Area Forecast Discussion
Issued by NWS Newport/Morehead, NC

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000 FXUS62 KMHX 181834 AFDMHX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 234 PM EDT THU SEP 18 2014 .SYNOPSIS... HIGH PRESSURE WILL CONTINUE TO NOSE SOUTH OVER EASTERN NORTH CAROLINA THIS EVENING. A WEAK COLD FRONT WILL APPROACH FROM THE NORTH TONIGHT THOUGH IT WILL DISSIPATE ACROSS SOUTHERN VIRGINIA. 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 /THROUGH TONIGHT/... AS OF 120 PM THURS...NO SIGNIFICANT CHANGES WITH THE ONGOING FORECAST. A COASTAL FLOOD ADVISORY CONTINUES FOR THE OBX DARE COUNTY...FOR MINOR OVERWASH POSSIBLE ALONG HWY 12 NEAR THE S-CURVES TO THE TEMPORARY BRIDGE SOUTH OF PEA ISLAND THIS AFTERNOON. LONG PERIOD SWELLS FROM DISTANT HURRICANE EDOUARD COMBINED WITH PERSISTENT NORTHEAST WINDS RESULTED IN MINOR OCEAN OVERWASH YESTERDAY AT HIGH TIDE...AND WITH NO CHANGES EXPECTED IN SEAS/WINDS THIS AFTERNOON...EXPECT ANOTHER ROUND OF MINOR OCEAN OVERWASH THIS AFTERNOON A FEW HOURS EITHER SIDE OF HIGH TIDE WHICH WILL BE BETWEEN 4:30 AND 5:00 PM EDT. A BROAD UPPER LEVEL TROUGH CONTINUES OVER THE EASTERN SEABOARD WHILE SURFACE HIGH PRESSURE CONTINUES TO NOSE SOUTH OVER EASTERN NORTH CAROLINA. PARTLY CLOUDY SKIES HAVE BECOME MOSTLY SUNNY THIS MORNING...AND HAVE TRENDED BACK CLOUD COVER THROUGH THE AFTERNOON HOURS...BUT MAINTAINED PARTLY CLOUDY CONDITIONS LATER THIS AFTERNOON BASED ON FORECAST SOUNDINGS WHICH INDICATE SCATTERED CLOUDS AROUND 4K FT WITH SOME MIXED HIGH CLOUDS. NORTHEAST WINDS WILL PERSIST OVER THE REGION TODAY WITH MOISTURE LIMITED THROUGHOUT THE COLUMN. HIGHS WILL RANGE IN THE UPPER 70S TO LOWER 80S INLAND TO MID 70S ALONG THE OBX/EASTERN COAST. 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 MID 60S ALONG THE OBX AND SOUTHERN COAST. && .SHORT TERM /FRIDAY/... AS OF 125 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 /19Z THURSDAY THROUGH TUESDAY/... SHORT TERM /THROUGH TONIGHT/ AS OF 130 PM THURS...PREDOMINANT VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. LIGHT NORTHEAST FLOW WILL PERSIST THROUGH THE PERIOD AND SLOWLY SHIFT MORE EASTERLY BY FRIDAY AFTERNOON. SCATTERED STRATOCUMULUS WILL DISSIPATE THIS EVENING BECOMING MOSTLY CLEAR. CANNOT RULE OUT BRIEF MVFR IN FOG/LOW STRATUS JUST PRIOR TO SUNRISE FRIDAY MORNING...BUT AGAIN FEEL THAT GUIDANCE IS OVERDONE PREDICTING IFR CONDITIONS AS IT HAS BEEN FOR THE PAST SEVERAL DAYS. 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 TONIGHT/ AS OF 135 PM THURS...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...COASTAL FLOOD ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NCZ103. MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR AMZ152- 154. && $$ SYNOPSIS...DAG NEAR TERM...DAG SHORT TERM...DAG LONG TERM...BTC/JME AVIATION...JME/DAG MARINE...JME/DAG

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