821
FXUS62 KCHS 070542
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
142 AM EDT WED MAY 7 2025
SYNOPSIS
A FRONT WILL REMAIN STALLED NEAR THE AREA THROUGH THE WEEKEND
BEFORE LOW PRESSURE MOVES UP THE COAST EARLY NEXT WEEK.
NEAR TERM /UNTIL 6 AM THIS MORNING/
EARLY THIS MORNING: OVERALL, QUIET CONDITIONS SHOULD PREVAIL
THROUGH SUNRISE. SATELLITE IMAGERY SHOWS CIRRUS STEADILY
APPROACHING FROM THE WEST, ASSOCIATED WITH THE LARGE CONVECTIVE
COMPLEX UPSTREAM ACROSS THE LOWER MS VALLEY AND THE GULF COAST.
HI-RES MODEL SOLUTIONS ARE IN GOOD AGREEMENT THAT ANY RESIDUAL
PRECIPITATION ASSOCIATED WITH THIS CONVECTION WILL NOT ARRIVE
INTO OUR WESTERN ZONES UNTIL AFTER SUNRISE. SO, WE HAVE KEPT THE
FORECAST DRY. WE ARE IN A WEAK PRESSURE ENVIRONMENT AND MOST
OBSERVATION SITES ACROSS THE AREA ARE REPORTING CALM WINDS. WE
SHOULD BE ABLE TO EXPERIENCE GOOD RADIATIONAL COOLING CONDITIONS
UNTIL THE CIRRUS THICKENS OVER THE NEXT FEW HOURS. THIS COULD
ALLOW FOR THE DEVELOPMENT OF SOME PATCHY FOG, AND MODEL GUIDANCE
SUPPORTS THIS THINKING. GRIDDED AND STATISTICAL GUIDANCE MOSTLY
FAVORS THE COASTAL CORRIDOR FOR THE BEST FOG POTENTIAL, AND WE
HAVE ADDED PATCHY FOG TO THE FORECAST. WE DON'T THINK VISIBILITY
REDUCTIONS WILL BE SIGNIFICANT, BUT WILL CONTINUE TO MONITOR.
SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/
A LARGE UPPER LOW ACROSS THE CENTRAL UNITED STATES WILL
STEADILY DEEPEN AS IT DIGS AND SHIFTS SOUTHEAST MID TO LATE
WEEK. THE BROAD UPPER RIDGE OFF THE EAST COAST WILL CONTINUE TO
WEAKEN AND SHIFT EAST. A FAIRLY MOIST SOUTHWEST FLOW WILL
PREVAIL ACROSS THE LOCAL AREA. A SERIES OF SHORTWAVES ARE
EXPECTED TO MOVE THROUGH THE SOUTHEAST WEDNESDAY THROUGH FRIDAY,
BRINGING SEVERAL WAVES OF SHOWERS AND THUNDERSTORMS. ON
WEDNESDAY, THE GREATEST COVERAGE IS EXPECTED IN SOUTHEAST GA,
WITH A CLUSTER OF CONVECTION POTENTIALLY DRIFTING INTO SOUTHERN
SC LATE IN THE AFTERNOON. THURSDAY COULD BE RELATIVELY DRY IN
THE MORNING BEFORE MODERATE INSTABILITY IN THE AFTERNOON AND
WEAK SHORTWAVE ENERGY RESULT IN SCATTERED TO NUMEROUS
SHOWERS/TSTMS. FRIDAY LOOKS POTENTIALLY THE MOST ACTIVE DUE TO A
STRONGER SHORTWAVE MOVING THROUGH AND DEEPER MOISTURE
OVERSPREADING THE AREA.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
THE CLOSED UPPER LOW WILL STALL OVER THE ARKLATEX REGION OVER
THE WEEKEND, THEN GRADUALLY OPEN AND LIFT NORTHEAST EARLY NEXT
WEEK. A STATIONARY FRONT WILL DEVELOP OVER THE AREA WHILE DEEP
TROPICAL MOISTURE STREAMS IN FROM THE SOUTH. A PERIOD OF WET
WEATHER IS IN STORE WITH THE POTENTIAL FOR SEVERAL INCHES OF
RAINFALL SPREAD OVER SEVERAL DAYS.
AVIATION /06Z WEDNESDAY THROUGH SUNDAY/
KCHS AND KJZI: THE FIRST FORECAST CONCERN IS FOR POTENTIAL FOG
DEVELOPMENT IN THE NEXT FEW HOURS. WE HAVE INTRODUCED A TEMPO
GROUP AT BOTH SITES TO ADVERTISE MVFR FOG, BUT IT ISN'T
COMPLETELY OUT OF THE QUESTION FOR IFR VISIBILITIES. THE MAIN
TIME PERIOD IS FROM ROUGHLY 08-12Z. THEN AS WE LOOK LATER IN THE
DAY THERE WILL BE THE POTENTIAL FOR SHOWERS TO MOVE THROUGH IN
THE EARLY TO MID AFTERNOON HOURS. MODEL GUIDANCE GENERALLY
HIGHLIGHTS THE MAIN TIME PERIOD OF CONCERN FROM 18-22Z AND WE
ARE CARRYING VCSH. THERE REMAINS ENOUGH UNCERTAINTY REGARDING
THE POTENTIAL FOR THE SITES TO BE DIRECTLY IMPACTED, SO FURTHER
REFINEMENTS WILL LIKELY BE NEEDED WITH THE 12Z TAF ISSUANCE. IF
SHOWERS DO DIRECTLY IMPACT THE TERMINALS, BRIEF PERIODS OF MVFR
CONDITIONS WILL BE POSSIBLE.
KSAV: THE FIRST FORECAST CONCERN IS FOR POTENTIAL FOG
DEVELOPMENT IN THE NEXT FEW HOURS. CURRENT THINKING IS THAT THE
FOG WILL MAINLY BE SHALLOW WITH NO REDUCTION IN FLIGHT CATEGORY.
ATTENTION THEN TURNS TO THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS STARTING AROUND MIDDAY. THE COMBINATION OF THE
ARRIVAL OF A DIMINISHING AREA OF SHOWERS AND THUNDERSTORMS FROM
THE WEST INTERACTING WITH THE SEA BREEZE ALONG THE GA COAST
SHOULD PRODUCE AN AREA OF SHOWERS AND THUNDERSTORMS NEAR THE
TERMINAL. AS SUCH, WE BRING IN VCSH AT 16Z AND HAVE A TEMPO
GROUP FROM 16-20Z TO ACCOUNT FOR DIRECT IMPACTS BRINGING THE
FLIGHT CATEGORY DOWN INTO THE MVFR RANGE. THUNDERSTORMS ARE
STILL POSSIBLE, BUT WE AREN'T QUITE CONFIDENT ENOUGH YET TO PUT
TSRA INTO THE TAF. ONCE THIS SHOWER AND THUNDERSTORM ACTIVITY
MOVES OFF TO THE EAST BY THE MID AFTERNOON, VFR CONDITIONS
SHOULD PREVAIL.
EXTENDED AVIATION OUTLOOK: SCATTERED MAINLY AFTERNOON/EVENING
SHOWERS AND THUNDERSTORMS EXPECTED THROUGH FRIDAY. MVFR OR
LOWER CEILINGS LIKELY OVER THE WEEKEND AS A FRONT STALLS OVER
THE AREA AND SCATTERED TO NUMEROUS SHOWERS AND TSTMS MOVE
THROUGH THE AREA.
MARINE
TONIGHT: A NEBULOUS PRESSURE PATTERN WILL DOMINATE OVERNIGHT AS
WEAK STATIONARY FRONT LINGERS SOUTH OF THE WATERS.
EAST/SOUTHEAST WINDS WILL VEER MORE SOUTHERLY OVERNIGHT WITH
SPEEDS DROPPING TO 5 KT OR LESS. SEAS WILL AVERAGE 1-2 FT
NEARSHORE WATERS WITH 3-4 FT OVER THE GEORGIA OFFSHORE WATERS.
THURSDAY THROUGH SUNDAY: WINDS OVER THE MARINE AREA WILL
FLUCTUATE BETWEEN SE AND NE WEDNESDAY THROUGH SUNDAY AS A FRONT
MEANDERS OVER THE AREA. WINDS/SEAS CURRENTLY EXPECTED TO REMAIN
BELOW ADVISORY LEVELS.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
NEAR TERM...BSH
SHORT TERM...
LONG TERM...
AVIATION...BSH
MARINE...
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