862  
FXUS61 KOKX 111433  
AFDOKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW YORK NY  
933 AM EST MON DEC 11 2017  
   
SYNOPSIS
 
 
HIGH PRESSURE BRIEFLY BUILDS TODAY. LOW PRESSURE WILL THEN PASS  
ACROSS THE GREAT LAKES TONIGHT, WHILE AN ASSOCIATED WARM FRONT  
LIFTS THROUGH TUESDAY MORNING. A STRONG COLD FRONT PASSES IN  
THE AFTERNOON. LOW PRESSURE WILL MOVE INTO THE CANADIAN  
MARITIMES TUESDAY NIGHT INTO WEDNESDAY NIGHT, WITH BRIEF HIGH  
PRESSURE BUILDING ACROSS THE AREA IN ITS WAKE. A WEAK ALBERTA  
CLIPPER PASSES TO THE SOUTH ON THURSDAY, FOLLOWED BY A LOW  
PRESSURE SYSTEM PASSING OFF THE COAST LATE FRIDAY INTO FRIDAY  
NIGHT. HIGH PRESSURE RETURNS FOR THE WEEKEND.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
UPPER SHORTWAVE PASSING THIS MORNING. WESTERLY FETCH PRODUCING  
CLOUDS ACROSS THE LI SOUND SEEN ON VISIBLE AND RADAR, AS  
SHORTWAVE PASSES.  
 
OTHERWISE, SUNSHINE WILL GIVE WAY TO AN INCREASE IN CLOUDS  
LATER TODAY. WINDS DIMINISH AS HIGH PRESSURE BEGINS TO BRIEFLY  
BUILD ACROSS THE AREA. HIGH TEMPERATURES TODAY WILL TOP OUT IN  
THE UPPER 30S TO LOWER 40S PER LATEST HOURLY GUIDANCE.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/
 
 
LOW PRESSURE MOVES ACROSS THE GREAT LAKES TONIGHT INTO TUESDAY  
MORNING. THE ASSOCIATED WARM FRONT APPROACHES THE AREA FROM THE  
SOUTH LATE TONIGHT INTO TUESDAY WITH INCREASING CHANCES OF  
PRECIPITATION, FOLLOWED BY A STRONG TRAILING COLD FRONT TUESDAY  
AFTERNOON.  
 
WARM ADVECTION AHEAD OF THE MAIN PORTION OF THE STORM WILL MAKE  
THIS A MIXED PRECIP EVENT. RAIN IS FORECAST FOR THE CITY,  
ADJACENT SUBURBS AND COASTAL SECTION, ALTHOUGH SOME SNOW CAN MIX  
IN AT FIRST. ACROSS INLAND AREAS, SNOW OR A SNOW/RAIN MIX  
CHANGES OVER TO RAIN AS TEMPERATURES RISE DURING THE MORNING  
HOURS ON TUESDAY. SNOW ACCUMULATIONS EXPECTED TO BE 1 OR 2  
INCHES FOR THE NORTHERN SUBURBS, WITH 2 TO 3 INCHES EXPECTED  
FURTHER NORTH ACROSS ORANGE COUNTY. LESS THAN AN INCH IS  
EXPECTED ANYWHERE ELSE WHERE SNOW MANAGES TO ACCUMULATE.  
 
HIGHS ON TUESDAY WILL BE IN THE UPPER 30S TO LOWER 40S INLAND  
AND MID TO UPPER 40S ALONG THE COAST, WITH EVEN SOME 50 DEGREE  
READINGS FOR LONG ISLAND.  
 

 
   
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/
 
 
A PERIOD OF BRISK WEATHER IS ANTICIPATED TUESDAY NIGHT INTO THURSDAY  
AS AN INTENSIFYING LOW PRESSURE SYSTEM MOVES TOWARDS THE CANADIAN  
MARITIMES. WITH THE TIGHTENING PRESSURE GRADIENT ON THE BACK SIDE OF  
THE LOW, STRONG COLD ADVECTION COMBINED WITH SUSTAINED WINDS AROUND  
20-30 MPH AND GUSTS ABOVE 40 MPH WILL LEAD TO WIND CHILL VALUES IN  
THE SINGLE DIGITS TO TEENS ON WEDNESDAY, AND LARGELY THE SINGLE  
DIGITS TO NEAR ZERO WEDNESDAY NIGHT. ALTHOUGH SOME MODERATION WILL  
OCCUR ON THURSDAY AS FLOW BACKS TO THE WSW AHEAD OF THE NEXT SYSTEM,  
TEMPERATURES WILL REMAIN WELL BELOW CLIMATOLOGICAL NORMALS, WITH  
COLD WIND CHILL VALUES IN LINGERING BREEZY FLOW.  
 
OVERALL, A BLOCKING PATTERN WITH LOW PRESSURE ANCHORED OVER THE EAST  
COAST WILL CONTINUE A PERIOD OF BELOW NORMAL TEMPERATURES AND ABOVE  
NORMAL PRECIPITATION AS A SERIES OF WAVES ROTATE AROUND THE BROADER  
LOW. CHANCES OF PRECIPITATION INCREASE AGAIN INTO FRIDAY AS THE  
SUBTROPICAL JET SHIFTS NORTHWARD, COMBINING WITH POLAR ENERGY AND  
LEADING TO THE DEVELOPMENT OF A COASTAL LOW. THE GENERAL TRACK AND  
INTENSITY OF THE LOW WILL NEED TO BE MONITORED, BUT EXPECTED AT  
LEAST A SLIGHT CHANCE OF SNOW SHOWERS ACROSS THE INTERIOR AND  
PERHAPS A RAIN/SNOW MIX ALONG THE COAST INTO FRIDAY NIGHT. GUSTY  
FLOW AND BELOW NORMAL TEMPERATURES WILL ONCE AGAIN BE POSSIBLE AS  
THE LOW DEPARTS, WITH A SLOW MODERATION OCCURRING THROUGH THE  
WEEKEND AS HIGH PRESSURE BUILDS ACROSS THE AREA.  
 

 
   
AVIATION /15Z MONDAY THROUGH FRIDAY/
 
 
A COLD FRONT WILL MOVE ACROSS THE AREA TODAY.  
 
VFR TODAY AND EARLY TONIGHT.  
 
CIGS FALL TO MVFR LATE IN THE TAF PERIOD, MAINLY AFTER 09Z TUESDAY  
AS A WARM FRONT PUSHES NORTH OF THE AREA AND ASSOCIATED LOW  
PRESSURE SYSTEM PASSES NORTH OF THE AREA. PRECIPITATION STARTS  
AFTER 06Z, MAINLY IN THE FORM OF A MIX OF RAIN AND SNOW FOR MOST  
TERMINALS, EXCEPT KSWF, WHERE PRECIPITATION SHOULD BE ALL SNOW.  
AS WARMER AIR WORKS INTO THE THE COASTAL LOCATIONS,  
PRECIPITATION SHOULD QUICKLY CHANGE OVER TO ALL RAIN. INTERIOR  
LOCATIONS SHOULD STAY SNOW THROUGH AT LEAST 12Z TUESDAY.  
 
GENERALLY WESTERLY WINDS TODAY. THERE MAY BE A FEW OCCASIONAL GUSTS  
THIS MORNING, THEN GUSTS BECOME MORE FREQUENT DURING THE  
AFTERNOON WITH SPEEDS AROUND 20 KT. GUSTS WILL END AFTER 23Z.  
TONIGHT, WINDS BECOME MORE SOUTHERLY AND REMAIN LESS THAN 10 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: GUSTS THIS AFTERNOON MAY BE OCCASIONAL.  
 
THE AFTERNOON KJFK HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES  
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.  
 
KLGA TAF COMMENTS: GUSTS THIS AFTERNOON MAY BE OCCASIONAL.  
 
THE AFTERNOON KLGA HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES  
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.  
 
KEWR TAF COMMENTS: GUSTS THIS AFTERNOON MAY BE OCCASIONAL.  
 
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES  
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.  
 
KTEB TAF COMMENTS: GUSTS THIS AFTERNOON MAY BE OCCASIONAL.  
 
KHPN TAF COMMENTS: GUSTS THIS AFTERNOON MAY BE OCCASIONAL.  
 
KISP TAF COMMENTS: GUSTS THIS AFTERNOON MAY BE OCCASIONAL.  
   
OUTLOOK FOR 12Z TUESDAY THROUGH FRIDAY
 
   
TUESDAY
 
MVFR OR LOWER POSSIBLE WITH A WINTRY MIX TO RAIN AT  
NORTHERN TERMINALS AND RAIN AT SOUTHERN TERMINALS. CONDITIONS  
IMPROVE TO VFR TUESDAY AFTERNOON. SE-SW WINDS G15-25KT POSSIBLE.   
TUESDAY NIGHT-WEDNESDAY
 
MAINLY VFR, WITH A CHANCE OF MVFR IN SNOW  
SHOWERS. W-NW WINDS G20-35KT PROBABLE.   
WEDNESDAY NIGHT-THURSDAY NIGHT
 
VFR. W-SW WINDS G15-25KT POSSIBLE.   
FRIDAY
 
MVFR POSSIBLE WITH SNOW. W-NW WINDS G15-20KT POSSIBLE.  
 

 
   
MARINE
 
 
AS HIGH PRESSURE BEGINS TO BUILD ACROSS THE AREA, GUSTS WILL  
GRADUALLY BEGIN TO DIMINISH, WITH SEAS SLOWLY SUBSIDING ON THE  
OCEAN WATERS LATER TODAY. WINDS AND SEAS THEN INCREASE AGAIN ON  
TUESDAY, WITH SCA CONDITIONS BECOMING LIKELY ON THE AREA WATERS.  
BY TUESDAY NIGHT, GALE- FORCE WINDS WILL BE POSSIBLE AS AN  
INTENSIFYING LOW PRESSURE SYSTEM EJECTS INTO THE CANADIAN  
MARITIMES. GUSTY FLOW AND AT LEAST SCA-LEVEL CONDITIONS WILL  
CONTINUE INTO THURSDAY BEFORE GRADUALLY SUBSIDING INTO THURSDAY  
NIGHT AS FLOW WEAKENS ACROSS THE AREA. RELATIVELY TRANQUIL  
CONDITIONS PERSIST THROUGH FRIDAY BEFORE WINDS AND SEAS INCREASE  
INTO FRIDAY NIGHT BEHIND A DEPARTING LOW PRESSURE SYSTEM.  
 

 
   
HYDROLOGY
 
 
NO SIGNIFICANT HYDROLOGIC IMPACTS EXPECTED.  
 

 
   
EQUIPMENT
 
 
NYC NOAA WEATHER RADIO STATION KWO-35 (162.55 MHZ) IS OFF THE  
AIR FOR AN EXTENDED PERIOD OF TIME. SEE OUR HEADLINE NEWS ON  
THE WEB AT: HTTP:/WEATHER.GOV/NYC  
 
THE RIVERHEAD NOAA WEATHER RADIO STATION WXM-80 (162.475 MHZ)  
IS CURRENTLY OUT OF SERVICE. NWS TECHNICIANS ARE WORKING WITH  
VERIZON TO RESTORE SERVICE. AN ESTIMATED TIME OF RETURN TO  
SERVICE IS NOT CURRENTLY KNOWN.  
 

 
   
OKX WATCHES/WARNINGS/ADVISORIES
 
 
CT...NONE.  
NY...NONE.  
NJ...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ350-  
353-355.  
 

 
 

 
SYNOPSIS...MD/FIG  
NEAR TERM...MD/FIG/PW  
SHORT TERM...FIG  
LONG TERM...MD  
AVIATION...BC/IRD  
MARINE...MD/FIG/PW  
HYDROLOGY...MD/FIG  
EQUIPMENT...  
 
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