OVER SOUTHEAST GEORGIA. HIGHS SHOULD PUSH INTO
THE MID TO UPPER 60S.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MOISTURE RETURN AND FAVORABLE ISENTROPIC ASCENT SHOULD RESULT IN
SHOWERS EXPANDING OVER THE AREA SATURDAY NIGHT INTO SUNDAY AHEAD OF
AN AREA OF LOW PRESSURE THAT DEVELOPS OVER THE NORTHERN GULF OF
MEXICO AND TRACKS THROUGH THE AREA BY SUNDAY NIGHT. AFTER A SHORT
LULL IN ACTIVITY ON MONDAY...THE PATTERN SUGGESTS UNSETTLED WEATHER
CONDITIONS ON TUESDAY AND PERHAPS INTO PARTS OF WEDNESDAY AS ANOTHER
AREA OF LOW PRESSURE TRACKS ALONG A DEVELOPING FRONT OVER OR NEAR
THE SOUTHEASTERN UNITED STATES. HIGH PRESSURE SHOULD THEN BUILD INTO
THE REGION FROM THE WEST LATE WEDNESDAY...RESULTING IN DRYER
CONDITIONS MID WEEK.

OVERALL HIGH AND LOW TEMPS WILL BE HIGHLY DEPENDENT ON CLOUD COVER
AND SHOWER COVERAGE...BUT SHOULD BE SLIGHTLY ABOVE OR NEAR NORMAL
INTO THE MIDDLE OF NEXT WEEK. IN GENERAL...EXPECT HIGHS IN THE
MID/UPPER 60S ON SUNDAY...THEN UPPER 50S TO LOWER 60S MONDAY THROUGH
WEDNESDAY AS CLOUD COVER AND SHOWERS EXPAND OVER THE AREA. OVERNIGHT
LOWS WILL GENERALLY RANGE IN THE UPPER 40S TO LOWER 50S SATURDAY
NIGHT AND SUNDAY NIGHT...THEN LOW TO MID 40S MONDAY NIGHT AND
TUESDAY NIGHT.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
PERIODS OF MVFR/IFR CEILINGS AND SCATTERED SHOWERS WILL GIVE WAY
TO VFR CEILINGS BY LATE TONIGHT...THEN VFR CONDITIONS WILL PREVAIL
THROUGH CHRISTMAS DAY.

EXTENDED AVIATION OUTLOOK...LOW CHANCES OF MVFR CIGS/VSBYS SATURDAY
INTO MONDAY AS MOISTURE INCREASES OVER THE AREA.

&&

.MARINE...
TONIGHT...DEWPOINTS IN THE 60S SPREADING OVER COOL SHELF WATERS
WILL SUPPORT AT LEAST PATCHY FOG UNTIL A COLD FRONT ARRIVES
OVERNIGHT. S/SW WINDS AS HIGH AS 20 KT WITHIN NEARSHORE WATERS AND
GUSTING TO 25 KT BEYOND 20 NM WILL SHIFT TO THE WEST AND WILL GUST
TO 25 KT ACROSS NEARSHORE WATERS AND AS HIGH AS 30-35 KT BEYOND
20-40 NM. EXTENDED THE SMALL CRAFT ADVISORY FOR CHARLESTON HARBOR
UNTIL 5 AM...EXTENDED THE GALE WARNING FOR AMZ374 UNTIL 5 AM AND
MAINTAINED OTHER SCAS FOR NEARSHORE WATERS WITHOUT CHANGE UNTIL 11
AM THURSDAY. ELEVATED SEAS TONIGHT WILL RANGE FROM AS HIGH AS 5-7
FT WITHIN NEARSHORE WATERS TO AS HIGH AS 8-9 FT BEYOND 20 NM.

THURSDAY THROUGH MONDAY...CONDITIONS WILL SLOWLY IMPROVE INTO
THURSDAY AS HIGH PRESSURE BUILDS FROM THE WEST. ALL ADVISORIES
SHOULD COME DOWN BY THE AFTERNOON. OTHERWISE...HIGH PRESSURE WILL BE
IN CONTROL INTO EARLY NEXT WEEK WITH NO SIGNIFICANT IMPACTS
EXPECTED.

&&

.HYDROLOGY...
RIVERS WILL RESPOND QUICKLY OVER THE NEXT DAY OR SO AS THE HEAVY
RAINS THAT FELL UPSTREAM IN THE VARIOUS BASINS WORK THEIR WAY DOWN
INTO SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA. THE OHOOPEE
RIVER AT REIDSVILLE /REDG1/ IS FORECAST TO BREACH FLOOD STAGE THIS
EVENING...SO A RIVER FLOOD WARNING HAS BEEN ISSUED.

OTHER RIVERS TO WATCH THROUGH THE REST OF THE WEEK INCLUDE:
* THE OGEECHEE RIVER AT MIDVILLE /MIDG1/ AND EDEN /EDEG1/.
* THE CANOOCHEE RIVER AT CLAXON /CNOG1/.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...LAKE WIND ADVISORY FROM 10 PM THIS EVENING TO 5 AM EST
     THURSDAY FOR SCZ045.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EST THURSDAY FOR AMZ350-352-
     354.
     GALE WARNING UNTIL 5 AM EST THURSDAY FOR AMZ374.
     SMALL CRAFT ADVISORY UNTIL 5 AM EST THURSDAY FOR AMZ330.

&&

$$

NEAR TERM...JAQ/SPR
SHORT TERM...RJB
LONG TERM...DPB
AVIATION...JAQ/RJB/SPR
MARINE...JAQ/RJB/SPR
HYDROLOGY...





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