951
FXUS62 KCAE 181857
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
257 PM EDT FRI SEP 18 2026
WHAT HAS CHANGED
POTENTIAL FOR COLD AIR DAMMING TO DEVELOP BY THE MIDDLE OF NEXT
WEEK. AVIATION DISCUSSION UPDATED FOR 18Z 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.
THE PATTERN FEATURES AN UPPER RIDGE CENTERED OVER TX AND AN UPPER
LOW OFF THE NORTHEAST COAST OF FL. AS THE RIDGE SLIDES SLOWLY WETS,
THE UPPER LOW WILL RETROGRADE WESTWARD INTO THE GULF THIS WEEKEND.
THE RESULT IS AN INCREASE IN MOISTURE ACROSS THE AREA DUE TO
CONFLUENT FLOW BETWEEN THE HIGH AND LOW. THERE HAS BEEN A BIT MORE
MID LEVEL CLOUD COVER ACROSS THE AREA THAN PREVIOUSLY EXPECTED,
WHICH HAS SLOWED WARMING, AND TEMPERATURES ARE SITTING IN THE MID TO
UPPER 80S WITH A FEW LOW 90S TOWARD THE NC/SC BORDER WHERE THERE HAS
BEEN MORE SUN. A WEAK SHORTWAVE AND SURFACE TROUGH ARE STILL
EXPECTED TO FORCE SOME SHOWERS AND THUNDERSTORMS MAINLY NORTH OF THE
I-20 CORRIDOR THIS EVENING. HOWEVER, THE TIMING SHOULD BE SLIGHTLY
LATER DUE TO THE LINGERING CLOUD COVER. A CU FIELD IS STARTING TO
GET ORGANIZED AS OF THIS WRITING, AS SEEN ON VISIBLE SATELLITE
IMAGERY. A FEW ROBUST STORMS ARE OBSERVED ACROSS CENTRAL NC AND
MOVING SOUTH. MESOANALYSIS/RAP FORECAST DOES SHOW A BIT BETTER
ENVIRONMENT DEVELOPING IN THE NEXT FEW HOURS, BUT THE SEVERE THREAT
(MAINLY DAMAGING WINDS) STILL APPEARS TO BE LOW. THE MARGINAL RISK
(1 OF 5) WILL BE LIMITED TO THE NORTH AND WESTERN PORTION OF THE
FORECAST AREA, WITH THE THREAT DIMINISHING QUICKLY WITH LOSS OF
HEATING. A FEW CAMS CONTINUE CONVECTION OVERNIGHT, BUT COVERAGE
SHOULD BE DECREASING OVERALL. THE UNSETTLED PATTERN WILL CONTINUE
INTO EARLY NEXT WEEK WITH PWATS HOLDING AROUND 125-150% OF NORMAL.
WHILE WIDESPREAD FORCING WILL LIKELY BE LIMITED, THIS DEEP LAYER
MOISTURE AND A UNSEASONABLY HOT AND HUMID AIR MASS WILL SUPPORT
SCATTERED SHOWERS AND STORMS EACH AFTERNOON THROUGH TUESDAY.
KEY MESSAGE 2: COOLER AND DRIER AIR RETURNS BY THE MIDDLE OF NEXT
WEEK BUT FORECAST UNCERTAINTY REMAINS.
THERE REMAINS SOME UNCERTAINTY AS TO THE EXACT PATTERN THAT
EVOLVES TOWARDS THE MIDDLE OF NEXT WEEK, BUT RUN TO RUN MODEL
CONSISTENCY IS INCREASING. THE AFOREMENTIONED UPPER LOW IS
PROGGED TO EJECT OUT OF THE NORTHEAST GULF AND UP THE EASTERN
SEABOARD TUESDAY INTO WEDNESDAY. THIS WILL MAKE WAY FOR HIGH
PRESSURE STRENGTHENING OVER THE NORTHEAST AND RIDGING DOWN THE
COAST TO POTENTIALLY SET UP A COLD AIR DAMMING SCENARIO.
HOWEVER, THE CLASSIC SOUTHWEST FLOW ALOFT DOESN'T APPEAR TO SET
IN UNTIL LATE IN THE WEEK OR ESSENTIALLY BEYOND THE SCOPE OF
THIS FORECAST PACKAGE, AND DRIER AIR IS EXPECTED TO MOVE IN FROM
THE NORTHWEST. THIS SHOULD LIMIT OUR RAIN CHANCES LATE NEXT
WEEK. IN THE MEANTIME, BLENDED GUIDANCE FAVORS NEAR NORMAL
TEMPERATURES FOR HIGHS THOUGH WITH LARGE IQRS DURING THIS PERIOD,
WITH THE DISTRIBUTIONS SKEWED TOWARDS LOWER VALUES. WE WILL
NEED TO CONTINUE TO MONITOR TRENDS OVER THE COMING DAYS.
AVIATION /18Z FRIDAY THROUGH WEDNESDAY/
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD
OUTSIDE OF POSSIBLE CONVECTION.
A BROKEN BAND OF LOW TO MID-LEVEL CLOUDS AND LIGHT SHOWERS HAVE
PERSISTED SOUTH OF THE I-20 CORRIDOR EARLY THIS AFTERNOON, WITH
RA NOTED AT AGS AND DNL IN THE PAST HOUR. HAVE ADDED VCSH
MENTIONS FOR THE NEXT HOUR AT AGS AND DNL WITH ONGOING SHOWERS
AND UNTIL 20Z WITH LIGHT SHOWERS APPROACHING OGB. FARTHER NORTH,
CONVECTION HAS BEGUN TO INITIATE CONVECTION OVER THE HIGHER
TERRAIN AND PIEDMONT OF NORTH CAROLINA EARLY THIS AFTERNOON.
THIS CONVECTION SHOULD MOVE SOUTHWARD INTO THROUGH THE FORECAST
AREA LATER THIS AFTERNOON THROUGH THIS EVENING, WITH CAM
GUIDANCE MOSTLY DEPICTING THIS CONVECTION ALONG OR NORTH OF THE
I-20 CORRIDOR. HAVE MAINTAINED PROB30 GROUP CONVECTION DURING
THE 22Z-04Z TIME FRAME AT ALL TERMINALS EXCEPT OGB, WHERE
CONFIDENCE IS LOWER. HIGHER CLOUDS (AT OR OVER 10KFT) WILL
REBUILD OVERNIGHT ACROSS MUCH OF THE FORECAST AREA, WHICH SHOULD
RESULT IN WARMER LOWS TONIGHT AND PREVENT VIS RESTRICTIONS
DEVELOPING. THESE CLOUDS SHOULD LOWER (AROUND 5KFT) INTO BROKEN
TO SCATTERED CUMULUS BY EARLY SATURDAY AFTERNOON.
EXTENDED AVIATION OUTLOOK...CHANCES FOR SHOWERS AND STORMS
CONTINUE THROUGH THE WEEKEND. MORNING CIG/VSBY RESTRICTIONS ARE
POSSIBLE THIS WEEKEND AS WELL.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...EC
AVIATION...SF
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