218  
FXUS61 KOKX 071813  
AFDOKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW YORK NY  
213 PM EDT TUE JUL 7 2020  
   
SYNOPSIS
 
 
A BACK DOOR COLD FRONT WILL REMAIN TO THE SOUTHWEST TODAY, THEN  
GRADUALLY DISSIPATE AS IT LIFTS BACK NORTH TONIGHT INTO  
WEDNESDAY MORNING. WEAK HIGH PRESSURE WILL THEN BRIEFLY BUILD IN  
THROUGH THURSDAY. LOW PRESSURE WILL THEN APPROACH FROM THE  
SOUTH FRIDAY INTO SATURDAY, FOLLOWED BY A SERIES OF WEAK FRONTS  
MOVING THROUGH FROM LATER SATURDAY INTO EARLY NEXT WEEK.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
WHILE CLOUDS ARE BEGINNING TO CLEAR ACROSS PORTIONS OF NEW YORK  
CITY, WESTERN LONG ISLAND, AND POINTS WEST, CONSIDERABLE CLOUD  
COVER REMAINS ACROSS THE EASTERN HALF OF THE AREA. LOWERED  
TEMPERATURES A FEW DEGREES THIS AFTERNOON, ESPECIALLY ACROSS  
AREAS WHERE THE CLOUD COVER IS EXPECTED TO REMAIN THE MOST  
PERSISTENT. THE CLOUDY START TO THE DAY WILL LIKELY HELP TEMPER  
CHANCES OF CONVECTION THIS AFTERNOON, WITH THE BEST CHANCES  
CONTINUING TO BE NORTH AND WEST OF THE CITY.  
 
MOST OF THE AREA ENSHROUDED IN LOW CLOUDS, WITH THE BACK DOOR  
FRONT WELL TO THE SOUTH AND WEST ACROSS SOUTHERN DE, CENTRAL MD,  
AND EAST CENTRAL PA. DAYTIME HEATING SHOULD ERODE SOME OF THIS  
CLOUDINESS FROM LATE MORNING INTO THE AFTERNOON, WITH ENOUGH  
LIFT VIA PASSING WEAK SHORTWAVE ALOFT PLUS INSTABILITY TO  
TRIGGER SCT SHOWERS AND A FEW TSTMS FROM NYC NORTH/WEST, WITH  
THE BETTER CHANCES INLAND. INSTABILITY AND SHEAR COMBO NOWHERE  
ON THE ORDER OF WHAT WAS SEEN YESTERDAY, SO DO NOT EXPECT STORMS  
TO ORGANIZE OR BECOME STRONG, THOUGH ANY INDIVIDUAL CELL COULD  
PRODUCE A QUICK DOWNPOUR. HIGH TEMPS TODAY WILL BE WARMEST FROM  
NYC NORTH/WEST, WITH MID 80S EXPECTED, AND COOLER ACROSS MOST OF  
LONG ISLAND AND SOUTHERN CT, WITH UPPER 70S TO NEAR 80 IN SPOTS.  
 
THE BACK DOOR FRONT MAY NOT SO MUCH LIFT THROUGH AS GRADUALLY  
DISSIPATE AS IT LIFTS INTO THE AREA TONIGHT INTO WED MORNING, AS  
HIGH PRESSURE ALONG THE NEW ENGLAND COAST AND A WEAK LOW TO ITS  
SOUTH BOTH RETREAT TO THE EAST, ALLOWING WINDS TO BECOME MORE  
SOUTHERLY. MAINLY DRY TONIGHT WITH SHORTWAVE RIDGING PASSING  
OVERHEAD. LOWS MAINLY UPPER 60S/LOWER 70S.  
 
A MODERATE RIP CURRENT RISK LIKELY TODAY VIA RELATIVELY LONG  
PERIOD SE SWELL OF 3-4 FT AND SE FLOW 15 KT.  
 

 
   
SHORT TERM /WEDNESDAY THROUGH THURSDAY/
 
 
WARMER CONDS EXPECTED THROUGHOUT ON WED WITH THE AREA BACK IN  
THE WARM SECTOR, WITH HIGHS MAINLY MID/UPPER 80S OUTSIDE OF THE  
HIGHER ELEVATIONS AND AWAY FROM SOUTH FACING COASTLINES. HEAT  
INDEX VALUES IN THE URBAN CORRIDOR OF NJ SHOULD FALL JUST SHY OF  
95, WITH UPPER 80S TO AROUND 90 ELSEWHERE. SCT TO NUMEROUS  
SHOWERS/TSTMS EXPECTED IN THE AFTERNOON AS A MORE VIGOROUS  
SHORTWAVE TROUGH APPROACHES IN NW FLOW ALOFT.  
 
RIDGING IN THE WAKE OF THE TROUGH PASSAGE WILL BE SHORT LIVED  
ON THU, BUT SHOULD HELP TEMPS RISE TO THE UPPER 80S AND LOWER  
90S. HEAT INDEX VALUES ON THU SHOULD REACH THE MID AND UPPER 90S  
IN THE INTERIOR VALLEYS VIA MOISTURE POOLING, BUT RISE NO  
HIGHER THAN THE LOWER 90S ELSEWHERE AS AFTERNOON DEWPOINTS LOWER  
SLIGHTLY IN NYC AND JUST NORTH/WEST. NO DISTINCT TRIGGER FOR  
CONVECTION ON THURSDAY, SO A CONDITIONAL POTENTIAL FOR ISOLATED  
TO WIDELY SCT SHOWERS/TSTMS OFF HIGHER TERRAIN AND PERHAPS SEA  
BREEZE BOUNDARIES ANTICIPATED IN AN UNSTABLE, BUT CAPPED AND  
WEAKLY SHEARED ENVIRONMENT.  
 
A MODERATE RIP CURRENT RISK SHOULD CONTINUE INTO WED VIA  
RELATIVELY LONG PERIOD SE-S SWELL OF 3 FT AND S FLOW 10-15 KT.  
 

 
   
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/
 
 
FORECAST DETAILS COMING INTO SOMEWHAT BETTER ALIGNMENT FOR  
FRIDAY INTO THE WEEKEND ON THE EVOLUTION, MOVEMENT, AND TIMING  
OF A WEAK WARM CORE LOW AS IT LIFTS UP THE COAST. SOLID MODEL  
AGREEMENT IN A NORTHERN STREAM TROUGH AMPLIFYING DOWN THROUGH  
THE GREAT LAKES/OHIO VALLEY AND DRIFTING TO THE EAST COAST  
THROUGH THE WEEKEND.  
 
THE LOW SHOULD WORK UP TOWARD THE AREA FRIDAY, AND THEN PASS  
OVER THE AREA FRIDAY NIGHT INTO SATURDAY MORNING. STILL SOME  
RUN TO RUN AND MODEL TO MODEL INCONSISTENCY TO BE IRONED OUT, IN  
TERMS OF THE TRACK/SPEED OF THE LOW UP THE COASTAL PLAIN OR  
JUST OFFSHORE, DEGREE OF INTENSIFICATION, AND TO WHAT DEGREE IT  
ACQUIRES ANY TROPICAL OR SUBTROPICAL CHARACTERISTICS. MAIN  
THREAT IS FOR A PERIOD OF HEAVY RAIN FRI-SAT TIMEFRAME, MOST  
LIKELY JUST NORTH EAST OF THE SFC LOW AS IT TAPS INTO A WARM  
CONVEYOR BELT OF GULF AND SUBTROPICAL ATLANTIC MOISTURE. STILL  
LOW CONFIDENCE ON LOCATION OF THIS HEAVY RAIN POTENTIAL, AS WELL  
AS POTENTIAL FOR BREEZY CONDITIONS ON THE EAST SIDE OF THE LOW,  
AS A POTENTIAL 30-40 KT LLJ DEVELOPS.  
 
BETTER AGREEMENT THAT MEAN TROUGHING WILL BE SLIDING TOWARDS THE  
EAST COAST THROUGH THE WEEKEND, WITH A SERIES OF SURFACE TROUGHS  
MOVING THROUGH THE AREA. POTENTIAL IS INCREASING FOR A RETURN  
TO HOT AND HUMID CONDITIONS FOR THE WEEKEND, WITH CHANCES FOR  
DIURNAL CONVECTION. EACH SUCCESSIVE TROUGH SUNDAY INTO EARLY  
NEXT WEEK, WILL BRING A POTENTIAL FOR DIURNAL CONVECTION AS  
WELL AS A GRADUAL TREND TO A MORE SEASONABLE AIRMASS EARLY NEXT  
WEEK.  
 

 
   
AVIATION /18Z TUESDAY THROUGH SUNDAY/
 
 
A WEAK FRONTAL BOUNDARY SOUTH OF THE REGION, WILL EVENTUALLY  
LIFT NORTHWARD AS A WARM FRONT TONIGHT WHILE WEAKENING.  
 
LINGERING LOW CLOUDS, MAINLY MVFR WITH ISOLATED IFR, CONTINUES  
ACROSS THE REGION THIS AFTERNOON. GRADUAL IMPROVEMENT TO VFR BY  
AROUND 20Z IS EXPECTED. EXACT INDIVIDUAL TERMINAL IMPROVEMENT  
TIME COULD VARY BY 1-2 HOURS COMPARED TO FORECAST.  
 
THERE IS A CHANCE OF SHOWERS AND A SLIGHT CHANCE OF  
THUNDERSTORMS BEFORE 00Z WITH RELATIVELY HIGHER CHANCES OF ANY  
RAIN AT KEWR/KTEB AND KSWF WHERE VCSH IS IN TAFS. THERE IS A  
CHANCE THAT MVFR STRATUS RETURN TONIGHT. UNCERTAIN ON THE EXTENT  
OF THIS SO THE CONFIDENCE LOWERS FOR CATEGORY FORECAST TONIGHT  
INTO EARLY WEDNESDAY BUT DID MENTION IN TAFS OF MVFR OUTSIDE OF  
NYC TERMINALS.  
 
ENE-ESE FLOW OF NEAR 8-10 KTS WILL BECOME MORE SOUTHERLY  
TONIGHT INTO EARLY WEDNESDAY WHILE MAINTAINING NEARLY THE SAME  
WIND SPEED.  
 
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: POSSIBLE MVFR STRATUS LATE TONIGHT.  
 
KLGA TAF COMMENTS: POSSIBLE MVFR STRATUS LATE TONIGHT.  
 
KEWR TAF COMMENTS: POSSIBLE MVFR STRATUS LATE TONIGHT.  
AMENDMENTS POSSIBLE TO BETTER REFINE SHRA TIMING.  
 
KTEB TAF COMMENTS: POSSIBLE MVFR STRATUS LATE TONIGHT.  
AMENDMENTS POSSIBLE TO BETTER REFINE SHRA TIMING.  
 
KHPN TAF COMMENTS: FORECAST END TIME OF IFR AND MVFR COULD BE  
1-2 HRS OFF.  
 
KISP TAF COMMENTS: FORECAST END TIME OF IFR AND MVFR COULD BE  
1-2 HRS OFF.  
   
OUTLOOK FOR 18Z WEDNESDAY THROUGH SATURDAY
 
   
WEDNESDAY-THURSDAY
 
MVFR OR LOWER POSSIBLE AT TIMES DURING  
AFTERNOON OR EVENING SHOWERS AND THUNDERSTORMS, MAINLY FROM THE  
NYC METROS NORTH/WEST. OTHERWISE, VFR.   
FRIDAY-SATURDAY
 
MVFR OR LOWER CONDITIONS POSSIBLE IN  
SHOWERS. THUNDERSTORMS ARE POSSIBLE AS WELL. CHANCE E-SE GUSTS  
20-25KT FOR FRIDAY INTO FRIDAY NIGHT.   
SUNDAY
 
MVFR OR LOWER POSSIBLE AT TIMES WITH A CHANCE OF  
SHOWERS AND THUNDERSTORMS.  
 

 
   
MARINE
 
 
CONDITIONS WILL REMAIN BELOW SMALL CRAFT LEVELS THROUGH MIDWEEK,  
THROUGH WAVES WILL REMAIN BETWEEN 3 AND 4 FT. SCA SEAS ARE LIKELY  
FRIDAY INTO THE WEEKEND WITH A PERSISTENT S/SW FLOW AND  
STRENGTHENING WIND FIELDS OWING TO A POSSIBLE COASTAL LOW NEARING  
THE REGION.  
 

 
   
HYDROLOGY
 
 
A LOCALIZED URBAN AND POOR DRAINAGE FLOODING THREAT EXISTS WITH  
ANY ISOLATED THUNDERSTORM ACTIVITY WED AND THU.  
 
THERE IS INCREASING POTENTIAL FOR MORE WIDESPREAD HEAVY RAIN  
FRIDAY INTO SATURDAY MORNING AS LOW PRESSURE MOVES UP THE COAST.  
MORE DETAILS AS THE WEEK PROGRESSES.  
 

 
   
EQUIPMENT
 
 
NYC NOAA WEATHER RADIO STATION KWO35 (162.55 MHZ) IS UNDERGOING  
ITS FINAL STAGES OF TESTING, AND IS OPERATING AT FULL POWER.  
 

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

 
 

 
SYNOPSIS...GOODMAN/NV  
NEAR TERM...FEB/GOODMAN  
SHORT TERM...GOODMAN  
LONG TERM...GOODMAN/NV  
AVIATION...JM  
MARINE...NV  
HYDROLOGY...GOODMAN/NV  
EQUIPMENT...  
 
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