233
FXUS62 KCAE 060600
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
200 AM EDT WED AUG 6 2025
SYNOPSIS
THE ATYPICAL COLD AIR DAMMING PATTERN LINGERS THROUGH THE
WORKWEEK BEFORE A COASTAL LOW ERODES THE WEDGE THIS WEEKEND.
BELOW NORMAL HIGH TEMPERATURES CAN BE EXPECTED EACH AFTERNOON
THROUGH AT LEAST SATURDAY DESPITE A GRADUAL WARMING TREND
WEDNESDAY INTO THE WEEKEND. SHOWER AND THUNDERSTORM CHANCES
STICK AROUND THIS WEEK, WITH THE POTENTIAL FOR LOCALLY HEAVY
RAINFALL EACH DAY.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGE(S):
- MODERATE RAIN LIKELY THROUGH MID-MORNING ACROSS THE WESTERN
AND NORTHERN FORECAST AREA
- ROBUST WEDGE CONDITIONS EXPECTED TO REMAIN LOCKED IN PLACE
THROUGH MUCH OF THE DAY
- BEST CHANCES FOR RAIN THIS AFTERNOON ARE ACROSS THE EASTERN
MIDLANDS
OUR CURRENT SETUP IS ACTUALLY FAIRLY SIMILAR TO WHAT WE SAW LAST
NIGHT. PERSISTENT TROUGHING TO OUR WEST IS PROVIDING THE UPPER LEVEL
SUPPORT FOR ISENTROPIC FLOW ACROSS THE WESTERN MIDLANDS. SURFACE
RIDGING REMAINS IN PLACE ACROSS THE ENTIRE AREA, WITH WEDGE
CONDITIONS NOTED AT ALL OBSERVATIONS THIS HOUR. THIS IS A FAVORABLE
SYNOPTIC SETUP FOR RAINFALL TO CONTINUE INCREASING IN COVERAGE
OVERNIGHT, WITH OUR NORTH AND WESTERN COUNTIES PRIMARILY UNDER THE
GUN FOR MORE RAINFALL. THIS DOES COINCIDE WITH THE AREAS THAT HAD
THE MOST RAINFALL YESTERDAY, SO EVEN THOUGH RAIN TOTALS SHOULD BE
LOWER, WE WILL NEED TO KEEP AN EYE ON THESE AREAS CLOSELY THROUGH
7A AS IT WON'T TAKE MUCH TO CAUSE FLASH FLOODING.
AS WE GET INTO TODAY, UNPRECEDENTED COLD AIR DAMMING FOR THE
WARM SEASON IS FORECAST TO CONTINUE. WANT TO START THIS
DISCUSSION OFF WITH SOME INTERESTING TRIVIA: AS OF THIS WRITING,
THERE ARE ONLY A FEW STRETCHES IN CAE'S OBSERVATION HISTORY
WITH A LONGER PERIOD OF TIME AT OR BELOW 80F. CAE HAS BEEN BELOW
80F SINCE THE 7:56P OBSERVATION ON AUGUST 1ST, WITH NOW 101
HOURS STRAIGHT BELOW 80F. A LEGITIMATE COLD-AIR DAMMING EVENT
DURING ANY OF THE SUMMER MONTHS IS PRETTY NOTEWORTHY, BUT IT
ESPECIALLY IS IN AUGUST. IN MY DIGGING OVER THE LAST COUPLE OF
NIGHTS, I CAN ONLY FIND A SINGLE SLAM-DUNK CAD EVENT IN AUGUST
THAT WAS OF THIS MAGNITUDE AND IT WAS BACK IN 1981 AND FEATURED
TEMPS AT OR BELOW 80F FOR 188 STRAIGHT HOURS. IT WOULD TAKE A
LOT FOR US TO GET TO THAT POINT, BUT THAT IS FOR A LATER
FORECAST. TODAY'S WEATHER LOOKS QUITE SIMILAR TO THE LAST COUPLE
OF DAYS. STRONG SURFACE RIDGING IS BEING HELD IN PLACE BY
CONVERGENCE IN THE NORTHEAST AS SPLIT FLOW ALOFT FOSTERS
SUBSIDENCE IN THE MID-ATLANTIC REGION. SO A REALLY ROBUST
SURFACE REMAINS RIDGING DOWN THE EASTERN SIDE OF THE
APPALACHIANS AND INTO THE CAROLINAS. LOW CLOUDS, DRIZZLE, AND
RAIN SHOULD BE ONGOING TO BEGIN THE PERIOD, WITH HI-RES GUIDANCE
SUGGESTING THE WEDGE ONLY SLOWLY ERODES AROUND THE EDGES
THROUGH THE DAY. THE CENTRAL AND NORTHERN MIDLANDS WILL LIKELY
REMAIN FIRMLY IN THE WEDGE, AS GUIDANCE IS USUALLY TOO
AGGRESSIVE WITH THE WEDGE BREAKING AND IT STILL ISN'T FORECAST
TO BREAK AT CAE AT ALL TODAY.
THE EDGES OF THE WEDGE ARE INTERESTING TODAY, AS SHORTWAVES PUSHING
THROUGH THE SOUTHWESTERLY FLOW ALOFT SHOULD FOSTER CONVECTIVE
DEVELOPMENT THIS AFTERNOON ALONG AND SOUTH OF THE WEDGE BOUNDARY.
DEPENDING ON WHERE THIS SETS UP, IT COULD POSE A PROBLEM FOR FLASH
FLOODING IN OUR COAST PLAIN COUNTIES. HREF AND REFS 6HR LPMM
GUIDANCE SUGGESTS SIGNIFICANT RAINFALL IS POSSIBLE WITH THESE
THUNDERSTORMS THIS AFTERNOON AND EVENING. A FLOOD WATCH WAS
CONSIDERED BUT THERE JUST ISN'T ENOUGH GUIDANCE SHOWING THE HIGH
RAINFALL TOTALS IN OUR AREA TO JUSTIFY ONE. SO IF THE WEDGE DOES MIX
NORTHWARD MORE THAN EXPECTED, THERE COULD BE NUMEROUS SHOWERS/STORMS
ACROSS THE EASTERN PARTS OF THE FA, WITH GENERALLY SCATTERED SHOWERS
EXPECTED ELSEWHERE. HIGHS WILL RANGE FROM THE LOW 70S TO THE LOW 80S
ACROSS THE AREA DEPENDING ON WHERE YOU ARE IN THE WEDGE. OVERNIGHT,
EXPECT LOW CLOUDS TO HOLD LOWS IN THE UPPER 60S AGAIN. RAIN CHANCES
ARE FORECAST TO BE LOWER IN GENERAL TONIGHT THAN THEY HAVE BEEN THE
PAST FEW NIGHTS.
SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/
KEY MESSAGE(S):
- PERSISTENT COOL, WET PATTERN CONTINUES
THE OVERALL WEATHER PATTERN CHANGES LITTLE ON THURSDAY WITH
SURFACE HIGH PRESSURE RIDGING INTO THE MID-ATLANTIC AND
SOUTHEAST. THIS WILL KEEP SKIES MOSTLY CLOUDY AND TEMPERATURES
WELL BELOW NORMAL. HOWEVER THE UPPER LEVEL TROUGH AXIS SHIFTS
EASTWARD ALLOWING DRIER AIR TO IMPINGING ON THE WESTERN FA.
SURFACE LOW PRESSURE OFFSHORE ALSO EDGES CLOSER TO THE FA. THIS
SHOULD FOCUS THE BULK OF THE RAINFALL ACROSS THE EASTERN FA
WHERE MOISTURE IS DEEPER. WITH LOWER QPF EXPECTED IN THE WESTERN
FA, WHICH HAS RECEIVED THE MOST RAIN OVER THE PAST FEW DAYS,
THE FLOODING THREAT IS LOW. A FEW THUNDERSTORMS ARE POSSIBLE IN
THE EASTERN FA BUT THE COOL LOW LEVELS WILL HINDER DEEP
CONVECTION. HIGHS WILL BE IN THE LOW TO MID 80S WITH LOWS
OVERNIGHT IN THE MID TO UPPER 60S.
LONG TERM /SATURDAY THROUGH TUESDAY/
KEY MESSAGE(S):
- CONTINUED SHOWER ACTIVITY EXPECTED THROUGH THE LONG TERM
PERIOD. MONITOR FOR THE LIKELY DEVELOPMENT OF A COASTAL LOW
THIS WEEKEND.
THE DAMMING HIGH PRESSURE WILL SLOWLY WEAKEN THROUGH THE PERIOD
EVEN AS IT REMAINS IN PLACE. THE WEAK UPPER TROUGH REMAINS IN
PLACE AS WELL WITH CONTINUED WEAK SHORT WAVE ACTIVITY MOVING
THROUGH THE FLOW. A LOW PRESSURE CENTER DEVELOPS NEAR THE SC
COAST FRIDAY OR SATURDAY AND MOVES SLOWLY NORTH ALONG OR NEAR
THE COAST THROUGH THE PERIOD. FORECAST MODELS DIFFER ON THE
STRENGTH AND LOCATION OF THE LOW BUT AGREE THAT A MOIST EASTERLY
LOW LEVEL FLOW REMAINS OVER THE AREA. THE GUIDANCE BLEND
MODERATES THE FEATURES KEEPING GENERALLY SCATTERED MAINLY
DIURNAL CONVECTION IN PLACE THROUGH THE PERIOD WITH ONLY A LOW
CHANCE OF HEAVY RAINFALL. THIS LOOKS TO BE A GOOD COMPROMISE FOR
NOW GIVEN THE UNCERTAINTY. HIGHS SLOWLY INCREASE BACK TO NEAR
NORMAL BY MONDAY AND TUESDAY. LOWS INCREASE TO ABOVE NORMAL.
AVIATION /06Z WEDNESDAY THROUGH SUNDAY/
CLASSIC WEDGE CONDITIONS ARE CURRENTLY IN PLACE ACROSS THE REGION,
WITH MVFR, IFR, AND LIFR CONDITIONS NOTED AT ALL SITES.
A WEDGE WITHOUT PREVIOUS PRECEDENT (IN AUGUST, AT LEAST) IS
CURRENTLY LOCKED INTO PLACE ACROSS THE FORECAST AREA, IMPACTING ALL
TAF SITES. THE FORECAST IS PRETTY STRAIGHTFORWARD AND GENUINELY
LOOKS LIKE SOMETHING OUT OF MID FEBRUARY. EXPECTING MVFR CONDITIONS
TO CONTINUE THROUGHOUT THE PERIOD AT AUGUSTA AND COLUMBIA SITES,
WITH ORANGEBURG POSSIBLY BREAKING OUT THIS AFTERNOON. IFR/LIFR
CONDITIONS ARE EITHER ONGOING OR EXPECTED TO DEVELOP OVER THE NEXT
SEVERAL HOURS, ONLY LIFTING BY MID-MRONING. THESE ARE THEN EXPECTED
TO RETURN AGAIN BY THE END OF THE PERIOD. RAIN GENERALLY LOOKS LIKE
AND SCATTERED THROUGHOUT THE DAY, WITH THE BEST CHANCE OF RAIN AT
OGB THIS AFTERNOON. THIS WILL BE MODULATED BY HOW FAR NORTH THE
ACTUAL WEDGE BOUNDARY MAKES IT, THOUGH. WINDS THROUGH THE PERIOD ARE
EXPECTED TO BE NORTH OR NORTHEASTERLY BETWEEN 5 AND 10 KNOTS.
EXTENDED AVIATION OUTLOOK...FLIGHT RESTRICTIONS ARE POSSIBLE
EACH DAY WITH WIDESPREAD SHOWERS EXPECTED INTO THE WEEKEND.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
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