Area Forecast Discussion
Issued by NWS Charleston, SC

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS62 KCHS 041356
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
956 AM EDT WED MAY 4 2016

.SYNOPSIS...
A COLD FRONT WILL MOVE OVER THE WESTERN ATLANTIC THIS MORNING. A
SECONDARY COLD FRONT WILL MOVE THROUGH THE AREA EARLY THURSDAY.
HIGH PRESSURE WILL THEN EXPAND INTO THE REGION FROM THE WEST LATE
WEEK AND PREVAIL THROUGH THE WEEKEND. A BACKDOOR COLD FRONT SHOULD
DROP INTO THE CAROLINAS EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
TODAY...A FEW SHOWERS COULD LINGER ALONG COASTAL AREAS LATE THIS
MORNING AS A LARGE MID LVL TROUGH OF LOW PRESSURE DIGS OVER THE
EASTERN CONUS BEHIND A SFC COLD FRONT SHIFTING OVER THE WESTERN
ATLANTIC. RAIN-FREE CONDITIONS ARE THEN EXPECTED BY THE AFTERNOON AS
A DRY WESTERLY FLOW DEVELOPS ACROSS THE REGION. DRY AIR WILL ALSO
HELP ERODE CLOUDS AS THEY SHIFT OFFSHORE INTO EARLY AFTERNOON.
THE SETUP WILL FAVOR A FULL SUN OVER MOST AREAS DURING PEAK
HEATING HOURS. IN GENERAL...HIGHS WILL RANGE IN THE UPPER 70S TO
AROUND 80 DEGREES.

TONIGHT...ANOTHER COLD FRONT WILL BE APPROACHING FROM THE NORTHWEST.
IT SHOULD PASS THROUGH OUR AREA LATE. THIS FRONT WILL BE DRY...BRINGING
JUST SOME CLOUDS...BUT NO PRECIPITATION. TEMPERATURES ARE EXPECTED
TO BE MUCH COOLER THAN RECENT NIGHTS...ALTHOUGH STILL CLOSE TO
NORMAL...THE MID TO UPPER 50S...AND NEAR 60 DEGREES AT THE
BEACHES.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
THURSDAY...A DEEP AND DIGGING UPPER LOW WILL REACH THE CAROLINAS
THURSDAY AFTERNOON. THE MAIN VORT LOBE ASSOCIATED WITH THE LOW
CENTER WILL SHIFT SE ACROSS THE FORECAST AREA THROUGH THE AFTERNOON
AS CYCLOGENESIS TAKES OVER EASTERN NORTH CAROLINA. GIVEN THE FORCING
IN PLACE...WE HAVE MAINTAINED SLIGHT CHANCE POPS ACROSS THE NORTHERN
ZONES IN CLOSER PROXIMITY TO AN IMPRESSIVE -25C 500 MB COLD POOL
REACHING THE CSRA AND MIDLANDS BY LATE DAY. FORECAST SOUNDINGS
INDICATE VERY SMALL REGIONS OF CAPE BETWEEN 6 KFT AND 10 KFT AND
POTENTIAL FOR ANY MIXED GRAUPEL/HAIL PCPN NW ZONES APPEARS QUITE
SLIM AS MOISTURE IS JUST NOT THERE. HIGH TEMPS WILL RUN MUCH COOLER
IN THE LOWER 70S...FALLING THROUGH THE 60S AFTER MID AFTERNOON. THE
PRESSURE GRADIENT WILL TIGHTEN AND WNW WINDS WILL BECOME GUSTY IN
THE AFTERNOON...ROUGHLY 25 TO 30 MPH UNDER PARTLY CLOUDY SKIES.
CONDITIONS SHOULD BE DRY THURSDAY NIGHT BUT QUITE CHILLY WITH LOWS
IN THE UPPER 40S TO LOWER 50S.

FRIDAY THE PATTERN DOES NOT CHANGE VERY MUCH WITH THE DEEP UPPER
TROUGH AND MID LEVEL CUT-OFF LOW REMAINING ALONG THE EAST COAST.
STEEP LOW AND MID LEVEL LAPSE RATES WILL PERSIST WITH CYCLONIC FLOW
ALOFT. WE HAVE ADDED SOME SLIGHT CHANCE POPS FOR SHALLOW DIURNALLY
ENHANCED CONVECTION ACROSS PARTS OF THE CENTRAL SOUTH CAROLINA
COASTAL REGION...OTHERWISE WE MAINTAINED A MAINLY DRY FORECAST AS
LARGE LOW LEVEL TEMP AND DEW POINT SPREADS REMAIN THE NORM.
ANOTHER COOLER THAN CLIMO DAY IN STORE WITH HIGHS IN THE MID 70S
MOST AREAS.

SATURDAY...THE DEEP UPPER LOW ALONG THE EASTERN SEABOARD WILL
FINALLY MOVE AWAY FROM THE REGION AS UPPER HEIGHTS BUILD ACROSS
GEORGIA AND SOUTH CAROLINA. THIS SHOULD RESULT IN SUNSHINE AND
WARMER TEMPERATURES NEARING 80 DEGREES ALONG COASTAL SOUTH
CAROLINA AND REACHING THE LOWER 80S ACROSS INLAND GEORGIA.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
DEEP LAYERED RIDGING SHOULD PERSIST FROM THE LATTER HALF OF THE
WEEKEND INTO EARLY NEXT WEEK. SUNDAY AND MONDAY HAVE THE LOOK OF
MUCH WARMER DAYS AS WEST FLOW IN THE BOUNDARY LAYER AND PLENTY OF
SUNSHINE ARE ON TAP. WE RAISED HIGHS A FEW DEGREES TO SHOW MUCH OF
THE FORECAST AREA REACHING 90 DEGREES. RIDGING SHOULD BEGIN TO BREAK
DOWN HEADED TOWARD MID WEEK WITH ONLY SLIGHT CHANCES OF CONVECTION
AND TEMPS LIKELY REMAINING ABOVE CLIMO.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDITIONS EXPECTED THROUGH 12Z THURSDAY. ISOLATED SHOWERS ARE
POSSIBLE FDR THE NEXT HOUR OR TWO THIS MORNING.

EXTENDED AVIATION OUTLOOK...VFR. GUSTY SURFACE WINDS ARE EXPECTED
ON THURSDAY IN THE WAKE OF A SECONDARY COLD FRONT DURING THE
AFTERNOON.

&&

.MARINE...
TODAY...CONDITIONS WILL REMAIN WELL BELOW SMALL CRAFT ADVISORY
LEVELS BEHIND A COLD FRONT SHIFTING OVER THE WESTERN ATLANTIC. IN
GENERAL...WEST SOUTHWEST WINDS WILL SLIGHTLY VEER TO WEST THIS
AFTERNOON AND REMAIN AT OR BELOW 10-15 KT. SEAS WILL RANGE BETWEEN
2-4 FT...BUT WILL SLOWLY SUBSIDE THROUGH THE EVENING.

TONIGHT...A SECOND COLD FRONT WILL APPROACH THE REGION FROM THE
NORTHWEST...PASSING THROUGH AROUND DAYBREAK. IN ADVANCE OF THIS
FRONT WINDS WILL GENERALLY BE FROM THE W AT 10-15 KT...INCREASING
TO AROUND 15-20 KT AFTER MIDNIGHT. A SMALL CRAFT ADVISORY MIGHT
BE NEEDED FOR THE OUTER GEORGIA WATERS LATE AT NIGHT DUE TO WIND
GUSTS. SEAS WILL BUILD TO ABOUT 3-5 FT BY DAYBREAK.

EXTENDED...THE ARRIVAL OF THE DEEP UPPER LOW AND STRONG VORTICITY
MAXIMA LATE THURSDAY AND THURSDAY NIGHT WILL INCITE STRONG LOW
LEVEL COLD AIR ADVECTION WHICH WILL RESULT IN SUBSTANTIAL SURGES
ACROSS THE COASTAL WATERS. SMALL CRAFT ADVISORIES WILL LIKELY BE
NEEDED BEGINNING EARLY THURSDAY MORNING...STARTING IN THE OUTER GA
WATERS THEN EXPANDING TO ALL WATERS AS WIND GUSTS EXCEED 25 KT.
SEAS WILL BUILD TO 3-5 FT NEAR SHORE AND 4-7 FT WELL OFFSHORE.
CANNOT RULE OUT A BRIEF SURGE OF GALE FORCE GUSTS FROM GRAYS REEF
SEAWARD THURSDAY EVENING AS THE VORT PASSES OVERHEAD.

CONDITIONS WILL BEGIN TO IMPROVE BY FRIDAY. HIGH PRESSURE WILL
RETURN FRIDAY AFTERNOON AND PERSIST OVER THE WEEKEND WITH WINDS
GENERALLY 15 KT OR LESS. SEAS ON AVERAGE LATE FRIDAY INTO THE
WEEKEND WILL AVERAGE 2-3 FEET. EARLY NEXT WEEK...A S TO SW SYNOPTIC
FLOW WILL PREVAIL ON THE PERIPHERY OF ATLC HIGH PRES OFFSHORE.

&&

.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...AND IT IS POSSIBLE THAT A
SITE VISIT WILL BE PERFORMED BY LATE IN THE WEEK.

THE GRAYS REEF BUOY 41008 ALSO REMAINS OUT OF SERVICE...AND A SITE
VISIT BY NDBC IS EXPECTED DURING THE LATTER PART OF MAY TO EITHER
REPAIR THE SITE OR EXCHANGE FOR A NEW BUOY SYSTEM.

&&

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

&&

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



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.