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FXUS62 KCAE 050610
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
210 AM EDT TUE AUG 5 2025
SYNOPSIS
UNUSUAL MID-SUMMER "COLD" AIR DAMMING 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):
- RAIN SHOWERS ACROSS THE CSRA AND WESTERN MIDLANDS WILL
DIMINISH BY MID-MORNING
- WEDGE CONDITIONS EXPECTED TO CONTINUE, ESPECIALLY NORTH OF
I20, TODAY
- SHOWERS AND THUNDERSTORMS LIKELY ALONG AND SOUTH OF THE WEDGE
BOUNDARY THIS AFTERNOON
THE PATTERN FOR THE PAST FEW DAY IS FORECAST TO CONTINUE THROUGH THE
DAY TODAY. EARLY THIS MORNING, COPIOUS MOISTURE IS STILL PRESENT
ACROSS THE AREA WITH PWS IN THE 2"-2.2" RANGE. STRONG MOISTURE
TRANSPORT VECTORS ARE NOTED ACROSS THE WESTERN FORECAST AREA AND
INTO THE UPSTATE WITH FLOW ENHANCED IN THE RIGHT-ENTRANCE REGION OF
AN UPPER LEVEL JET STREAK. ISENTROPIC LIFT IS ALSO NOTED IN
ASSOCIATION WITH THIS FEATURE, WITH ALL OF THIS LEADING TO
WIDESPREAD RAIN ACROSS THE NORTHERN CSRA AND WESTERN MIDLANDS AS OF
THIS WRITING. THIS IS EXPECTED TO CONTINUE FOR THE NEXT 6-8 HOURS AS
THE RIGHT ENTRANCE REGION PERSISTS OVER THE AREA, WITH AERIAL
RAINFALL GENERALLY DIMINISHING AFTER ~15Z AS THE JET STREAK
PROPAGATES NORTHWARD OUT OF THE AREA.
THE SETUP FOR TODAY LOOKS FAIRLY SIMILAR, WITH COPIOUS MOISTURE IN
PLACE ACROSS THE AREA AND PERSISTENT TROUGHING TO OUR WEST. SURFACE
RIDGING IN ASSOCIATION WITH THE STRONG HIGH PRESSURE WILL CONTINUE,
WITH AUGUST CAD CONDITIONS PERSISTING ALONG AND NORTH OF I20. EVEN
WITH THE RAIN PUSHING OUT MID-MORNING, STRATUS IS LIKELY TO HOLD
STRONG EVEN INTO EARLY AFTERNOON ALONG THE WEDGE BOUNDARY ITSELF,
MAKING IT DIFFICULT TO FORECAST JUST HOW FAR NORTH THE BOUNDARY
ACTUALLY MAKES IT. THIS MAKES HIGH TEMP FORECASTS CHALLENGING
TO SAY THE LEAST, AS THE LOCATION OF THIS WILL DELINEATE THE
LOCATIONS THAT STAY IN THE MID 70S AND THOSE THAT GET INTO THE
MID 80S THIS AFTERNOON. THE HREF ILLUSTRATES THIS WELL, WITH THE
IQR SPREAD FOR TEMPS ALONG THE I20 CORRIDOR THIS AFTERNOON IS
8F TO 10F. THIS DOES HAVE SENSIBLE WEATHER IMPACTS AS GUIDANCE
CONTINUES TO SHOW SCATTERED TO NUMEROUS SHOWERS AND STORMS
DEVELOPING ALONG AND SOUTH OF THE BOUNDARY THIS AFTERNOON. HREF
MEAN INSTABILITY IS GENERALLY 1000-1500 J/KG DOWN HERE, AND THIS
COINCIDES WELL WITH A WEAK SHORTWAVE THAT IS FORECAST TO PASS
THROUGH THE REGION THIS AFTERNOON. SEVERE WEATHER IS UNLIKELY
WITH MOIST ADIABATIC SOUNDINGS NOTED, BUT HEAVY RAINFALL COULD
CERTAINLY BE A PROBLEM. HREF AND REFS 6 HOUR LPMM GUIDANCE IS
SUGGESTING THAT ISOLATED RAINFALL TOTALS OF 2"+ ARE POSSIBLE.
FLASH FLOODING IS LIKELY TO BE THE PRIMARY THREAT WITH ANY
STORMS THAT DEVELOP. TONIGHT, LOOK FOR LOWS IN THE LOW TO MID
70S AGAIN WITH SHOWERS PROBABLY PERSISTING INTO THE OVERNIGHT
HOURS AGAIN.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/
KEY MESSAGE(S):
- LITTLE CHANGE IN THE THINKING FOR THE MIDDLE OF THE WEEK, WITH
WIDESPREAD SHOWERS AND BELOW AVERAGE TEMPS.
THE GENERAL SYNOPTIC PATTERN WILL REMAIN IN PLACE THROUGHOUT THE
SHORT TERM PERIOD. THE ONLY NOTABLE CHANGES WILL BE A WEAKENING OF
THE MID-UPPER LEVEL TROUGH AND THE SURFACE RIDGING LEE OF THE
APPALACHIANS WILL SLIGHTLY WEAKEN. BUT REGARDLESS, DEEP MOISTURE
ADVECTION WITH SOUTHERLY COMPONENT FLOW ALOFT AND NORTHEAST SURFACE
FLOW WILL CONTINUE THE WEDGE-LIKE SETUP AND DRIVE ISENTROPIC LIFT
THROUGHOUT THE MIDDLE OF THE WEEK. WITH BROAD SYNOPTIC SCALE
FAVORABILITY, PWAT'S UP NEAR 2.0", AND SOME MODEST ELEVATED CAPE,
WIDESPREAD SHOWERS ARE LIKE BOTH WEDNESDAY AND THURSDAY. RAINFALL
TOTALS ARE BIT UNCERTAIN DUE TO THE NATURE OF THIS RELATIVELY WEAKLY
FORCED AND ONLY LIMITED INSTABILITY SETUP; INHERENTLY SENSITIVE AND
TOUGH SETUP FOR GUIDANCE. BUT OVERALL, THESE WAVES OF SHOWERS AND
STORMS SHOULD YIELD A FAIRLY WIDESPREAD 1-2" ACROSS THE FORECAST
AREA WEDNESDAY AND THURSDAY, WITH HIGHEST TOTALS FOCUSED IN THE
WESTERN MIDLANDS. TEMPS WILL REMAIN BELOW AVERAGE DUE TO PERSISTENT
THICK CLOUD COVER AND PRECIP, BUT BY THURSDAY, ENOUGH SURFACE
HEATING SHOULD TRANSITION THE RAINFALL POTENTIAL TO BE MORE
DIURNALLY DRIVEN.
LONG TERM /FRIDAY THROUGH MONDAY/
KEY MESSAGE(S):
- CONTINUED WET PATTERN EXPECTED THROUGH THE LONG TERM PERIOD WITH
SOME OFFSHORE LOW PRESSURE LIKELY BY THE WEEKEND.
OVERALL, THE SYNOPTIC SCALE PATTERN WILL SLOWLY BECOME MORE DIFFUSE
AND WEAKER INTO THE LONG TERM PERIOD WITH SURFACE RIDGING WEAKENING
LEE OF THE APPALACHIANS ALONG WITH SOUTHWESTERLY FLOW ALOFT.
HOWEVER, PERSISTENT SOUTHEASTERLY 850-500MB FLOW WILL CONTINUE TO
DRIVE VERY HIGH MOISTURE ADVECTION INTO THE REGION WITH PWAT'S
CLIMBING OVER 2.0". THIS SOUTHEASTERLY FLOW INTO THE REGION WILL
LIKELY BE ENHANCED BY A DEVELOPING OFFSHORE LOW PRESSURE SYSTEM THAT
DEVELOPS ALONG A RESIDUAL BAROCLINIC ZONE. GUIDANCE GENERALLY KEEPS
THESE CIRCULATION QUITE BROAD, BUT THERE IS A NON-ZERO CHANCE IT
DEVELOPS SOME TROPICAL CHARACTERISTICS. REGARDLESS IT WILL LEAD TO
WIDESPREAD SHOWERS AND STORMS ARE LIKELY THROUGHOUT THIS PERIOD AS
THIS LOW SLOWLY PIVOTS UNDERNEATH THE WEAKENING SYNOPTIC SCALE FLOW
ALOFT. SINCE THE SURFACE RIDGING SHOULD WEAKEN SOME, THE SHOWERS-
STORMS SHOULD BE MORE DIURNALLY DRIVEN THEN WHAT WE SAW EARLIER IN
THE WEEK, PEAKING IN THE AFTERNOON AND EVENING. RAINFALL TOTALS ARE
QUITE VARIED ACROSS ENSEMBLE GUIDANCE BUT THE LACK OF SYNOPTIC
FORCING SHOULD KEEP PRECIP RELATIVELY WIDESPREAD AND DIURNALLY
DRIVEN; EC EFI DOESN'T REALLY HIGHLIGHT ANY PARTICULAR AREAS FOR
PERSISTENT HEAVY RAINFALL.
AVIATION /06Z TUESDAY THROUGH SATURDAY/
WIDESPREAD RESTRICTIONS AREA AGAIN EXPECTED ACROSS THE AREA TODAY,
WITH THE WEDGE POTENTIALLY BREAKING FOR A FEW HOURS THIS AFTERNOON.
MVFR RESTRICTIONS ARE NOTED AT ALL SITES AS OF THIS WRITING. THIS IS
EXPECTED TO GRADUALLY PUSH INTO IFR, THOUGH THERE IS A QUESTION AS
TO WHEN AND WHERE THIS HAPPENS. THE RAIN IS CURRENTLY PUSHING MOSTLY
NORTH OF THE AUGUSTA AND COLUMBIA TAF SITES, AND THE RAIN WOULD
TYPICALLY BE WHERE THE IFR WOULD DEVELOP. IT IS POSSIBLE, EVEN
PROBABLY, THAT THE STRATUS THAT IS OUT THERE NOW DEVELOPS INTO IFR
AS THE NIGHT GOES ON BUT IT ISN'T A CERTAINTY RIGHT NOW. REGARDLESS,
MVFR CIGS ARE AT LEAST EXPECTED AT ALL SITES THROUGH MID-MORNING.
NAM AND HRRR GUIDANCE THEN SUGGESTS THAT THE WEDGE WILL SLOWLY
RETREAT NORTHWARD, WITH OGB MOST LIKELY TO BREAK OUT FOR A BIT
THIS AFTERNOON. HEDGE TOWARDS THAT AT AGS AND CAE BUT THE LINE
BETWEEN CLOUDS AND SUN WILL LIKELY RUN ALONG A LINE FROM AGS TO
CAE CASTING A LOT OF UNCERTAINTY ON THE FORECAST. WHAT DOES SEEM
LIKELY IS THAT WIDESPREAD SHOWERS AND STORMS WILL DEVELOP ALONG
AND SOUTH OF THE SHARP WEDGE FRONT THIS AFTERNOON. HAVE VCTS AT
ALL SITES FROM 19Z THROUGH 03Z, WHICH WILL LIKELY BE HONED A
BIT SUBSEQUENT TAF UPDATES. STRATUS IS LIKELY TO DEVELOP AGAIN
TONIGHT AS THE WEDGE ADVANCES SOUTHWARD AGAIN. WINDS THROUGHOUT
THE PERIOD SHOULD BE NORTHEASTERLY OR EASTERLY BETWEEN 5 AND 10
KNOTS.
EXTENDED AVIATION OUTLOOK...FLIGHT RESTRICTIONS ARE POSSIBLE
EACH DAY WITH WIDESPREAD SHOWERS EXPECTED THROUGHOUT THE WEEK.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
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