347
FXUS62 KCAE 200547
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
147 AM EDT SUN SEP 20 2026
WHAT HAS CHANGED
PRECIPITATION CHANCES FOR DIURNALLY DRIVEN CONVECTION TODAY
HAVE DECREASED. AVIATION DISCUSSION UPDATED FOR 06Z TAFS.
KEY MESSAGES
- 1. ABOVE AVERAGE TEMPERATURES AND INCREASED CHANCES FOR
SHOWERS AND STORMS CONTINUE INTO EARLY NEXT WEEK.
- 2. COOLER AND DRIER AIR RETURNS BY THE MIDDLE OF NEXT WEEK
BUT FORECAST UNCERTAINTY REMAINS.
DISCUSSION
KEY MESSAGE 1: ABOVE AVERAGE TEMPERATURES AND INCREASED CHANCES
FOR SHOWERS AND STORMS CONTINUE INTO EARLY NEXT WEEK.
A FEW CLUSTERS OF SHOWERS AND THUNDERSTORMS CONTINUE TO OUR
WEST AND DRIFTING SOUTHWARD EARLY THIS MORNING ALONG REMNANT
OUTFLOWS. ACTIVITY SHOULD REMAIN LIMITED, THOUGH HEAVY DOWNPOURS
CANNOT BE COMPLETELY RULED OUT.
UNSETTLED WEATHER REMAINS OVER THE AREA THE NEXT FEW DAYS, WITH
ISOLATED TO SCATTERED CONVECTION EXPECTED TODAY THROUGH EARLY
NEXT WEEK. ABOVE NORMAL TEMPERATURES AND PWATS OVER 1.75 INCHES
WILL SUPPORT SEASONABLE INSTABILITY. GIVEN THE RELATIVELY WEAK
FORCING, CONVECTION TODAY AND MONDAY SHOULD REMAIN LIMITED AND
DIURNAL IN NATURE. BETTER CHANCES FOR PRECIPITATION IS EXPECTED
TUESDAY INTO WEDNESDAY AS THE UPPER-AIR PATTERN EVOLVES AND A
FRONT NEARS. A MID- LEVEL LOW CURRENTLY OVER THE FAR EASTERN
GULF IS FORECAST TO LIFT NORTHWARD ALONG THE EASTERN SEABOARD,
WHILE DEVELOPING TROUGHING MOVES IN FROM THE MIDWEST. THESE
FEATURES WILL PROVIDE INCREASING SYNOPTIC FORCING AND SUPPORT
GREATER COVERAGE OF SHOWERS AND STORMS. OVERALL, THE SEVERE
THREAT REMAINS LOW. HOWEVER LOCALLY HEAVY RAIN WILL REMAIN
POSSIBLE, WITH THE POTENTIAL INCREASING TUESDAY AND WEDNESDAY AS
COVERAGE BECOMES MORE WIDESPREAD.
KEY MESSAGE 2: COOLER AND DRIER AIR RETURNS BY THE MIDDLE OF
NEXT WEEK BUT FORECAST UNCERTAINTY REMAINS.
TROUGHING OVER THE MIDWEST WILL SHIFT EASTWARD THROUGH THE
WEEK, SUPPORTING THE DEVELOPMENT OF A ROBUST AREA OF HIGH
PRESSURE THAT BUILDS SOUTHWARD INTO THE MID-ATLANTIC. HOWEVER,
CONSIDERABLE UNCERTAINTY REMAINS REGARDING THE EXTENT OF SURFACE
RIDGING, AS REFLECTED BY THE SPREAD AMONG ENSEMBLE MEMBERS AND
LREF CLUSTERS. THE DEGREE OF MOISTURE ADVECTION ATOP THE
POTENTIAL SURFACE WEDGE WILL LIKELY DEPEND ON THE TIMING AND
STRENGTH OF THE AFORMENTIONED TROUGHING. THE ECMWF REMAINS
WEAKER AND SHOWERS, MAINTAINING A MORE SOUTHWESTERLY FLOW ALOFT
ALLOWING GREATER MOISTURE TO OVERRUN THE SURFACE WEDGE. THE GFS
AND NAM FAVOR A STRONGER TROUGH WITH MORE NORTHWESTERLY TO
NORTHERLY FLOW RESULTING IN DIRER AIR.
GIVEN THE CONTINUED SPREAD, CONFIDENCE REMAINS LOW FROM
WEDNESDAY THROUGH LATE WEEK, PARTICULARLY REGARDING TEMPERATURES
AND POPS. WIDESPREAD PRECIPITATION APPEARS UNLIKELY, BUT SHOULD
SUFFICIENT MOISTURE AND ISENTROPIC LIFT DEVELOP OVER THE
POTENTIAL WEDGE, TYPICAL CAD PRECIPITATION CANNOT BE RULED OUT,
INCLUDING PERIODS OF LIGHT STRATIFORM RAIN/DRIZZLE.
AVIATION /06Z SUNDAY THROUGH THURSDAY/
POSSIBLE MVFR/IFR VISIBILITY RESTRICTIONS TOWARDS SUNRISE, THEN
VFR CONDITIONS FOR THE REMAINDER OF THE DAY.
SCATTERED TO NUMEROUS SHOWERS/STORMS STILL SHOWING UP ON REGIONAL
RADARS, BUT MAINLY OFF TO THE WEST/NORTH OF ALL TERMINALS AT
ISSUANCE TIME. OUT FLOW BOUNDARY IS MOVING SOUTHWARD TOWARDS THE
CSRA, BUT MOST GUIDANCE SEEMS TO INDICATE LITTLE DEVELOPMENT
AROUND AUGUSTA. WITH THAT SAID, LATEST GUIDANCE REALLY DOESN'T
HAVE A GOOD HANDLE ON WHAT IS CURRENTLY GOING ON, SO CONFIDENCE
REMAINS LOW. CAN NOT COMPLETELY RULE OUT A FEW SHOWERS AT
AGS/DNL/AIK IN THE NEXT FEW HOURS, SO WILL CONTINUE TO MONITOR
AND AMEND AS NECESSARY. NEAR TERM GUIDANCE OVERNIGHT AND INTO
THE EARLY MORNING HOURS CONTINUES TO SHOW THE DEVELOPMENT OF LOW
CIGS AND POSSIBLE VIS RESTRICTIONS BY 08-09Z. HAVE CONTINUED TO
MENTION TEMPO GROUPS BETWEEN 09-13Z FOR THE POTENTIAL FOR
MVFR/IFR CONDITIONS WITH BKN CLOUDS BELOW 1000FT AT ALL SITES,
AS WELL AS POTENTIAL FOR VIS DOWN TO 1-2 SM AT THE MORE FOG-
PRONE AGS AND OGB TERMINALS. ANY LOW CIGS AND/OR VIS SHOULD
LIFT/IMPROVE BY LATE MORNING, WITH A RETURN TO PRIMARILY VFR
CONDITIONS BY LATE MORNING. WINDS GENERALLY LIGHT AND FROM THE
EAST. AS FOR AFTERNOON CONVECTION, BLENDED GUIDANCE SHOWING
MOSTLY A DRY FORECAST THIS UPCOMING AFTERNOON, SO FOR NOW NO
MENTION OF ANY RAINFALL.
EXTENDED AVIATION OUTLOOK...CHANCES FOR SHOWERS AND/OR
THUNDERSTORMS WILL CONTINUE THROUGH EARLY NEXT WEEK. MORNING
CIG/VSBY RESTRICTIONS ARE POSSIBLE AS WELL.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...ND
AVIATION...73
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