Area Forecast Discussion
Issued by NWS Charleston, SC

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000
FXUS62 KCHS 061724
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
124 PM EDT FRI MAY 6 2016

.SYNOPSIS...
AN UPPER LEVEL LOW WILL LINGER THIS AFTERNOON THEN LIFT AWAY FROM
THE AREA TONIGHT. HIGH PRESSURE WILL PREVAIL SATURDAY THROUGH
WEDNESDAY THEN A FRONTAL SYSTEM IS EXPECTED TO AFFECT THE AREA
LATE NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...A LARGE MID/UPPER LVL TROUGH OF LOW PRESSURE
WILL LINGER OVER THE EASTERN CONUS WITH ITS CENTER POSITIONED JUST
OFF THE MID ATLANTIC COAST. ALTHOUGH THE CORE OF THE LOW WILL
GRADUALLY SHIFT NORTH AND AWAY FROM THE AREA THROUGHOUT THE
AFTERNOON...TEMPS NEAR -23C AT THE H5 LVL WILL SUPPORT MID LVL
LAPSE RATES NEAR 7.5 C/KM OVER THE SOUTHEASTERN UNITED STATES.
THESE RATES ALONG WITH MUCAPE BETWEEN 200-500 J/KG AND PWATS NEAR
0.75 INCHES SHOULD SUPPORT A FEW SHOWERS AND PERHAPS AN ISOLATED
THUNDERSTORM CAPABLE OF PRODUCING SMALL HAIL AND/OR GRAUPEL WITH
FORCING THAT ARRIVES ALONG THE SOUTHWEST EDGE OF THE DEPARTING LOW
ALOFT. CHANCES OF PRECIP WILL BE HIGHEST OVER NORTHERN AREAS WHERE
MARGINAL MOISTURE IS PRESENT. FURTHER SOUTH...ACTIVITY WILL BE
LIMITED GIVEN CONSIDERABLE DRY AIR ASSOCIATED WITH A DOWNSLOPING
WEST/NORTHWEST WIND. HIGH TEMPS WILL REMAIN BELOW NORMAL FOR THIS
TIME OF YEAR. IN GENERAL...TEMPS WILL PEAK IN THE LOW TO MID 70S
FOR MOST LOCATIONS.

TONIGHT...THE BASE OF THE UPPER TROUGH WILL DEPART AND WE WILL SEE
RISING HEIGHTS ALOFT. RADIATIONAL COOLING UNDER CLEARING SKIES
SHOULD RESULT IN LOWS AROUND 50 IN MANY AREAS.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
AN UPPER LEVEL RIDGE WILL TAKE HOLD ACROSS THE SOUTHEAST U.S.
SATURDAY AND PERSIST THROUGH MONDAY AS DRY HIGH PRESSURE SETTLES
IN AT THE SURFACE. SATURDAY WILL FEATURE MOSTLY SUNNY SKIES AND
HIGHS IN THE LOWER 80S. BY SUNDAY...LOW-LEVEL THICKNESSES INCREASE
SUBSTANTIALLY AS THE 850 MB RIDGE BUILDS EAST. THIS WILL YIELD
HIGH TEMPS IN THE UPPER 80S TO AROUND 90 BOTH SUNDAY AND MONDAY
WITH NO RAIN EXPECTED. SUNDAY MORNING LOWS WILL BE AROUND 60 DUE
TO LIGHT WINDS AND MOSTLY CLEAR SKIES. A BIT MORE SKY COVER MONDAY
MORNING WILL HOLD LOW TEMPS IN THE MIDDLE 60S.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
DEEP LAYERED RIDGING WILL PERSIST MONDAY NIGHT THROUGH TUESDAY
NIGHT...MAINTAINING DRY WEATHER AND ABOVE-NORMAL TEMPS. ON
WEDNESDAY SOME UPPER LEVEL VORTICITY ENERGY APPROACHES WESTERN
AREAS...PUSHING A WEAK COLD FRONT TOWARD THE FORECAST AREA. THIS
FRONT IS EXPECTED TO MEANDER OVER THE AREA THURSDAY AND THURSDAY
NIGHT...THEN POSSIBLY MOVING OFFSHORE FRIDAY MORNING. MODEL
INSTABILITY PARAMETERS ARE SUPPORTIVE OF ISOLATED TO SCATTERED
THUNDERSTORMS MID TO LATE WEEK IN ASSOCIATION WITH THE UPPER
SHORTWAVE ENERGY AND THE LINGERING SURFACE FRONT.

&&

.AVIATION /17Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS ARE EXPECTED AT BOTH CHS AND SAV TERMINALS THROUGH
18Z SATURDAY. HOWEVER...THERE WILL REMAIN A LOW CHANCE OF A SHOWER
CAUSING FLIGHT RESTRICTIONS AT THE CHS TERMINAL THIS AFTERNOON
INTO EARLY EVENING.

EXTENDED AVIATION OUTLOOK...VFR.

&&

.MARINE...
THIS AFTERNOON AND TONIGHT...WINDS/SEAS WILL SLOWLY IMPROVE
AS A LARGE MID/UPPER LVL LOW LIFTS FURTHER NORTH AND AWAY FROM
THE AREA. IN GENERAL...WEST/NORTHWEST WINDS WILL PEAK BETWEEN
15-20 KT EARLY...WITH GREATEST SPEEDS IN NORTHERN SC WATERS WHERE
AMPLE LOW LVL MIXING OCCURS. EXPECT WINDS TO DIMINISH TO 10-15 KT
LATE AFTERNOON AND EVENING...WITH A GRADUAL IMPROVEMENT CONTINUING
THROUGH THE OVERNIGHT PERIOD. SEAS WILL RANGE BETWEEN 2-3 FT...HIGHEST
IN OFFSHORE GEORGIA WATERS.

WEAK OFFSHORE FLOW SATURDAY AND SATURDAY NIGHT GRADUALLY SHIFTS TO
SOUTHWEST LATE SUNDAY AS ATLANTIC HIGH PRESSURE BECOMES THE
DOMINANT FEATURE. SUNDAY THROUGH THE MIDDLE OF NEXT WEEK THE MAIN
MARINE HIGHLIGHT WILL BE AFTERNOON SEA BREEZE CIRCULATIONS ALONG
THE COAST THOUGH SPEEDS SHOULD MAINLY STAY BELOW 15 KT.

&&

.TIDES/COASTAL FLOODING...
DESPITE THE OFFSHORE WINDS TODAY AND SATURDAY...THE PERIGEAN SPRING
TIDES COULD RESULT IN A PERIOD OF COASTAL FLOOD ADVISORIES WITH THE
EVENING HIGH TIDE CYCLES. ON SUNDAY...THE FLOW ATTEMPTS TO SHIFT A
LITTLE MORE ONSHORE...AGAIN CAUSING A RISK FOR SHALLOW COAST FLOOD
CONCERNS WITH THE EVENING HIGH TIDE.

&&

.CLIMATE...
RECORD LOWS FOR MAY 6...

CHARLESTON AIRPORT /CHS/...44/1973
SAVANNAH AIRPORT /SAV/...46/1957
DOWNTOWN CHARLESTON /CXM/...53/1921

&&

.EQUIPMENT...
THE CHARLESTON HARBOR NOS TIDE GAUGE AND GRAYS REEF BUOY 41008 REMAIN
OUT OF SERVICE.

&&

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

&&

$$
SYNOPSIS...
NEAR TERM...DPB
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...DPB/JRL
MARINE...DPB/JRL
TIDES/COASTAL FLOODING...
CLIMATE...
EQUIPMENT...



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