Area Forecast Discussion
Issued by NWS Charleston, SC

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FXUS62 KCHS 042008
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
408 PM EDT WED MAY 4 2016

.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE AREA LATE TONIGHT. HIGH PRESSURE
WILL THEN EXPAND INTO THE REGION FROM THE WEST LATE WEEK AND PREVAIL
THROUGH EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
THIS EVENING AND TONIGHT...A STRONG MID LVL TROUGH OF LOW PRESSURE
WILL DIG SOUTH OVER THE EASTERN CONUS...HELPING FORCE A SFC COLD
FRONT THROUGH THE AREA LATE TONIGHT INTO EARLY THURSDAY MORNING.
OTHER THAN A FEW CLOUDS ASSOCIATED WITH THE PASSING FRONT...THE
ATMOSPHERE WILL REMAIN QUITE DRY. THUS...A RAIN-FREE FORECAST WILL
BE IN PLACE THROUGH THE OVERNIGHT PERIOD. COLD AIR ADVECTION TO THE
REGION WILL HELP MAINTAIN A WEST/NORTHWEST WIND BETWEEN 5-10
MPH...KEEPING OVERNIGHT LOWS IN THE MID TO UPPER 50S...WARMEST
ALONG THE COAST.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
A RATHER ANOMALOUS PATTERN WILL PERSIST THROUGH MUCH OF THE PERIOD
AS A DEEP UPPER LOW OVER THE CAROLINAS ON THURSDAY...GRADUALLY MOVES
NORTH INTO THE MID ATLANTIC STATES BY LATER FRIDAY AND SATURDAY.
THIS PATTERN WILL RESULT IN COOLER THAN NORMAL TEMPERATURES THURSDAY
AND FRIDAY AND THEN MODERATING BACK TOWARD NORMAL BY SATURDAY.
EXPECT HIGHS ONLY IN THE LOWER 70S THURSDAY...MID 70S FRIDAY THAN
AROUND 80 TO THE LOWER 80S SATURDAY. LOWS WILL BE CHILLY IN THE
UPPER 40S TO LOWER 50S BY FRIDAY MORNING...THEN MID 50S SATURDAY
MORNING.

NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH THE PERIOD.
HOWEVER...GIVEN THE NORTHERN PART OF THE AREA WILL BE CLOSEST TO THE
SOUTHERN PERIPHERY OF THE UPPER LOW...THERE WILL BE OCCASIONAL WEAK
VORT LOBES THAT ROTATE ACROSS MAINLY THE NORTHERN 1/3 TO 1/2 OF THE
AREA...MAINLY THURSDAY AND FRIDAY AFTERNOONS. DEEP LAYER MOISTURE
WILL BE VERY MARGINAL. THUS...HAVE KEPT ONLY SLIGHT CHANCE POPS FOR
MAINLY SHOWERS. BY SATURDAY...THE UPPER LOW MOVES FURTHER NORTH AND
KEEPS THE THREAT FOR ANY MEASURABLE PRECIPITATION NORTH OF THE AREA.

EXPECT BREEZY WEST-NORTHWEST WINDS FOR THURSDAY WITH 15 TO 20 MPH
SUSTAINED WINDS WITH GUST 25 TO 30 MPH POSSIBLE. THE PRESSURE
GRADIENT BEGINS TO GRADUALLY WEAKEN FRIDAY AND SATURDAY...WITH
LIGHTER WINDS EXPECTED.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
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 /20Z WEDNESDAY THROUGH MONDAY/...
VFR CONDITIONS ARE EXPECTED AT BOTH CHS AND SAV TERMINALS THROUGH
18Z THURSDAY.

EXTENDED AVIATION OUTLOOK...VFR WILL PREVAIL. GUSTY WEST-NORTHWEST
WINDS EXPECTED FOR THURSDAY AFTERNOON WITH 15-20 KNOTS SUSTAINED
ALONG WITH GUSTS 25-30 KNOTS POSSIBLE.

&&

.MARINE...
THIS EVENING AND TONIGHT...CONDITIONS WILL REMAIN BELOW SMALL CRAFT
ADVISORY LEVELS THROUGH MIDNIGHT WITH A WEST WIND AT OR BELOW 10-15
KT AND SEAS BETWEEN 2-4 FT. A STRONG MID/UPPER LVL TROUGH OF LOW
PRESSURE WILL THEN DIG SOUTH OVER THE EASTERN CONUS...FORCING A SFC
COLD FRONT OVER THE COASTAL WATERS LATE. AS THIS OCCURS...THE
PRESSURE GRADIENT WILL ENHANCE AND COLD AIR ADVECTION WILL HELP
PROMOTE MIXING LOW LVL WINDS OVER THE WATERS. EXPECT WINDS/SEAS TO
INCREASE/BUILD AFTER MIDNIGHT...PROMPTING THE ISSUANCE OF A SMALL
CRAFT ADVISORY IN OFFSHORE GEORGIA WATERS LATE. IN GENERAL...WEST
WINDS WILL BECOME NORTHWEST AROUND 20 KTS OUTSIDE THE CHS HARBOR.
GUSTS WILL BE AROUND 25 KTS IN OFFSHORE GEORGIA WATERS LATE. SEAS
WILL BUILD FROM 2-4 FT TO 3-5 FT...HIGHEST IN OFFSHORE GEORGIA
WATERS LATE.

THURSDAY...LOW END SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED TO
PERSIST THROUGH THE DAY AND POSSIBLY INTO THE EVENING FOR THE
OFFSHORE GA WATERS. MODELS INDICATING THAT WINDS COULD REACH LOW END
SMALL CRAFT LEVELS FOR THE REST OF THE WATER DURING THE AFTERNOON
AND INTO THE EVENING...BUT CONDITIONS ARE TOO MARGINAL TO RAISE THE
ADVISORY ON THIS PACKAGE.

THURSDAY NIGHT THROUGH MONDAY...WINDS AND SEAS ARE EXPECTED TO
GRADUALLY DECREASE THROUGH THE WEEKEND AS THE DEEP LOW CENTER OVER
THE CAROLINAS AND THE MID ATLANTIC MOVES SLOWLY NORTHWARD AWAY FROM
THE WATERS. COULD SEE MARGINAL SMALL CRAFT CONDITIONS HANG ON OVER
THE OFFSHORE/BEYOND 20 NM WATERS THROUGH THURSDAY NIGHT...BUT FEEL
NO HIGHLIGHTS WILL BE NEEDED BY FRIDAY AND BEYOND.

&&

.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...SMALL CRAFT ADVISORY FROM 4 AM THURSDAY TO 2 AM EDT FRIDAY FOR
     AMZ374.

&&

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



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