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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