975  
FXUS61 KOKX 272019  
AFDOKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW YORK NY  
419 PM EDT TUE SEP 27 2016  
   
SYNOPSIS
 
 
A WEAKENING COLD FRONT WILL REMAIN OFFSHORE THROUGH WEDNESDAY  
NIGHT WHILE HIGH PRESSURE BUILDS IN FROM THE CANADIAN MARITIMES. A  
NEARLY STATIONARY LOW PRESSURE SYSTEM OVER THE OHIO VALLEY AND MID  
ATLANTIC REGIONS, WITH AN ASSOCIATED WARM FRONT REMAINING TO OUR  
SOUTH DUE TO STRONG HIGH PRESSURE OVER NEW ENGLAND AND THE  
CANADIAN MARITIMES, WILL THEN BRING AN EXTENDED PERIOD OF  
UNSETTLED WEATHER FROM WEDNESDAY NIGHT INTO THE WEEKEND. THE LOW  
WILL WEAKEN AND MOVE SLOWLY NORTHEAST EARLY NEXT WEEK.  
 

 
   
NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/
 
 
THE COLD FRONT FURTHER WEAKENS AS IT REMAINS SOUTHEAST OF LONG  
ISLAND. WINDS AT THE SURFACE WILL BE LIGHT OUT OF A GENERAL  
SOUTHWEST DIRECTION.  
 
THE FORECAST IS GENERALLY ON TRACK WITH DRY CONDITIONS STILL  
ANTICIPATED. CLOUDS ARE THINNING OUT FROM NW TO SE GOING INTO THE  
AFTERNOON AS DRIER AIR WORKS IN WITH THE MORE WESTERLY FLOW.  
 
THE DRY CONDITIONS WILL CONTINUE INTO TONIGHT.  
 
STARTING ALOFT WITH TONIGHT, THERE WILL BE SOME RIDGING TAKING  
PLACE ACROSS THE REGION. THIS WILL ALLOW FOR SUBSIDENCE AND HELP  
DECREASE CLOUDS FOR THE EVENING. THE LOCAL REGION WILL ACTUALLY  
BE INBETWEEN A LARGE CUTOFF UPPER LEVEL LOW IN THE OHIO VALLEY  
AND AN ELONGATING UPPER LEVEL TROUGH IN THE CANADIAN MARITIMES AS  
IT BECOMES MORE OF AN OPEN WAVE. CLOUDS INCREASE LATE FROM EAST TO  
WEST.  
 
AT THE SURFACE, THE FRONT WILL FURTHER WEAKEN AND MOVE FARTHER  
OFFSHORE AS HIGH PRESSURE BUILDS INTO THE CANADIAN MARITIMES.  
MAINLY DRY CONDITIONS SHOULD PREVAIL BUT THERE COULD BE A FEW  
SHOWERS SOUTHEAST OF LONG ISLAND TONIGHT, CLOSER TO THE LINGERING  
FRONTAL BOUNDARY.  
 
LOWS TONIGHT WERE TAKEN FROM THE ECS GUIDANCE WHICH WAS  
RELATIVELY WARMER AND EXHIBITED LESS SPATIAL RANGE BETWEEN  
TEMPERATURES.  
 
THERE REMAINS A MODERATE RISK OF RIP CURRENT DEVELOPMENT AT THE  
OCEAN BEACHES INTO THE EARLY EVENING.  
 

 
   
SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/
 
 
THE WEATHER CONTINUES TO BECOME MORE UNSETTLED DURING THIS  
TIMEFRAME.  
 
FOR WEDNESDAY THROUGH WEDNESDAY NIGHT, THE REGION WILL REMAIN  
BETWEEN A SOUTHWARD SHIFTING LARGE CUTOFF UPPER LEVEL LOW GOING  
TOWARDS THE TENNESSEE VALLEY AND THE UPPER LEVEL SHORTWAVE IN THE  
CANADIAN MARITIMES. THERE WILL BE CONTINUED RIDGING BETWEEN THE  
TWO UPPER LEVEL FEATURES. HOWEVER, AT THE SURFACE, THE CENTER OF  
HIGH PRESSURE REMAINS STRONG AND CENTERED MORE TOWARDS SOUTHEAST  
CANADA. THERE WILL BE A LOW PRESSURE AREA WELL SOUTHWEST OF THE  
REGION THAT WILL BE APPROACHING. THERE IS EVIDENT TOO FROM THE  
MODEL MSLP FIELDS AN INVERTED TROUGH THAT WILL BE APPROACHING  
AHEAD OF THE SURFACE LOW. ALOFT, THERE WILL BE INCREASING  
ISENTROPIC LIFT ESPECIALLY WEDNESDAY AFTERNOON THROUGH WEDNESDAY  
NIGHT. THIS GOES ALONG WITH THE SW FLOW IN THE MID TO UPPER LEVELS  
SETTING UP WARM AIR ADVECTION ALOFT.  
 
AT THE SURFACE, A PERSISTENT PATTERN WITH HIGH PRESSURE IN SOUTHEAST  
CANADA AND THE LOCAL REGION BEING ON THE SW PERIPHERY OF THIS  
HIGH. THIS WILL GIVE THE REGION INCREASING NE FLOW AND WITH THE  
HIGH BEING STRONG CENTERED IN THE CANADIAN MARITIMES, A STEEP  
PRESSURE GRADIENT WILL SETUP, RESULTING IN WINDS BECOMING GUSTY.  
 
MODEL PRECIPITATION FIELDS ARE SHOWING SOME VERY LIGHT  
PRECIPITATION AMOUNTS ACROSS THE REGION WEDNESDAY AND INCREASING  
TOWARDS THE WESTERN PORTIONS OF THE REGION WEDNESDAY NIGHT. THIS  
ALL CONVEYS HERE A SITUATION WITH MOISTURE GETTING TRAPPED UNDER  
AN INVERSION. THIS LOW LEVEL MOISTURE WILL INCREASE WEDNESDAY AND  
EVENTUALLY MATERIALIZE AS DRIZZLE OR LIGHT RAIN TO START WITH AND  
A HIGHER CHANCE OF RAIN WEDNESDAY NIGHT WHEN IT WILL INCREASE IN  
INTENSITY, COVERAGE, AND BECOME MORE STEADY. AT THAT TIME, THE  
ATMOSPHERIC COLUMN BECOMES MORE MOIST AS WELL.  
 
REGARDING TEMPERATURES WEDNESDAY, USED THE ECS GUIDANCE AND  
SLIGHTLY ADJUSTED DOWNWARD. NE FLOW AND INCREASING CLOUDS POINTS  
TO A COOLER THAN NORMAL DAY ON AVERAGE OUT EAST WHILE FARTHER WEST  
HIGHS ARE FORECAST TO BE NEAR NORMAL. WEDNESDAY NIGHT FEATURES  
LOWS FROM A MAV/MET BLEND WITH AGAIN NOT MUCH OF A SPATIAL RANGE,  
MOSTLY MID 50S TO NEAR 60 ACROSS THE AREA.  
 

 
   
LONG TERM /THURSDAY THROUGH TUESDAY/
 
 
NWP GUIDANCE IS IN REMARKABLY GOOD AGREEMENT ON THE BIG PICTURE  
THROUGH THE WEEKEND, WITH A LARGE UPPER LOW COMPLETELY CUTTING OFF  
FROM THE WESTERLIES AND STALLING OVER THE OHIO VALLEY FROM THU  
THROUGH SAT, THEN LIFTING ACROSS THE GREAT LAKES ON SUNDAY AND  
WEAKENING INTO AN UPPER TROUGH THAT SLIDES ACROSS THE NORTHEAST ON  
MONDAY. MEANWHILE, AS A STRONG UPPER HIGH BUILDS OVER THE WESTERN  
ATLANTIC, UPPER LEVEL CONFLUENCE TO ITS NORTH WHERE IT MEETS THE  
WESTERLIES WILL MAINTAIN STRONG SURFACE HIGH PRESSURE OVER  
NORTHERN NEW ENGLAND AND THE CANADIAN MARITIMES,THAT SHOULD NOSE  
DOWN INTO OUR AREA AND KEEP A WARM FRONT TO OUR SOUTH. THIS  
COMBINATION WILL KEEP US IN AN UNSETTLED WEATHER PATTERN THROUGH  
AT LEAST THE WEEKEND, WITH PERIODS OF MODERATE TO HEAVY RAIN. THE  
FIRST OF THESE IS LIKELY TO COME THU NIGHT INTO FRI MORNING VIA  
STRENGTHENING EASTERLY LOW LEVEL ATLANTIC INFLOW, MOISTENING MID  
LEVELS VIA DEEP SOUTHERLY FLOW ALOFT, A MID LEVEL VORT MAX RIDING  
UP THE COAST, AND INCREASINGLY DIFLUENT FLOW ALOFT. ANOTHER BOUT  
OF HEAVY RAIN MAY COME TO LONG ISLAND AND SOUTHERN CT ON SATURDAY  
AS ANOTHER MID LEVEL IMPULSE RIDES UP THE COAST AND AS A WEAK WAVE  
OF LOW PRESSURE FORMS ALONG THE FRONT JUST TO THE SOUTH. IN  
BETWEEN THESE BOUTS OF HEAVIER RAIN SKIES SHOULD REMAIN OVERCAST,  
WITH PERIODS OF INTERMITTENT LIGHT RAIN. AN EXCEPTION TO THIS MAY  
TAKE PLACE THU AFTERNOON, WHEN SOME GUIDANCE INDICATES THE HIGH  
MAY BUILD DOWN STRONGLY ENOUGH FROM THE NORTH TO SHUT OFF PRECIP  
FOR A TIME ACROSS THE INTERIOR. SOME ELEVATED INSTABILITY WILL BE  
PRESENT SAT INTO SAT NIGHT, WITH SOME RUMBLES OF THUNDER POSSIBLE.  
 
AS THE UPPER LOW LIFTS INTO THE GREAT LAKES ON SUNDAY, AN  
ASSOCIATED WEAK TRIPLE-POINT LOW AND/OR OCCLUDED FRONT SHOULD  
SLOWLY LIFT ACROSS, WITH PRECIP BECOMING MORE SHOWERY IN NATURE.  
THE UPPER LOW WILL CONTINUE TO WEAKEN AND MOVE EAST, BUT NOT CLEAR  
OUR AREA UNTIL TUE MORNING, SO FORECAST CARRIES AT LEAST SLIGHT  
CHANCE POP UNTIL THEN.  
 
HIGH TEMPS IN THIS REGIME WILL BE SLIGHTLY BELOW AVERAGE THU-FRI,  
WITH A RETURN TO NEAR AVERAGE SAT INTO MON, AND THEN SLIGHTLY  
BELOW AVERAGE ON TUE AS CANADIAN HIGH PRESSURE STARTS TO RETURN.  
LOW TEMPS MEANWHILE SHOULD BE MOSTLY WARMER THAN AVERAGE UNTIL MON  
NIGHT.  
 

 
   
AVIATION /20Z TUESDAY THROUGH SUNDAY/
 
 
LONG STRETCH OF UNSETTLED WEATHER BEGINS WEDNESDAY. VFR EXPECTED  
ACROSS ALL TERMINALS FOR A GOOD PART OF THE NIGHT BUT POCKETS OF  
MVFR CAN'T BE RULED TOWARD MIDNIGHT AND ESPECIALLY TOWARD  
WEDNESDAY MORNING. BY EARLY WEDNESDAY AFTERNOON, CLOUDS LOWER AND  
THICKEN WITH A CHANCE OF DRIZZLE/LIGHT RAIN IN MVFR AND LOWER  
CONDITIONS, ESPECIALLY AT COASTAL TERMINALS.  
 
LIGHT WIND AND VARIABLE WIND THIS EVENING BECOMING NE AROUND 10 KT  
EARLY WEDNESDAY MORNING. BY MIDDAY...NE WINDS INCREASE TO NEAR 15 KT  
AND BECOME GUSTY AT TIMES NEAR 20-25 KT.  
 
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...  
 
DETAILED INFORMATION, INCLUDING HOURLY TAF WIND COMPONENT FORECASTS,  
CAN BE FOUND AT: HTTP:/WWW.WEATHER.GOV/ZNY/N90  
 
KJFK TAF COMMENTS: AMENDMENTS POSSIBLE TO ADJUST WIND DIRECTION  
AND/OR CEILINGS, ESPECIALLY WEDNESDAY MORNING.  
 
KLGA TAF COMMENTS: AMENDMENTS POSSIBLE TO ADJUST WIND DIRECTION  
AND/OR CEILINGS, ESPECIALLY WEDNESDAY MORNING.  
 
KEWR TAF COMMENTS: AMENDMENTS POSSIBLE TO ADJUST WIND DIRECTION  
AND/OR CEILINGS, ESPECIALLY WEDNESDAY MORNING.  
 
KTEB TAF COMMENTS: AMENDMENTS POSSIBLE TO ADJUST WIND DIRECTION  
AND/OR CEILINGS, ESPECIALLY WEDNESDAY MORNING.  
 
KHPN TAF COMMENTS: AMENDMENTS POSSIBLE TO ADJUST WIND DIRECTION  
AND/OR CEILINGS, ESPECIALLY WEDNESDAY MORNING.  
 
KISP TAF COMMENTS: AMENDMENTS POSSIBLE TO ADJUST WIND DIRECTION  
AND/OR CEILINGS, ESPECIALLY WEDNESDAY MORNING.  
   
OUTLOOK FOR 18Z WEDNESDAY THROUGH SATURDAY
 
   
WED
 
BECOMING MVFR LATE MORNING/EARLY AFTERNOON. NE WINDS G25KT  
POSSIBLE IN THE AFTERNOON.   
THU-SAT
 
IFR/MVFR IN SHOWERS. NE WINDS 15-20 KT WITH GUSTS  
25-30 KT POSSIBLE THU-FRI.   
SUN
 
MAINLY VFR BUT MVFR POSSIBLE WITH A CHANCE OF SHOWERS. N  
WINDS 10-20 KT.  
 

 
   
MARINE
 
 
SUB SCA INITIALLY BUT WITH A WEAK WIND FIELD, THERE WILL NOT BE  
MUCH TO RESIST INCOMING SWELLS FROM THE SOUTH. THINKING THERE WILL  
BE SOME HIGHER SEAS EVENTUALLY GETTING BACK INTO THE OCEAN ZONES  
THAT MAY MEET SCA CRITERIA TONIGHT WITH OTHERWISE SUB SCA  
CONDITIONS. THERE IS POTENTIAL HERE THAT SCA MAY NEED TO START  
EARLIER AND SOMETIME TONIGHT IF THE SWELLS REACH CLOSE ENOUGH TO  
THE OCEAN WATERS.  
 
THEN WEDNESDAY INTO WEDNESDAY NIGHT, SCA LOOKS MORE PROBABLE  
ACROSS ALL WATERS ESPECIALLY ON THE OCEAN. THERE WILL BE A TIGHT  
PRESSURE GRADIENT SETTING UP BETWEEN A SOUTHEAST CANADA HIGH AND  
LOW PRESSURE SOUTHWEST OF THE REGION. THINK MAX GUSTS REACH NEAR  
30 KT, MOSTLY WEDNESDAY NIGHT.  
 
THEN AS THE PRESSURE GRADIENT TIGHTENS FURTHER, EASTERLY GALES  
APPEAR LIKELY FROM THU INTO FRI MORNING MAINLY ON THE OCEAN, BUT  
PERHAPS ALSO ON THE NEARBY BAYS OF EASTERN LONG ISLAND AND EASTERN  
LONG ISLAND SOUND, WITH SCA CONDS ON THE HARBOR AND WESTERN SOUND.  
ISSUED GALE WATCH FOR THE OCEAN FOR THU INTO THU NIGHT.  
 
SCA CONDS ARE LIKELY TO CONTINUE THEREAFTER ON ALL WATERS INTO  
FRI, ON THE EASTERN SOUND/BAYS INTO FRI NIGHT, AND ON THE OCEAN  
INTO SAT.  
 

 
   
HYDROLOGY
 
 
DRY WEATHER EXPECTED THROUGH TONIGHT AND ANY RAIN WEDNESDAY  
THROUGH WEDNESDAY NIGHT WILL BE LIGHT WITH RAINFALL TOTALS LESS  
THAN A QUARTER OF AN INCH.  
 
THE HEAVIEST RAINFALL AMOUNTS WITH A NEARBY LOW PRESSURE SYSTEM  
SHOULD FALL TO OUR WEST, BUT THERE COULD STILL BE SOME PERIODS OF  
HEAVIER RAIN THU NIGHT INTO FRI MORNING, ALSO ON SATURDAY. TOTAL  
BASIN AVERAGE RAINFALL FROM THU THROUGH SAT SHOULD RANGE FROM 3/4  
TO 1-3/4 INCHES, WITH POTENTIAL FOR LOCAL AMOUNTS OF 2-3 INCHES  
ACROSS PARTS OF LONG ISLAND AND SOUTHERN CT. THIS IS NOT EXPECTED  
TO CAUSE MAJOR HYDROLOGIC IMPACTS.  
 

 
   
TIDES/COASTAL FLOODING
 
 
A PERSISTENT MODERATE EASTERLY FLOW DURING MID TO LATE WEEK MAY  
COMBINE WITH INCREASING ASTRONOMICAL HIGH TIDES ASSOCIATED WITH  
THE NEW MOON ON FRIDAY TO CAUSE MINOR TO LOCALLY MODERATE COASTAL  
FLOODING. THE HIGH TIDE CYCLES FROM THU NIGHT INTO FRI MORNING  
APPEAR TO BE OF MOST CONCERN.  
 

 
   
OKX WATCHES/WARNINGS/ADVISORIES
 
 
CT...NONE.  
NY...NONE.  
NJ...NONE.  
MARINE...SMALL CRAFT ADVISORY FROM NOON WEDNESDAY TO 6 AM EDT THURSDAY  
FOR ANZ330-335-338-340-345.  
GALE WATCH FROM THURSDAY MORNING THROUGH LATE THURSDAY NIGHT  
FOR ANZ350-353-355.  
SMALL CRAFT ADVISORY FROM 10 AM WEDNESDAY TO 6 AM EDT THURSDAY  
FOR ANZ350-353-355.  
 

 
 

 
 
SYNOPSIS...GOODMAN/JM  
NEAR TERM...JM  
SHORT TERM...JM  
LONG TERM...GOODMAN  
AVIATION...IRD  
MARINE...GOODMAN/JM  
HYDROLOGY...GOODMAN/JM  
TIDES/COASTAL FLOODING...GOODMAN  
 
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