615  
FXUS61 KOKX 041944  
AFDOKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW YORK NY  
344 PM EDT SUN MAY 4 2025  
   
SYNOPSIS
 
 
A FRONTAL BOUNDARY WILL REMAIN NEARLY STATIONARY FROM THE LOWER  
HUDSON VALLEY INTO CENTRAL NEW ENGLAND. THE FRONTAL BOUNDARY  
EVENTUALLY MOVES FARTHER SOUTH WITHIN THE REGION MONDAY INTO  
TUESDAY. THE SYSTEM WILL THEN PASS THROUGH ON WEDNESDAY, WITH A  
COLD FRONT PASSING THROUGH ON THURSDAY. THE AREA WILL THEN  
REMAIN BETWEEN HIGH PRESSURE TO THE WEST AND LOW PRESSURE  
DEVELOPING EAST OF NEW ENGLAND ON FRIDAY. THE LOW SHOULD SLOWLY  
PULL AWAY FROM NEW ENGLAND ON SATURDAY.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
SOME HEAVIER SHOWERS WILL WORKING ACROSS THE LOWER HUDSON  
VALLEY AND NE NJ WITH WEAK INSTABILITY IN A DEEP-LAYERED  
SOUTHERLY FLOW. THIS ACTIVITY WILL CONTINUE TO WORK UP FROM THE  
SOUTH DURING THE DAY AND THEN EVER SO SLOWLY TRANSLATE EAST.  
BRIEF DOWNPOURS ARE POSSIBLE BUT STORM MOVEMENT WILL BE SOUTH TO  
NORTH AS 25 MPH. WILL HAVE TO WATCH FOR SOME TRAINING OF CELLS,  
BUT DEEP CONVECTION IS UNLIKELY TODAY SO NOT EXPECTING HIGH  
HOURLY RATES.  
 
ONLY WEAK INSTABILITY THIS AFTERNOON SO ONLY HAVE A SLIGHT  
CHANCE THUNDERSTORMS WHERE THE MODELS SHOW THIS INSTABILITY,  
WHICH IS WITHIN THE WESTERN HALF OF THE REGION.  
 
SE WINDS STABILIZE SURFACE LAYER WITH COOLER TEMPERATURES OVERALL.  
HOWEVER, NOTING TEMPERATURES A LITTLE ABOVE MOS INITIALLY SO WENT  
WITH NBM FOR THE HIGH TEMPERATURE FORECAST WHICH SEEMS PLAUSIBLE  
GIVEN SUFFICIENT DIURNAL WARMING THIS MORNING INTO EARLY AFTERNOON  
BEFORE MORE SHOWERS DEVELOP. UPPER 60S TO LOWER 70S FOR THE HIGH  
TEMPERATURE FORECAST FOR MOST LOCATIONS BUT RELATIVELY COOLER ALONG  
THE SOUTHERN HALF OF LONG ISLAND AND NYC, WHICH ARE MORE IN THE  
LOW TO MID 60S.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/
 
 
CUTOFF UPPER LEVEL LOW CONTINUES TO APPROACH FROM THE WEST.  
CONTINUED SOUTHERLY LOWER TO UPPER LEVEL FLOW WILL BE PARALLEL.  
OMEGA INCREASES.  
 
WITH SYNOPTIC LIFT INCREASING AND SOME TIME PERIODS WHERE THERE  
WILL BE MORE ELEVATED INSTABILITY, ESPECIALLY MONDAY NIGHT  
THROUGH TUESDAY, THERE WILL BE MORE COVERAGE OF SHOWERS AND  
THUNDERSTORMS.  
 
TONIGHT SHOWERS CONTINUE BUT NOT EXPECTING TOO MUCH HEAVY  
RAINFALL. INSTABILITY LOWERING SO NO THUNDERSTORMS TONIGHT.  
THERE WILL BE MORE LOW CLOUDS AND FOG. UNCERTAIN HOW DENSE OR  
EXTENSIVE THE FOG GETS. KEPT FOG WITH PATCHY COVERAGE. LESS RAIN  
THAN FORECAST WILL PROBABLY LEAD TO MORE EXTENT OF FOG AND  
INCREASE THE POSSIBILITY FOR SOME DENSE FOG FOR SOME LOCATIONS.  
 
MONDAY IS WHEN THE RAIN SHOWERS BECOME MORE WIDESPREAD AND THIS  
IS EXPECTED TO CONTINUE MONDAY NIGHT THROUGH TUESDAY.  
COMBINATION OF HIGHEST SYNOPTIC FORCING AND RELATIVELY MORE  
INSTABILITY WILL LEAD TO A GREATER CHANCE FOR HEAVY RAIN AS WELL  
ESPECIALLY FOR ANY THUNDERSTORMS THAT DEVELOP. PARALLEL FLOW  
FROM LOWER TO UPPER LEVELS WILL LEAD TO TRAINING OF CONVECTION  
ALLOWING FOR MULTIPLE ROUNDS OF HEAVY SHOWERS AND THUNDERSTORMS.  
 
SYNOPTIC FORCING DECREASES TUESDAY NIGHT WITH HIGHEST POSITIVE  
VORTICITY ADVECTION AREAS SHIFTING EAST OF THE AREA AS UPPER  
LEVEL LOW CENTER MOVES IN. LOW LEVELS NOT EXPECTED TO BE AS  
UNSTABLE ALSO, SO LESS HEAVY RAIN POTENTIAL. HOWEVER, STILL HAVE  
RAIN SHOWERS IN THE FORECAST.  
 
MONDAY NIGHT BOTH WINDS AT 925MB AND 250MB INCREASE AND ARE  
SOUTHERLY. THEY BOTH HAVE SOME EASTERLY COMPONENT.  
 
TUESDAY, SHOWERS LINGER AND COULD POTENTIALLY BE HEAVY AS RIGHT  
REAR QUAD OF UPPER LEVEL JET MOVES INTO THE REGION.  
 
DIVERGENCE INCREASES MONDAY INTO TUESDAY WITH THE UPPER LEVEL  
WINDS INCREASING.  
 
REGARDING TEMPERATURES, FOR TONIGHT USED A COMBINATION OF MAV  
AND MET MOS AS WELL AS THE NBM. THEN BLENDED IN MORE RAW DATA  
FOR MONDAY THROUGH TUESDAY NIGHT AS DIURNAL TEMPERATURE  
DIFFERENCES BECOME SMALLER.  
 

 
   
LONG TERM /WEDNESDAY THROUGH SATURDAY/
 
 
UPPER LEVEL LOW AND WEAK SFC REFLECTION PASS THROUGH ON WED WITH  
CHANCE OF SHOWERS. AN UPPER TROUGH DIGGING SE FROM ONTARIO AND  
QUEBEC IN THEIR WAKE WILL SEND A COLD FRONT THROUGH ON THU WITH  
ANOTHER CHANCE FOR SHOWERS. THE TROUGH IS PROGGED TO CLOSE OFF OVER  
THE NORTHEAST FRI INTO SAT, WITH A DEVELOPING WEAK SFC LOW SE OF  
LONG ISLAND ON FRI PIVOTING TO E OF NEW ENGLAND. WITH THE UPPER LOW  
AND ASSOCIATED COLD POOL ALOFT/LOW LEVEL CYCLONIC FLOW HAVE PARTLY  
CLOUDY SKIES AND SLIGHT CHANCE FOR SHOWERS FOR BOTH FRI/SAT.  
 
ABOVE NORMAL TEMPS ON WED SHOULD RETURN TO NEAR NORMAL ON THU AND A  
FEW DEG BELOW NORMAL ON FRI. TEMPS ON SAT COULD MODERATE TO A FEW  
DEG ABOVE NORMAL, BUT THIS WILL DEPEND ON HOW QUICKLY THE UPPER LOW  
PULLS AWAY ON SAT. IF SLOWER TO EXIT TEMPS ON SAT COULD BE MORE  
SIMILAR TO THOSE FCST FOR FRI.  
 

 
   
AVIATION /18Z SUNDAY THROUGH FRIDAY/
 
 
FRONTAL BOUNDARY REMAINS STATIONARY ACROSS THE REGION TONIGHT.  
AS A RESULT SHOWERS WILL CONTINUE TO DEVELOP AND GRADUALLY MAKE  
THEIR WAY FARTHER EAST WITHIN THE REGION THROUGH TONIGHT.  
 
MVFR CONDITIONS PERSIST THROUGH THIS EVENING WITH THE CHANCE OF  
RAIN SHOWERS. HIGHER CHANCE OF IFR AND LOCALIZED LIFR CONDITIONS  
EXPECTED TONIGHT AND INTO MONDAY.  
 
SOUTHERLY WINDS BECOME MORE EASTERLY TONIGHT. WIND SPEEDS VARY  
FROM NEAR 5 KTS TO NEAR 15 KTS. SOME GUSTS CAN BE EXPECTED  
BETWEEN 20-25 KT AT TIMES ALTHOUGH THIS IS NOT EXPECTED TO BE  
WIDESPREAD. WIND SPEEDS TONIGHT LOWER TO LESS THAN 10 KTS, THEN  
INCREASE AGAIN MONDAY.  
 
...NY METRO (KEWR/KLGA/KJFK/KTEB) TAF UNCERTAINTY...  
 
AMENDMENTS LIKELY TO REFINE TIMING OF SHOWERS AND THUNDERSTORMS.  
   
OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY
 
 
MONDAY: SHOWERS LIKELY WITH MVFR OR LOWER EXPECTED. A CHANCE OF  
TSTMS MAINLY AT NIGHT. E WINDS G15-20KT.  
 
TUESDAY: SHOWERS WITH MVFR OR LOWER EXPECTED. A CHANCE OF  
THUNDERSTORMS. SE WINDS G15-20KT DAY INTO EARLY EVE POSSIBLE.  
 
WEDNESDAY: CHANCE OF MVFR OR LOWER WITH A SLIGHT CHANCE OF  
SHOWERS/THUNDERSTORMS.  
 
THURSDAY: VFR.  
 
FRIDAY: VFR WITH SLIGHT CHANCE OF SHOWERS.  
 
DETAILED INFORMATION, INCLUDING HOURLY TAF WIND COMPONENT  
FORECASTS, CAN BE FOUND AT: HTTPS:/WWW.WEATHER.GOV/ZNY/N90  
 

 
   
MARINE
 
 
EXPECTING ALL WATERS TO REMAIN BELOW SCA THIS MORNING AND  
THROUGH MONDAY MORNING. THEREAFTER, SCA POTENTIAL INCREASES  
THROUGH TUESDAY NIGHT ON THE OCEAN AS FORECAST SEAS REACH NEAR 5  
TO 6 FT AT TIMES.  
 
QUIET FOR WED/THU WITH WINDS/SEAS BELOW SCA THRESHOLDS.  
 

 
   
HYDROLOGY
 
 
MARGINAL FLASH FLOOD RISK FOR MUCH OF THE AREA THROUGH EARLY  
THIS WEEK. HOURLY RAIN RATES AT TIMES COULD REACH NEAR 1 INCH IN  
1 HOUR. ISOLATED FLASH FLOODING POSSIBLE. LAYER PRECIPITABLE  
WATER REACHES NEAR 1.5 INCHES.  
 
TOTAL RAINFALL FORECAST FROM THIS AFTERNOON THROUGH TUESDAY  
EVENING IS NEAR 2 TO 3.5 INCHES. LOCALLY HIGHER AMOUNTS WILL BE  
POSSIBLE.  
 
CURRENT FORECAST SHOWS ENOUGH TIME PERIOD TO KEEP FLASH FLOOD  
RISK MARGINAL. WOULD EXPECT A RELATIVELY GREATER CHANCE OF MINOR  
NUISANCE FLOODING IN THE LOW LYING, URBAN, AND OTHER POOR  
DRAINAGE AREAS.  
 
NO HYDROLOGIC CONCERNS MID TO LATE THIS WEEK.  
 

 
   
OKX WATCHES/WARNINGS/ADVISORIES
 
 
CT...NONE.  
NY...NONE.  
NJ...NONE.  
MARINE...NONE.  
 

 
 

 
 
SYNOPSIS...BG/JM  
NEAR TERM...JM/DW  
SHORT TERM...JM  
LONG TERM...BG  
AVIATION...20  
MARINE...BG/JM  
HYDROLOGY...BG/JM  
 
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