554
FXUS62 KCAE 200035
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
835 PM EDT SAT SEP 19 2026
WHAT HAS CHANGED
AVIATION DISCUSSION UPDATED FOR 00Z 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 LINGERING SHOWERS AND STORMS WILL CONTINUE INTO THE
EVENING BUT COVERAGE WILL BE LIMITED WITH MINIMAL THREAT OF
SEVERE WEATHER.
THIS CHANCE FOR ISOLATED TO SCATTERED DIURNAL CONVECTION
CONTINUES SUNDAY AND INTO EARLY NEXT WEEK, WHERE COVERAGE HAS
TRENDED SLIGHTLY HIGHER ON TUESDAY. SLIGHTLY ABOVE NORMAL
TEMPERATURES AND PWAT'S REMAINING ABOVE 1.75" WILL LIKELY DRIVE
SEASONABLE INSTABILITY, BUT WITH WEAK FORCING, ACTIVITY SUNDAY
AND MONDAY WILL LIKELY BE MORE DIURNALLY DRIVEN. COME TUESDAY,
THE UPPER AIR PATTERN BEGINS TO SHIFT WITH THE MID LEVEL LOW
CURRENTLY OVER THE FAR EASTERN GULF, DRIFTING NORTHWARD ALONG
THE EASTERN SEABOARD. THIS FEATURE ALONG WITH DEVELOPING
TROUGHING MOVING IN FROM THE MIDWEST COULD BRING INCREASED
SYNOPTIC FORCING, AIDING IN INCREASING COVERAGE OF
SHOWERS/STORMS. OVERALL, THE SEVERE WEATHER RISK THROUGH THE
EARLY WEEK IS ON THE LOWER END, BUT CANNOT RULE OUT PERIODS OF
HEAVY RAINFALL, ESPECIALLY INTO TUESDAY.
KEY MESSAGE 2: COOLER AND DRIER AIR RETURNS BY THE MIDDLE OF
NEXT WEEK BUT FORECAST UNCERTAINTY REMAINS.
THERE IS BETTER AGREEMENT THAT TROUGHING FROM THE MIDWEST WILL
GENERALLY SHIFT EASTWARD THROUGH THE WEEK, WITH THE
AFOREMENTIONED MID LEVEL LOW CONTINUING TO GLIDE NORTHWARD,
EVENTUALLY GENERATING A SURFACE RESPONSE OFF THE EAST COAST. THE
MAIN SURFACE FEATURE OF NOTE WILL BE THE ROBUST AREA OF HIGH
PRESSURE THAT BUILDS INTO THE QUEBEC, RIDGING DOWN INTO THE MID-
ATLANTIC DURING THE MID TO LATE WEEK. THIS HIGH IS EXPECTED TO
BE NEAR THE NAEFS CLIMATOLOGICAL MAX. GENEROUS UNCERTAINTY
REMAINS IN THE DEGREE OF SURFACE RIDGING THAT REACHES THE CWA,
WHICH IS DISPLAYED WELL ACROSS THE SPREAD OF ENSEMBLE MEMBERSHIP
IN LREF CLUSTERS. THE DEGREE OF MOISTURE ADVECTION ATOP THE
POTENTIAL SURFACE WEDGE WILL LIKELY BE MODULATED BY THE TIMING
AND STRENGTH OF THE TROUGHING MENTIONED ABOVE. THE LATEST ECMWF
RUN KEEPS THE TROUGH A BIT WEAKER AND SLOWER, KEEPING A BIT MORE
SOUTHWESTERLY FLOW ALOFT WITH INCREASED MOISTURE OVERRIDING THE
SURFACE WEDGE, WHILE THE GFS AND NAM ARE FAVORING A STRONGER
TROUGH, MORE NORTHWESTERLY TO NORTHERLY FLOW ALOFT, AND THUS
DRIER AIR ATOP THE WEDGE. THE EOF PATTERNS FROM THE LREF CLUSTER
ANALYSIS REALLY HIGHLIGHT THE IMPORTANCE THE STRENGTH AND
TIMING OF TROUGHING WILL HAVE ON POTENTIAL CAD CONDITIONS. DUE
TO THE UNCERTAINTY THAT REMAINS, THERE IS FAIRLY LOW CONFIDENCE
WEDNESDAY INTO THE LATE WEEK IN TERMS OF TEMPERATURES AND POP'S.
THE POTENTIAL FOR BELOW NORMAL TEMPERATURES EXISTS, BUT NEARLY
10 DEGREE IQR RANGES REMAIN DURING THIS PERIOD. WIDESPREAD
PRECIPITATION SEEMS FAIRLY LOW, BUT IF MOIST ISENTROPIC LIFT CAN
RIDE OVER THE POTENTIAL WEDGE, CANNOT RULE OUT TYPICAL CAD
CONDITIONS WITH LIGHT STRATIFORM RAIN OR DRIZZLE, ACTING TO
REINFORCE THE WEDGE.
AVIATION /00Z SUNDAY THROUGH THURSDAY/
POSSIBLE MVFR/IFR VISIBILITY RESTRICTIONS TOWARDS SUNRISE
SUNDAY, THEN VFR CONDITIONS FOR THE REMAINDER OF THE DAY.
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS HAVE JUST ABOUT
MOVED OUT OF ALL TERMINALS, WITH SOME LINGERING ACTIVITY
TOWARDS AGS/DNL. CONVECTION SHOULD DISSIPATE HERE SHORTLY UNDER
BKN TO SCT SKIES. RECENT GFS-MOS AND LAMP GUIDANCE HAS SHOWN
CONSISTENCY IN DEVELOPING LOW CIGS AND POSSIBLE VIS RESTRICTIONS
BY 07-09Z SUNDAY. HAVE MAINTAINED 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. WILL CONTINUE
TO MONITOR NEAR TERM GUIDANCE AND ADJUST THESE VALUES AS
NECESSARY, ESPECIALLY FOLLOWING RAINFALL WITH CONVECTION THIS
AFTERNOON AND EVENING. ANY LOW CIGS AND/OR VIS SHOULD
LIFT/IMPROVE BY LATE MORNING SUNDAY WITH LIGHT WINDS GENERALLY
FROM THE EAST.
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...DH/CJR
AVIATION...ND
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