664
FXUS62 KILM 120454
AFDILM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
1254 AM EDT SAT SEP 12 2026
WHAT HAS CHANGED
AVIATION SECTION UPDATED. COASTAL FLOOD ADVISORY FOR DOWNTOWN
WILMINGTON HAS BEEN CANCELLED.
KEY MESSAGES
1) DEEP GULF MOISTURE AND A BREAK IN THE RIDGE ALOFT WILL
MAINTAIN GOOD CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH
SUNDAY.
2) WELL-ABOVE NORMAL TEMPERATURES AND HIGH HUMIDITY WILL
MAINTAIN DAYTIME HEAT INDICES AT OR ABOVE 100 DEGREES THROUGH
MONDAY.
3) A MODIFIED CANADIAN AIRMASS SHOULD BRING NEAR-NORMAL
TEMPERATURES BEGINNING TUESDAY.
DISCUSSION
KEY MESSAGE 1...DEEP GULF MOISTURE AND A BREAK IN THE RIDGE ALOFT WILL
MAINTAIN GOOD CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH
SUNDAY.
THIS MORNING'S 12Z CHS WEATHER BALLOON MEASURED A PRECIPITABLE
WATER OF 2.35 INCHES. THAT'S ONE-THIRD OF AN INCH ABOVE THE 90TH
CLIMATOLOGICAL PERCENTILE AND NEAR THE DAILY MAX FOR THIS TIME
OF YEAR. DEEP GULF MOISTURE WILL CONTINUE TO STREAM NORTHEASTWARD
ACROSS THE EASTERN CAROLINAS THROUGH SUNDAY MORNING BETWEEN A
MID LEVEL RIDGE EAST OF THE BAHAMAS AND A TROUGH OVER THE MID-
MISSISSIPPI VALLEY.
SURFACE-BASED CAPE NEAR 2000 J/KG, FORECAST 0-6 KM BULK SHEAR
AROUND 10 KNOTS, AND LITTLE-TO-NO DRY AIR ALOFT ARGUES FOR
SINGLE-CELL STORM DEVELOPMENT ON SATURDAY WITH HEAVY RAIN
POTENTIAL. SOME LOOSE STORM ORGANIZATION COULD OCCUR ALONG THE
SEABREEZE FRONT AND ANY OUTFLOW BOUNDARIES, BUT SEVERE WEATHER
RISK SHOULD REMAIN VERY LOW. HREF ENSEMBLE 24-HR MAX PRECIP OF
3-5 INCHES IMPLIES THERE WILL BE A FEW ISOLATED HEAVY TOTALS
WITHIN THE SEA OF 0.25 TO 0.50 INCH WEEKEND AMOUNTS.
THE UPPER TROUGH PRODUCING THE BREAK IN THE RIDGE SHOULD SLIDE
EASTWARD ACROSS THE CAROLINAS ON SUNDAY, PERHAPS ENHANCING BULK
SHEAR TO AROUND 20 KNOTS. MULTICELLS SHOULD BECOME POSSIBLE,
PERHAPS BRINGING BETTER POTENTIAL FOR GUSTY WINDS. THE UPPER
TROUGH SHOULD SHIFT OFFSHORE SUNDAY NIGHT AHEAD OF RISING MID
AND UPPER LEVEL HEIGHTS SPREADING EASTWARD FROM THE MID SOUTH.
KEY MESSAGE 2...WELL-ABOVE NORMAL TEMPERATURES AND HIGH HUMIDITY WILL
MAINTAIN DAYTIME HEAT INDICES AT OR ABOVE 100 DEGREES THROUGH
MONDAY.
850 MB TEMPS IN THE +18C TO +19C RANGE SHOULD CONTINUE THROUGH
THE WEEKEND. THIS IS AT OR ABOVE THE 90TH CLIMATOLOGICAL
PERCENTILE FOR MID SEPTEMBER. IF IT WEREN'T FOR THE INCREASED
CLOUDINESS AND CONVECTION EXPECTED THIS WEEKEND WE'D PROBABLY BE
LOOKING AT HEAT ADVISORY-LEVEL CONDITIONS.
AS IT STANDS NOW, FORECAST HIGHS IN THE UPPER 80S TO AROUND 90
COUPLED WITH DEWPOINTS WELL INTO THE 70S SHOULD YIELD HEAT
INDICES IN THE 100-103 RANGE THROUGH MONDAY.
NWS ILM HAS NEVER ISSUED A HEAT ADVISORY LATER THAN SEPTEMBER 5
SINCE THE INTRODUCTION OF VTEC PRODUCT CODES TWENTY YEARS AGO.
(AND THAT LATEST ADVISORY WAS EARLIER THIS MONTH)
KEY MESSAGE 3...A MODIFIED CANADIAN AIRMASS SHOULD BRING NEAR-NORMAL
TEMPERATURES BEGINNING TUESDAY.
MODELS HAVE ALL COME INTO LINE OVER THE PAST 24 HOURS SHOWING
THE STRONGEST CANADIAN HIGH WE'VE SEEN SINCE LAST SPRING MOVING
ACROSS NEW ENGLAND TUESDAY INTO WEDNESDAY. THIS SHOULD PUSH A
COLD FRONT SOUTHWARD ACROSS THE EASTERN CAROLINAS MONDAY NIGHT,
ALLOWING A MODIFIED CANADIAN AIRMASS TO SPREAD ACROSS THE AREA
TUESDAY INTO WEDNESDAY. THIS WON'T BE CRISP, DRY CANADIAN AIR BY
ANY MEANS GIVEN ITS LONG PASSAGE ACROSS WATER TEMPS IN THE 70S
AND 80S, BUT IT SHOULD BRING COOLER AIR ACROSS THE AREA KNOCKING
TEMPERATURES BACK DOWN CLOSER TO NORMAL FOR MID SEPTEMBER.
FORECAST LOWS IN PARTICULAR LOOK REFRESHING WITH 60S EXPECTED
FOR ALL BUT EAST-FACING BEACHES TUESDAY NIGHT AND WEDNESDAY
NIGHT. SOME INLAND LOCATIONS COULD CONCEIVABLY DIP TO 60
DEGREES.
AVIATION /06Z SATURDAY THROUGH WEDNESDAY/
REST OF TONIGHT... MIXING SHOULD MAINTAIN VFR FOR COASTAL
TERMINALS, BUT CAN'T RULE OUT SOME BRIEF MVFR CIGS. LIGHT
BOUNDARY LAYER WINDS, WET SOILS, AND ENHANCED LOW LEVEL MOISTURE
SHOULD PRODUCE IFR ACROSS A LARGE PORTION OF INLAND TERMINALS.
EXPECT SOME CIGS TO REACH LIFR BY SUNRISE. LIGHT WIND SHOULD
MIX-OUT RESTRICTIONS A COUPLE OF HOURS AFTER SUNRISE.
SATURDAY... ISOLATED SHOWERS NEAR THE NC COAST MAY PRODUCT
BRIEF RESTRICTIONS AT ILM THIS MORNING (AROUND SUNRISE). AS THE
SEA BREEZE DEEPENS DURING THE EARLY AFTERNOON, CONVECTION SHOULD
MATURE NEAR THE COAST AND GRADUALLY PUSH INLAND THROUGH THE
AFTERNOON. ADDITIONAL DEVELOPMENT IS POSSIBLE INLAND DURING THE
EARLY AFTERNOON. MOST AREAS ARE EXPECTED TO SEE IMPACTS FROM
THUNDERSTORMS BY THE END OF THE DAY AS SHOWERS BECOME
WIDESPREAD.
EXTENDED OUTLOOK... SCATTERED SHOWERS AND THUNDERSTORMS
BRINGING BRIEF MVFR/IFR CONDITIONS ARE EXPECTED TO CONTINUE
INTO SATURDAY EVENING. SOME SHOWERS ARE POSSIBLE ON SUNDAY, BUT
COVERAGE SHOULD BE LESS THAN PREVIOUS DAYS. THERE IS ALSO A LOW
POTENTIAL FOR LATE NIGHT/EARLY MORNING STRATUS OR GROUND FOG
AFFECTING KLBT AND KFLO LATE SATURDAY NIGHT AND AGAIN LATE
SUNDAY NIGHT. VFR CONDITIONS SHOULD PREVAIL MONDAY THROUGH
WEDNESDAY AS A MORE STABLE AND DRIER CANADIAN AIRMASS BUILDS IN
FROM THE NORTHEAST.
MARINE
TONIGHT THROUGH TUESDAY NIGHT...MODELS CONTINUE TO CONSISTENTLY
SHOW A COLD FRONT STALLING ACROSS INTERIOR NORTH CAROLINA
TONIGHT, THEN LIFTING BACK NORTH ON SATURDAY WITH NO DIRECT
IMPACT ON OUR WEATHER OR WINDS THIS FAR SOUTH. LIGHT TO MODERATE
SOUTHWESTERLY WINDS ARE EXPECTED TO CONTINUE THROUGH THE
WEEKEND ALONG WITH MULTIPLE WAVES OF SHOWERS AND THUNDERSTORMS
SATURDAY THROUGH SUNDAY NIGHT.
DRIER WEATHER SHOULD DEVELOP ON MONDAY AS HIGH PRESSURE
STRENGTHENS ALOFT OVER THE CAROLINAS. THE STRONGEST CANADIAN
HIGH WE'VE SEEN SINCE LAST SPRING SHOULD MOVE ACROSS NEW ENGLAND
TUESDAY AND WEDNESDAY, PUSHING A COLD FRONT SOUTHWARD ACROSS THE
CAROLINA COASTAL WATERS MONDAY NIGHT. NORTHEAST WINDS BEHIND THE
FRONT SHOULD INCREASE TO A SOLID 20 KNOTS OFFSHORE AND 15-20
KNOTS NEARSHORE TUESDAY INTO TUESDAY NIGHT. SEAS WITHIN 20
MILES OF SHORE COULD BUILD TO 4-6 FEET WITH DOMINANT WAVE
PERIODS NEAR 6 SECONDS.
ILM WATCHES/WARNINGS/ADVISORIES
NC...NONE.
SC...NONE.
MARINE...NONE.
WHAT HAS CHANGED...TRA
KEY MESSAGES...TRA
DISCUSSION...TRA
AVIATION...21
MARINE...TRA
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