Area Forecast Discussion
Issued by NWS Wilmington, NC

Current Version | Previous Version | Text Only | 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
000
FXUS62 KILM 030543
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
143 AM EDT THU SEP 3 2015

.SYNOPSIS...
ABOVE NORMAL TEMPERATURES ARE EXPECTED THROUGH FRIDAY. A WEAK
TROUGH WILL LINGER IN THE AREA THROUGH EARLY FRIDAY. A RIDGE OF
HIGH PRESSURE WILL BUILD IN FROM THE NORTH BEHIND A COLD FRONT BY
THIS WEEKEND...BRINGING UNSETTLED WEATHER AND COOLER TEMPERATURES
THROUGH EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 130 AM THURSDAY...RADAR LOOPS AND OBS SHOW IMPRESSIVE GUST
FRONT DROPPING SOUTH INTO THE FORECAST AREA FROM STORM ACTIVITY TO
THE NORTH. EXPECT NO BIG IMPACTS...JUST A WIND SHIFT TO THE NORTH.
STILL POSSIBLE THAT WE COULD SEE SOME OF THIS CONVECTION TO THE
NORTH DROP INTO OUR NORTHERN TIER OF COUNTIES. PREVIOUS
DISCUSSIONS FOLLOW:

STORMS IN NORTHEASTERN NORTH CAROLINA HAS DEVELOPED A MASSED
OUTFLOW BOUNDARY PUSHING SOUTH THROUGH RALEIGH AND GREENVILLE AT
THIS TIME. A SECOND CLUSTER OF STORMS FROM ASHEBORO TO LEXINGTON
IS MOVING SOUTHEASTWARD. THIS OUTFLOW BOUNDARY IS SURPRISINGLY
DEEP...THE RALEIGH RADAR SHOWS THE BOUNDARY EXTENDING UP TO AROUND
7000 FEET NEAR GREENVILLE WHICH IS DEEP ENOUGH TO LIFT PARCELS AT
THE LFC. ODDS ARE STILL ABOUT 1-IN-4 TO 1-IN-5 CONVECTION WILL
SURVIVE ALL THE WAY DOWN TO LUMBERTON...ELIZABETHTOWN AND BURGAW.
A SMALL (20%) POP IS BEING MAINTAINED HERE AFTER MIDNIGHT.
OTHERWISE MOSTLY CLEAR SKIES WILL CONTINUE OVERNIGHT WITH LOWS
70-75. DISCUSSION FROM 730 PM FOLLOWS...

CLOSELY WATCHING SCATTERED CONVECTIVE SHOWERS AND STORMS ACROSS
THE NORTHWESTERN HALF OF NC SINKING SOUTHEASTWARD. WHILE THE 500
MB COLD POOL CENTERED OVER VIRGINIA SHOULD NOT DIVE THIS FAR
SOUTH...A SURPRISING NUMBER OF MODELS STILL SHOW SHOWERS MAKING IT
INTO SE NORTH CAROLINA STARTING AROUND 3-4 AM. FORECAST SOUNDINGS
SHOW THIS WOULD NOT BE SURFACE- BASED CONVECTION BUT INSTEAD
ROOTED IN A LAYER AROUND 7000 FEET UP. LAPSE RATES BETWEEN 800-400
MB ARE STEEP ENOUGH THAT SHOULD ANYTHING SURVIVE THAT LATE IT
COULD STILL HAVE THUNDER. TO BLEND WITH NWS RAH AND MHX I HAVE
ADDED A 20 POP LATE TONIGHT FROM LUMBERTON TO ELIZABETHTOWN TO
BURGAW...OTHERWISE VERY FEW CHANGES WERE NEEDED TO THE FORECAST
WITH THIS EARLY EVENING UPDATE.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...UPPER RIDGE BUILDS STRONGLY ACROSS MIDDLE
AMERICA AND THIS WILL RESULT IN A TROUGH DIGGING DOWN THE EAST
COAST THU INTO FRI. DEVELOPING NW FLOW ALOFT WILL ALLOW WEAK MID-
LEVEL DISTURBANCES...EMBEDDED IN FLOW...TO IMPACT THE EASTERN
CAROLINAS. THE STRONGEST OF THESE FEATURES DURING THIS TIME FRAME
WILL REACH THE AREA LATER THU AFTERNOON AND THU NIGHT. AT THE
SURFACE...HIGH PRESSURE WILL ASSERT A STRONG ENOUGH PUSH TO BRING
A BACKDOOR COLD FRONT ACROSS THE AREA FRIDAY NIGHT. THE PIEDMONT
TROUGH AND SEABREEZE BOUNDARIES WILL STRENGTHEN THU AFTERNOON AND
THESE MESOSCALE BOUNDARIES SHOULD PROVIDE SOME MODEST LIFT...THUS
ALLOWING SOME CONVECTION TO DEVELOP AS STRONG HEATING INCREASES
THE INSTABILITY.

THE HIGHEST PRECIPITABLE WATER VALUES AND THE GREATEST MOISTURE
DEPTH ARE STILL EXPECTED THU/THU NIGHT...ALTHOUGH NOT THAT
IMPRESSIVE EVEN FOR EARLY SEPTEMBER. AT THIS TIME...WILL KEEP
POPS IN THE SLIGHT CHANCE/CHANCE CATEGORY. HOWEVER...HIGHER POPS
MAY BE WARRANTED AS WE PROGRESS THROUGH LATE WEEK AND ARE BETTER
ABLE TO NAIL DOWN THE TIMING OF THE VARIOUS FEATURES PREVIOUSLY
DISCUSSED.

THE WARMEST DAY WILL BE THU WHEN HIGHS ARE EXPECTED MAINLY IN THE
MID 90S WITH LOWER 90S VERY NEAR THE COAST AND UPPER 80S AT THE
BEACHES. HIGHS ON FRI WILL BE MAINLY IN THE LOWER 90S...STILL ABOVE
NORMAL...UPPER 80S AT THE BEACHES. LOWS WILL BE IN THE LOWER 70S THU
NIGHT AND UPPER 60S TO LOWER 70S FRI NIGHT.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 PM WEDNESDAY...COMPLEX MID-LEVEL PATTERN WILL LEAD TO A
CHALLENGING FORECAST WITH LIKELY AN EXTENDED PERIOD OF UNSETTLED
WEATHER ACROSS THE SOUTHEAST. GFS AND ECMWF ARE IN PRETTY GOOD
AGREEMENT THROUGH THE EXTENDED WHICH CREATES HIGHER CONFIDENCE THIS
PERIOD...AND IT APPEARS MUCH OF THE EXTENDED WILL BE UNSETTLED WITH
BELOW NORMAL HIGHS AND SEASONABLE LOWS.

LARGE UPPER RIDGE WILL BUILD ACROSS THE NORTHEAST FROM THE GULF
COAST...DRIVING A SURFACE RIDGE DOWN THE EASTERN SEABOARD. AS THIS
OCCURS...A BACK DOOR TYPE FRONT WILL STALL SOUTH OF THE AREA...AS A
WEAKNESS IN THE PRESSURE FIELD STRENGTHENS AND EXPANDS FROM THE
NE...SOUTH OF THE RIDGE. THIS UPPER TROUGH WILL SHARPEN AND CUT OFF
ACROSS THE SOUTHEAST...AND THEN SIT BASICALLY IN PLACE THROUGH
TUESDAY AS IT IS BLOCKED BY RIDGING ON ALL SIDES. BENEATH THIS
TROUGH...THE REMNANTS OF ERIKA WILL MEANDER NEAR THE SOUTHEAST COAST
MAINTAINING CLOUDS...SHOWERS...AND COOL TEMPERATURES...ESPECIALLY
ALONG THE COAST. STILL SOME UNCERTAINTY INTO HOW MUCH QPF IS
EXPECTED SINCE FORCING IS WEAK...BUT TROPICAL MOISTURE IN THE
VICINITY OF ERIKAS REMNANTS WILL CREATE THE POTENTIAL FOR
SHOWERS...SOME OF WHICH MAY BE HEAVY AT TIMES...ESPECIALLY SUNDAY
THROUGH TUESDAY. WPC QPF SHOWS 1-2 INCHES THROUGH THE
PERIOD...HEAVIEST ALONG THE COAST. GUIDANCE SUGGESTS ERIKAS REMNANTS
WILL FINALLY DISSIPATE ENTIRELY BY WEDNESDAY AND LIFT TO THE NORTH
AS THE BLOCKING RIDGE WEAKENS...THIS WILL LEAD TO IMPROVING AND MORE
SEASONABLE WEATHER AT THE END OF THE EXTENDED.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...THE HRRR MODEL HAS BEEN FAIRLY CONSISTENT IN BRINGING
SOME CONVECTION FROM THE NORTHWEST...ASSOCIATED WITH A MODERATE
VORT MAX DROPPING IN FROM VIRGINIA. THE CONVECTION WILL LIKELY
DISSIPATE BY 10-11Z AS IT MOVES OFF THE COAST OF SOUTHEAST NORTH
CAROLINA. THIS IS MAINLY LEANING ON THE NAM MODEL AS THE GFS
SHIFTS THE PRECIP OFFSHORE BEFORE IT GETS HERE. TOOK OUT THE TEMPO
LOWER FOG AT LBT AS THERE WILL LIKELY BE TOO MANY CLOUDS TO
RADIATE EFFECTIVELY. THURSDAY...ANOTHER HOT DAY WITH WEST
NORTHWEST FLOW. SOME SCATTERED CONVECTION MAY DEVELOP AROUND MAX
HEATING...ESPECIALLY ALONG THE RESULTANT.

EXTENDED OUTLOOK...PREDOMINATELY VFR WITH BRIEF MORNING FOG AND
ISOLATED/SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 AM THURSDAY...ABSOLUTELY NO CHANGES WERE NEEDED TO THE
FORECAST WITH THIS LATEST EVENING UPDATE. DISCUSSION FROM 300 PM
FOLLOWS...

A TROUGH WILL BE STRUNG OUT FROM WEST TO EAST SOUTH OF OUR LOCAL
WATERS BUT WEAK HIGH PRESSURE WILL HOLD LOCALLY THROUGH TODAY.
BASICALLY FLOW WILL BE DOMINATED BY THE SEA BREEZE THIS AFTERNOON
WITH ON SHORE GUSTIER WINDS...BASICALLY SE-S. WITH WINDS GENERALLY
10 KT OR LESS...SEAS WILL REMAIN 2 FT OR LESS.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...THE SLACK PRESSURE GRADIENT...WHICH HAS
BEEN IN PLACE FOR SEVERAL DAYS...WILL FINALLY BEGIN TO TIGHTEN...
AND WITH THAT WE WILL SEE WIND SPEEDS INCREASING. THE HIGHEST
WINDS THIS PERIOD ARE EXPECTED IN THE WAKE OF A BACKDOOR COLD
FRONT FRI NIGHT. WIND SPEEDS FRI NIGHT ARE EXPECTED TO BE UP TO 15
TO 20 KT AS A NE SURGE EXPANDS SOUTHWARD ACROSS THE WATERS AS HIGH
PRESSURE BUILDS FROM THE N.

A LAND BREEZE WILL ALLOW FOR A LIGHT OFFSHORE WIND THU MORNING. THE
SEABREEZE AND PIEDMONT TROUGH WILL INCREASE SW WINDS TO AROUND 10 KT
THU AFTERNOON AND EVE. SEAS WILL BE 2 FT OR LESS WITH 3 FT SEAS
EXPANDING SOUTHWARD ACROSS THE WATERS FRI NIGHT.

LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 300 PM WEDNESDAY...HIGH PRESSURE WILL RIDGE DOWN THE COAST
STRONGLY SAT/SUN BEFORE SLOWLY WEAKENING EARLY NEXT WEEK. AS THIS
HIGH BUILDS SW FROM NEW ENGLAND...IT WILL BE ACCOMPANIED BY A NE
SURGE...DRIVING WINDS UP TO AROUND 15 KT SATURDAY AND SUNDAY.
WINDS WILL VEER SLOWLY ON MONDAY TO BECOME MORE EASTERLY AS THE
RIDGE WEAKENS...WITH SPEEDS DROPPING TO AROUND 10 KT AT THE END OF
THE PERIOD. THE SEA SPECTRUM WILL BE SIGNIFICANTLY DOMINATED BY A
NE WIND WAVE THROUGH THE PERIOD...WHICH WILL MASK A LOW-AMPLITUDE
SE SWELL. WAVE HEIGHTS WILL BE 2-3 FT EARLY SATURDAY...RISING TO
3-4 FT LATE SATURDAY AND SUNDAY AS THE NE FETCH PERSISTS. WAVE
HEIGHTS WILL THEN EASE A BIT MONDAY ON THE SLACKENING WINDS.

&&

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

&&

$$

SYNOPSIS...RJD
NEAR TERM...REK/TRA/RGZ
SHORT TERM...RJD
LONG TERM...JDW
AVIATION...DL
MARINE...REK/RJD/TRA/JDW/RGZ/SRP



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