568  
FXUS61 KOKX 221446  
AFDOKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW YORK NY  
1046 AM EDT THU APR 22 2021  
   
SYNOPSIS
 
 
DEEPENING LOW PRESSURE OVER THE CANADIAN MARITIMES WILL SLOWLY  
LIFT NORTH AND EAST TODAY, BECOMING NEARLY STATIONARY TONIGHT,  
THEN SLOWLY WEAKENING AND RESUMING ITS TREK NORTHWARD ON FRIDAY.  
AT THE SAME TIME, HIGH PRESSURE BUILDS TO THE SOUTH AND WEST,  
PASSING OFFSHORE ON SATURDAY. LOW PRESSURE APPROACHES FROM THE  
SOUTHWEST LATE SATURDAY AND PASSES TO THE SOUTH AND EAST ON  
SUNDAY. HIGH PRESSURE THEN BUILDS IN FROM THE WEST SUNDAY NIGHT  
INTO MONDAY BEFORE SETTLING OVER THE AREA ON TUESDAY. THE HIGH  
SHIFTS OFFSHORE ON WEDNESDAY.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
STRONG LOW PRESSURE IN THE CANADIAN MARITIMES AND A SURFACE  
TROUGH WILL KEEP EXTRA CLOUDS AND GUSTY WINDS THROUGH THIS  
AFTERNOON. FORECAST TEMPERATURES ARE ON TRACK AND FORECAST  
DEWPOINTS WERE LOWERED SLIGHTLY. CHANCE OF SNOW FLURRIES ADDED  
FOR PARTS OF LOWER HUDSON VALLEY AND SOUTHERN CONNECTICUT WHICH  
SHOULD BE ENDING BEFORE THE START OF THIS AFTERNOON. DRY LOW  
LEVELS WITH LARGE SPREAD BETWEEN TEMPERATURES AND DEWPOINTS WILL  
MAKE FOR A LOT OF PRECIPITATION NOT TO REACH THE GROUND.  
 
DEEPENING LOW PRESSURE OVER THE CANADIAN MARITIMES AND HIGH  
PRESSURE BUILDING TO THE SOUTH AND WEST WILL MAINTAIN A STRONG  
PRESSURE GRADIENT ACROSS THE REGION. THIS WILL RESULT IN STRONG  
WEST WINDS WITH GUSTS UP TO 35 MPH. A FEW PEAK WIND GUSTS UP TO  
AROUND 40 MPH WILL BE POSSIBLE ESPECIALLY LATE THIS AFTERNOON  
INTO THE START OF THIS EVENING.  
 
DEEP-LAYERED CYCLONE FLOW WILL ALLOW FOR INSTABILITY CLOUDS TO  
FORM ABOVE 5000 FT LATE THIS MORNING INTO THIS AFTERNOON. AT  
THE SAME TIME, AN UNSEASONABLY COLD AIRMASS WILL BE IN PLACE FOR  
LATE APRIL, WITH HIGHS STRUGGLING TO GET MUCH ABOVE 50. THIS  
WILL BE ABOUT 10 DEGREES BELOW NORMAL AND WILL FEEL EVEN COLDER  
WITH THE GUSTY WEST WINDS.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/
 
 
WINDS WILL SLACKEN SOMEWHAT TONIGHT WITH THE LOSS OF THE DEEP  
DAYTIME MIXING. STILL THOUGH, GUSTS UP TO 25 MPH WILL BE  
POSSIBLE AND EVEN WITH MOSTLY CLEAR SKIES, THE RADIATIONAL  
COOLING COMPONENT WILL BE HINDERED. THE AIRMASS WILL MODERATE  
SOMEWHAT AS WELL.  
 
CONFIDENCE FOR FREEZING OR LOWER TEMPERATURES IS HIGH ENOUGH AT  
THIS TIME TO ISSUE A FREEZE WATCH FOR WESTERN PASSAIC NJ, ORANGE  
AND PUTNAM NY AS WELL AS NORTHERN PARTS OF FAIRFIELD AND NEW  
HAVEN CT. THESE LOCATIONS HAVE A PRETTY HIGH LIKELIHOOD OR  
DROPPING TO 30 TO 32 DEGREES FOR LOW TEMPERATURES, CONSIDERING  
MOST OF THE GUIDANCE IS BELOW FREEZING INCLUDING NEW RUNS OF THE  
LAMP GUIDANCE FOR LATE TONIGHT INTO EARLY FRIDAY.  
 
LESS CONFIDENCE FOR FREEZING TEMPERATURES CLOSER TO THE COAST,  
SOUTHEAST CT AND FOR NYC WHERE LOWS ARE GENERALLY MORE IN THE  
MID TO UPPER 30S BUT NEAR 40 FOR NYC. STILL THINK THE GUSTY  
WINDS WILL PREVENT THE FORMATION OF FROST SO NO FROST ADVISORIES  
ARE EXPECTED AT THIS TIME.  
 
FRIDAY WILL CONTINUE TO BE GUSTY, BUT LESS SO THAN PRIOR DAY,  
AND TEMPERATURES WILL TO SEASONABLE LEVELS WITH HIGHS GENERALLY  
IN THE LOWER 60S.  
 
AS LOW PRESSURE WEAKENS FRIDAY INTO SATURDAY, GUSTS WILL BE  
LOST FRIDAY NIGHT AND HIGH PRESSURE WILL BUILD IN FROM THE  
SOUTHWEST. CONDITIONS WILL REMAIN DRY AND MILD ON SATURDAY AS  
THE HIGH BUILDS OFFSHORE AND WINDS TURN AROUND TO THE SOUTH IN  
THE AFTERNOON.  
 
GLOBAL MODELS REMAIN IN GOOD AGREEMENT WITH A PROGRESSIVE  
SOUTHERN BRANCH LOW THAT INTERACTS WITH A NORTHERN BRANCH  
SHORTWAVE TROUGH MOVING ACROSS THE GREAT LAKES. THERE HAS BEEN  
NO INDICATION AT THIS TIME OF PHASING OF THE TWO BRANCHES. RAIN  
FROM THE SYSTEM WILL OVERSPREAD THE AREA FROM SW TO NE DURING  
THE EVENING AND INTO THE OVERNIGHT HOURS.  
 

 
   
LONG TERM /SUNDAY THROUGH WEDNESDAY/
 
 
THE UPPER TROUGH CROSSES THE AREA ON SUNDAY, WITH ITS ASSOCIATED  
SURFACE LOW PASSING SOUTH OF LONG ISLAND DURING THE DAY. AFTER A WET  
START TO THE DAY, RAIN WILL TAPER OFF FROM WEST TO EAST DURING THE  
AFTERNOON AS THE LOW MOVES EAST OF THE AREA. GUSTY NORTHWEST FLOW  
THEN DEVELOPS SUNDAY NIGHT INTO MONDAY AS THE PRESSURE GRADIENT  
TIGHTENS BETWEEN THE DEPARTING LOW AND HIGH PRESSURE BUILDING TO THE  
WEST.  
 
THE HIGH BUILDS OVER THE AREA ON TUESDAY BEFORE SHIFTING OFFSHORE ON  
WEDNESDAY. WITH RISING HEIGHTS ALOFT, THIS SHOULD LEAD TO A GRADUAL  
WARMING TREND. AFTER NEAR NORMAL TEMPERATURES ON SUNDAY AND MONDAY,  
TEMPERATURES RETURN TO ABOVE NORMAL TUESDAY, AND BY WEDNESDAY  
TEMPERATURES MAY BE AS MUCH AS 10 DEGREES ABOVE SEASONAL  
NORMALS.  
 

 
   
AVIATION /15Z THURSDAY THROUGH MONDAY/
 
 
LOW PRESSURE CONTINUES TO EXIT TO THE NORTHEAST. HIGH PRESSURE  
BUILDS TOWARDS THE AREA TODAY.  
 
VFR CONDITIONS THROUGH THE TAF PERIOD.  
 
WNW WINDS WILL INCREASE THIS MORNING WITH GUSTS TO 30-35 KT FROM  
LATE THIS MORNING THROUGH THE AFTERNOON. WINDS THEN DECREASE  
THIS EVENING, WITH GUSTS FALLING TO 25 KT OR LESS AT COASTAL  
TERMINALS. GUSTS MAY COME TO AN END ENTIRELY FOR A FEW HOURS  
VERY LATE TONIGHT INTO EARLY FRIDAY MORNING AT OUTLYING  
TERMINALS.  
 
...NY METRO (KEWR/KLGA/KJFK/KTEB) TAF UNCERTAINTY...  
 
NO UNSCHEDULED AMENDMENTS EXPECTED.  
   
OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY.
 
   
FRIDAY
 
VFR. WNW WINDS G20-25KT.   
SATURDAY
 
VFR.   
SATURDAY NIGHT-SUNDAY
 
MVFR/IFR IN RAIN.   
MONDAY
 
VFR.  
 
DETAILED INFORMATION, INCLUDING HOURLY TAF WIND COMPONENT FORECASTS,  
CAN BE FOUND AT: HTTP:/WWW.WEATHER.GOV/ZNY/N90  
 

 
   
MARINE
 
 
MARGINAL GALES WILL CONTINUE ACROSS ALL WATERS TODAY AND INTO  
THIS EVENING, ENDING ON THE NON-OCEAN WATERS FIRST. THERE IS  
THE POSSIBILITY THAT THE GALES WILL NEED TO BE LOWERED EARLIER  
AS THE GUSTS MAY BECOME MORE OCCASIONAL AT 35 KT LATE IN THE  
DAY. SCA CONDITIONS WILL REMAIN ACROSS THE WATERS ON FRIDAY  
WITH ONLY LINGERING 5 FT SEAS ON THE OCEAN FRIDAY NIGHT AS HIGH  
PRESSURE BUILDS IN FROM THE SOUTHWEST. SUB-SCA CONDITIONS ARE  
FORECAST ACROSS ALL WATERS SATURDAY AND SATURDAY NIGHT.  
 
SCA CONDITIONS WILL DEVELOP ON SUNDAY AS BOTH WINDS AND SEAS  
INCREASE IN RESPONSE TO DEEPENING LOW PRESSURE PASSING SOUTH OF LONG  
ISLAND. AS THE LOW MOVES OFF TO THE NORTHEAST, WINDS WILL SHIFT TO  
THE NW WITH SCA GUSTS CONTINUING SUNDAY NIGHT BEFORE GRADUALLY  
DIMINISHING DURING THE DAY ON MONDAY. BY MONDAY NIGHT, BOTH WINDS  
AND SEAS WILL LIKELY FALL BELOW SCA LEVELS ON ALL WATERS AS HIGH  
PRESSURE BEGINS TO BUILD ACROSS THE WATERS.  
 

 
   
FIRE WEATHER
 
 
AN SPS HAS BEEN COORDINATED WITH THE STATE OF CT AND NJ FOR THE  
MENTION OF ELEVATED RISK OF WILDFIRE SPREAD SHOULD IGNITION  
OCCUR.  
 
BOTH TODAY AND FRIDAY WILL POSE AN ELEVATED RISK OF WILDFIRE  
SPREAD DUE TO LOW RH AND GUSTY WEST WINDS. MIN RH VALUES BOTH  
DAYS WILL GENERALLY BE LESS THAN 30 PERCENT.  
 
RAINFALL AMOUNTS ON THE ORDER OF 0.25 TO 0.50 INCHES FROM  
WEDNESDAY WILL LIKELY FACTOR INTO HOW QUICKLY FINE FUELS CAN  
DRY OUT. THIS SHOULD OCCUR QUICKLY THOUGH DUE TO GUSTY WEST  
WINDS AND LOW RH VALUES. THE GREATER RISK FOR POTENTIAL FIRE  
SPREAD APPEARS TO BE ON FRIDAY WHEN CONDITIONS ARE EXPECTED TO  
BE DRIER.  
 

 
   
HYDROLOGY
 
 
NO HYDROLOGIC IMPACTS ARE EXPECTED THROUGH THE PERIOD.  
 

 
   
OKX WATCHES/WARNINGS/ADVISORIES
 
 
CT...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR  
CTZ005-006.  
NY...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR  
NYZ067-068.  
NJ...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR  
NJZ002.  
MARINE...GALE WARNING UNTIL 8 PM EDT THIS EVENING FOR ANZ331-332-335-  
338-340-345.  
GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR ANZ350-353-355.  
 

 
 

 
SYNOPSIS...FEB/DW  
NEAR TERM...JM/DW  
SHORT TERM...JM/DW  
LONG TERM...FEB  
AVIATION...FEB/JP  
MARINE...FEB/DW  
FIRE WEATHER...  
HYDROLOGY...FEB/DW  
 
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