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Area Forecast Discussion
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000
FXUS61 KOKX 170522
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
122 AM EDT WED SEP 17 2014

.SYNOPSIS...
HIGH PRESSURE BUILDS IN FROM THE WEST AND GETS REINFORCED
WEDNESDAY NIGHT AND THURSDAY...STAYING ACROSS THE REGION THROUGH
FRIDAY NIGHT. HIGH PRESSURE MOVES OFFSHORE FOR THE WEEKEND WITH A
COLD FRONT APPROACHING THE BEGINNING OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
UPDATES MADE TO INCLUDE PATCHY FOG ACROSS EASTERN LONG ISLAND AND
LOWERING THE LOW TEMPS A LITTLE OVER THE PINE BARRENS REGION. SOME
OF THIS FOG MAY DISSIPATE OR AT LEAST THIN OUT AT TIMES AS SOME
MID LEVEL CLOUDS PASS THROUGH. REST OF THE FORECAST PRETTY MUCH ON
TRACK.

HIGH PRESSURE AT THE SURFACE BUILDS IN FROM THE WEST TONIGHT...
GIVING THE REGION MORE OF A NORTHERLY FLOW. THIS WILL ADVECT IN
COOLER...DRIER AIR. RADIATIONAL COOLING WILL BE SOMEWHAT EFFICIENT
AS WELL. THEREFORE...PREFERRED LOWER MAV GUIDANCE COMPARED TO MET
GUIDANCE FOR LOWS...WHICH ARE FORECAST TO RANGE FROM THE LOWER 40S
TO UPPER 50S...LOWEST FOR RURAL INTERIOR SECTIONS AND HIGHEST NEAR
NYC.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
OVERALL...SUBTROPICAL JET WILL STILL BE SOUTH OF THE AREA. THE
OVERALL TROUGH IN THE MID TO UPPER LEVEL WILL BECOME ONE OF
DECREASED WAVELENGTH...INDICATING A SHARPENING OF THE TROUGH AND
THIS WILL HELP USHER IN A STRONGER HIGH PRESSURE AREA BY WEDNESDAY
NIGHT FROM SOUTH CENTRAL CANADA.

ONE SURFACE HIGH PRESSURE WEAKENS AS IT CENTERS OVER THE REGION
WEDNESDAY. THE FLOW ALOFT WILL BECOME LIGHTER WITH THE
GEOPOTENTIAL HEIGHT GRADIENT DECREASE AND SURFACE PRESSURE
GRADIENT DECREASING AS WELL. LIGHT WINDS AT THE SURFACE SHOULD
EASILY GIVE WAY TO SEA BREEZE CIRCULATIONS AS LAND TEMPERATURES
EXCEED SEA SURFACE TEMPERATURES. NOT EXPECTING SUBSIDENCE TO BE
THAT STRONG...SO THINKING THAT SOME DIURNAL CU WILL DEVELOP AGAIN
LATER IN THE AFTERNOON. MAX TEMPS WERE A BLEND OF NAM12 AND
GMOS...WITH SLIGHTLY COOLER READING ALONG THE COAST BUT OVERALL
MOSTLY LOWER 70S.

DRY CONDITIONS WITH CLEARING SKIES EXPECTED AGAIN WEDNESDAY NIGHT
AS A STRONGER CANADIAN HIGH PRESSURE AREA STARTS TO BUILD SOUTHEAST
CLOSER TO OUR REGION. THIS WILL ESSENTIALLY REINFORCE HIGH
PRESSURE ACROSS THE LOCAL REGION. USED A BLEND OF 3/4 MET AND 1/4
MAV GUIDANCE FOR LOWS. AGAIN EXPECTING COLD AIR ADVECTION AND
RADIATIONAL COOLING TO CONTRIBUTE.

THERE IS A MODERATE RISK OF RIP CURRENT DEVELOPMENT AT THE
ATLANTIC BEACHES ON WED. THIS MAY INCREASE TO A HIGH RISK LATE IN
THE DAY DUE TO SWELLS FROM TROPICAL CYCLONE EDOUARD...SITUATED
WELL OUT TO SEA.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
GENERALLY DECENT AGREEMENT AMONG THE 12Z MODEL SUITE WITH SYNOPTIC 
FEATURES HEADING INTO THIS WEEKEND...WITH DIVERGING SOLUTIONS ON THE 
HANDLING OF THE APPROACHING COLD FRONT. WEAK SFC LOW TREKS THROUGH 
SOUTHERN CANADA EARLY THURS...WITH ASSOCIATED COLD FRONT TRAILING 
ACROSS NEW ENGLAND. BUILDING SURFACE HIGH TRAVERSES THE REGION FROM 
THE GREAT LAKES REGION THROUGH THE NORTHEAST THURS INTO THE COMING 
WEEKEND. ALOFT...MID LEVEL TROUGH SWINGS THROUGH THURS/FRI...WITH 
ZONAL FLOW TAKING HOLD THROUGH THE REMAINDER OF THE WEEKEND. 
MULTIPLE WEAK SHORTWAVES EMBEDDED WITH THE FLOW ALOFT WILL PUSH 
THROUGH DURING THIS TIME...BUT OVERALL WEAK DYNAMICS COMBINED WITH 
MINIMAL MOISTURE SHOULD RESULT IN A PREDOMINATELY DRY FORECAST. NAM 
AND GFS HINT AT AFTN DEVELOPMENT THURS CORRESPONDING WITH THE 
PASSAGE OF THE STRONGEST WAVE...BUT CONFIDENCE IS TOO LOW TO INCLUDE 
POP MENTION AT THIS TIME. SUBSIDENCE BUILDING IN ALOFT SHOULD AID IN 
KEEPING MOSTLY SUNNY CONDITIONS FRIDAY.

FOR THE WEEKEND...ZONAL FLOW BEGINS TO WEAKEN BY SAT WITH THE NEXT 
TROUGH DIPPING SOUTH ACROSS THE NORTH PLAINS. SURFACE HIGH PUSHES 
OFFSHORE AS THE LOW PRESSURE SYSTEM LIFTS INTO THE GREAT LAKES 
REGION...PLACING THE NORTHEAST INTO THE WARM SECTOR BY SUNDAY. 
TIMING AND STRENGTH DIFFERENCES...WITH THE 12Z GFS SOLUTION A MORE 
POTENT SOLUTION SUN/MON...THEN ALIGNING ONCE AGAIN WITH THE ECMWF BY 
TUES. CMC LOOKS TO DEEPEN TOO MUCH/TOO QUICKLY SO SIDED MORE TO A 
COMPROMISE OF THE GFS/ECMWF FOR NOW. AS SUCH...SWING THE COLD FRONT 
THROUGH SOMETIME MONDAY-MONDAY NIGHT WITH HIGH PRESSURE BUILDING IN 
BY TUESDAY. CHC POPS IN FOR MONDAY WITH STILL UNCERTAINTY ON WHEN 
EXACTLY THE PCPN WILL OCCUR...THOUGH ANTICIPATING IT RIDING THE 
FRONTAL PASSAGE...WITH THINGS QUICKLY DRYING IN THE WAKE WITH THE 
HIGH. 

THURSDAY TEMPS REMAIN NEAR NORMAL. FRIDAY TEMPS BELOW NORMAL WITH A 
SHOT OF CAA AS THE HIGH BUILDS INTO THE REGION. ALONG WITH THE 
DIPPING TEMPS...SHOULD SEE DEW PTS DROPPING...WITH SOME INTERIOR 
REGIONS EVEN DROPPING INTO THE 30S. AT THE MOMENT...FROST 
DEVELOPMENT LOOKS TO REMAIN NORTH OF THE FORECAST AREA...BUT WILL BE 
WATCHFUL. TEMPS REBOUND QUICKLY BACK TO NORMAL FOR THE 
WEEKEND...WITH RISING HEIGHTS ALOFT AND DECENT WAA RIDING THE 
SOUTHERLY WINDS AS THE HIGH PUSHES OFFSHORE.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
HIGH PRESSURE BUILDS INTO THE REGION TODAY.

VFR THROUGH THE TAF PERIOD.

N/NW WINDS AT 5 KT OR LESS THROUGH MORNING. WINDS WILL BE LIGHT 
ENOUGH TO CARRY VRB IN THE TAF. NORTH WINDS INCREASE TO 5-7 KT AFTER 
12-14Z. SEA BREEZES WILL SHIFT WINDS TO THE SOUTH AROUND 5 TO 10 KT 
IN THE AFTERNOON. THEN WINDS LIGHTEN ONCE AGAIN BY EVENING.

.OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY...
.THURSDAY-SUNDAY...VFR.

&&

.MARINE...
LOWERED OCEAN SEA HEIGHTS FOR THE OVERNIGHT PERIOD BASED ON OBS
AND TRENDS. OTHERWISE...A CONTINUANCE OF SUB SCA CONDITIONS ARE
EXPECTED WITH A WEAK PRESSURE GRADIENT IN PLACE. HOWEVER...SWELLS
FROM EDOUARD WILL BUILD OCEAN SEAS THROUGH WEDNESDAY NIGHT. LEANED
CLOSER TO THE NORTH ATLANTIC HURRICANE MODEL GUIDANCE AND NOT
WAVEWATCH...SO NOT GOING WITH SCA AT THIS TIME AND LIMITED OCEAN
SEAS TO 4 FT.

SUB-SCA CONDITIONS THURSDAY WITH WEAK OFFSHORE FLOW AND ANY SWELLS 
FROM EDOUARD DECREASING. INCREASING NE FLOW FRIDAY SHOULD AID IN 
PUSHING SEAS TO 5-6 FT ON THE OCEAN INTO THE WEEKEND. OCNL GUSTS TO 
25 KT PSBL AS WELL DURING THIS TIME ON THE OCEAN. CONDITIONS 
DIMINISH BACK DOWN TO SUB-SCA EVERYWHERE BY SAT AND REMAIN AS SUCH 
HEADING INTO NEXT WEEK.

&&

.HYDROLOGY...
NO SIGNIFICANT PRECIPITATION RESULTING IN HYDROLOGIC ISSUES IS 
EXPECTED THROUGH THIS WEEKEND.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...JM/SEARS
NEAR TERM...JC/JM/DW
SHORT TERM...JM/DW
LONG TERM...SEARS
AVIATION...PW
MARINE...JC/JM/SEARS
HYDROLOGY...JM/SEARS







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