984  
FXUS61 KOKX 280913  
AFDOKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW YORK NY  
513 AM EDT TUE MAR 28 2017  
   
SYNOPSIS
 
 
A FRONTAL SYSTEM WILL APPROACH TODAY, AND PASS EARLY WEDNESDAY.  
HIGH PRESSURE WILL BUILD IN FOR THURSDAY, AND DRIFT OFFSHORE  
THURSDAY NIGHT. A LOW PRESSURE SYSTEM WILL IMPACT THE REGION  
THURSDAY NIGHT INTO SATURDAY. HIGH PRESSURE BUILDS IN SUNDAY AND  
MONDAY.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
SATELLITE INDICATES THE MAIN UPPER LEVEL SYSTEM WAS OVER  
NORTHERN KENTUCKY THIS MORNING. ELEVATED INSTABILITY WAS  
INCREASING ACROSS THE FORECAST AREA EVIDENCED BY SHOWERS AND  
THUNDERSTORMS. THESE SHOULD CONTINUE TO DEVELOP PER THE NAM  
WHICH APPEARS TO HAVE A VERY GOOD HANDLE ON THE ACTIVITY THUS  
FAR. FOG HAS MAINLY BEEN PATCHY OVERNIGHT, SO WITH WIDESPREAD  
DENSE FOG NO LONGER EXPECTED, ESPECIALLY WITH CONVECTION  
APPROACHING, THE ADVISORY HAS BEEN CANCELLED. AS THE MAIN  
SYSTEM APPROACHES THIS AFTERNOON AND EVENING, MORE SHOWERS CAN  
BE EXPECTED. SOME EMBEDDED THUNDERSTORMS CANNOT BE RULED OUT  
UNTIL THE INSTABILITY AXIS EXITS, LEAVING REMNANT STRATIFORM  
LIGHT RAIN. THE MODELS WERE IN GOOD AGREEMENT SO A BLEND WAS  
USED FOR TEMPERATURES THROUGH TONIGHT.  
 

 
   
SHORT TERM /WEDNESDAY/
 
 
DRY WEATHER WITH A NORTHWESTERLY BREEZE. DESPITE A COOLER  
AIRMASS IN PLACE, TEMPERATURES WILL ACTUALLY BE WARMER THAN  
TUESDAY BECAUSE OF DEEP MIXING. MOSTLY SUNNY SKIES ARE PROGGED,  
ALTHOUGH SOME FAIR WEATHER CONVECTIVE CLOUDS WILL BE POSSIBLE IF  
THEY ARE ABLE TO OVERCOME THE SUBSIDENCE. A BLEND OF THE  
GUIDANCE WAS USED FOR TEMPERATURES.  
 

 
   
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/
 
 
THE EXTENDED PERIOD WILL FEATURE A SPLIT FLOW ACROSS THE CONTINENTAL  
UNITED STATES WITH SYSTEMS MOVING THROUGH ACTIVE NORTHERN AND  
SOUTHERN STREAMS. AS A RESULT, EVEN THROUGH THERE ARE SIMILARITIES  
IN THE LONGWAVE AND OVERALL SOLUTIONS, THE DETAILS OF THE FORECAST  
HAVE BECOME MORE UNCERTAIN, AND INCONSISTENCIES FROM RUN TO RUN HAVE  
INCREASED. CURRENTLY THERE IS NOW LITTLE TO NO PHASING OF SYSTEMS  
IMPACTING THE EAST, AND IN PARTICULAR THE REGION, THURSDAY NIGHT  
INTO SATURDAY, AND YET ANOTHER SYSTEM MONDAY NIGHT INTO TUESDAY.  
THERE ARE NOW MORE UNCERTAINTIES AS TO THE DEPTH OF THE LOWS,  
TIMING, AND TRACKS.  
 
FOR LATE THURSDAY NIGHT THROUGH SATURDAY NIGHT HAVE LONG PERIOD OF  
PROBABILITIES, AND EVEN LIKELY PROBABILITIES FROM FRIDAY INTO  
SATURDAY. THIS IS LIKELY TOO LONG A PERIOD HOWEVER, WITH THE  
UNCERTAINTIES WANTED TO MAINTAIN SOME CONSISTENCY WITH PRIOR  
FORECASTS. BOTH THE ECMWF AND GFS HAVE SOME LINGERING COLD AIR  
ACROSS THE NORTHERN PORTIONS OF THE CWA THURSDAY NIGHT BEFORE WARM  
ADVECTION INCREASES. SO HAVE KEPT A MIX OF SNOW AND RAIN INLAND.  
 
CANADIAN HIGH PRESSURE BUILDS IN FOR LATE SATURDAY NIGHT INTO  
MONDAY, AND POSSIBLY TUESDAY IF RIDGING REMAINS AS PER THE GFS.  
THE ECMWF IS QUICKER TO WEAKEN AND SHIFT THE RIDGE OFF SHORE  
TUESDAY. HAVE INTRODUCED A LOW CHANCE OF PRECIPITATION FOR  
TUESDAY.  
 

 
   
AVIATION /09Z TUESDAY THROUGH SATURDAY/
 
 
A FRONT REMAINS JUST SOUTH OF THE TERMINALS AND ATTEMPTS TO  
PUSH BACK NORTH AS A WARM FRONT ON TUESDAY.  
 
LIGHT ENE OVERNIGHT FOR TUESDAY MORNING WITH AREAS OF RAIN  
AND FOG. LIFR CONDITIONS AT TIMES THIS MORNING, OTHERWISE AREAS  
OF RAIN THIS MORNING WILL RESULT IN IFR CONDITIONS AT TIMES,  
AND THEN BACK DOWN TO LIFR WHEN THE RAIN LIGHTENS OR STOPS.  
 
ANOTHER AREA OF RAINFALL WILL ARRIVE LATER IN THE DAY AND FOR  
THE EVENING. THERE IS A THUNDERSTORM CHANCE WITH THIS NEXT AREA  
OF RAINFALL FOR THE CITY TERMINALS, BUT NOT CONFIDENT ENOUGH TO  
PUT IN TAFS AT THIS TIME. IFR TO LIFR CONDITIONS ARE EXPECTED  
TO PREVAIL UNTIL ABOUT 6Z LATE TONIGHT, WITH IMPROVING  
CONDITIONS THEREAFTER FROM WEST TO EAST.  
   
..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: TIMING OF NEXT AREA OF RAIN MAY BE OFF BY +/-  
2 HOURS THIS AFTERNOON. THERE IS A THUNDERSTORM CHANCE LATE  
TODAY BUT CONFIDENCE IS LOW.  
 
KLGA TAF COMMENTS: TIMING OF NEXT AREA OF RAIN MAY BE OFF BY +/-  
2 HOURS THIS AFTERNOON. THERE IS A THUNDERSTORM CHANCE LATE  
TODAY BUT CONFIDENCE IS LOW.  
 
KEWR TAF COMMENTS: TIMING OF NEXT AREA OF RAIN MAY BE OFF BY  
+/- 2 HOURS THIS AFTERNOON. THERE IS A THUNDERSTORM CHANCE LATE  
TODAY BUT CONFIDENCE IS LOW.  
 
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS YELLOW...WHICH  
IMPLIES SLANT RANGE VISIBILITY 4-6SM OUTSIDE OF CLOUD.  
 
KTEB TAF COMMENTS: TIMING OF NEXT AREA OF RAIN MAY BE OFF BY +/-  
2 HOURS THIS AFTERNOON. THERE IS A THUNDERSTORM CHANCE LATE  
TODAY BUT CONFIDENCE IS LOW.  
 
KHPN TAF COMMENTS: TIMING OF NEXT AREA OF RAIN MAY BE OFF BY +/-  
2 HOURS THIS AFTERNOON. THERE IS A THUNDERSTORM CHANCE LATE  
TODAY BUT CONFIDENCE IS LOW.  
 
KISP TAF COMMENTS: TIMING OF NEXT AREA OF RAIN MAY BE OFF BY +/-  
2 HOURS THIS AFTERNOON. THERE IS A THUNDERSTORM CHANCE LATE  
TODAY BUT CONFIDENCE IS LOW.  
   
OUTLOOK FOR 09Z WEDNESDAY THROUGH SATURDAY
 
   
TUE NIGHT
 
IFR OR LOWER IN RAIN/LOW CLOUDS/FOG, IMPROVING  
LATE, ESPECIALLY WESTERN TERMINALS.   
WEDNESDAY
 
VFR. N-NW GUSTS 15-20KT.    
THURSDAY
 
VFR.   
FRIDAY
 
A WINTRY MIX POSSIBLE EARLY NORTH AND WEST WITH IFR  
CONDITIONS POSSIBLE BEFORE A CHANGE TO RAIN, OTHERWISE SUB VFR  
CONDITIONS WITH RAIN ELSEWHERE.   
FRIDAY NIGHT AND SATURDAY
 
CHANCE OF RAIN WITH MVFR OR LOWER  
CONDITIONS. E WINDS G20-25KT AT COASTAL TERMINALS FOR SATURDAY.  
 

 
   
MARINE
 
 
WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY LEVELS  
THROUGH TONIGHT. PATCHY FOG MAY LIMIT VISIBILITIES TO LESS THAN  
1 NM AT TIMES TODAY, BUT IT IS NO LONGER EXPECTED TO BE  
WIDESPREAD. THE DENSE FOG ADVISORY WAS THEREFORE CANCELLED.  
MARGINAL SMALL CRAFT ADVISORY LEVEL WINDS ARE POSSIBLE ON  
WEDNESDAY AFTER THE FRONTAL PASSAGE.  
 
SMALL CRAFT ADVISORY CONDITIONS WILL BE LIKELY ACROSS THE OCEAN  
FORECAST WATERS WEDNESDAY NIGHT INTO THURSDAY, WITH STRONG AND  
GUSTY NORTHWEST WINDS, AS HIGH PRESSURE BUILDS IN BEHIND A COLD.  
OCEAN SEAS WILL BUILD WEDNESDAY NIGH INTO EARLY THURSDAY AND MAY  
BE AROUND SMALL CRAFT LEVELS. IN ADDITION, OCCASIONAL GUSTS  
ACROSS EASTERN LONG ISLAND SOUND, AND THE EASTERN BAYS MAY BE  
NEAR SMALL CRAFT LEVELS WEDNESDAY NIGHT.  
 
NORTHWESTERLY WINDS WILL DEVELOP BEHIND THE COLD FRONT AND THEN  
INCREASE INTO WEDNESDAY AND WEDNESDAY NIGHT AS HIGH PRESSURE  
BUILDS TO THE NORTH. MINIMAL SCA CONDITIONS ARE POSSIBLE ACROSS  
THE OCEAN WATERS WEDNESDAY NIGHT INTO EARLY THURSDAY.  
 
SUB ADVISORY CONDITIONS ARE EXPECTED LATE THURSDAY INTO FRIDAY  
AS HIGH PRESSURE MOVES ACROSS THE WATERS.  
 
THE NEXT CHANCE OF SMALL CRAFT CONDITIONS WILL BE LATE FRIDAY  
THROUGH SATURDAY NIGHT AS SOUTHERLY WINDS INCREASE AHEAD OF A  
LOW PRESSURE SYSTEM.  
 

 
   
HYDROLOGY
 
 
BASIN AVERAGE RAINFALL OF A HALF INCH OR LESS CAN BE EXPECTED  
THROUGH TONIGHT. LOCALLY HEAVIER AMOUNTS CAN BE EXPECTED HOWEVER  
IN ANY THUNDERSTORMS THAT DEVELOP.  
 
ADDITIONAL RAINFALL OF 1/2 INCH TO 1 INCH WILL BE POSSIBLE  
THURSDAY NIGHT THROUGH SATURDAY. NO HYDROLOGIC CONCERNS ARE  
ANTICIPATED.  
 

 
   
TIDES/COASTAL FLOODING
 
 
ASTRONOMICAL TIDES REMAIN HIGH DUE TO A RECENT NEW MOON.  
 
WATER LEVELS MAY APPROACH MINOR FLOOD THRESHOLDS DURING THE HIGH  
TIDE CYCLES THURSDAY NIGHT, WITH MINOR FLOODING POSSIBLE FRIDAY  
NIGHT AS A LOW PRESSURE SYSTEM APPROACHES.  
 

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

 
 

 
SYNOPSIS...12/MET  
NEAR TERM...12  
SHORT TERM...12  
LONG TERM...MET  
AVIATION...JC/JE  
MARINE...12/MET  
HYDROLOGY...12/MET  
TIDES/COASTAL FLOODING...  
 
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