311
FXUS62 KILM 301035
AFDILM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
635 AM EDT SUN MAR 30 2025
SYNOPSIS
AN UPPER LEVEL DISTURBANCE WILL PASS ACROSS THE AREA THIS
AFTERNOON AND TONIGHT, WITH SHOWERS AND ISOLATED THUNDERSTORMS
POSSIBLE. ADDITIONAL SHOWERS WITH STRONG TO ISOLATED SEVERE
THUNDERSTORMS EXPECTED MONDAY AFTERNOON AND EVENING AHEAD OF A
COLD FRONT. FORECAST MOSTLY DRIES OUT FOR THE REST OF THE WORK
WEEK, AS THE WARMEST TEMPERATURES OF THE YEAR SO FAR TAKE HOLD.
NEAR TERM /THROUGH TONIGHT/
THIS PERIOD WILL FEATURE THE 5H S/W RIDGE AXIS SLIDING OUT OVER
THE ATLANTIC ALLOWING THE APPROACHING 5H DAMPENING S/W TROF TO
APPROACH AND REACH THE FA TONIGHT. MID TO UPPER LEVEL MOISTURE
ACCOMPANYING THE UPPER TROF WHILE LOW LEVEL ATLANTIC MOISTURE
CONTINUES TO OVERSPREAD THE FA. BEST CHANCES FOR SHOWERS AND
ISOLATED TSTORMS TODAY WILL GENERALLY BE ACROSS THE ILM SC CWA,
AND OVERSPREADING THE ILM NC CWA TONIGHT. THE BEST FORCING AND
UVVS ASSOCIATED WITH THE PASSAGE OF THE 5H S/W TROF OCCURS
DURING THIS EVENING THRU THE OVERNIGHT TONIGHT. TOTAL RAINFALL
ACROSS THE FA DURING THE NEXT 24 HRS WILL RANGE FROM ONE TENTH
OF AN INCH INLAND TO ONE QUARTER OF AN INCH AT THE COAST. ENOUGH
INSOLATION TODAY AND WITH A MILD AIRMASS ESTABLISHED ACROSS THE
FA, WILL GENERALLY OBSERVE MAX TEMPS IN THE 75 TO 80 DEGREE
RANGE. EXCEPT LOW 70S ALONG THE IMMEDIATE COAST DUE TO ONSHORE
FLOW ACROSS UPPER 50S TO LOWER 60S ADJACENT SSTS. TONIGHTS LOWS
WILL ONLY DROP BACK INTO THE 60S AS CLOUDS AND PCPN BLANKET THE
FA.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/
ALL EYES ON THE COLD FRONT THAT WILL MOVE THROUGH THE AREA MONDAY
NIGHT. AHEAD OF THE FRONT, A LINE OF SHOWERS AND STORMS IS PROGGED
TO MOVE THROUGH THE AREA FROM WEST TO EAST. SEVERE WEATHER CONTINUES
TO BE ADVERTISED.
BUT GOODNESS, THE GUIDANCE (AND CONFIDENCE) IS MESSY. AMPLE
SOUTHERLY FLOW WILL NO DOUBT PUMP PLENTY OF MOISTURE INTO THE
CAROLINAS. DEWPOINTS IN THE LOWER 60S MONDAY MORNING KICK UP TO THE
MID 60S BY THE AFTERNOON, WITH PRECIPITABLE WATER VALUES POTENTIALLY
ECLIPSING 1.5 INCHES. DESPITE CLOUD COVER, THIS SHOULD STILL PROVIDE
ENOUGH BUOYANCY TO SUPPORT SBCAPE VALUES AROUND 1000 J/KG, GIVE OR
TAKE 100-200 J/KG IN EITHER DIRECTION. WHILE THIS ISN'T EXPLOSIVE,
THIS IS CERTAINLY MORE CAPE THAN WE'VE SEEN IN QUITE SOME TIME
(HELLO, SPRING). NEXT BIG THING THAT STICKS OUT IS THE INCREASING
HELICITY. GLOBAL ENSEMBLES AND EVEN SOME MEMBERS OF THE HREF ARE
WANTING TO PUMP VALUES AROUND 150 M2/S2 OF 0-3 KM AND 0-1 KM SRH. IF
YOU MAX OUT THE VALUES (95TH PERCENTILE AND ABOVE), YOU GET CLOSER
TO 200 M2/S2. THESE TRENDS HAVE HELD PRETTY STEADY THE LAST FEW
FORECAST CYCLES.
HERE IS THE DILEMMA (TWO THINGS, REALLY):
- TIMING AND DEPTH OF THE SHEAR
- SKEWED DISTRIBUTION OF THE DATA
CONFIDENCE IS INCREASING ON THE TIMING OF THIS LINE OF STORMS,
MOVING ACROSS THE AREA DURING THE AFTERNOON AND EVENING HOURS. WHILE
THE CAPE AND HELICITY ARE INDICATIVE OF A DAMAGING WIND AND HAIL
THREAT, STRONG WIND SHEAR WOULD REALLY SELL THIS NARRATIVE MORE THAN
ANYTHING. FOR ONE THING, THE SHEAR JUST DOESN'T LOOK AS STRONG AS
I'VE SEEN IN PREVIOUS EVENTS THE LAST COUPLE OF MONTHS. YES, BULK
SHEAR ATTEMPTS TO GET UP TO 50-60 KTS, BUT IT DOESN'T SEEM TO
TRANSLATE AS WELL TO THE 0-3 KM OR 0-1 KM LAYERS. DESPITE THE CAPE,
THERE IS ALSO SOME CIN TO CONTEND WITH, LIKELY DUE TO THE LINGERING
CLOUD COVER THROUGHOUT THE DAY. THIS MAY PROTECT THE SURFACE FROM
THE STRONGER WINDS ALOFT (NOT THAT THE LLJ LOOKS THAT STOUT). THERE
APPEARS TO BE SOME BETTER SHEAR VORTICITY THAT COMES THROUGH WITH
THE ACTUAL FROPA ITSELF, BUT THIS IS AFTER THE LINE OF SHOWERS AND
STORMS.
ANOTHER PROBLEM WITH THE SHAKY CONFIDENCE IS THAT THERE IS A
NOTICEABLE RIGHT SKEW IN THE DATA DISTRIBUTION WITHIN THE
PROBABILISTIC GUIDANCE. THIS PATTERN SHOWS UP IN THE MEDIUM-RANGE
GUIDANCE AND WITHIN THE HREF (PARTICULARLY WITH THE NAM, A NON-
HYDROSTATIC MODEL THAT LIKES TO BE EXPLOSIVE MORE OFTEN THAN NOT
AROUND HERE).
IF THOSE OUTLIERS ARE REALIZED (SBCAPE 1500+ J/KG, SRH 200+ M2/S2, 0-
1 KM SHEAR 30+ KTS) AT THE RIGHT TIME, THEN WE COULD CERTAINLY HAVE
A POTENT EVENT ON OUR HANDS, WITH DAMAGING WINDS, LARGE HAIL, AND
ISOLATED TORNADOES. WHILE I'M NOT RULING ANY OF THESE THINGS OUT, I
AM DUBIOUS OF THESE PARAMETERS COMING TOGETHER AT THE "RIGHT" PLACE
AND TIME.
ONE FINAL THING THAT I NOTICE IS THAT MOST OF THE HREF MEMBERS
ELEVATE ALL THESE PARAMETERS OVER PARTS OF NORTHERN FL, SOUTHEAST
GA, AND SC LOWCOUNTRY AS THE LINE MOVES THROUGH. THIS WOULD SHIFT
THE SEVERE WEATHER THREAT TO THESE AREAS, AS THE ENERGY GETS
"STOLEN" FROM NORTHEAST SC AND SOUTHEAST NC. THIS IS A VERY COMMON
THEME AROUND HERE, AND I THINK THERE'S SOMETHING TO THIS AGAIN.
HIGHS MONDAY IN THE LOWER 80S INLAND, MID-TO-UPPER 70S AT THE COAST.
FRONT PUSHES OFFSHORE MONDAY NIGHT, AND THE RAIN CHANCES DIE OUT
OVERNIGHT, WITH LOWS IN THE MID-TO-UPPER 50S. HIGH PRESSURE TO THE
NORTH KEEPS THE FORECAST DRY TUESDAY AND TUESDAY NIGHT. HIGHS IN THE
MID 70S, LOWS IN THE LOW-TO-MID 50S.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
WEDNESDAY INTO THURSDAY, THE OLD FRONTAL BOUNDARY OFFSHORE SURGES
NORTHWARD AS A WARM FRONT. THIS BRINGS SSW BACK INTO THE FOLD
THROUGH THE REST OF THE FORECAST PERIOD. MOSTLY DRY THROUGH
SATURDAY, WITH ONLY A SLIGHT CHANCE OF SHOWERS OR AN ISOLATED
THUNDERSTORM POSSIBLE INLAND. BIGGEST THING HERE IS THE STRONG
WARMING TREND THAT KICKS IN, PARTICULARLY BY THURSDAY. WIDESPREAD
HIGH TEMPERATURES IN THE MID-TO-UPPER 80S WILL BE THE NORM. BY
FRIDAY AND SATURDAY, SOME SPOTS IN THE PEE DEE REGION MAY TRY TO HIT
90 DEGREES FOR THE FIRST TIME IN 2025. BREAK OUT THE SUNSCREEN.
AVIATION /12Z SUNDAY THROUGH THURSDAY/
APPROACHING FROM THE SW, A DAMPENING UPPER TROF ACCOMPANIED BY
MOISTURE WILL PUSH ACROSS THE AREA TERMINALS LATER THIS AFTERNOON
THRU TONIGHT. LOW LEVEL ATLANTIC MOISTURE WILL SIPHON ACROSS THE
AREA THRU TONIGHT. GUIDANCE SUGGESTS A DELAY IN THE PCPN
GENERALLY SPREADING FROM SW TO NE, AFFECTING THE SC TERMINALS
THIS AFTERNOON AND TONIGHT AND THE NC TERMINALS MAINLY TONIGHT.
MODERATE TO HIGH CONFIDENCE FOR VFR TO DOMINATE INTO THE
AFTERNOON WITH THE THREAT FOR MVFR CONDITIONS LATE THIS
AFTERNOON THRU TONIGHT FOR SC TERMINALS AND MAINLY TONIGHT FOR
THE NC TERMINALS. AT THIS POINT, USED A PROB30 GROUP TO IDENTIFY
THE POTENTIAL MVFR, MAINLY FROM CEILINGS. LOW CONFIDENCE FOR IFR
CONDITIONS FROM CEILINGS DURING THE PRE-DAWN MON HRS BUT ENOUGH
TO PLACE IN ATLEAST THE INLAND TERMINALS. THE SFC RIDGE AXIS
FROM THE OFFSHORE HIGH CONTINUES TO EXTEND ACROSS THE EASTERN
CAROLINAS WITH FLOW GENERALLY 140-170 DEGREES AROUND 5 KT THIS
MORNING AND 160-180 DEGREES AT 10-15 KT WITH FEW GUSTS AOB 20
KT THIS AFTN/EVENING MAINLY AT THE COASTAL TERMINALS. WINDS WILL
DROP BACK TO 5 KT OR LESS BY 04Z.
EXTENDED OUTLOOK...THERE IS LOW TO MODERATE CONFIDENCE IN
MVFR/IFR CEILINGS AND VISIBILITY EARLY MONDAY ALONG WITH
SCATTERED SHOWERS. THIS INCREASES TO A MODERATE CONFIDENCE OF
CEILING AND VSBY IMPACTS MON INTO MON NIGHT FROM CONVECTION
PRECEDING A COLD FRONT THAT IS EXPECTED TO MOVE THROUGH MON
NIGHT. POTENTIAL FOR SEVERE WITH THIS ACTIVITY, ESPECIALLY
ACROSS THE INLAND TERMINALS. VFR CONDITIONS SHOULD DOMINATE
TUE THRU THU, HOWEVER THERE IS LOW CONFIDENCE FOR PERIODIC
FLIGHT RESTRICTIONS ASSOCIATED WITH A WFP WED.
MARINE
THROUGH TONIGHT...EXPANSIVE HIGH PRESSURE CENTERED WELL
OFFSHORE FROM THE CAROLINAS WILL CONTINUE TO RIDGE WEST BACK
ACROSS THE AREA WATERS DURING THIS PERIOD. THIS WILL RESULT IN
SSE-SSW WIND DIRECTIONS AND WITH A SLIGHTLY TIGHTENED GRADIENT
TODAY THAT TIGHTENS SLIGHTLY TONIGHT WILL PRODUCE 5 TO 10 KT
SPEEDS TODAY AND 10-15 KT SPEEDS TONIGHT. NEARSHORE THIS AFTN
AND EVENING IF A SEA BREEZE IS ABLE TO DEVELOP AND PROGRESS
INLAND, SPEEDS NEARSHORE MAY HOVER AROUND 15 KT WITH A PERIODIC
GUST TO 20 KT. THE EXPANSIVE HIGH HAS CREATED A RATHER DECENT
FETCH FOR SEA TO BUILD UPON AND AS A RESULT, SEAS WILL BE
DOMINATED BY A MODEST 2 TO 3 FT SE SWELL AT 8 TO 10 SECOND
PERIODS. SOME GUIDANCE SUGGESTS UP TO 4 FT IN A SE SWELL LATER
TODAY THRU TONIGHT. SEA FOG STILL IN QUESTION WITH SFC DEWPOINT
APPROACHING AROUND 60 DURING THIS PERIOD. SSTS HAVE COME UP IN
THE UPPER 50S TO LOW 60S. IF SFC DEWPOINTS ABLE TO REACH THE
MID AND UPPER 60S, THEN SEA FOG HAS A POSSIBILITY GIVEN THE
CONTINUED SOUTHERLY WIND DIRECTIONS.
MONDAY THROUGH THURSDAY...SOUTHERLY WINDS INCREASE AHEAD OF A COLD
FRONT MONDAY. WINDS GRADUALLY VEER TO THE SOUTHWEST JUST AHEAD
OF THE FRONT, INCREASING TO 10-15 KTS AND FREQUENT GUSTS UP TO
AND ABOVE 20 KTS. WINDS AND SEAS MAY BRIEFLY CROSS OVER INTO
SMALL CRAFT ADVISORY THRESHOLDS MONDAY NIGHT, PARTICULARLY OVER
THE SOUTHEAST NC COASTAL WATERS FROM SURF CITY TO CAPE FEAR OUT
20 NM. FRONT ITSELF MOVES OUT OF THE OUT BY EARLY TUESDAY
MORNING, AND GRADIENT WINDS LOOSEN AS THEY VEER WESTERLY AT
FIRST, BECOMING MORE VARIABLE THROUGHOUT THE DAY (SEAS DROP DOWN
TO 2-4 FT THROUGHOUT THIS TIME). WEDNESDAY AND THURSDAY,
EASTERLY WINDS AT 10-15 KTS GRADUALLY BECOME SOUTHERLY AGAIN,
WITH SEAS INCREASING SLIGHTLY TO 3-4 FT.
ILM WATCHES/WARNINGS/ADVISORIES
NC...NONE.
SC...NONE.
MARINE...NONE.
SYNOPSIS...IGB
NEAR TERM...DCH
SHORT TERM...IGB
LONG TERM...IGB
AVIATION...DCH
MARINE...DCH/IGB
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page