Area Forecast Discussion
Issued by NWS Charleston, SC

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000
FXUS62 KCHS 141152
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
652 AM EST SUN FEB 14 2016

.SYNOPSIS...
COLD HIGH PRESSURE WILL REMAIN IN CONTROL TODAY. A LOW PRESSURE
SYSTEM WILL THEN IMPACT THE REGION LATE MONDAY INTO EARLY TUESDAY
FOLLOWED BY HIGH PRESSURE THROUGH THE REMAINDER OF THE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
SURFACE HIGH PRESSURE AND ITS VERY DRY AIR ARCTIC CONTINENTAL AIR
MASS FROM THE MID ATLC TO NEW ENGLAND HAS GRIPS ON THE CAROLINAS
THIS MORNING WITH SOUTHERN FRINGE OF THE COLDEST AIR JUST BRUSHING
SE GEORGIA. A COLD DAY ON TAP ACROSS THE FORECAST AREA TODAY WITH
MOST AREAS NOT EXPECTED TO REACH 50 DEGREES THIS AFTERNOON.
COLDEST AIR OVER THE CHARLESTON TRI-COUNTY WHERE 40-45 DEGREE
HIGHS ARE ANTICIPATED. SAVANNAH LOOKS TO WARM ONLY TO THE UPPER
40S AND PERHAPS AROUND 50-52 ON THE ALTAMAHA RIVER TODAY. CHILLY
NE WINDS WILL KEEP TEMPS FEELING EVEN COLDER ALL DAY.

SUNSHINE FOR THE MORNING WILL GIVE WAY TO AN INCREASE IN HIGH
CLOUDS BY MIDDAY THEN THE SKY COVER FORECAST BECOMES A BIT MORE
COMPLICATED THIS AFTERNOON AS A WARM AIR ADVECTION PATTERN ATOP
THE SHALLOW COLD AIR MASS ENSUES. THE NAM SHOWS SIGNIFICANT
MOISTURE ADVECTION AT 925 MB INTO SE GEORGIA AND INCREASES
STRATOCU COVERAGE RATHER QUICKLY PRIOR TO NOON. THIS MAY BE A
BIT OVERDONE AND WE HAVE TRENDED MORE TOWARD THE ECMWF/GFS
SOLUTIONS OF INCREASING CLOUDS A FEW HOURS LATER TODAY.

A COMPLEX AND TRICKY FORECAST TONIGHT AS WARM AIR ADVECTION
BUILDS ACROSS THE REGION. LOW TEMPS SOME AREAS SHOULD BE THIS
EVENING IF CLOUDS ARE NOT PRESENT AND MAY FALL TO AROUND FREEZING
NORTHERN ZONES IF THIS IS THE CASE. OTHERWISE LOWER CLOUDS SHOULD
EXPAND AND TEMPS WILL LIKELY REMAIN STEADY OR SLOWLY RISE
OVERNIGHT. THE SURFACE PATTERN WILL REMAIN WEDGED AS THE ARCTIC
AIR RETREATS TO THE N AND A COASTAL TROUGH MOVES TOWARD THE COAST
LATE. THE NAM IS AN OUTLIER BREAKING OUT LIGHT MEASURABLE PCPN IN
SE GEORGIA NOT LONG AFTER SUNSET. GIVEN THE LACK OF MOISTURE DEPTH
AND HIGH CONDENSATION PRES DEFICITS WE MAINTAINED A DRY FORECAST
ALL AREAS THROUGH MOST OF THE NIGHT ALTHOUGH A FEW SPRINKLES ARE
CERTAINLY POSSIBLE. THE NOSE OF THE COASTAL TROUGH NEARING THE
UPPER SOUTH CAROLINA COAST LATE MAY PRODUCE A FEW SHOWERS ALONG SE
SOUTH CAROLINA LATE TONIGHT. BUILD DOWN STRATUS DECKS OVER SE
GEORGIA MAY RESULT IN SOME PATCHY FOG LATE TONIGHT AS FORECAST
SOUNDINGS SUGGEST BUT OPTED TO NOT MENTION IN THE FORECAST UNTIL
TRENDS ARE MORE DEFINITIVE.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
MONDAY...HIGH PRESSURE WILL QUICKLY ERODE AS A COASTAL TROUGH LIFTS
NORTH ALONG THE SOUTHEAST COAST. MOST AREAS WILL BE DRY EARLY...BUT
A FEW SHOWERS ARE POSSIBLE ALONG THE CHARLESTON COUNTY COAST. STRONG
ISENTROPIC ASCENT WILL THEN DEVELOP MONDAY AFTERNOON...HELPING
PRODUCE CHANCES OF SHOWERS OVER MANY AREAS AS A SOUTHERLY FLOW HELPS
ADVECT HIGHER MOISTURE LEVELS TO THE SOUTHEASTERN UNITED STATES.
AFTERNOON HIGHS SHOULD PEAK LATE AFTERNOON UNDER MOSTLY CLOUDY
SKIES...WITH LOCATIONS REACHING THE UPPER 50S IN NORTHERN AREAS AND
LOW/MID 60S IN SOUTHEAST GEORGIA.

MONDAY NIGHT INTO EARLY TUESDAY...GREATER PRECIP COVERAGE IS
EXPECTED AS A COLD FRONT PUSHES THROUGH THE AREA AFTER MIDNIGHT.
GIVEN STRONG FORCING ASSOCIATED WITH THE PASSING LOW PRESSURE SYSTEM
ALONG WITH MODEST MID LVL LAPSE RATES AND WEAK INSTABILITY...HAVE
ADDED A SLIGHT CHANCE OF THUNDERSTORMS OVER ALL AREAS UNTIL DAYBREAK
TUESDAY. AT THIS TIME...SEVERE WEATHER POTENTIAL REMAINS LOW. IN
GENERAL...LOW TEMPS WILL RANGE IN LOW/MID 50S.

TUESDAY AFTERNOON THROUGH WEDNESDAY...DEEPENING LOW PRESSURE WILL
TRACK OVER NEW ENGLAND...WHILE DRY HIGH PRESSURE SHIFTS INTO THE
AREA FROM THE WEST. EXPECT MOST PRECIP TO SHIFT NORTH/NORTHEAST OF
THE AREA BY TUESDAY AFTERNOON...FOLLOWED BY DRY HIGH PRESSURE
THROUGH WEDNESDAY. CLEARING SKIES WITHIN A WEST FLOW WILL SUPPORT
AFTERNOON TEMPS IN THE MID 60S ON TUESDAY...THEN LOW/MID 60S ON
WEDNESDAY AS THE SFC FLOW SLOWLY TURNS TO THE NORTH.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
DRY HIGH PRESSURE WILL BUILD OVER THE AREA...RESULTING IN A LIGHT
NORTHERLY WIND THROUGH THURSDAY. IN GENERAL...AFTERNOON HIGHS SHOULD
PEAK NEAR 60 DEGREES ON THURSDAY...THEN MODIFY INTO THE MID/UPPER
60S ON FRIDAY AS AN ONSHORE WIND DEVELOPS IN RESPONSE TO HIGH
PRESSURE SLOWLY SHIFTING OFF THE EASTERN SEABOARD. OVERNIGHT LOWS
WILL BE IN THE UPPER 30S TO AROUND 40 WEDNESDAY NIGHT...BEFORE
RETURNING TO THE LOW/MID 40S THURSDAY NIGHT. DRY HIGH PRESSURE WILL
THEN BECOME MORE ESTABLISHED OVER THE WESTERN ATLANTIC...SETTING UP
SLIGHTLY WARMER CONDITIONS WITHIN A LIGHT SOUTHERLY FLOW. IN
GENERAL...TEMPS WILL PEAK NEAR 70 DEGREES SATURDAY AND SUNDAY.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
VFR AT KCHS/KSAV THROUGH 00Z MONDAY. STRATOCUMULUS SHOULD DEVELOP
THIS AFTERNOON AND LOWER/THICKEN TONIGHT. MVFR CIGS ARE POSSIBLE
BY SUNSET AT KSAV AND MAINLY LATER THIS EVENING AT KCHS. MVFR/IFR
CIGS ARE EXPECTED AFTER 06Z AT BOTH TERMINALS ALONG WITH A CHANCE
OF A FEW SPRINKLES. FORECAST SOUNDINGS INDICATE STRONG WARM AIR
ADVECTION ALOFT WEDGE CLOUDS LOWER OVERNIGHT AND AT THIS TIME OUR
CONFIDENCE IN STRATUS/IFR CIGS LATE TONIGHT WOULD BE AT THE KSAV
TERMINAL.

EXTENDED AVIATION OUTLOOK...FLIGHT RESTRICTIONS ARE LIKELY MONDAY
NIGHT INTO EARLY TUESDAY AS WIDESPREAD SHOWERS AND/OR ISOLATED
THUNDERSTORMS OCCUR WITH A PASSING LOW PRESSURE SYSTEM. A STRONG LOW
LVL JET COULD ALSO SUPPORT SOME GUSTY WINDS...ESPECIALLY OVER THE
CHS TERMINAL AROUND DAYBREAK TUESDAY.

&&

.MARINE...
A COMPLICATED COASTAL WATERS FORECAST THROUGH TONIGHT AS VERY
STRONG THERMAL AND MOISTURE GRADIENTS ARE NOTED DURING THE NEXT 24
HOURS. COLD HIGH PRES WAS WEDGING DOWN THE COAST EARLY THIS
MORNING AND WILL EXPAND THE PINCHING PRES GRADIENT THAT WAS
SETTING UP PRE-DAWN ALONG THE SOUTH CAROLINA COAST. IT WILL BE
CLOSE TO SMALL CRAFT ADVISORY CONDITIONS OVER MOST ALL NEAR SHORE
WATERS BY MID MORNING AND WE STILL MAY NEED TO RAISE ADVISORIES AT
SOME POINT THIS MORNING. WE DID ISSUE AN ADVISORY FOR GEORGIA
WATERS FROM 20-60 NM TODAY AS SEAS BUILD AND WINDS GUST OVER 25 KT
AT TIMES. MUCH DEPENDS ON WHERE THE BEST PINCHING DEVELOPS AND
UNCERTAINTIES CONTINUE INTO TONIGHT AS THE COASTAL WARM APPROACHES
THE SHELF WATERS. WINDS AND SEAS EXPECTED TO SUBSIDE AS THE
GRADIENT WEAKENS OVERNIGHT.

MONDAY THROUGH THURSDAY...A COASTAL TROUGH WILL LIFT NORTH ALONG THE
SOUTHEAST COAST EARLY MONDAY...FOLLOWED BY DETERIORATING CONDITIONS
MONDAY AFTERNOON AND MONDAY NIGHT AS A STRENGTHENING LOW PRESSURE
TRACKS INLAND AND TO THE NORTHEAST COAST. STRONG LOW LVL WINDS
ASSOCIATED WITH THE SYSTEM WILL LIKELY RESULT IN A PERIOD OF SMALL
CRAFT ADVISORY LEVEL WINDS/SEAS FOR MOST WATERS MONDAY NIGHT INTO
EARLY TUESDAY. WIDESPREAD SHOWERS AND A FEW THUNDERSTORMS WILL ALSO
BE POSSIBLE UNTIL A COLD FRONT PUSHES THROUGH THE WATERS LATE
TUESDAY MORNING. CONDITIONS WILL THEN IMPROVE TUESDAY AFTERNOON AS
HIGH PRESSURE BUILDS OVER THE COASTAL WATERS FROM THE WEST. WEST
WINDS AT OR BELOW 10 KTS WILL SLOWLY SHIFT TO NORTH/NORTHWEST ON
THURSDAY AS HIGH PRESSURE CONTINUES TO BUILD ALONG/OVER THE EASTERN
SEABOARD.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR AMZ374.

&&

$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...DPB
LONG TERM...DPB
AVIATION...
MARINE...DPB


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