Area Forecast Discussion
Issued by NWS Charleston, SC

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944
FXUS62 KCHS 132307
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
607 PM EST SAT FEB 13 2016

.SYNOPSIS...
COLD HIGH PRESSURE WILL BUILD OVER THE REGION TONIGHT...REMAINING
IN CONTROL UNTIL EARLY NEXT WEEK. A LOW PRESSURE SYSTEM IMPACTS
THE REGION MONDAY INTO TUESDAY FOLLOWED BY HIGH PRESSURE RETURNING
MID TO LATE NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
THE LONG WAVE TROUGH THAT HAS PLAGUED THE EAST/SE MUCH OF THE
WINTER IS AGAIN THE PROMINENT LARGE SCALE FEATURE AGAIN
TONIGHT...ALLOWING FOR A 1036 MB ARCTIC HIGH TO BUILD FROM THE
MIDWEST AND OHIO VALLEY. THIS CAUSES AIR AT 850 MB TO DROP AS LOW
AS -6 OR -7C NORTH AND -1 OR -2C SOUTH...INDICATIVE OF THE
BITTERLY COLD ARCTIC AIR MASS.

THERE REMAINS ENOUGH MIXING OF THE BOUNDARY LAYER TO PREVENT ANY
SIGNIFICANT RADIATIONAL COOLING. THAT ALONG WITH THE COLD BIAS OF
THE MOS GUIDANCE DURING COLD WEATHER OUTBREAKS PREVIOUSLY THIS
SEASON SUPPORTS MIN TEMPS IN THE LOWER OR MIDDLE 20S
NORTH/NW...UPPER 20S MOST ELSEWHERE...EXCEPT 30-35 ON THE BARRIER
ISLANDS AND WARMEST COASTAL SE GA. TEMPS WILL DROP BELOW FREEZING
AND STAY THERE UNTIL SUNDAY MORNING FOR AS MUCH AS 8-12 HOURS...SO
REMEMBER TO PRACTICE COLD WEATHER SAFETY.

WE/RE STILL ARRIVING AT A VERY MARGINAL WIND CHILL ADVISORY FOR
THE CHARLESTON AND TIDAL BERKELEY COUNTY LATE TONIGHT AND SUNDAY
MORNING. BUT AREAL COVERAGE IS RATHER LIMITED...SO NO WIND CHILL
ADVISORY AT THIS TIME. EVEN SO...MINIMUM WIND CHILLS COULD BE AS
LOW AS IN THE 13-15F RANGE FOR A AN HOUR OR TWO FROM ABOUT 5 TO 8
AM.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
SUNDAY...SURFACE HIGH PRESSURE AND ITS ASSOCIATED ARCTIC
TEMPERATURES WILL BE SITUATED OVER THE MID-ATLANTIC STATES.
NORTHEAST WINDS WILL ADVECT THESE COLD TEMPERATURES AND DRY
CONDITIONS INTO OUR AREA. HIGH TEMPERATURES ARE EXPECTED TO BE IN
THE LOWER 40S ACROSS THE TRI-COUNTY AREA AND THE UPPER 40S TO LOWER
50S ACROSS SOUTHEAST GEORGIA. THESE TEMPERATURES ARE ABOUT 15-18
DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. A TRANSITION IN THE
PATTERN BEGINS SUNDAY NIGHT AS THE HIGH MOVES OFF OF THE MID-
ATLANTIC COAST AND A COASTAL TROUGH STARTS TO FORM OFF OF THE
SOUTHEAST COAST LATE IN THE NIGHT. TEMPERATURES WILL BE "WARMER" AS
A LIGHT ONSHORE WIND DEVELOPS...FALLING INTO THE LOWER TO MID 30S
ACROSS THE TRI-COUNTY AREA AND THE UPPER 30S TO LOWER 40S ACROSS
SOUTHEAST GEORGIA. MODELS HINT AT SOME LIGHT PRECIPITATION
DEVELOPING OFFSHORE AND POSSIBLY MOVING ONTO THE IMMEDIATE COAST
AROUND DAYBREAK. TEMPERATURES IN THESE LOCATIONS ARE EXPECTED TO BE
ABOVE FREEZING...MEANING ALL LIQUID PRECIPITATION IS EXPECTED.

MONDAY...THE DAY WILL START OFF COOL...THEN QUICKLY WARM UP AS
SOUTHERLY FLOW STRENGTHENS AHEAD OF LOW PRESSURE TRACKING OVER THE
MISSISSIPPI RIVER VALLEY. AFTERNOON HIGHS SHOULD BE IN THE 60S
ACROSS MOST AREAS...POSSIBLY REACHING 70 DEGREES IN SOME PARTS OF
SOUTHEAST GEORGIA. POPS WILL INCREASE INTO THE AFTERNOON...MAINLY
NEAR A COASTAL TROUGH THAT SKIRTS ALONG THE SOUTHEAST COAST.
MONDAY NIGHT LOWS WILL BE CONSIDERABLY WARMER THAN PREVIOUS NIGHTS
AS THE LOW TRACKS CLOSER TO THE AREA. THE HIGHEST POPS WILL BE AFTER
MIDNIGHT AS THE LOW QUICKLY TRACKS TO THE MID ATLANTIC STATES BY
DAYBREAK TUESDAY MORNING. LOWS WILL BE IN THE 50S.

TUESDAY...DEEPENING LOW PRESSURE WILL TRACK ALONG THE NEW ENGLAND
COAST...WHILE DRY HIGH PRESSURE SHIFTS INTO THE AREA FROM THE WEST.
EXPECT MOST PRECIP TO SHIFT NORTH/NORTHEAST OF THE AREA BY LATE
MORNING HOURS. CLEARING SKIES WITHIN A WEST/SOUTHWEST FLOW WILL
SUPPORT AFTERNOON TEMPS IN THE LOWER 60S FOR MOST AREAS. WE COULD
SEE A FEW TEMPS IN THE MID 60S SOUTH OF INTERSTATE 16 IN SOUTHEAST
GEORGIA.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
WEAK HIGH PRESSURE WILL PREVAIL OVER THE SOUTHEASTERN UNITED STATES
TUESDAY NIGHT BEFORE AN AREA OF LOW PRESSURE PASSES NORTH OF THE
AREA...THEN OFFSHORE BY DAYBREAK WEDNESDAY. DRY HIGH PRESSURE WILL
THEN BUILD OVER THE AREA...RESULTING IN A LIGHT AND COOLER NORTHERLY
WIND THROUGH THURSDAY. IN GENERAL...AFTERNOON HIGHS SHOULD PEAK NEAR
60 DEGREES WEDNESDAY AND THURSDAY...THEN MODIFY INTO THE LOW/MID 60S
ON FRIDAY AS AN ONSHORE WIND DEVELOPS IN RESPONSE TO HIGH PRESSURE
SLOWLY SHIFTING OFF THE EASTERN SEABOARD. OVERNIGHT LOWS SHOULD
RANGE IN THE LOW/MID 40S TUESDAY NIGHT...THEN COOL INTO THE UPPER
30S TO AROUND 40 WEDNESDAY NIGHT...BEFORE RETURNING TO THE LOW/MID
40S THURSDAY NIGHT. MILD TEMPS WILL CONTINUE ON SATURDAY...BUT
PRECIP IS POSSIBLE AHEAD OF A COLD FRONT APPROACHING FROM THE NORTH
SATURDAY NIGHT.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
VFR AT KCHS/KSAV THROUGH 18Z SUNDAY.

EXTENDED AVIATION OUTLOOK...FLIGHT RESTRICTIONS ARE LIKELY MONDAY
NIGHT INTO TUESDAY MORNING DUE TO RAIN SHOWERS ASSOCIATED WITH A LOW
PRESSURE SYSTEM. GUSTY WINDS ARE ALSO POSSIBLE MONDAY NIGHT INTO
TUESDAY MORNING.

&&

.MARINE...
TONIGHT...WE START THE NIGHT WITH NORTH/NE WINDS AT OR BELOW 15
KT AS A POST-FRONTAL TROUGH THAT LIES SE-NW ACROSS THE WATERS HAS
CAUSED SOME BAGGINESS TO THE PRESSURE PATTERN. BUT THIS IS ONLY
TEMPORARY AS ARCTIC HIGH PRESSURE BUILDS FROM THE NORTH/NW AND
PRESSURES STEADILY CLIMB. THIS ALLOWS FOR A DECENT SURGE IN WINDS
OVERNIGHT...BORDERLINE WITH THE NECESSITY FOR A SMALL CRAFT
ADVISORY ON AT LEAST SOME OF THE WATERS AS WINDS AND SEAS RISE.
FOR NOW WE HAVE LIMITED CONDITIONS JUST SHY OF THE ADVISORY
THRESHOLDS.

SUNDAY THROUGH WEDNESDAY...EXPECT NORTH/NORTHEAST WINDS SUNDAY
MORNING WITH COLD AIR ADVECTION OVER ACROSS ALL OF THE WATERS.
CONDITIONS SHOULD THEN BRIEFLY IMPROVE SUNDAY NIGHT INTO EARLY
MONDAY AS A COASTAL TROUGH DEVELOPS OFF THE SOUTHEAST COAST.
CONDITIONS ARE THEN EXPECTED TO DETERIORATE MONDAY AFTERNOON INTO
EARLY TUESDAY AS A STRENGTHENING LOW PRESSURE SYSTEM QUICKLY TRACKS
OVER THE DEEP SOUTH AND THEN OFF THE MID ATLANTIC 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
INTO PART OF TUESDAY. A WEAKER LOW PRESSURE SYSTEM SHOULD THEN PASS
NORTH OF THE REGION ON WEDNESDAY WITH THE SOUTHERN EXTENT OF A COLD
FRONT REACHING COASTAL WATERS OFF THE SOUTHEAST COAST...BUT
WINDS/SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY LEVEL
CONDITIONS.

&&

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

&&

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



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