989  
FXUS61 KOKX 201740  
AFDOKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW YORK NY  
1240 PM EST WED FEB 20 2019  
   
SYNOPSIS
 
 
A LOW PRESSURE SYSTEM WILL IMPACT THE REGION THROUGH TONIGHT. A  
COLD FRONT FOLLOWS ON THURSDAY WITH HIGH PRESSURE RETURNING  
THURSDAY NIGHT THROUGH SATURDAY. ANOTHER LOW PRESSURE SYSTEM  
THEN IMPACTS THE REGION SATURDAY NIGHT INTO SUNDAY. HIGH  
PRESSURE BUILDS BACK EARLY NEXT WEEK.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
WITH THE PRECIPITATION, LIGHT SNOW, JUST MOVING INTO  
SOUTHEASTERN PENNSYLVANIA AT 14Z HAVE LOWERED THE PROBABILITIES  
OF PRECIPITATION ACROSS THE WESTERN ZONES, WITH LOW END CHANCE  
POPS BY 16Z. ALSO, SKY COVER WAS INCREASED TO 100% INTO TONIGHT.  
FINALLY WITH THE PROLONGED PERIOD OF FREEZING RAIN ACROSS THE  
HAVE INCREASED THE ICE AMOUNTS ACROSS THE WESTERN HALF OF ORANGE  
COUNTY NY AND INTO THE EXTREME PORTION OF WESTERN PASSAIC COUNTY  
NJ. THIS BETTER REFLECTS THE AMOUNTS THAT WPC IS FORECASTING  
FOR THESE AREAS.  
 
STRONG HIGH PRESSURE CENTERED OVER NEW ENGLAND AND INTO SUFFOLK  
COUNTY NY WILL SLOWLY MOVE EAST AND OFFSHORE INTO THE ATLANTIC  
THROUGH THE DAY.  
 
CLOUDS CONTINUE TO LOWER IN ADVANCE OF A WARM FRONT APPROACHING  
FROM THE SW. INITIALLY, THE FORECAST SOUNDINGS SHOW DRIER AIR  
FROM THE SURFACE THROUGH ABOUT 15KFT. BY AROUND NOON TIME  
THOUGH, MOST OF THE ATMOSPHERIC COLUMN BECOMES SATURATED WITH  
SOME REMAINING DRY AIR BELOW 5KFT.  
 
THE VERTICAL FORCING BECOMES MORE NOTICEABLE AS 850-700 MB  
FRONTOGENESIS INCREASES AND MOVES SW TO NE ACROSS THE REGION AND  
THE ATMOSPHERIC COLUMN WILL SOON BECOME FULLY SATURATED. THIS  
WILL BE IN ADVANCE OF A DEVELOPING WARM FRONT THAT WILL HAVE LOW  
PRESSURE STARTING TO DEVELOP ALONG IT. THE MAIN PARENT LOW WILL  
BE MOVING INTO THE GREAT LAKES AND WILL BE THE MORE DOMINANT  
LOW. MODELS INDICATE CONSISTENT WARMING ALOFT AT 700MB THAT WILL  
COINCIDE WITH THE INCREASING PRECIPITATION DEVELOPING AND  
MOVING ACROSS THE REGION.  
 
THE SNOW WILL BECOME MORE WIDESPREAD THIS AFTERNOON FROM SW TO  
NE AND IS EXPECTED TO BECOME A MODERATE STEADY SNOW. WITH THE  
ANTECEDENT ENVIRONMENT, WET BULB COOLING KEEPS THE TEMPERATURES  
BELOW FREEZING AND WILL ALLOW FOR 1-4 INCHES OF SNOW TO  
ACCUMULATE WITH POTENTIAL FOR SNOW TO BE 1-2 INCHES HIGHER THAN  
FORECAST IF SNOW BECOMES HEAVY FOR PROLONGED PERIODS OF TIME.  
 

 
   
SHORT TERM /THURSDAY/
 
 
FOR TONIGHT, THE SURFACE WINDS INCREASE OUT OF THE SSE TO SE,  
ALLOWING FOR COASTAL LOCATIONS TO WARM UP ABOVE FREEZING. FIRST  
LOCATIONS TO SEE THIS WILL BE LONG ISLAND AND THEN NYC, FOLLOWED  
BY OTHER COASTAL AREAS. THE WINDS REMAIN LIGHTER FOR A LONGER  
PERIOD OF TIME FARTHER INLAND. WINTER WEATHER ADVISORY SEGMENTED  
TO MARK THE TIME DIFFERENCE WITH ESSEX NJ, UNION NJ, HUDSON NJ,  
NYC, LONG ISLAND ENDING AT 1AM THURSDAY AND THE REST OF THE  
REGION TO THE NORTH ENDING AT 6AM THURSDAY.  
 
BEFORE TEMPERATURES RISE ABOVE FREEZING EVEN ALONG THE COAST,  
THERE IS EXPECTED TO BE A TIME WINDOW FOR A WINTRY MIX OF  
PRECIPITATION INCLUDING SLEET AND FREEZING RAIN WITH  
TEMPERATURES RISING A FEW DEGREES C ABOVE FREEZING IN THE  
850-700MB LAYER. LONG ISLAND ONLY EXPECTED TO SEE A BRIEF  
PERIOD OF THIS WINTRY MIX WITH TRACE AMOUNTS OF ICE EXPECTED.  
HENCE, EVEN EASTERN LONG ISLAND REMAINS IN THE WINTER WEATHER  
ADVISORY DUE TO THE ICE FORECAST. MOST COASTAL AREAS EXPECTED TO  
HAVE A GLAZE WITH ICE AMOUNTS UNDER A TENTH OF AN INCH FARTHER  
INLAND WITH A LONGER PERIOD OF FREEZING RAIN EXPECTED WITH  
INLAND LOCATIONS HAVING LIGHTER WINDS AND HAVING TERRAIN BLOCK  
THE SOUTHERLY FLOW.  
 
ATMOSPHERE STARTS TO DRY OUT ABOVE 700MB ESPECIALLY LATE TONIGHT  
INTO EARLY THURSDAY SO LESS ICE NUCLEI WOULD LEAD TO THOSE AREAS  
WITH ENOUGH MOISTURE TO EITHER HAVE DRIZZLE IF TEMPERATURES ARE  
ABOVE FREEZING OR FREEZING DRIZZLE IF TEMPERATURES ARE AT  
FREEZING OR BELOW.  
 
FOR TEMPERATURES, THE HIGHEST TEMPERATURES WILL ACTUALLY BE  
TONIGHT WITH A NON-DIURNAL TREND. TEMPERATURES SLOWLY RISE  
TONIGHT FROM MID 20S TO LOWER 30S TO LOWER 30S TO LOWER 40S.  
 
FOR THURSDAY, DRIER CONDITIONS ARE EXPECTED. LOW PRESSURE WILL  
BE MOVING EAST OF THE REGION INTO THE VICINITY OF NOVA SCOTIA  
WHILE STRENGTHENING A LITTLE. A COLD FRONT MOVES ACROSS DURING  
THE AFTERNOON WITH HIGH PRESSURE THEN STARTING TO BUILD INTO  
THE LOCAL REGION FROM THE WEST THEREAFTER. A MORE WESTERLY FLOW  
DEVELOPS WITH SOME GUSTS DEVELOPING AS WELL. A MID LEVEL  
SHORTWAVE PASSES WELL NORTH OF THE REGION WITH MID LEVEL FLOW  
REMAINING NEARLY ZONAL. EXPECTING HIGHS TO BE IN THE UPPER 40S  
TO LOWER 50S WITH JUST SOME WEAK COLD AIR ADVECTION BEHIND THE  
FRONT.  
 

 
   
LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/
 
 
THE COLD FRONT MOVES WELL OFFSHORE THURSDAY NIGHT WITH A MORE  
SEASONABLE AIRMASS RETURNING ITS WAKE. TEMPERATURES WILL FALL BACK  
INTO THE UPPER 20S INLAND AND THE LOWER 30S CLOSER TO THE COAST.  
DEEP LAYERED RIDGING BUILDS OVER THE EASTERN STATES ON FRIDAY WITH A  
SURFACE HIGH SETTLING ACROSS THE TRI-STATE. HIGHS WILL BE IN THE LOW  
TO MIDDLE 40S.  
 
UPPER HEIGHTS CONTINUE TO RISE FRIDAY NIGHT INTO SATURDAY AHEAD OF  
THE NEXT STORM SYSTEM. AN UPPER SHORTWAVE TROUGH DIGS INTO THE  
PLAINS ON SATURDAY SPAWNING AN INTENSIFYING LOW PRESSURE THAT TRACKS  
UP INTO THE GREAT LAKES SATURDAY NIGHT. THE SURFACE HIGH OVER THE  
AREA WILL SHIFT OFFSHORE WITH A RETURN SOUTHERLY DEVELOPING. THE  
ANTECEDENT AIR MASS MAY HAVE MARGINAL TEMPERATURES THAT ANY PRECIP  
INITIALLY ACROSS THE INTERIOR COULD BE A WINTRY MIX. HOWEVER, THERMAL  
PROFILES ARE SUPPORTIVE OF A MOSTLY RAIN EVENT SATURDAY NIGHT. THERE  
IS NO HIGH TO THE NORTH AND THE MODEL GUIDANCE CONTINUES TO PROG A  
STRONG LOW (AROUND 980 MB) TRACKING ACROSS THE LAKES INTO SE CANADA  
SATURDAY NIGHT INTO SUNDAY.  
 
A WARM FRONT LIKELY APPROACHES FROM THE SOUTH SATURDAY NIGHT AND  
THEN LIFTS NORTH SUNDAY MORNING INTO SUNDAY AFTERNOON. WARM  
ADVECTION PRECIP BREAKS OUT SATURDAY NIGHT AND CONTINUES INTO SUNDAY  
MORNING. THE TRAILING COLD FRONT SHOULD CROSS THE REGION LATE SUNDAY  
AS THE LOW LIFTS NORTH OF THE REGION. DEEPENING ON HOW FAR NORTH OF  
THE REGION THE WARM FRONT GETS, TEMPERATURES COULD RISE INTO THE  
50S, ESPECIALLY FOR NYC AND LONG ISLAND.  
 
HIGH PRESSURE RETURNS EARLY NEXT WEEK WITH DRY CONDITIONS AND A  
GRADUAL RETURN TO NEAR SEASONABLE TEMPERATURES.  
 

 
   
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
 
 
LOW PRESSURE APPROACHES FROM THE SOUTHWEST AND MOVES THROUGH THE  
AREA TONIGHT INTO THURSDAY MORNING.  
 
GENERALLY IFR OR LOWER EXPECTED AS SNOW HAS DEVELOPED ACROSS  
NEARLY ALL OF THE AIRSPACE THIS AFTERNOON. PRECIPITATION WILL  
CHANGE TO A WINTRY MIX, THEN TO PLAIN RAIN, FROM SOUTH TO NORTH  
TONIGHT. THE ONE EXCEPTION TO THIS IS KSWF, WHERE PRECIPITATION  
MAY REMAIN A WINTRY MIX THROUGH THE NIGHT, WITH A PROLONGED  
PERIOD OF FREEZING RAIN POSSIBLE. WHILE VISIBILITIES WILL BEGIN  
TO IMPROVE ONCE PRECIPITATION CHANGES TO ALL RAIN, CEILINGS WILL  
REMAIN IFR OR LIFR INTO THURSDAY MORNING BEFORE STEADILY IMPROVING  
AFTER DAYBREAK.  
 
SNOWFALL ACCUMULATIONS WILL RANGE FROM 2-4 INCHES AT  
KEWR/KTEB/KJFK/KLGA/KHPN/KSWF, 2-3 INCHES AT KISP/KBDR, AND AROUND  
AN INCH AT KGON.  
 
GENERALLY LIGHT WINDS WILL RETURN OUT OF THE SOUTHEAST THIS  
AFTERNOON. WINDS THEN BACK TO THE EAST- SOUTHEAST BY LATE  
AFTERNOON/EARLY EVENING AT AROUND 10 KT BEFORE BECOMING LIGHT  
AND VARIABLE AGAIN OVERNIGHT. WINDS AT INLAND TERMINALS COULD  
REMAIN LIGHT AND VARIABLE THROUGH THE DAY TODAY.  
 
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: CEILINGS MAY FLUCTUATE BETWEEN IFR AND LIFR  
IN SNOW. CHANGE OVER TIMES TO MIXED PRECIPITATION AND RAIN MAY  
BE +/- 1 HR OF FORECAST.  
 
KLGA TAF COMMENTS: CEILINGS MAY FLUCTUATE BETWEEN IFR AND LIFR  
IN SNOW. CHANGE OVER TIMES TO MIXED PRECIPITATION AND RAIN MAY  
BE +/- 1 HR OF FORECAST.  
 
KEWR TAF COMMENTS: CEILINGS MAY FLUCTUATE BETWEEN IFR AND LIFR  
IN SNOW. CHANGE OVER TIMES TO MIXED PRECIPITATION AND RAIN MAY  
BE +/- 1 HR OF FORECAST.  
 
KTEB TAF COMMENTS: CEILINGS MAY FLUCTUATE BETWEEN IFR AND LIFR  
IN SNOW. CHANGE OVER TIMES TO MIXED PRECIPITATION AND RAIN MAY  
BE +/- 1 HR OF FORECAST.  
 
KHPN TAF COMMENTS: CEILINGS MAY FLUCTUATE BETWEEN IFR AND LIFR  
IN SNOW. CHANGE OVER TIMES TO MIXED PRECIPITATION AND RAIN MAY  
BE +/- 1 HR OF FORECAST.  
 
KISP TAF COMMENTS: CEILINGS MAY FLUCTUATE BETWEEN IFR AND LIFR  
IN SNOW. CHANGE OVER TIMES TO MIXED PRECIPITATION AND RAIN MAY  
BE +/- 1 HR OF FORECAST.  
   
OUTLOOK FOR 18Z THURSDAY THROUGH SUNDAY
 
   
THURSDAY MORNING
 
RAPID IMPROVEMENT TO VFR AFTER DAYBREAK.   
THURSDAY AFTERNOON-SATURDAY MORNING
 
VFR. W-NW WINDS G15-25KT  
POSSIBLE FROM LATE THURSDAY MORNING INTO FRIDAY MORNING.   
SATURDAY AFTERNOON-SUNDAY
 
MVFR OR LOWER IN RAIN, WITH A WINTRY  
MIX POSSIBLE ACROSS NORTHERN TERMINALS SATURDAY NIGHT.   
MONDAY
 
VFR. WNW 15-25KT G25-30KT.  
 

 
   
MARINE
 
 
CONDITIONS WILL REMAIN TRANQUIL ON THE WATERS THROUGH THIS  
AFTERNOON AS HIGH PRESSURE REMAINS IN CONTROL. AN AREA OF LOW  
PRESSURE THEN CROSSES THE WATERS TONIGHT INTO THURSDAY,  
RESULTING IN AN INCREASE IN BOTH WINDS AND SEAS, ESPECIALLY ON  
THE OCEAN WATERS. A SMALL CRAFT ADVISORY REMAINS IN EFFECT ON  
THE OCEAN TONIGHT. WHILE WINDS BRIEFLY DIMINISH THURSDAY  
MORNING, SCA CONDITIONS WILL LIKELY CONTINUE INTO THE DAY ON  
THURSDAY AS SEAS ON THE OCEAN WILL REMAIN AROUND 5 FEET AND  
WINDS INCREASE AGAIN DURING THE AFTERNOON.  
 
MARGINAL SCA GUSTS MAY CONTINUE THURSDAY NIGHT ON THE OCEAN. OCEAN  
SEAS WILL ALSO GRADUALLY SUBSIDE BELOW 5 FT THURSDAY NIGHT INTO  
FRIDAY. HIGH PRESSURE OVER THE WATERS FRIDAY INTO SATURDAY WILL LEAD  
TO SUB-SCA CONDITIONS. SCA CONDITIONS RETURN ON SUNDAY INTO SUNDAY  
NIGHT AS THE NEXT FRONTAL SYSTEM LIKELY IMPACTS THE WATERS.  
 

 
   
HYDROLOGY
 
 
LIQUID EQUIVALENT PRECIPITATION AMOUNTS TODAY INTO EARLY  
THURSDAY MORNING WILL GENERALLY BE AROUND ONE HALF TO EIGHT  
TENTHS OF AN INCH.  
 
A STORM SYSTEM FOR SATURDAY NIGHT INTO SUNDAY COULD BRING 0.5 TO 1  
INCH OF RAIN. IT IS TO EARLY TO TELL IF ANY HYDROLOGIC IMPACTS WILL  
OCCUR WITH THIS RAINFALL.  
 

 
   
TIDES/COASTAL FLOODING
 
 
THERE IS A CHANCE FOR SOME MINOR COASTAL FLOODING FOR HIGH TIDE  
CYCLES EARLY THURSDAY, PARTICULARLY ACROSS THE SOUTH SHORE BACK  
BAYS OF LONG ISLAND AND WESTERN LONG ISLAND SOUND ALONG THE  
SHORELINES OF SOUTHWEST CONNECTICUT.  
 

 
   
EQUIPMENT
 
 
NYC CENTRAL PARK WINDS ARE OUT OF SERVICE UNTIL FURTHER NOTICE.  
LOSS OF DATA IS DUE TO A SEVERED CABLE. PARTS ARE ON ORDER.  
 
NYC NOAA WEATHER RADIO STATION KWO35 (162.55 MHZ) WILL REMAIN OFF  
THE AIR FOR AN EXTENDED PERIOD OF TIME.  
 

 
   
OKX WATCHES/WARNINGS/ADVISORIES
 
 
CT...WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR CTZ005>012.  
NY...WINTER WEATHER ADVISORY UNTIL 1 AM EST THURSDAY FOR NYZ078>081.  
WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR NYZ067>071.  
WINTER WEATHER ADVISORY UNTIL 1 AM EST THURSDAY FOR NYZ072>075-  
176>179.  
NJ...WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR NJZ002-004-  
103-104.  
WINTER WEATHER ADVISORY UNTIL 1 AM EST THURSDAY FOR NJZ006-  
105>108.  
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST  
THURSDAY FOR ANZ350-353-355.  
 

 
 

 
SYNOPSIS...JM/DS  
NEAR TERM...FEB/JM/19  
SHORT TERM...JM  
LONG TERM...DS  
AVIATION...FEB/MD  
MARINE...FEB/DS/19  
HYDROLOGY...JM/DS  
TIDES/COASTAL FLOODING...  
EQUIPMENT...  
 
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