688  
FXUS61 KOKX 241738  
AFDOKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW YORK NY  
1238 PM EST TUE JAN 24 2017  
   
SYNOPSIS
 
 
STRONG LOW PRESSURE JUST SOUTH OF LONG ISLAND WILL TRACK SLOWLY  
NORTHEAST THROUGH TONIGHT AND UP INTO THE CANADIAN MARITIMES ON  
WEDNESDAY. HIGH PRESSURE BUILDS IN BRIEFLY FOR WEDNESDAY. LOW  
PRESSURE MOVES ACROSS THE GREAT LAKES WEDNESDAY NIGHT AND DEEPENS  
AS IT MOVES INTO SOUTHEAST CANADA, REMAINING NEARLY STATIONARY  
THROUGH THE UPCOMING WEEKEND. THIS LOW WILL SEND A SERIES OF COLD  
FRONTS THROUGH THE AREA, ONE ON THURSDAY AND THEN AGAIN OVER THE  
WEEKEND.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
THE WINTER WEATHER ADVISORY HAS BEEN EXTENDED INTO EARLY EVENING  
ACROSS PUTNAM, ORANGE, AND WESTERN PASSAIC COUNTIES. TEMPERATURES  
ARE CURRENTLY IN THE LOW TO MID 30S ACROSS THESE ZONES, AND BASED  
ON NORTHERLY WINDS AND UPSTREAM OBS, TEMPS EXPECTED TO DROP TO  
AROUND FREEZING. AT THE SAME TIME, MAX TEMP IN THE WARM NOSE ALOFT  
INCREASES A LITTLE BEFORE DROPPING OFF LATE THIS AFTERNOON INTO  
THIS EVENING. THE LAYER BENEATH THIS WARM NOSE COULD BE JUST COLD  
ENOUGH FOR SOME SLEET, BUT MORE SO LATE DAY/EARLY EVENING. RAIN  
AND FREEZING RAIN WITH PERHAPS SOME SLEET IS THEREFORE FORECAST  
FOR THESE ZONES. THERE IS A CHANCE THAT FREEZING RAIN IS NOT  
WIDESPREAD, BUT FELT IT WOULD BE BETTER OPTION TO EXTEND THE  
ADVISORY FOR THESE AREAS. SLEET ACCUMULATION OF UNDER AN INCH  
WITH UNDER A TENTH OF AN INCH OF ICE ACCRETION EXPECTED. FOR  
ROCKLAND AND NORTHERN WESTCHESTER COUNTIES, THERE IS MORE  
CONFIDENCE THAT FREEZING RAIN WOULD NOT BE WIDESPREAD - PERHAPS  
LIMITED TO THE HIGHEST ELEVATIONS.  
 
ELSEWHERE, PLAIN RAIN IS FORECAST AS A DEFORMATION BAND SETS UP  
OVER THE CENTRAL PART OF THE CWA. UP TO AN ADDITIONAL QUARTER TO  
HALF INCH OF RAINFALL IS EXPECTED THIS AFTERNOON.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/
 
 
THE VERTICALLY STACKED LOW MOVES SLOWLY ALONG THE NEW ENGLAND  
COAST TONIGHT WITH THE CHANCES OF PRECIPITATION SLOWLY LOWERING  
FROM THE SOUTHWEST TO THE NORTHEAST. HEIGHTS BEGIN TO RISE LATE  
AT NIGHT AS WEAK RIDGING BUILDS TO THE WEST.  
 
SOME OF THE RAIN ON THE BACKSIDE OF THIS SYSTEM COULD TRANSITION  
OVER TO SLEET OR FREEZING RAIN BRIEFLY BEFORE COMING AN TO END  
TONIGHT. OVERNIGHT LOWS WILL DROP TO AROUND FREEZING INLAND, AND  
IN THE MID AND UPPER 30S AT THE COAST.  
 
HIGH PRESSURE AND SUNNY SKIES WILL BE ON TAP FOR WEDNESDAY.  
BUILDING HEIGHTS ALOFT AND WINDS BACKING TO THE WEST WILL RESULT  
IN A MUCH WARMER DAY, WITH HIGHS IN THE MID AND UPPER 40S. THIS  
IS ABOUT 10 DEGREES ABOVE NORMAL.  
 

 
   
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/
 
 
THE NEXT SHORTWAVE TROUGH MOVES ACROSS THE GREAT LAKES WEDNESDAY  
NIGHT AND SWINGS ACROSS THE REGION ON THURSDAY. THE GFS AND SOME  
OF ITS ENSEMBLE MEMBERS INDICATE POTENTIAL FOR SHOWERS AS THE COLD  
FRONT ASSOCIATED WITH THIS SHORTWAVE MOVES THROUGH THURSDAY. OTHER  
MODELS AND ENSEMBLES ARE DRIER. THIS APPEARS TO BE DUE TO THE  
AMPLITUDE OF H5 ENERGY AND MOISTURE RETURN. WILL CAP POPS OFF AT  
30 PERCENT AT THIS TIME.  
 
COLD FRONT MOVES OFFSHORE THURSDAY AFTERNOON AND EVENING. THIS FRONT  
SIGNIFIES A RETURN TO MORE SEASONABLE TEMPERATURES, POTENTIALLY A  
FEW DEGREES BELOW NORMAL. THERE IS ALSO GOOD AGREEMENT AMONG THE  
MODELS AND ENSEMBLE MEANS WITH A HEMISPHERIC PATTERN CHANGE WITH  
DEEP RIDGING ACROSS WESTERN NORTH AMERICA AND MEAN TROUGHING OVER  
THE EAST. DRY FORECAST INTO THE WEEKEND ALTHOUGH THERE IS ENOUGH  
ENERGY ALOFT WITHIN CYCLONIC FLOW THAT A FEW SNOW SHOWERS MAY REACH  
INTERIOR SECTIONS.  
 
LATE IN THE WEEKEND INTO EARLY NEXT WEEK, THERE ARE SIGNALS THE MEAN  
TROUGH ACROSS THE EAST MAY SHARPEN UP, BUT IT IS A BIT EARLY TO SAY  
IF THERE ANY IMPACTS TO SENSIBLE WEATHER.  
 

 
   
AVIATION /18Z TUESDAY THROUGH SUNDAY/
 
 
LOW PRESSURE TRACKS INTO THE GULF OF MAINE THROUGH TONIGHT, THEN  
INTO THE CANADIAN MARITIME PROVINCES INTO WEDNESDAY AFTERNOON.  
 
IFR CONDITIONS DEVELOPING/CONTINUING INTO THIS EVENING, EXCEPT AT  
KSWF WHERE PROBABLY WILL REMAIN MVFR. CONDITIONS COULD VARY +/- 1  
CATEGORY THROUGH THE EVENING. CONDITIONS SHOULD IMPROVE TO VFR  
5-7Z...EXCEPT AROUND 11Z KGON.  
 
WINDS CONTINUE TO BACK TO THE NW INTO THIS EVENING 15-20G25-30KT.  
WINDS SUBSIDE SLIGHTLY LATE TONIGHT/EARLY WEDNESDAY MORNING  
THROUGHOUT AND BACK TO THE WNW AT MAINLY CITY TERMINALS.  
 
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 LIKELY INTO THIS EVENING FOR  
VARYING CONDITIONS BETWEEN IFR AND MVFR. TIMING OF CHANGES IN WIND  
SPEED AND DIRECTION COULD BE OFF +/- 1-2 HOURS.  
 
KLGA TAF COMMENTS: AMENDMENTS LIKELY INTO THIS EVENING FOR  
VARYING CONDITIONS BETWEEN IFR AND MVFR. TIMING OF CHANGES IN WIND  
SPEED AND DIRECTION COULD BE OFF +/- 1-2 HOURS.  
 
KEWR TAF COMMENTS: AMENDMENTS LIKELY INTO THIS EVENING FOR  
VARYING CONDITIONS BETWEEN IFR AND MVFR. TIMING OF CHANGES IN WIND  
SPEED AND DIRECTION COULD BE OFF +/- 1-2 HOURS.  
 
KTEB TAF COMMENTS: AMENDMENTS LIKELY INTO THIS EVENING FOR  
VARYING CONDITIONS BETWEEN IFR AND MVFR. TIMING OF CHANGES IN WIND  
SPEED AND DIRECTION COULD BE OFF +/- 1-2 HOURS.  
 
KHPN TAF COMMENTS: AMENDMENTS LIKELY INTO THIS EVENING FOR  
VARYING CONDITIONS BETWEEN IFR AND MVFR. TIMING OF CHANGES IN WIND  
SPEED AND DIRECTION COULD BE OFF +/- 1-2 HOURS.  
 
KISP TAF COMMENTS: AMENDMENTS LIKELY INTO THIS EVENING FOR  
VARYING CONDITIONS BETWEEN IFR AND MVFR. TIMING OF CHANGES IN WIND  
SPEED AND DIRECTION COULD BE OFF +/- 1-2 HOURS.  
   
OUTLOOK FOR 18Z WEDNESDAY THROUGH SATURDAY
 
   
WEDNESDAY AFTERNOON-WEDNESDAY EVENING
 
VFR. WNW_WSW WINDS  
G15-20KT POSSIBLE.   
LATE WEDNESDAY NIGHT/THURSDAY MORNING
 
LOW CHANCE OF MVFR.    
THURSDAY AFTERNOON-SUNDAY
 
VFR. W-WSW WINDS G15-25KT POSSIBLE.  
 

 
   
MARINE
 
 
GALE WARNING OVER THE OCEAN WATERS HAS BEEN EXTENDED THROUGH  
TONIGHT. THERE COULD BE A FEW HOURS THIS AFTERNOON WHERE CRITERIA  
ISN'T BEING MET, BUT GUIDANCE AND A TIGHT PRESSURE GRADIENT BEHIND  
THE DEPARTING STORM SUGGESTS WINDS INCREASING BACK TO GALES BY  
TONIGHT. FOR THE OTHER WATERS, SCA CONTINUES THROUGH TONIGHT.  
 
WINDS DIMINISH ON ALL WATERS WEDNESDAY WITH A WEAKENING PRESSURE  
GRADIENT AS HIGH PRESSURE SETTLES OVER THE WATERS. OCEAN SEAS  
SHOULD ALSO SUBSIDE BELOW 5 FT BY EVENING.  
 
SCA CONDITIONS ARE LIKELY ON ALL WATERS ON THURSDAY WITH A  
STEEPENING PRESSURE GRADIENT WITH A COLD FRONT PASSAGE. THESE  
CONDITIONS MAY CONTINUE INTO FRIDAY AND POSSIBLY INTO SATURDAY,  
ESPECIALLY ON THE OCEAN WATERS.  
 

 
   
HYDROLOGY
 
 
AN ADDITIONAL QUARTER TO HALF INCH OF RAINFALL IS POSSIBLE TODAY  
AS A BAND OF MODERATE RAIN DEVELOPS ON THE BACKSIDE OF DEPARTING  
LOW PRESSURE. THIS BAND IS EXPECTED TO BE CENTERED NEAR THE CITY  
AND LOWER HUDSON VALLEY. THESE AMOUNTS SHOULD NOT POSE ANY  
HYDROLOGIC ISSUES.  
 

 
   
TIDES/COASTAL FLOODING
 
 
HIGH TIDE HAS PASSED. HOWEVER, THERE IS SOME RESIDUAL MINOR  
COASTAL FLOODING FOR SHORELINES OF SOUTHWEST SUFFOLK COUNTY ON  
LONG ISLAND, PARTICULARLY AT LINDENHURST. FOR SOUTHERN NASSAU  
COUNTY ON LONG ISLAND, THIS IS EXPECTED TO BE QUITE LOCALIZED WITH  
THE RESIDUAL MINOR COASTAL FLOODING. EXPECTING ALL GAGES TO FALL  
BELOW MINOR COASTAL FLOODING BENCHMARKS BY 1PM. TIDAL DEPARTURES  
ARE APPROXIMATELY 2 TO 2.5 FT ABOVE ASTRONOMICAL.  
 
TONIGHT'S HIGH TIDE LEVELS WILL BE THE LOWER OF THE DAILY HIGH  
TIDAL CYCLES AND ALONG WITH INCREASING OFFSHORE FLOW, NO OTHER  
COASTAL FLOODING IS EXPECTED. HOWEVER, WEDNESDAY MORNING'S HIGH  
TIDES WILL BE APPROXIMATELY 0.1 TO 0.2FT HIGHER THAN THIS  
MORNING'S HIGH TIDES. THERE WILL BE INCREASING OFFSHORE FLOW AS  
WINDS BECOME MORE WESTERLY. THERE COULD BE SOME ISOLATED TIDAL  
GAGES THAT TOUCH OR SLIGHTLY EXCEED MINOR COASTAL FLOODING  
THRESHOLDS ACROSS THE SOUTH SHORE BAYS BUT THIS IS A LOW  
PROBABILITY AT THIS TIME.  
 
THE OTHER CONTINUING CONCERN WILL BE FOR WIDESPREAD DUNE EROSION  
AND LOCALIZED WASHOVERS AT ATLANTIC OCEAN BEACHES FROM ELEVATED  
WATERS LEVELS AND AN EAST TO WEST SWEEP OF 9 TO 13 FT SURF.  
 

 
   
OKX WATCHES/WARNINGS/ADVISORIES
 
 
CT...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR CTZ005.  
NY...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR NYZ067-  
068.  
COASTAL FLOOD ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR  
NYZ080.  
NJ...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR NJZ002.  
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST WEDNESDAY FOR ANZ330-335-  
338-340-345.  
GALE WARNING UNTIL 6 AM EST WEDNESDAY FOR ANZ350-353-355.  
 

 
 

 
 
SYNOPSIS...DW  
NEAR TERM...JC/DW  
SHORT TERM...DW  
LONG TERM...DS/DW  
AVIATION...MALOIT  
MARINE...DW  
HYDROLOGY...DW  
TIDES/COASTAL FLOODING...JM  
 
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