Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 011919
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
319 PM EDT FRI AUG 1 2014

.SYNOPSIS...
A TROUGH WILL REMAIN STALLED ALONG THE COAST THROUGH THE WEEKEND.
THIS WILL BRING A HEIGHTENED RISK FOR FLOODING AS NUMEROUS TO
WIDESPREAD SHOWERS AND THUNDERSTORMS PLAGUE THE AREA FOR MUCH OF
THE WEEKEND. THE AIR MASS WILL ONLY SLOWLY DRY OUT DURING THE
MIDDLE AND LATER PORTIONS OF NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM FRIDAY...TROUGH REMAINS STALLED ALONG THE COAST
WHILE DEEP GULF MOISTURE CONTINUES TO SPREAD NORTHEAST. ALONG WITH
LOW LEVEL CONVERGENCE ASSOCIATED WITH THE BOUNDARY...WEAK
DIVERGENCE ALOFT CONTINUES. THIS COUPLED WITH MODERATE
INSTABILITY...CAPE IS 1000-1500 J/KG...HAS BEEN PRODUCING SHOWERS
AND THUNDERSTORMS ACROSS MUCH OF THE AREA. EXPECT ACTIVITY TO
CONTINUE AND INCREASE IN COVERAGE FOR THE REMAINDER OF THE
AFTERNOON. LOSS OF DIURNAL HEATING SHOULD BRING ABOUT A DECREASE
IN COVERAGE BUT DO NOT THINK ACTIVITY WILL COMPLETELY DISAPPEAR
THIS EVENING.

TROUGH WILL REMAIN STALLED ALONG OR JUST INLAND OF THE COAST WITH
PRECIPITABLE WATER VALUES HANGING AROUND 2 INCHES OVERNIGHT.
ADDITIONALLY THERE APPEARS TO BE A WEAK DEFORMATION ZONE EAST OF THE
AREA. THIS FEATURE WILL SLOWLY DRIFT WEST THIS EVENING AND OVERNIGHT
AS THE MID LEVEL WESTERN ATLANTIC RIDGE EXPANDS. BASED ON THIS HAVE
HELD ONTO LIKELY POP ALONG THE COAST ALL NIGHT BUT DROP INLAND AREAS
TO HIGH CHANCE AROUND MID NIGHT. MID LEVEL PATTERN AND LACK OF
SURFACE LOW IN EASTERN TX SUGGESTS THE TROUGH WILL REMAIN STALLED
ALONG THE COAST THROUGH THE END OF THE PERIOD AND THIS IS WHERE THE
HIGHEST QPF SHOULD BE FOUND.

CLOUD COVER AND MOISTURE ALONG WITH BOUNDARY LAYER WINDS WILL KEEP
LOWS NEAR TO ABOVE CLIMO. WEST OF THE BOUNDARY LOWS WILL BE CLOSE TO
CLIMO...AROUND 70. ON THE EAST SIDE OF THE BOUNDARY MODEST ONSHORE
FLOW WILL KEEP TEMPERATURES IN THE MID 70S.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 PM FRIDAY...A FLOOD WATCH IS IN EFFECT THROUGH SUNDAY. A
COASTAL TROUGH WILL REMAIN POSITIONED ALONG THE CAROLINA COAST
THIS PERIOD. WHILE SOME OF THE MODELS ARE INDICATING THE TROUGH
WILL VERY SLOWLY MOVE INLAND...THE MID-LEVEL FLOW SUGGESTS
OTHERWISE. AN EXTREMELY DEEP S/SW FLOW WILL REMAIN LOCKED IN PLACE
ALONG WITH A MOIST COLUMN THROUGH A VERY DEEP LAYER. THE PERSISTENT
UPPER DIFFLUENCE WITHIN THE ENTRANCE REGION OF JET STREAK ACROSS
THE NORTHEAST AND THE LOW LEVEL CONVERGENCE ALONG THE TROUGH WILL
PROVIDE THE NECESSARY LIFT FOR A LARGE SCALE...SIGNIFICANT
RAINFALL EVENT. WE ARE EXPECTING TOTAL RAINFALL AMOUNTS TO AVERAGE
2 TO 4 INCHES WITH UPWARDS OF 4 AND 5 INCHES ALONG COASTAL CAPE
FEAR. HOWEVER...HIGHER AMOUNTS ARE POSSIBLE AND GIVEN THE GROUND
IS WET FROM A VERY WET JULY...WE FEEL THE RISK FOR SIGNIFICANT
FLOODING IS HIGH ENOUGH TO WARRANT A FLOOD WATCH.

THE CLOUDS...RAIN...AND LOWERED THICKNESSES WILL KEEP HIGHS BELOW
NORMAL FOR EARLY-AUGUST...BUT AT THE SAME TIME MAINTAIN NORMAL OR
SLIGHTLY ABOVE NORMAL LOWS. EXPECT HIGHS IN THE LOWER TO MID 80S
BOTH DAYS...AND LOWS IN THE LOWER TO MID 70S.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 300 PM FRIDAY...MID-LEVEL TROUGH AXIS WILL REMAIN WEST OF
THE AREA MONDAY AND TUESDAY...RESULTING IN A CONTINUED AMPLE
SUPPLY OF MOISTURE TO ENHANCE THE POTENTIAL FOR SHOWERS AND TSTMS.
SURFACE CONVERGENCE WILL BE PROVIDED BY THE STALLED FRONTAL
BOUNDARY WHICH WILL LINGER ALONG THE COAST AS WELL AS WEAK WAVES
OF LOW PRESSURE WHICH MODELS INDICATE MAY DEVELOP ALONG THE
BOUNDARY. EXPECT TEMPS WILL BE HELD IN CHECK BY CLOUD COVER
MONDAY...BUT LESS SO TUESDAY-WEDNESDAY. THE MID-LEVEL TROUGH AXIS
WILL SLOWLY TRANSITION EAST AND ALLOW SOME DRIER AIR TO FILTER IN
BY MIDWEEK...SO ALTHOUGH POPS WILL BE INCLUDED EACH DAY...TREND
WILL BE DOWNWARD. ANOTHER WEAK FRONTAL BOUNDARY WILL DROP INTO THE
AREA THURSDAY AND LINGER INTO FRIDAY...SO SLIGHT/LOW CHANCE POPS
WILL BE WARRANTED THOSE DAYS AS WELL.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 18Z...SHOWERS WILL BE IN THE FORECAST THROUGH THE
WEEKEND...ALTHOUGH RATHER LOW CONFIDENCE ON TIMING THE CONVECTION.
LOOKS LIKE THE MAIN BATCH OF CONVECTION THIS MORNING HAS
PROPAGATED OFF TO THE NORTHEAST...ALTHOUGH MORE CONVECTION IS
LIKELY TO FIRE WITH AFTERNOON HEATING...MAINLY OVER SOUTH CAROLINA
WHERE THERE HAVE BEEN LESS CLOUDS. SOUTHERLY WINDS ARE EXPECTED
OVER THE SOUTHERN TERMINALS...MORE SOUTHEAST AS YOU MOVE
NORTHWARD. OVERNIGHT...STRATUS IS EXPECTED TO FORM INLAND. ANOTHER
DISTURBANCE WILL MOVE UP THE COAST...WITH CONVECTION EXPECTED AT
THE MYRTLES AND ILM...MAINLY AFTER 08Z. SATURDAY...MORE OF THE
SAME WITH SCATTERED TO NUMEROUS CONVECTION. BRIEF PERIODS OF
VISIBILITIES BELOW A MILE ARE POSSIBLE. WINDS WILL BE MORE SOUTH
SOUTHWESTERLY WITH THE WARM FRONT WELL NORTH OF THE REGION.

EXTENDED OUTLOOK...SHRA/TSRA LIKELY WITH PERIODS OF MVFR
CONDITIONS THROUGH TUESDAY AS A FRONT STALLS AND FINALLY DISSIPATES
OVER THE EASTERN CAROLINAS. A CHANCE OF SHOWERS CONTINUES ON
WEDNESDAY LATE.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM FRIDAY...COASTAL TROUGH STALLED NEAR THE COAST KEEPS
SOUTHEAST FLOW IN PLACE OVER THE WATERS THROUGH THE END OF THE
PERIOD. LITTLE CHANGE TO THE GRADIENT IS EXPECTED AND WINDS WILL
REMAIN IN THE 10 TO 15 KT RANGE. PROLONGED ONSHORE FLOW WILL KEEP
SEAS 3 TO 4 FT.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 PM FRIDAY...A COASTAL TROUGH WILL LIKELY NOT MOVE MUCH
THROUGH THE PERIOD AND WE EXPECT THE TROUGH WILL BE OVER THE AREA
OR JUST TO THE WEST THROUGH SUNDAY NIGHT. THE WIND DIRECTION ON THE
WEST SIDE OF THE TROUGH WILL BE MORE NORTHERLY WHILE WINDS ON THE
EAST SIDE WILL BE MORE SOUTHERLY. AT THIS TIME...EXPECT THE WIND
DIRECTION ACROSS THE WATERS WILL BE PREDOMINATELY FROM A S OR SE
DIRECTION. THE PROXIMITY OF THE TROUGH SHOULD KEEP WIND SPEEDS
FROM EXCEEDING 10 TO 15 KT. SEAS WILL BE 3 TO 4 FT WITH PERHAPS
SOME 5 FT SEAS DEVELOPING ACROSS THE OUTERMOST WATERS LATE IN THE
WEEKEND. A STILL RATHER WEAK 9 TO 11 SECOND SE SWELL WILL BE PRESENT.

LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 300 PM FRIDAY...SURFACE FLOW IS EXPECTED TO REMAIN
RELATIVELY LIGHT AS THE PRESSURE GRADIENT WILL REMAIN WEAK THROUGH
THE PERIOD. HOWEVER THERE IS UNCERTAINTY IN THE WIND DIRECTION
DURING THIS TIME AS A STALLED FRONTAL BOUNDARY WILL LINGER ALONG
THE COAST. A 3 TO PERHAPS 4 FOOT SWELL WITH 11 SECOND PERIOD WILL
BE POSSIBLE TUESDAY-WEDNESDAY FROM BERTHA...WHICH IS CURRENTLY
FORECAST TO BE MOVING NORTHWARD WELL OFF THE CAROLINA COAST AT
THAT TIME.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...FLOOD WATCH THROUGH SUNDAY EVENING FOR SCZ017-023-024-032-033-
     039-053>056.

NC...FLOOD WATCH THROUGH SUNDAY EVENING FOR NCZ087-096-099-105>110.

MARINE...NONE.

&&

$$
NEAR TERM...III
SHORT TERM...RJD
LONG TERM...CRM
AVIATION...III/DL



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