Area Forecast Discussion
Issued by NWS Newport/Morehead, NC

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000
FXUS62 KMHX 221125
AFDMHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC
725 AM EDT FRI AUG 22 2014

.SYNOPSIS...
A SERIES OF SHORTWAVES WILL CROSS THE AREA GIVING WAY TO
UNSETTLED WEATHER OVER THE NEXT COUPLE DAYS. MEANWHILE...A
BACKDOOR COLD FRONT WILL SAG SOUTH OF THE REGION THROUGH THE
WEEKEND.

&&

.NEAR TERM /TODAY/...
AS OF 730 AM FRIDAY...SOME LINGERING SHORTWAVE ENERGY IS CROSSING
THE NORTHEAST PORTIONS OF THE CWA WITH A BULK OF THE SHOWERS
MOVING QUICKLY OFFSHORE. MODIFIED THE POP/WX TO ACCOUNT FOR THIS.
HOURLY TEMP TRENDS HAVE BEEN STEADY WITH LOWS TEMPS THAT DROPPED INTO
THE LOW/MID 70S INLAND TO MID/UPPER 70S ALONG THE BEACHES.
ANTICIPATE TEMPS TO RISE QUICKLY OVER THE NEXT COUPLE HOURS WITH
SOME CLOUDS MID/HIGH LEVEL CLOUDS MOVING IN FROM THE NW.

PREVIOUS DISCUSSION... WITH A TROUGH TO THE EAST AND RIDGING SET
TO THE WEST...EASTERN NC HAS BEEN UNDER PERSISTENT NW FLOW ALOFT.
THIS WILL STREAM ANOTHER BATCH OF MID/UPPER LEVEL DISTURBANCES
ACROSS THE REGION THROUGH THE PERIOD. THE FIRST BEING AN UPPER
LEVEL SHORTWAVE MOVING OFFSHORE WITH LINGERING SCHC
SHOWER/THUNDERSTORMS DURING THE MORNING HOURS. THE NEXT IMPULSE
WILL BE APPROACHING FROM THE NW BY EARLY AFTERNOON. CURRENTLY AN
MCS MIGRATING ACROSS THE OHIO RIVER VALLEY WILL CROSS THE VA
MOUNTAINS TOWARD EASTERN NC BY MID-DAY. THE TIMING OF THIS NEXT
SYSTEM WILL MAKE ALL THE DIFFERENCE IN TERMS OF THE SEVERE
POTENTIAL AND PRECIPITATION TIMING DURING THE AFTERNOON INTO THE
OVERNIGHT PERIOD.

WITH TEMPS CLIMBING INTO THE LOW/MID 90S INLAND AND POTENTIAL BREAKS
IN THE CLOUDS DURING THE DAY...INSTABILITY WILL BE ON THE RISE. IF
THE SHORTWAVE IS ABLE TO CROSS THE VA MOUNTAINS AND ARRIVE DURING
PEAK HEATING THAN WE WILL LIKELY HAVE ENOUGH INITIATION FOR ISOLATED
STRONG TO SEVERE THUNDERSTORMS ACROSS THE REGION. WITH UPPER LEVEL
DIVERGENCE...MID LEVEL SHORTWAVE AND SFC INSTABILITY (MUCAPE
NEARING 3 J/KG AND 25KTS SHEAR)...THIS COULD MAKE FOR ORGANIZED
THUNDERSTORMS MOVING FROM THE NW TO THE SE THROUGH THE
AFTERNOON/EVENING HOURS. THE STORMS WILL BE MOVING AT A PRETTY
GOOD PACE WITH THE MAIN THREAT BEING DAMAGING WIND.

HOWEVER...IT SHOULD BE NOTED THAT THE MCS MAY REQUIRE REDEVELOPMENT
IF THE MOUNTAINS IMPACTED THE ORGANIZED CONVECTION.  IF THIS
OCCURS...THAN WE WILL LIKELY SEE MORE ACTIVITY GETTING INTO THE
EVENING/OVERNIGHT PERIOD. GIVEN SUCH UNCERTAINTY...HAVE CHC
SHOWER/THUNDERSTORM ACTIVITY THROUGH FRIDAY WITH THE MORE LIKELY
SCENARIO FAVORED FOR A LATER ARRIVAL OF THE SHORTWAVE.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
AS 330 AM FRIDAY...THE CONVECTION ASSOCIATED WITH A POTENT
SHORTWAVE WILL EITHER BE CROSSING THE REGION AND EXITING
OFFSHORE...OR REDEVELOPING DURING THE START OF THE PERIOD.
CURRENTLY FEEL THE SHORTWAVE WILL APPROACH FRIDAY EVENING AND EXIT
OFF THE NC/VA COAST OVERNIGHT....WITH MUCH OF THE PRECIPITATION ON
GOING THROUGH EARLY AM. A BACKDOOR COLD FRONT ASSOCIATED WITH THE
SHORTWAVE WILL MOVE THROUGH THE AREA BY EARLY SATURDAY MORNING.
WHILE SFC INSTABILITY WILL BE WANING AFTER PEAK HEATING...THERE IS
STILL AMPLE UPPER/MID LEVEL LIFT TO HAVE CHC SHOWER/THUNDERSTORMS
MOVING THROUGH DURING THE PERIOD. WITH PLENTY OF CLOUD COVER IN
PLACE TEMPS WILL BE IN THE LOW/MID 70S INLAND TO MID 70S ALONG THE
COAST.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
AS OF 355 AM FRIDAY...SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE SAT
INTO SAT EVENING AS A COLD FRONT SLOWLY PUSHES S THROUGH THE REGION
AND SHORTWAVES CROSS IN NW FLOW ALOFT. DIFFICULT TO PINPOINT WHERE
BEST PRECIP CHANCES WILL BE AND WHEN IT WILL OCCUR GIVEN THE
DIFFICULTY IN TIMING INDIVIDUAL SHORT WAVE ENERGY/VORTICITY MAXIMA
SO WILL MAINTAIN HIGH CHANCE POPS FOR MUCH OF THE AREA THROUGH SAT
EVENING. AS NE FLOW DEVELOPS IN WAKE OF FRONT LATE SAT WILL SEE
TEMPS HOLD IN THE 80S WITH SOME SOUTHWESTERN ZONES APPROACHING 90F.

SURFACE FRONT WILL DRIVE SOUTH ALONG THE SE U.S. COAST SUN AND STALL
WELL SOUTH OF THE AREA EARLY NEXT WEEK. A DRIER NW UPPER FLOW AND
SURFACE HIGH PRESSURE TO THE NE BUILDING DOWN THE MID ATLANTIC COAST
SHOULD LEAD TO REDUCED PRECIP CHANCES SUNDAY INTO MONDAY, SO HAVE
MAINTAINED SLIGHT CHANCE POPS FOR INLAND AREAS TO COINCIDE WITH
FAVORABLE DIURNAL CYCLES. ATYPICAL ONSHORE FLOW FOR AUGUST WILL LEAD
TO SLIGHTLY BELOW NORMAL MAX TEMPS SUN/MON...MAINLY LOW TO MID 80S.

FOR THE EXTENDED FORECAST PERIOD...MODEL CONSENSUS SUGGESTS A
BUILDING OF THE MIDWEST UPPER RIDGE TOWARD THE EAST COAST AS SURFACE
HIGH PRESSURE REMAINS CENTERED TO THE NORTH. THIS SHOULD LEAD TO A
MAINLY DRY MID WEEK. TEMPS WILL REMAIN BELOW NORMAL EARLY IN  THE
WEEK THEN BEGIN TO MODERATE BACK TO NEAR OR SLIGHTLY ABOVE NORMAL
DURING MIDWEEK.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
SHORT TERM /THROUGH 12Z SATURDAY/...
AS OF 730 AM FRIDAY...VFR CONDITIONS EXPECTED THROUGH MUCH OF THE
PERIOD. HOWEVER...EXPECT SOME LINGERING MVFR/IFR VSBYS THIS
MORNING AS LOW LEVEL MOISTURE SLOWLY MIXES. ANTICIPATE HIGH/MID
LEVEL CLOUDS MOVING THROUGH FRIDAY MORNING AS THE NEXT IMPULSE
APPROACHES THE AREA. WEST WINDS WILL PICK UP THROUGHOUT THE DAY.
COULD BE AN ACTIVE AFTERNOON/EVENING WITH CONVECTION. THE TIMING
AND LOCATION IS STILL IN QUESTION. GIVEN THE UNCERTAINTIES...HAVE
VCTS FROM 18Z-06Z FOR ALL AREA TAF SITES. EXPECT SUB-VFR
CIGS/VSBYS TO CORRESPOND TO ANY SHOWER/THUNDERSTORM ACTIVITY.
ANTICIPATE MVFR VSBYS AFTER 06Z AS PRECIPITATION MOVES OUT AND
SOME CLEARING/DECOUPLING TAKES SHAPE.

LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 345 AM FRIDAY...PREDOMINANT VFR EXPECTED THROUGH THE EXTENDED
PERIOD. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE SAT AS A SHORT
WAVE MOVING ACROSS THE REGION IN NW FLOW ALOFT. THERE WILL BE SOME
BRIEF REDUCED CIGS/VSBYS WHEN SHRA/TSRA CROSS OTHERWISE MOSTLY VFR
EXPECTED. PRECIP COVERAGE EXPECTED TO DIMINISH SUN AND MON AS HIGH
PRESSURE AND A LITTLE DRIER AIRMASS BUILDS IN FROM THE MID-ATLANTIC
STATES...MAINTAINING VFR CONDITIONS THROUGH TUES.

&&

.MARINE...
SHORT TERM /THROUGH FRIDAY/...
AS OF 730 AM FRIDAY...NO CHANGES NEEDED AT THIS UPDATE.

PREVIOUS DISCUSSION...BENIGN BOATING CONDITIONS WITH A SERIES OF
SHORTWAVES MOVING THROUGH DURING THIS PERIOD. A SHORTWAVE WILL BE
EXITING THE VA/NC COAST EARLY AND ANOTHER SHORTWAVE APPROACHING BY
THE AFTERNOON. THIS WILL LEAD TO CHC SHOWER/THUNDERSTORM ACTIVITY
THROUGH THE DAY...ESPECIALLY LATER INTO THE AFTERNOON/EVENING
HOURS. WINDS WILL BE VARIABLE TO START AND THEN PICK UP FROM THE
WEST AROUND 10-12 KTS. A BACKDOOR COLD FRONT WILL MOVE SOUTH
FRIDAY NIGHT BRINGING WIND AROUND FROM THE NORTHEAST. SEAS WILL
GENERALLY BE AROUND 2 FEET FRIDAY AND BEGIN TO INCREASE 2 TO 3
FEET OVERNIGHT.

LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 345 AM FRIDAY...COLD FRONT WILL SLOWLY PUSH S ACROSS THE WATERS
INTO SAT. INITIALLY WINDS WILL BE LIGHT OVER THE COASTAL WATERS AS
THE FRONT CROSSES...THEN NE WINDS WILL INCREASE TO 10-15 KTS SAT
AFTERNOON WITH HIGHER GUSTS...ESPECIALLY ACROSS THE NORTHERN WATERS.
SEAS AROUND 2-3 FT SAT AND MAY SEE SOME 4 FT SEAS FOR THE OUTER
NORTHERN WATERS LATE SAT. NE WINDS WILL INCREASE TO 15-20 KTS SAT
NIGHT AND SUN AS THE NE PRESSURE GRADIENT TIGHTENS WITH HIGH PRESSURE
BUILDING S OVER INLAND AREAS. AS WINDS INCREASE SEAS WILL BUILD TO
3-5 FT...POSSIBLE REACHING 6 FT OUTER WATERS SUN NIGHT INTO MON. THE
NE FLOW WILL GRADUALLY WEAKEN AS THE PRESSURE GRADIENT LOOSENS TUES
BUT COULD POTENTIAL SEE ELEVATED SEAS CONTINUE FROM TROPICAL SYSTEM
SWELL THROUGH MIDWEEK. LOCAL SWAN/NWPS AND 00Z WAVEWATCH IN GOOD
AGREEMENT FOR THE MEDIUM RANGE...THUS USED BLEND OF THESE TWO WITH
PREVIOUS FORECAST...THEN 00Z WAVEWATCH FOR THE EXTENDED SEAS.

&&

.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...LEP
NEAR TERM...LEP
SHORT TERM...LEP
LONG TERM...DAG
AVIATION...DAG/LEP
MARINE...DAG/LEP





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