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FXUS62 KCAE 020618
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
218 AM EDT SAT AUG 2 2025
SYNOPSIS
A COLD FRONT WILL BRING COOLER CONDITIONS FOR THE WEEKEND WITH
CHANCES FOR RAIN EACH DAY. CHANCES FOR TYPICAL AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS CONTINUE EACH DAY THROUGH THE
FORECAST PERIOD AS THIS FRONT LINGERS ACROSS THE AREA INTO THE
MIDDLE OF NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGE(S):
- MUCH COOLER TODAY WITH CHANCES FOR RAIN.
A SIGNIFICANT PATTERN CHANGE BEGINS TODAY AS ANOMALOUSLY STRONG HIGH
PRESSURE MOVES INTO THE GREAT LAKES WITH THE NAEFS MEAN INDICATING
MSLP NEAR THE CLIMATOLOGICAL MAXIMUM FOR THIS TIME OF YEAR. A COLD
FRONT, WHICH TYPICALLY IS NOT CLIMATOLOGICALLY FAVORED TO PROGRESS
THROUGH THE AREA IN EARLY AUGUST WILL BE ABLE TO PUSH THROUGH AS A
RESULT. HIGHS EXPECTED TO BE AROUND 10 DEGREES COOLER TODAY. A MOIST
AIR MASS REMAINS IN PLACE, WITH HREF PROBABILITIES OF PWATS GREATER
THAN 2 INCHES VERY HIGH OVER MUCH OF THE AREA (80-90%) WITH A
MOISTURE GRADIENT IN THE NORTHERN PORTION OF THE FORECAST AREA. THIS
WILL LEAD TO CHANCES FOR RAIN, ALTHOUGH WITH WIDESPREAD LOW CLOUDS
AND COOLER TEMPERATURES, DESTABILIZATION WILL BE WEAK. WITH LIMITED
INSTABILITY, RAIN EXPECTED TO GENERALLY BE LIGHT WITH ISOLATED
THUNDERSTORMS. STILL SOME UNCERTAINTY AS TO THE EXACT LOCATION
OF THE FRONT TODAY WHICH WILL DETERMINE THE MORE FAVORED AREAS
FOR RAIN. BY MID TO LATE AFTERNOON, SOME DRIER AIR LIKELY WORKS
ITS WAY INTO THE NORTHERN PORTION OF THE FORECAST AREA,
LIMITING POTENTIAL FOR RAIN. COOLER CONDITIONS CONTINUE INTO
TONIGHT WITH LOWS DROPPING INTO THE MID TO UPPER 60S.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/
KEY MESSAGE(S):
- SLOW MOVING FRONT WILL ESSENTIALLY STALL OVER THE AREA, BRINGING
MUCH COOLER TEMPS BUT WIDESPREAD SHOWERS.
THE FRONT AND ASSOCIATED MOISTURE GRADIENT WILL SLOWLY START TO LIFT
NORTH ON SUNDAY, BUT NOTABLE GUIDANCE DISAGREEMENTS CONTINUE IN THE
EXTENT. AS SURFACE HIGH PRESSURE ACROSS NEW ENGLAND AND OFFSHORE LOW
PRESSURE DEVELOPS, NORTHEASTERLY SURFACE FLOW WILL STRENGTHEN
REGARDLESS AND THE MAIN DISAGREEMENTS ARE IN THE STRENGTH OF
ISENTROPIC LIFT ALOFT AND THE POSITIONING OF HIGHEST PWAT'S. AS A
RESULT, CONFIDENCE IS HIGHEST IN CONSISTENT AND WIDESPREAD SHOWERS
ACROSS THE SOUTHERN FORECAST AREA WHERE PWAT'S, ISENTROPIC LIFT, AND
SURFACE DEW POINTS WILL BE HIGHEST. ACROSS THE NORTHERN MIDLANDS,
CONFIDENCE IN SHOWERS IS LOWER WITH POTENTIALLY NOTABLY LOWER DEW
POINTS AND PWAT'S ALONG WITH WEAKER ISENTROPIC LIFT; GEFS AND THE HI-
RES GUIDANCE GENERALLY KEEPS THE PEE DEE AND NORTHERN MIDLANDS DRY,
WHILE THE ECE BRINGS WIDESPREAD RAIN ACROSS SC. SO OVERALL, ITS A
FAIRLY LOW CONFIDENCE FORECAST ACROSS THE CENTRAL MIDLANDS IN
PARTICULAR WITH LIKELY A LARGE POP AND RAINFALL GRADIENT.
IT'S ESSENTIALLY THE SAME STORY FOR MONDAY, WITH THE PWAT GRADIENT
AND FRONT SLOWING LIFTING NORTHWARD BUT NOTABLE DIFFERENCES IN
EXPECTED SENSIBLE IMPACTS ACROSS GUIDANCE. THE STRENGTH OF THE
ISENTROPIC LIFT AND OVERALL PRECIP INTENSITY SHOULD DECREASE AND
BECOME WIDESPREAD, BUT MUCH LIKE MONDAY, THE EXACT NATURE OF HOW
THIS UNFOLDS ISN'T CLEAR. GEFS AGAIN LOCKS IN DRIER AIR ACROSS THE
AREA AND IS RELATIVELY DRY COMPARED TO THE ECE. REGARDLESS IT
APPEARS THAT THE RAIN POTENTIAL SHOULD INCREASE ESPECIALLY ACROSS
THE CENTRAL AND NORTHERN MIDLANDS. RAINFALL TOTALS THROUGH THE SHORT
TERM ARE AS RESULT QUITE UNCERTAIN, BUT BROADLY 1-3" LOOKS PLAUSIBLE
ACROSS THE SOUTHERN MIDLANDS AND CSRA, DECREASING TO THE NORTH.
TEMPS WILL RUN MUCH BELOW AVERAGE AS A RESULT OF WIDESPREAD CLOUD
COVER AND RAIN, WITH HIGHS IN THE UPPER 70'S OR LOW 80'S.
LONG TERM /TUESDAY THROUGH FRIDAY/
KEY MESSAGE(S):
- COOLER TEMPS AND A RELATIVELY WET PERIOD SHOULD CONTINUE THROUGH
THE LONG TERM PERIOD.
BEHIND THE SURFACE FRONT AND MOISTURE GRADIENT LIFTING NORTHWARD
EARLIER IN THE WEEK, GENERAL TROUGHING WILL CONTINUE ACROSS THE
EASTERN US. THIS SHOULD AS RESULT YIELD GENERALLY COOLER TEMPS AS
HIGHLIGHTED IN THE NAEFS WITH ELEVATED POP'S EACH DAY. EC EFI IS
CONSISTENT IN SHOWING A MODEST SIGNAL FOR QPF THROUGHOUT THIS
PERIOD, BUT NO PARTICULAR TIME-DAY OF NOTE. OVERALL, THIS PATTERN
FAVORS WAVES OF SHOWERS-STORMS EACH DAY WITH DIURNAL FAVORABILITY TO
POP'S. QPF TOTALS ARE PRETTY UNCERTAIN WITH A WIDESPREAD IN THE GEFS
AND ECE THROUGHOUT THE PERIOD. GENERALLY ANOTHER BROAD 1-3" SEEMS
LIKELY THROUGHOUT THE PERIOD WITH TEMPS AGAIN RUNNING A BIT BELOW
AVERAGE.
AVIATION /06Z SATURDAY THROUGH WEDNESDAY/
WIDESPREAD RESTRICTIONS EXPECTED AT ALL TERMINALS.
RESTRICTIONS ARE BEGINNING TO DEVELOP EARLY THIS MORNING WITH
LOW CLOUDS BEHIND A COLD FRONT SHIFTING THROUGH THE TERMINALS AS
LOW LEVEL MOISTURE REMAINS PLENTIFUL. WIDESPREAD IFR CEILINGS
ARE EXPECTED BEFORE SUNRISE WITH GUIDANCE CONSISTENT IN THESE
RESTRICTIONS LINGERING INTO THIS AFTERNOON. WHILE SCATTERED
LIGHT RAIN OR DRIZZLE REMAINS POSSIBLE LEADING TO BRIEF
VISIBILITY RESTRICTIONS, THE PREDOMINANT AVIATION CONCERN WILL
BE LOW CEILINGS. POTENTIAL FOR SOME IMPROVEMENT AS DRY AIR
BEGINS TO MOVE IN FROM THE NORTH BUT MVFR CEILINGS ARE EXPECTED
TO PERSIST BEGINNING IN THE AFTERNOON AND CONTINUING THROUGH THE
END OF THE PERIOD.
EXTENDED AVIATION OUTLOOK...A COLD FRONT IN THE AREA WILL KEEP
CHANCES OF MORE WIDESPREAD RESTRICTIONS AND RAIN THIS WEEKEND
INTO THE MIDDLE OF NEXT WEEK.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
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