Area Forecast Discussion
Issued by NWS Newport/Morehead, NC

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000
FXUS62 KMHX 190209
AFDMHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC
1009 PM EDT THU SEP 18 2014

.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO NOSE SOUTH OVER EASTERN NORTH
CAROLINA OVERNIGHT. THE HIGH WILL MOVE EAST OFF THE NEW ENGLAND
COAST AND CONTINUE TO IMPACT THE REGION THROUGH SATURDAY. LOW
PRESSURE WILL MOVE NORTHEAST SUNDAY JUST OFF THE COAST. A COLD
FRONT WILL MOVE THROUGH MONDAY. HIGH PRESSURE BEHIND THE FRONT
WILL PASS BY TO THE NORTH TUESDAY AND WEDNESDAY.

&&

.NEAR TERM /TONIGHT/...
AS OF 615 PM...ONLY MINOR ADJUSTMENTS NEEDED TO TEMP/DEW POINT
TRENDS. TEMPS ARE FALLING QUICKLY TONIGHT WITH PLENTY OF CLEAR
SKIES ACROSS THE REGION. DRIER AIR IS MOVING IN FROM THE NORTH AT
A QUICKER PACE AS WELL. HOWEVER...THIS SHOULD SLOW A BIT AS MID
LEVEL MOISTURE MOVES INTO THE REGION FROM THE WEST. THIS WILL GIVE
WAY TO SOME CLOUD COVER OVERNIGHT. LOWS IN THE LOW 60S INLAND TO
AROUND 70 ALONG THE IMMEDIATE COAST.

PREVIOUS DISCUSSION...A WEAK COLD FRONT WILL APPROACH FROM THE
NORTH/NORTHWEST TONIGHT BUT GUIDANCE NOW INDICATES THE FRONT WILL
STALL ACROSS VIRGINIA THEN WASHOUT...THUS THE STRONG RIDGE SLIDING
THROUGH SOUTHERN NEW ENGLAND WILL REMAIN THE DOMINANT FEATURE
THROUGH THE OVERNIGHT HOURS. NORTHEASTERLY FLOW WILL PERSIST
TONIGHT WITH DRY CONDITIONS EXPECTED. LOWS WILL FALL LOW 60S
INLAND TO UPPER 60S ALONG THE OBX AND SOUTHERN COAST.

&&

.SHORT TERM /FRIDAY/...
AS OF 325 PM THURS...SURFACE HIGH PRESSURE OVER NEW ENGLAND WILL
CONTINUE TO NOSE SOUTH DOWN THE EASTERN SEABOARD AND ACROSS
EASTERN NORTH CAROLINA ON FRIDAY. THE BROAD UPPER TROUGH WILL
SHIFT EAST ALLOWING MORE ZONAL FLOW ALOFT TO DEVELOP FRIDAY
AFTERNOON. NORTHEASTERLY FLOW WILL SHIFT MORE EASTERLY AS THE DAY
PROGRESSES...WITH AN AIRMASS SIMILAR TO TODAY THEREFORE NOT
EXPECTING SHOWERS/TSTORMS ACROSS THE AREA. TEMPERATURES WILL
REMAIN A FEW DEGREES COOLER THAN CLIMATOLOGY FOR MID SEPTEMBER.
EXPECT HIGHS IN THE LOWER 80S INLAND TO MID/UPPER 70S ALONG THE
OBX AND SOUTHERN COAST.

&&

.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
AS OF 230 PM THURSDAY...THERE CONTINUES TO BE STRONG AGREEMENT IN
THE MEDIUM RANGE GUIDANCE WITH RESPECT TO THE UPPER FLOW REGIME OVER
THE CONUS DURING THE PERIOD. TO START THE PERIOD THE PERSISTENT
EASTERN UPPER TROUGH WILL BRIEFLY LIFT INTO ZONAL FLOW FRIDAY INTO
SATURDAY WHILE THE SOUTHERN PORTION OF THE UPPER TROUGH CLOSES OFF
INTO AN UPPER LOW OVER THE SOUTHEAST. THIS WILL LEAD TO SURFACE
CYCLOGENESIS SATURDAY ALONG A FRONT STALLED OFF THE COAST. THEN
AMPLIFICATION OF THE UPSTREAM WESTERN UPPER RIDGE SUNDAY WILL LEAD
TO AMPLIFICATION OF THE EASTERN UPPER TROUGH WITH THIS PATTERN
FORECAST TO PERSIST INTO THE EARLY NEXT WEEK. AS THE UPPER TROUGH
AMPLIFIES IT WILL PICK UP THE COASTAL LOW AND MOVE IT NORTHEAST AWAY
FROM THE AREA BY MONDAY. THE FLOW WILL BECOME PROGRESSIVE MID WEEK
ALLOWING HEIGHTS TO RISE AGAIN OVER THE EASTERN US.

TEMPERATURES ARE EXPECTED TO BE NEAR OR SLIGHTLY BELOW NORMAL
THROUGH MOST OF THE PERIOD DUE TO ONSHORE FLOW AND EXPECTED CLOUD
COVER. EXCEPTION WILL BE MONDAY WHICH SHOULD BE WARMEST DAY OF THE
PERIOD WITH READINGS POSSIBLY REACHING SLIGHTLY ABOVE NORMAL WITH
ISOLATED READINGS INTO THE MID 80S AS SW FLOW DEVELOPS AHEAD OF AN
APPROACHING COLD FRONT. BELOW NORMAL TEMPERATURES ARE EXPECTED
BEHIND THE FRONT TUESDAY INTO THURSDAY AS NORTHEASTERLY FLOW
REDEVELOPS OVER THE AREA IN RESPONSE TO A LARGE SURFACE HIGH
BUILDING OVER THE AREA FROM THE NORTH.

THE MOST COMPLICATED PORTION OF THE FORECAST WILL BE THE
PRECIPITATION FORECAST SATURDAY INTO SUNDAY PERIOD WHEN THE
AFOREMENTIONED CYCLOGENESIS TAKES PLACE AND THE FRONTAL WAVE MOVES
NORTHEAST PARALLELING THE COAST. THE GFS/CMC ARE STRONGEST AND
CLOSEST TO THE COAST WHILE ECMWF IS WEAKER/FURTHER OFFSHORE. DUE TO
THIS UNCERTAINTY A MIDDLE OF THE ROAD APPROACH SEEMS BEST WHICH WILL
MEAN MAINTAINING THE 20-30% POPS FOR A LIGHT QPF EVENT EAST OF
HIGHWAY 17 (HIGHEST IMMEDIATE COAST) DURING THIS PERIOD.

LATEST GFS/ECMWF OPERATIONAL MODEL RUNS ARE IN DECENT AGREEMENT IN
SPEEDING UP THE ARRIVAL OF A COLD FRONT ON MONDAY SO WILL CONTINUE
CHANCE POPS FOR MOST AREAS BY AFTERNOON, AND TAPERED POPS BACK MORE
QUICKLY MONDAY NIGHT. THE MODELS CONTINUE TO BE IN GOOD AGREEMENT
WITH PROVIDING PLEASANTLY COOL AND DRY WEATHER CONDITIONS TUESDAY
THROUGH THURSDAY AS STRONG SURFACE HIGH PRESSURE BUILDS INTO THE
AREA FROM THE NORTH.

&&

.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
SHORT TERM /THROUGH FRI/
AS OF 615 PM THU...WL CONT WITH VFR FCST THRU THE PERIOD. HIGH
PRES BUILDING IN FROM THE N WILL RESULT IN MCLR TO PC SKIES THRU
FRI. CANNOT RULE OUT BRIEF PATCHY MVFR IN FOG/LOW STRATUS JUST
PRIOR TO SUNRISE...BUT GIVEN DROP IN DEWPTS TODAY COMBINED WITH
POTENTIAL FOR SCT CLOUDS IN THE 5 TO 10 THOUSAND FOOT LVL LATE
DONT THINK WILL SEE MUCH.

LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 230 PM THURSDAY...MAY SEE CIGS OCCASIONALLY LOWER TO MVFR
LEVELS (OR LOWER) DURING THE WEEKEND GIVEN THE PERSISTENT MOIST
ONSHORE LOW LEVEL FLOW. THE BEST CHANCES FOR LOWERED CIGS WOULD BE
SATURDAY NIGHT THROUGH EARLY SUNDAY AS A NOCTURNAL INVERSION
STRENGTHENS OVERNIGHT THEN WANES AFTER SUNRISE SUNDAY. MONDAY
AFTERNOON AN APPROACHING COLD FRONT COULD TRIGGER A FEW SHOWERS AND
THUNDERSTORMS WITH BRIEF SUB-VFR CONDITIONS AS IT CROSSES THE
REGION. PREVAILING VFR CONDITIONS ARE EXPECTED TUESDAY AS DRY HIGH
PRESSURE BUILDS OVER THE AREA.

&&

.MARINE...
SHORT TERM /THROUGH FRI/
AS OF 615 PM THU...ADJUSTED WIND SPEED UP A BIT...ESPECIALLY
ACROSS THE CENTRAL WATERS NEAR DIAMOND AND LOOKOUT. WINDS ARE
STILL GUSTING BETWEEN 15-20KTS. OTHERWISE...FORECAST IS ON TRACK
WITH SEAS 3 TO 5 FEET AND NE WINDS AROUND 8-15 KTS WITH HIGHER
GUSTS.

PREV DISC...LATEST SURFACE AND BUOY DATA INDICATE LONG PERIOD
SWELLS CONTINUE ACROSS THE WATERS NORTH OF DIAMOND SHOALS. SMALL
CRAFT ADVISORIES FOR THE CENTRAL WATERS CONTINUE THROUGH THIS
AFTERNOON DUE TO PERSISTENT SWELLS CAUSING HAZARDOUS SEAS 4 TO 6
FEET. DIAMOND SHOALS BUOY CONTINUES AT 6 FT...WITH 4 FT SWELLS
AROUND 11-13 SECONDS. ELEVATED SEAS WILL SLOWLY DISSIPATE THIS
EVENING. HIGH PRESSURE NORTH OF THE WATERS TODAY AND TONIGHT WILL
MAINTAIN A NORTHEAST FLOW OVER THE MARINE ZONES...THEN AS THE HIGH
SHIFTS EAST THROUGH THE NEW ENGLAND WATERS WINDS WILL SHIFT MORE
EASTERLY DURING THE DAY FRIDAY. SPEEDS WILL RANGE 10-15 KNOTS BUT
A BIT HIGHER IN THE OUTER WATERS OF THE OREGON INLET TO OCRACOKE
ZONES. EXPECT A RESPITE FROM THE ELEVATED SEAS LATER TONIGHT AND
FRIDAY MORNING...THEN INCREASING SEAS BACK TO SMALL CRAFT ADVISORY
LEVELS LATE FRIDAY INTO FRIDAY NIGHT.

LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 230 PM THURSDAY...MARINERS CAN EXPECT SMALL CRAFT ADVISORY
CONDITIONS FOR SEAS AND WIND GUSTS OVER THE WEEKEND DUE TO A
COMBINATION OF COLD ADVECTION SATURDAY THEN DUE TO THE GRADIENT
BETWEEN A DEVELOPING LOW PRESSURE SYSTEM OFF THE COAST AND HIGH
PRESSURE BUILDING IN FROM THE NORTH. WE CONTINUE TO EXPECT A
MODERATE NORTHEAST FLOW TO 20 KT WITH A FEW GUSTS TO 25 KT SATURDAY
WHICH WILL BUILD SEAS TO 6 FT OVER THE OUTER WATERS. THERE IS BELOW
NORMAL CONFIDENCE WITH THE FORECAST FOR SUNDAY DUE TO UNCERTAINTIES
REGARDING THE INTENSITY AND TRACK OF AN AREA OF LOW PRESSURE OFF OF
THE COAST. THERE IS ENOUGH CONSENSUS IN THE GUIDANCE TO INDICATE
THAT AT LEAST SEAS OVER THE WATERS PERSISTING AROUND 6 FT THROUGH
SUNDAY EVENING. WINDS SUNDAY SHOULD BE STRONGEST IN THE MORNING THEN
BACK TO WEST AND DIMINISH LATE IN THE DAY. WINDS WILL BE VEERING
FROM THE WEST EARLY MONDAY TO NORTH MONDAY EVENING AS A RAPIDLY
MOVING COLD FRONT CROSSES THE WATERS. BEHIND THE FRONT NORTHERLY
FLOW INITIALLY WILL BE AROUND 15 KT TUESDAY BUT IS EXPECTED TO
INCREASE TO AROUND 20 KT MID TO LATE WEEK WITH RESULTING SEAS
REACHING ADVISORY LEVELS AS STRONG HIGH PRESSURE BUILDS OVER THE
WATERS FROM THE NORTH.

&&

.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 11 AM FRIDAY TO 11 PM EDT SUNDAY FOR
     AMZ152-154.
     SMALL CRAFT ADVISORY FROM 5 PM FRIDAY TO 11 PM EDT SATURDAY
     FOR AMZ156-158.
     SMALL CRAFT ADVISORY FROM 8 AM SATURDAY TO 11 PM EDT SUNDAY
     FOR AMZ150.

&&

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





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