Area Forecast Discussion
Issued by NWS Wilmington, NC

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
476
FXUS62 KILM 281402
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
1002 AM EDT THU APR 28 2016

.SYNOPSIS...
WARM AND HUMID AIR TODAY WILL HELP CREATE SHOWERS AND THUNDERSTORMS.
A WEAK COLD FRONT WILL MOVE OFF THE COAST EARLY FRIDAY MORNING...
FOLLOWED BY ANOTHER FRONT EARLY SATURDAY MORNING. HIGH PRESSURE
WILL MOVE ACROSS THE GREAT LAKES AND NEW ENGLAND THIS WEEKEND
BRINGING COOLER AIR TO THE CAROLINAS. LOW PRESSURE FROM THE
PLAINS STATES WILL MOVE THROUGH THE MID-ATLANTIC REGION MONDAY...
DRAGGING ANOTHER COLD FRONT THROUGH THE CAROLINAS. HIGH PRESSURE
WILL BUILD IN FROM THE WEST TUESDAY AND WEDNESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM THURSDAY...THIS NEAR TERM UPDATES FOCUS ON THE LINE
OF THUNDERSTORMS MOVING QUICKLY EASTWARD ACROSS SOUTH CAROLINA.
THIS ACTIVITY IS TIED TO AN UPPER LEVEL DISTURBANCE EASILY PICKED
OUT IN WATER VAPOR SATELLITE IMAGERY NOW APPROACHING THE
INTERSTATE 95 CORRIDOR. LIFT JUST AHEAD OF THIS DISTURBANCE SHOULD
MAINTAIN THESE SHOWERS AND STORMS AS THEY PUSH EASTWARD TO MYRTLE
BEACH AND EVENTUALLY WILMINGTON OVER THE NEXT FEW HOURS. SURFACE-
BASED PARCELS ARE CAPPED...AND THIS CONVECTION APPEARS TO BE
ROOTED IN A LAYER OF ELEVATED INSTABILITY BETWEEN 4000-7000 FEET
AGL AS DIAGNOSED ON THE 12Z CHS SOUNDING.

THE UPPER DISTURBANCE SHOULD TAKE THIS CONVECTION LARGELY OFF THE
COAST BY NOON. DRIER AIR AT AND ABOVE THE 700 MB LAYER WILL BUILD
OVER THE AREA FOR THE AFTERNOON HOURS WITH A SHARP REDUCTION IN
THE COVERAGE OF STORMS EXPECTED INITIALLY. AS SURFACE
TEMPERATURES SOAR THROUGH THE 80S AND SURFACE-BASED INSTABILITY
GROWS TO 1500-2000 J/KG I ANTICIPATE 20-30 PERCENT COVERAGE OF
SHOWERS AND STORMS TO REDEVELOP MAINLY DUE TO INSTABILITY ALONE.
THE DRY AIR ALOFT ENTRAINING INTO THE STORMS SHOULD CAUSE THE RISK
FOR GUSTY WINDS TO GROW AS DIAGNOSED BY FORECAST DOWNDRAFT CAPE
(DCAPE) VALUES OF 800-1000 J/KG IN FORECAST SOUNDINGS. BULK SHEAR
THROUGH THE 0-6 KM LAYER REMAINS TOO WEAK FOR CONCERN...SO THE
MARGINAL RISK FROM SPC IS LIKELY TIED TO THIS DRY AIR ALOFT.

SEVERAL OF THE HIGH-RES MODELS ARE KEYING ON A WEAK DISTURBANCE
LATE THIS AFTERNOON ACROSS NORTHERN NORTH CAROLINA TO DEVELOP A
POSSIBLY SIGNIFICANT CONVECTIVE CLUSTER THERE. SHOULD THIS
OCCUR...VEERING MID-LEVEL FLOW PLUS THE DRY AIR ALOFT COULD CAUSE
THIS CONVECTION TO TURN SOUTHEASTWARD AND RACE TOWARD OUR PORTION
OF THE CAROLINAS THIS EVENING. THIS IS A CONDITIONAL RISK BASED
ON CONVECTION DEVELOPING AND BEHAVING AS I AM EXPECTING...BUT THIS
FINAL CLUSTER OF STORMS COULD IMPACT THE AREA DURING THE LATE
EVENING HOURS. I HAVE BUMPED POPS UP TO 40 PERCENT IN THE
WILMINGTON AREA...20-30 PERCENT ELSEWHERE...FOR THIS POTENTIAL.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 400 AM THURSDAY...THE TREND FOR FRIDAY THRU SATURDAY WILL BE
FOR A STRENGTHENING MID-LEVEL RIDGE ACROSS THE SE STATES.

FOR FRI HOWEVER...THE W TO NW FLOW THRU THE ATM COLUMN...AND THUS
A DOWNSLOPE TRAJECTORY OFF THE APPALACHIANS...WILL AID MAX TEMPS
ON FRI THAT REACH THE MID TO POSSIBLY UPPER 80S. THE W-NW FLOW
ALOFT WILL ALSO SCOUR OUT ANY CLOUDINESS OR MOISTURE ALOFT BY THE
TIME IT REACHES THE ILM CWA.

THE UPPER RIDGE WILL AID THE SFC HIGH CENTERED OVER THE NE
STATES...TO TEMPORARILY RIDGE SOUTHWARD ACROSS THE FA LATE FRI
NIGHT THRU SAT. THIS WILL PRODUCE A NE-ENE COOL SURGE PEAKING
DURING SAT. NO PCPN EXPECTED WITH THIS SURGE DUE TO A DRY ATM
COLUMN UNDER W TO NW FLOW ALOFT. THE UPPER RIDGE AXIS PUSHES OVER
THE ILM CWA SAT NIGHT ENDING THE COOL SURGE OF AIR. IN ADDITION...
MOISTURE ALOFT WILL INCREASE AS THE UPPER FLOW BACKS TO THE SW
AFTER THE UPPER RIDGE AXIS PASSES BY. RETURN SE FLOW AT THE
SFC...WILL START PUSHING LOW LEVEL MOISTURE BACK ACROSS THE FA.
HAVE HELD POPS AT BAY UNTIL DAYTIME SUN. STAYED CLOSE TO THE GFS
MOS GUIDANCE FOR BOTH MAX AND MIN TEMPS THIS PERIOD.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 330 AM THURSDAY...LOW PRESSURE MAKES ITS WAY TOWARD THE
CAROLINAS FROM THE WEST AS NORTHERN STREAM SHORTWAVE PUSHES RIDGE
OVER THE SOUTHEAST OUT TO SEA. A DEEP SOUTHWESTERLY FLOW AHEAD OF
THIS SYSTEM WILL STREAM MOISTURE INTO THE EASTERN CAROLINAS. PCP
WATER VALUES WILL REACH UP NEAR 1.5 INCHES SUN AFTN. OVERALL
EXPECT INCREASE IN CLOUDS AND SHOWER ACTIVITY SUNDAY AFTN THROUGH
EARLY MONDAY. LOOKS LIKE THIS SYSTEM WILL BE MOVING OFF OF THE MID
ATLANTIC COAST ON MONDAY DRAGGING A COLD FRONT EAST. OVERALL
EXPECT SLIGHTLY COOLER BUT MAINLY DRIER AIR FOR LATE MON INTO TUES
AS HIGH PRESSURE BUILDS IN. ECMWF MUCH WETTER FOR MIDWEEK WITH
SHORTWAVE DIGGING SOUTH AND CONVECTION FLARING UP OVER THE
CAROLINAS WHILE THE GFS KEEPS MUCH BROADER MID TO UPPER TROUGH
WITH BEST CHC OF PCP TO THE SOUTH WHERE BEST LIFT WILL BE. EITHER
WAY IT LOOKS LIKE IT WILL REMAIN UNSETTLED WITH A INCREASED
POTENTIAL FOR CLOUDS AND SHOWERS TUES INTO WED.

TEMPS IN THE 80S SUN INTO MON WILL COOL MON NIGHT INTO TUES
BEHIND COLD FRONT. OVERALL SHOULD STAY BETWEEN 75 AND 80 MOST
PLACES THROUGH THE WEEKEND THEN WARMING AHEAD OF FRONT MONDAY AND
RELATIVELY COOLER AGAIN TUES INTO WED.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 12Z...AREAS OF BRIEF MVFR/IFR LOW STRATUS THIS MORNING ALONG
THE COAST. ELSEWHERE...EXPECT VFR THIS MORNING WITH MVFR/IFR THIS
AFTERNOON AS CLOUDS INCREASE ALONG WITH CHANCES FOR SHOWERS AND
ISOLATED THUNDERSTORMS AHEAD OF A COLD FRONT DROPPING FROM THE
NORTH.

VFR PREVAILS ACROSS THE AREA THIS MORNING WITH THE EXCEPTION OF KCRE
WHERE LOW CIGS ARE CREATING IFR ATTM. EXPECT MVFR/IFR AT
KCRE/POTENTIALLY KMYR OVER THE NEXT HOUR OR TWO. LATEST RADAR
IMAGERY DEPICTS SHOWERS JUST SOUTH AND EAST OF KILM AS WELL AS JUST
WEST OF THE FORECAST AREA. WHILE SHOWERS NEAR KILM WILL CONTINUE TO
MOVE OFFSHORE...EXPECT SHOWERS JUST WEST OF THE AREA TO CONTINUE
MIGRATING EASTWARD TOWARDS THE INLAND TERMINALS. FOR THE REST OF
TODAY...EXPECT INCREASING CHANCES FOR ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS WITH SOUTHWEST WINDS INCREASING TO AOB
15 KTS AND HIGHER GUSTS NEAR 20 KTS AT TIMES. SLIGHTLY HIGHER
GUSTS AND LOWER CIGS ARE POSSIBLE WHICH MAY CREATE MVFR/IFR IN
ANY HEAVY DOWNPOURS OR THUNDERSTORMS. TONIGHT...SHRA/TSRA ACTIVITY
WILL GRADUALLY TAPER OFF AND WEST-SOUTHWEST WINDS WILL DECREASE
TO AROUND 5 KTS OVERNIGHT. VFR WILL PREVAIL THOUGH AREAS OF FOG
ARE POSSIBLE TOWARDS EARLY FRIDAY MORNING.

EXTENDED OUTLOOK...AREAS OF FOG POSSIBLE FRIDAY MORNING. MVFR
POSSIBLY IFR CONDITIONS FROM CONVECTION SUNDAY INTO MONDAY.
OTHERWISE EXPECT VFR.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM THURSDAY...AN UPPER LEVEL DISTURBANCE MOVING QUICKLY
EASTWARD ACROSS THE EASTERN CAROLINAS SHOULD PUSH SHOWERS AND
THUNDERSTORMS ACROSS THE GRAND STRAND COASTAL WATERS OVER THE NEXT
HOUR. THESE MAY SPREAD NORTHEASTWARD TO IMPACT THE CAPE FEAR
WATERS BEFORE NOON. THIS ACTIVITY SHOULD DELAY THE FORMATION OF
TODAY`S SEABREEZE BY SEVERAL HOURS...AND I DON`T EXPECT TO SEE
NEARSHORE WIND SPEEDS KICK UP SUBSTANTIALLY UNTIL MID AFTERNOON.

BEHIND THIS UPPER LEVEL DISTURBANCE THE COVERAGE OF SHOWERS AND
STORMS SHOULD DECREASE FOR THE AFTERNOON HOURS...BUT WE`LL BE
WATCHING FOR SOME GUSTY STORMS TO POSSIBLY ARRIVE FROM THE
NORTHWEST LATE THIS EVENING. OTHERWISE...HIGH PRESSURE WELL
OFFSHORE IS CONTINUING TO PROVIDE A SOUTHWEST WIND ACROSS THE
WATERS. A WEAK FRONT SHOULD PUSH THROUGH THE AREA LATE TONIGHT
VEERING WIND DIRECTIONS MORE NORTHWESTERLY.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 400 AM THURSDAY...A RELAXED SFC PG ON FRIDAY WILL PRODUCE
WINDS AT 10 KT OR LESS. THE PRESSURE PATTERN WILL RESULT IN A
WESTERLY DIRECTION. THE SEA BREEZE DEVELOPMENT FRI AFTN WILL
RESULT IN SOUTH WINDS UP TO 15 KT ACROSS THE NEAR SHORE
WATERS...WITHIN 10 NM FROM THE COAST. SIGNIFICANT SEAS FRI WILL
RUN 2 TO 3 FT. THE ENE GROUND SWELL AT 9 SECOND PERIODS WILL
OCCASIONALLY DOMINATE THE SIGNIFICANT SEAS DURING FRI.

A COOL NE WIND SURGE WILL OCCUR LATER FRI NIGHT THRU SAT AS HIGH
PRESSURE TEMPORARILY NOSES DOWN THE EAST COAST TO THE ILM CWA.
FROM CAPE FEAR NORTHWARD...LOOK FOR WINDS AT A SOLID 15 TO
POSSIBLY 20 KT DEPENDING ON THE AMOUNT OF CAA...AND SOUTH OF THE
CAPE...10 TO 15 KT. WINDS WILL QUICKLY VEER TO THE E-SE SAT NIGHT
DUE TO THE BREAK FROM THE SFC RIDGING FROM THE NORTH. THE GRADIENT
WILL PRODUCE 10 TO 15 KT WIND SPEEDS. SIGNIFICANT SEAS SAT THRU
SAT NIGHT WILL ELEVATE TO 3 TO 4 FT CAPE FEAR NORTH...AND HOLD AT
3 FT OR LESS SOUTH OF THE CAPE. WIND DRIVEN 3 TO 5 SECOND PERIODS
TO DOMINATE SIGNIFICANT SEAS SAT.

LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 330 AM THURSDAY...WINDS WILL BECOME MORE SOUTHERLY BY SUN
AFTN AS HIGH PRESSURE SHIFTS OFF THE NORTHEAST COAST AND LOW
PRESSURE APPROACHES THE CAROLINAS FROM THE WEST. THIS LOW WILL
MOVE EAST OFF THE MID ATLANTIC COAST BY MONDAY DRAGGING A COLD
FRONT THROUGH THE WATERS. WINDS WILL VEER AROUND TO THE NORTH
BEHIND THE FRONT AS HIGH PRESSURE BUILDS IN HEADING INTO TUES.

SEAS WILL REMAIN IN THE 2 TO 4 FT RANGE THROUGH SUN BUT WILL
BEGIN TO INCREASE OVERNIGHT SUN INTO MON MORNING AS LOW PRESSURE
MOVES INTO THE CAROLINAS TIGHTENING THE GRADIENT FLOW OUT OF THE
S-SW. WNA SHOWS SEAS REACHING 4 TO 5 FT IN OUTER WATERS MON AFTN
BUT THEN DECREASING HEADING INTO TUES.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...TRA
NEAR TERM...TRA
SHORT TERM...DCH
LONG TERM...RGZ
AVIATION...SGL



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.