245  
FXUS61 KOKX 292011  
AFDOKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW YORK NY  
411 PM EDT WED MAR 29 2023  
   
SYNOPSIS  
 
AN ARCTIC COLD FRONT MOVES THROUGH THE AREA LATE THIS EVENING AND  
OVERNIGHT. HIGH PRESSURE THEN BUILDS IN THURSDAY, REMAINING IN  
CONTROL THROUGH THURSDAY NIGHT. DEEPENING LOW PRESSURE OVER THE  
CENTRAL PLAINS ON FRIDAY WILL THEN TRACK ACROSS THE GREAT LAKES  
AND INTO EASTERN CANADA ON SATURDAY, SENDING A STRONG FRONTAL  
SYSTEM ACROSS THE AREA. HIGH PRESSURE WILL BUILD IN ON SUNDAY  
AND THEN OFFSHORE TO START THE WEEK. ANOTHER FRONTAL SYSTEM MAY  
IMPACT AREA LATE MONDAY INTO WEDNESDAY.  
 
 
   
NEAR TERM /UNTIL 6 AM THURSDAY MORNING/  
 
AN UPPER LEVEL TROUGH IS CURRENTLY APPROACHING THE AREA AND WILL  
BECOME NEGATIVELY TILTED AS IT PASSES THROUGH TONIGHT. AT THE  
SURFACE, ASSOCIATED LOW PRESSURE PASSES WELL TO OUR NORTH AND DRAGS  
AN ARCTIC COLD FRONT THROUGH THE AREA. AHEAD OF THE FRONT, A BRISK  
SOUTHERLY FLOW DEVELOPS AND STRONG FORCING WILL PRODUCE A LINE OF  
CONVECTIVE SHOWERS JUST AHEAD OF IT. THIS CONVECTIVE LINE/SNOW  
SQUALL WILL LIKELY BE STRONGEST IN WESTERN AND CENTRAL NY. THE  
COLD FRONT IS CURRENTLY OVER THE EASTERN GREAT LAKES. ONCE IT  
GETS A BIT FARTHER EAST, A MORE ORGANIZED LINE SHOULD START TO  
DEVELOP. CAMS CONTINUE TO BE IN AGREEMENT THAT THIS ACTIVITY IS  
EXPECTED TO REACH OUR AREA AROUND 03Z TONIGHT AND EXIT BY 08Z.  
 
GIVEN THE LACK OF INSTABILITY BY THE TIME THE FRONT GETS HERE,  
MOST OF THE SHOWERS ARE EXPECTED TO BE MAINLY LIGHT. HOWEVER,  
THERE IS A CHANCE THAT FAR NORTHERN AND WESTERN AREAS SEE BRIEF  
MODERATE TO HEAVY SHOWERS. AS FOR PRECIP TYPE, SURFACE  
TEMPERATURES WILL BE ABOVE FREEZING EVERYWHERE INITIALLY, BUT  
DRIER AIR AT THE SURFACE IS EXPECTED TO QUICKLY COOL AS IT  
SATURATES WITH THE ONSET OF ANY PRECIPITATION AND IT MAY ALLOW A  
MIX WITH OR CHANGE OVER TO WET SNOW ACROSS THE LOWER HUDSON  
VALLEY AND INTERIOR CT AS TEMPERATURES QUICKLY TUMBLE INTO THE  
LOW AND MIDDLE 30S. ELSEWHERE, ONLY PLAIN RAIN IS EXPECTED.  
ACCUMULATIONS OF ONLY UP TO A TENTH OF AN INCH ARE POSSIBLE  
WHERE THE HEAVIEST SNOW, IF ANY, OCCURS. THIS WILL LIKELY BE  
CONFINED TO GRASSY AND UNTREATED SURFACES.  
 
GUSTY WINDS ARE ALSO POSSIBLE WITH THE FRONTAL PASSAGE, UP TO 35  
MPH. BEHIND THE FRONT A GUSTY NW FLOW SETS UP, ADVECTING IN  
COLDER AND DRIER AIR. THIS SHOULD HELP DRY OUT ANY WET SURFACES  
FROM THE SNOW AND RAIN. LOWS REACH THE MID 20S TO UPPER 30S.  
 
 
   
SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/  
 
BY THURSDAY MORNING THE COLD FRONT WILL BE WELL OFFSHORE AND HIGH  
PRESSURE WILL BE BUILDING IN FROM THE WEST. THE CENTER OF THE HIGH  
WILL MOVE OFFSHORE TO OUR SOUTH THURSDAY EVENING, BUT REMAIN IN  
CONTROL THROUGH THURSDAY NIGHT.  
 
A GUSTY NORTHWEST FLOW CONTINUES THROUGH THURSDAY, SLOWLY DECREASING  
THROUGHOUT THE DAY AS THE PRESSURE GRADIENT RELAXES. WITH THE COLD,  
DRY AIRMASS IN PLACE, TEMPERATURES WILL BE ABOUT 5-10 DEGREES BELOW  
NORMAL FOR LATE MARCH. HIGHS ARE EXPECTED TO BE IN THE LOW TO MID  
40S. THE GUSTY NORTHWEST FLOW WILL MAKE IT FEEL A FEW DEGREES COOLER.  
 
SKIES WILL BE CLEAR DURING THE DAY AND OVERNIGHT. THIS COMBINED WITH  
LIGHT WINDS AND THE DRY AIRMASS OVERNIGHT WILL ALLOW FOR EFFICIENT  
RADIATIONAL COOLING. THE INTERIOR AND LI PINE BARRENS LIKELY FALL TO  
THE LOWER 20S. HOWEVER, WITH OFFSHORE LOW PRESSURE SHIFTING EAST,  
WINDS MAY BECOME SOUTHERLY JUST BEFORE DAYBREAK. HIGH CLOUDS ALSO  
APPROACH IN THE EARLY MORNING HOURS. THE TIMING OF THE WIND SHIFT  
AND CLOUDS WILL IMPACT HOW LOW TEMPERATURES CAN GET.  
 
 
   
LONG TERM /FRIDAY THROUGH WEDNESDAY/  
 
OPERATIONAL GLOBAL MODELS REMAIN IN GOOD OVERALL AGREEMENT WITH THE  
UPPER AIR PATTERN AND SURFACE FEATURES THROUGH MUCH OF THE PERIOD.  
THE TARGET OF OPPORTUNITY REMAINS THE WIND FORECAST LATE FRIDAY  
NIGHT INTO SATURDAY IN ASSOCIATION WITH A STRONG FRONTAL SYSTEM.  
 
A CLOSED UPPER LOW OVER THE CENTRAL PLAINS ON FRIDAY WILL SEND A  
DEEPENING SURFACE LOW ACROSS THE GREAT LAKES FRIDAY NIGHT, AND THEN  
ACROSS EASTERN CANADA SATURDAY INTO SATURDAY NIGHT. A STRONG FRONTAL  
SYSTEM WILL IMPACT THE AREA DURING THIS TIME, WITH OVERRUNNING RAIN  
LATE FRIDAY THROUGH FRIDAY NIGHT AHEAD OF THE WARM FRONT AND THEN  
SHOWERS WITH A CHANCE OF THUNDERSTORMS IN THE WARM SECTOR SATURDAY.  
THE BEST CHANCE FOR THUNDERSTORMS WILL BE NORTH AND WEST OF THE  
NYC/NJ METRO IN THE AFTERNOON/EARLY EVENING HOURS ALONG AND AHEAD OF  
THE COLD FRONT WHERE THERE WILL BE MARGINAL INSTABILITY AND STRONG  
DEEP-LAYER SHEAR. THE QUESTION IS WHETHER THE INSTABILITY WILL BE  
SUFFICIENT TO OVERCOME THE SHEAR AND WORK IN TANDEM. CLOSER TO THE  
COAST AND AWAY FROM ANY MARINE INFLUENCE, THERE ARE STILL SIGNALS  
FOR SOME ELEVATED INSTABILITY WITH ISOLATED THUNDER POSSIBLE.  
 
THE WARM SECTOR SATURDAY WILL ALSO FEATURE GUSTY SW WINDS WITH THE  
POTENTIAL FOR GUSTS IN EXCESS OF 30 MPH. IT'S ALWAYS TRICKY AT THIS  
TIME OF YEAR AS TO HOW MUCH OF THE LLJ MIXES DOWN AT THE COAST WITH  
A STRONG ONSHORE FLOW AND MARINE LAYER IN PLACE. 925 MB WINDS  
CURRENTLY PROGGED AT 55-70 KT OVER EASTERN LI AND SE CT AT TIMES  
LATE FRIDAY NIGHT AND SATURDAY. RAINFALL AMOUNTS LOOK TO BE UNDER AN  
INCH AT THIS TIME.  
 
COLD FRONT PASSES THROUGH EARLY SATURDAY EVENING WITH STRONG COLD  
ADVECTION AND GUSTY W-NW WINDS. ANY SHOWER ACTIVITY COMES TO AN END  
EARLY. HIGH PRESSURE WILL THEN BUILD IN FROM THE WEST SUNDAY INTO  
SUNDAY NIGHT AND OFFSHORE ON MONDAY. A COLD FRONT DROPS DOWN FROM  
THE NORTH MONDAY NIGHT AND REMAINS IN CLOSE PROXIMITY THROUGH  
MIDWEEK WITH A CHANCE OF SHOWERS.  
 
 
   
AVIATION /20Z WEDNESDAY THROUGH MONDAY/  
 
HIGH PRESSURE WILL PASS OFFSHORE THIS AFTERNOON. AN ARCTIC COLD  
FRONT WILL THEN APPROACH FROM THE GREAT LAKES AND MOVES THROUGH  
OVERNIGHT.  
 
VFR THROUGH THE EVENING PUSH. COLD FROPA WILL BE ACCOMPANIED BY  
AN ABRUPT WIND SHIFT TO THE NW WITH G30KT THROUGHOUT, ALSO  
SHOWERS WITH MVFR OR LOWER COND. KSWF/KGON MOST LIKELY TO GO  
COULD GO BRIEFLY IFR.  
 
WINDS AFTER FROPA NW 15-20G25KT AT THE METROS AND 10-15G20KT  
INLAND.  
 
...NY METRO (KEWR/KLGA/KJFK/KTEB) TAF UNCERTAINTY...  
 
KEWR/KTEB HAS MORE OF A SW FLOW AS OF 20Z, BUT SHOULD TAKE MORE  
OF A SE-S DIRECTION THIS EVENING, AFTER 22Z.  
 
KLGA LIGHT S FLOW SHOULD PICK UP NY 21Z.  
 
...OUTLOOK FOR 18Z THURSDAY THROUGH SUNDAY...  
 
LATE THURSDAY AFTERNOON: VFR. NW WINDS G20KT.  
 
THURSDAY NIGHT: VFR.  
 
FRIDAY: MVFR POSSIBLE WITH CHANCE OF SHOWERS, ESPECIALLY AFTERNOON.  
RAIN AT NIGHT WITH MVFR OR LOWER COND. S WINDS G15-20 KT,  
BECOMING MORE SW AT NIGHT AND INCREASING TO AROUND 25 KT. LLWS  
POSSIBLE LATE FROM KJFK/KLGA TO POINTS EAST.  
 
SATURDAY: MVFR OR LOWER IN RAIN IN THE MORNING. CHANCES FOR  
MVFR AND RAINFALL LOWER AFTERNOON INTO EARLY EVENING. VFR  
FORECAST THEREAFTER. SW WINDS G25-30KT AM, INCREASING TO 30-35KT  
PM WITH LLWS FROM KJFK/KLGA TO POINTS EAST. W-NW WINDS G30KT AT  
NIGHT.  
 
SUNDAY: VFR. NW WINDS G25-30 KT IN THE MORNING, DIMINISHING  
CLOSER TO 20 KT FOR THE AFTERNOON.  
 
MONDAY: VFR. S WINDS 15G20-25KT.  
 
DETAILED INFORMATION, INCLUDING HOURLY TAF WIND COMPONENT FORECASTS,  
CAN BE FOUND AT: HTTPS:/WWW.WEATHER.GOV/ZNY/N90.  
 
 
   
MARINE  
 
A COLD FRONT PASSES THROUGH THE WATERS LATE THIS EVENING AND  
OVERNIGHT. THE SOUTHERLY FLOW WILL SHIFT TO THE NW BEHIND THE FRONT  
AND INCREASE. GUSTS 25 - 30 KT ARE EXPECTED ON ALL WATERS. A SMALL  
CRAFT ADVISORY IS IN EFFECT FROM MIDNIGHT TONIGHT THROUGH 10 AM  
THURSDAY MORNING. WAVES ON THE OCEAN WATERS MAY BRIEFLY REACH 5 FT  
EARLY THURSDAY MORNING. HIGH PRESSURE BUILDS IN THEREAFTER AND WINDS  
AND SEAS DIMINISH. SUB SCA CONDITIONS EXPECTED AFTER 10 AM THURSDAY  
AND THROUGH THURSDAY NIGHT.  
 
A TIGHTENING PRESSURE GRADIENT FROM AN APPROACHING STORM SYSTEM WILL  
THEN BRING A STRENGTHENING SOUTHERLY FLOW ACROSS THE WATERS FRIDAY  
INTO FRIDAY NIGHT WITH SCA CONDITIONS OVERSPREADING THE AREA DURING  
THE AFTERNOON AND NIGHT. GALES WILL ALSO BE POSSIBLE SATURDAY,  
ESPECIALLY ON THE OCEAN WATERS.  
 
A NW GALE IS THEN POSSIBLE ACROSS ALL WATERS SATURDAY NIGHT.  
HIGH PRESSURE THEN BUILDS IN FOR SUNDAY WITH DIMINISHING WINDS  
AND SEAS THROUGH THE DAY.  
 
 
   
HYDROLOGY  
 
NO HYDROLOGIC CONCERNS ARE EXPECTED THROUGH THE FORECAST PERIOD.  
 
 
   
OKX WATCHES/WARNINGS/ADVISORIES  
 
CT...NONE.  
NY...NONE.  
NJ...NONE.  
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 11 AM EDT  
THURSDAY FOR ANZ331-332-335-338-340-345-350-353-355.  
 
 
 
 
 
SYNOPSIS...JT/DW  
NEAR TERM...JT  
SHORT TERM...JT  
LONG TERM...DW  
AVIATION...BG  
MARINE...JT/DW  
HYDROLOGY...JT/DW  
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