AP-AN--NYC-NY NY Area Forecast Discussion, AN

000

FXUS61 KOKX 151514

AFDOKX

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE NEW YORK NY

1114 AM EDT WED JUL 15 2015

.SYNOPSIS...

LOW PRESSURE PASSES JUST TO OUR SOUTH TODAY WHILE A COLD FRONT MOVES

THROUGH THIS AFTERNOON INTO EARLY EVENING. HIGH PRESSURE THEN

FOLLOWS THE FRONT TONIGHT AND SHIFTS OFFSHORE FRIDAY INTO FRIDAY

NIGHT. A SERIES OF FRONTAL BOUNDARIES WILL IMPACT THE AREA OVER THE

WEEKEND AND INTO THE START OF THE NEW WEEK. A COLD FRONT APPROACHES

FOR THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

A FEW SHOWERS HAVE DEVELOPED BUT HAVE RESULTED IN ONLY AROUND AN

ADDITIONAL TENTH OF AN INCH. THE CLOUDS HAVE BEEN PREVALENT ACROSS

THE REGION. A THICKER CLOUD COVER IS CONVEYED BY VISIBLE SATELLITE

ACROSS NORTHEAST NJ AND NYC...WHICH IS WHY THE EARLIER SHOWERS

HAVE NOT EXPANDED AND INTENSIFIED. THIS IS FROM A LACK OF

INSTABILITY AND A NE SURFACE FLOW WITHOUT MUCH CONVERGENCE

OCCURRING.

THE RAIN CURRENTLY FALLING ACROSS STATEN ISLAND AND PARTS OF

NORTHEAST NJ IS ACTUALLY THE NW PART OF THE STRATIFORM AREA

ASSOCIATED WITH THE MCS THAT HAS MOVED OFF THE COAST OF SOUTHERN

NEW JERSEY. THE MCS HAS GENERATED THE EXPANDING CLOUDS THAT HAVE

BEEN MOVING INTO THE REGION...REDUCING THE AMBIENT INSTABILITY

THAT OTHERWISE WOULD BE GENERATED DUE TO DIURNAL WARMING.

SO THE FORECAST HAS BEEN MODIFIED TO ONLY MENTION A SLIGHT CHANCE

OF THUNDERSTORMS UNTIL AFTER 1PM THIS AFTERNOON...WHEN CHANCES

INCREASE FOR THUNDERSTORMS. HIGHEST CHANCES OF SHOWERS TOWARDS

NORTHEAST NEW JERSEY...WESTERN LOWER HUDSON VALLEY...AND NYC AND

THE CHANCES ALSO INCREASE FOR THIS AFTERNOON...BECOMING LIKELY FOR

MOST LOCATIONS. THE HEAVY RAIN THREAT WILL BE DIRECTLY TIED TO

THUNDERSTORMS.

BIGGEST IMPACT WILL BE LOCALLY HEAVY DOWNPOURS WITH A CHANCE TO

CAUSE AT LEAST MINOR URBAN/SMALL STREAM FLOODING AS STEERING FLOW

IS WEAK AND CELLS WILL BE SLOW-MOVING. WITH THE COLD FRONT SLOWING

DOWN AS IT APPROACHES THE OLD WARM FRONT BOUNDARY...LOOKS LIKE THE

BEST MOISTURE CONVERGENCE WOULD BE GENERALLY OVER THE SE HALF OF

THE CWA. CONFIDENCE IN A WIDESPREAD FLASH FLOODING EVENT IS NOT

HIGH ENOUGH TO GO WITH A WATCH AS GENERALLY HIGHER RAINFALL

AMOUNTS ARE REQUIRED TO REACH FFG VALUES OVER THE SE HALF OF THE

CWA. BUT LOCALIZED FLASH FLOODING IS STILL POSSIBLE. WOULD HAVE

HAD MORE CONFIDENCE TO GO WITH A WATCH IF MODELS HAD PROGGED THE

STRONGER FORCING TO OUR SOUTH A LITTLE FARTHER NORTH. ALSO WOULD

HAVE LIKED TO HAVE SEEN MODELS SHOWING HIGHER POPS AND QPF

OUTPUT...ALTHOUGH MODELS HAVE DIFFICULTY DETECTING/PINPOINTING

HIGH QPF IN CONVECTIVE SCENARIOS.

HAVE GONE WITH THE COOLER GUIDANCE FOR HIGH TEMPS DUE TO CLOUD COVER.

THERE IS A MODERATE RISK FOR THE METEOROLOGICAL ENHANCEMENT OF RIP

CURRENT DEVELOPMENT AT ATLANTIC BEACHES TODAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...

COLD FRONT EXITS EARLY IN THE EVENING WITH HIGH PRESSURE BUILDING

IN BEHIND THE FRONT. ONLY A LINGERING SHOWER/TSTM POSSIBLE TO

START...THEN DRY BY MIDNIGHT.

NOTICEABLY LESS HUMID CONDITIONS FOR THURSDAY WITH A MOSTLY SUNNY

SKY. USED A BLEND OF NAM/MAV MOS WITH SLIGHT ADJUSTMENTS FOR TEMPS

IN THE SHORT TERM PERIOD.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...

HIGH PRESSURE OVER THE AREA THURSDAY NIGHT WILL SLOWLY MOVES

OFFSHORE THROUGH FRIDAY NIGHT. LOWS THURSDAY NIGHT WILL GENERALLY

RANGE FROM THE MID TO UPPER 60S ACROSS NYC AND NORTHEAST NJ...AND IN

THE UPPER 50S TO LOW 60S MOST ELSEWHERE. OUTLYING AREAS WILL DROP

INTO THE LOWER 50S. SUNNY SKIES ON TAP FRIDAY WITH TEMPS GENERALLY

IN THE LOW TO MID 80S...AND THEN LOWS FRIDAY NIGHT WILL RANGE FROM

THE MID TO UPPER 60S THROUGHOUT AS SOUTHERLY FLOW USHERS WAA INTO

THE REGION.

THEREAFTER...UNSETTLED WEATHER ON TAP FOR THE WEEKEND AND INTO THE

START OF THE NEW WEEK. A WARM FRONT LIFTS NORTH ON SATURDAY...

FOLLOWED BY A SERIES OF UPPER LEVEL DISTURBANCES IMPACTING THE

REGION DURING THE WEEKEND AND INTO THE START OF THE NEW WEEK.

BY TUESDAY...AN UPPER TROUGH/SFC COLD FRONT WILL MOVE THROUGH THE

GREAT LAKES/OHIO VALLEY AND WILL APPROACH THE NORTHEAST LATE TUESDAY

AND MOVE ACROSS THE REGION ON WEDNESDAY. THERE ARE DIFFERENCES

BETWEEN THE 00Z GFS AND THE 00Z ECMWF...SO WILL FOLLOW WPC GUIDANCE

AND CARRY CHANCE POPS EACH DAY WITH EACH PASSING DISTURBANCE. NOT

EXPECTING SHOWERS/TSTMS OVER THE ENTIRE AREA EACH DAY...BUT THE

POTENTIAL WILL EXIST FOR CONVECTION.

SOUTHERLY FLOW WILL USHER A WARM AND HUMID AIRMASS ACROSS THE AREA

WITH TEMPS GENERALLY A FEW DEGREES ABOVE NORMAL DURING THIS TIME

WITH HIGHS IN THE MID TO UPPER 80S AND LOWS IN THE 70S. SFC

DEWPOINTS WILL GRADUALLY CREEP UP FROM THE 60S ON SATURDAY INTO THE

LOW 70S BY MONDAY.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...

A COLD FRONT WILL APPROACH FROM THE WEST THIS AFTERNOON AND MOVE

ACROSS THE AREA TONIGHT. CIGS AND VSBYS VARY ACROSS THE REGION

FROM VFR TO SUB IFR. CONDITIONS SHOULD IMPROVE TO MVFR. MOST

TERMINALS BECOME VFR BY EARLY AFTERNOON. THINKING THIS WILL

OCCUR...OUTSIDE OF SHOWERS AND THUNDERSTORMS.

WITH RESPECT TO PRECIPITATION...SHOWERS AND THUNDERSTORMS BECOME MORE

NUMEROUS THIS AFTERNOON AND REFINED THE TAFS TO 18Z-22Z. STILL

HAVING A HARD TIME WITH EXACT PLACEMENT AND TIMING OF

THUNDER...CAN CANNOT RULE OUT THUNDER AND CB'S IN ANY ONE

LOCATION.

LIGHT NORTHERLY WINDS AROUND 10 KT. MODERATE TO HIGH CONFIDENCE

IN WINDS.

COLD FRONT MOVES ACROSS THE REGION TONIGHT...WITH VFR CONDITIONS

AND GUSTY NORTH WINDS.

...NY METRO ENHANCED AVIATION WEATHER SUPPORT...

DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN

BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)

KJFK FCSTER COMMENTS: AMENDMENTS LIKELY FOR CHANGING FLIGHT

CATEGORIES AND CONVECTION.

KLGA FCSTER COMMENTS: AMENDMENTS LIKELY FOR CHANGING FLIGHT

CATEGORIES AND CONVECTION.

KEWR FCSTER COMMENTS: AMENDMENTS LIKELY FOR CHANGING FLIGHT

CATEGORIES AND CONVECTION.

THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES

SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.

KTEB FCSTER COMMENTS: AMENDMENTS LIKELY FOR CHANGING FLIGHT

CATEGORIES AND CONVECTION.

KHPN FCSTER COMMENTS: AMENDMENTS LIKELY FOR CHANGING FLIGHT

CATEGORIES AND CONVECTION.

KISP FCSTER COMMENTS: AMENDMENTS LIKELY FOR CHANGING FLIGHT

CATEGORIES AND CONVECTION.

.OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...

.WED NIGHT...VFR CONDS RETURNING IN THE EVE.

.THU-FRI...VFR.

.SAT-SUN...MVFR OR LOWER POSSIBLE IN SCT SHRA/TSRA.

&&

.MARINE...

SSE SWELL BUILDS TODAY ON THE OCEAN WHILE WINDS REMAIN RELATIVELY

LIGHT MUCH OF THE DAY. HAVE PUSHED UP START TIME OF THE SCA ON THE

OCEAN EAST OF FIRE ISLAND INLET AS PER GUIDANCE TREND AND NEARBY

BUOYS ALREADY AROUND 4 FT EARLY THIS MORNING. MIGHT NEED TO PUSH UP

TIME FARTHER WEST ON THE OCEAN...BUT A 5 FT SWELL MIGHT ONLY AFFECT

A SMALL PORTION OF THIS ZONE DURING THE DAY. BETTER CHANCES FOR

HIGHER SEAS HERE WILL BE TONIGHT. IN ADDITION...COLD AIR ADVECTION

BEHIND A COLD FRONT AND A TIGHTENING PRESSURE GRADIENT COULD HELP

PRODUCE GUSTS UP TO 25 KT TONIGHT ON THE OCEAN. FOR THE OTHER

ZONES...SUCH GUSTS COULD HAPPEN...BUT IT APPEARS TO BE MARGINAL AND

LIKELY NOT FREQUENT/WIDESPREAD ENOUGH TO WARRANT A SCA AT THIS TIME.

WINDS DIMINISH LATE TONIGHT INTO THURSDAY...BUT THE SWELL ON THE

OCEAN SHOULD KEEP SEAS UP TO AT LEAST 5 FT. SCA FOR ALL OF THE OCEAN

ZONES HAS THEREFORE BEEN EXTENDED THROUGH THURSDAY AFTERNOON.

5 FT SEAS ON THE EASTERN OCEAN WATERS THURSDAY NIGHT WILL GRADUALLY

SUBSIDE TO SUB-SCA LEVELS BY FRIDAY MORNING. A RELATIVELY LIGHT PRES

GRADIENT OVER THE AREA WILL KEEP SUB-SCA CONDS ON THE WATERS THROUGH

THE WEEKEND AND INTO THE START OF THE NEW WEEK.

&&

.HYDROLOGY...

A BASIN AVERAGE OF A HALF TO 3 QUARTERS OF AN INCH OF RAINFALL IS

FORECAST TODAY INTO THIS EVENING. DUE TO THE CONVECTIVE NATURE AND

RELATIVELY SLOW FORWARD MOTION OF SHOWERS...FAIRLY LARGE DEVIATIONS

FROM THIS AVERAGE WILL PROBABLY OCCUR. PINPOINTING LOCATIONS THAT

WILL RECEIVE THE GREATEST AMOUNTS...AND HOW MUCH ABOVE THE BASIN

AVERAGE THOSE LOCATIONS WOULD RECEIVE IS DIFFICULT WITH THIS SETUP.

BETTER OVERALL CHANCES OF SHOWERS WOULD BE LATE MORNING THROUGH THE

AFTERNOON.

THERE WILL PROBABLY BE A FEW AREAS OF MINOR URBAN/SMALL STREAM/POOR

DRAINAGE FLOODING...AND LOCALIZED FLASH FLOODING WILL BE POSSIBLE.

NO HYDROLOGIC PROBLEMS AFTER SUNDOWN THROUGH THE END OF THE WEEK.

SCATTERED SHOWERS AND THUNDERSTORMS ARE IN THE FORECAST FOR THE

WEEKEND AND EARLY NEXT WEEK. A WIDESPREAD RAINFALL IS NOT EXPECTED.

ANY SLOW MOVING SHOWER OR THUNDERSTORM COULD PRODUCE HEAVY RAIN WITH

ISOLATED FLOODING.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...

CT...NONE.

NY...NONE.

NJ...NONE.

MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 PM EDT

THURSDAY FOR ANZ355.

SMALL CRAFT ADVISORY UNTIL 6 PM EDT THURSDAY FOR ANZ350-353.

&&

$$

SYNOPSIS...JC/MPS

NEAR TERM...JC/JM/MPS

SHORT TERM...JC

LONG TERM...MPS

AVIATION...IRD

MARINE...JC/MPS

HYDROLOGY...JC/MPS

Delivered by Weather Underground Inc. Wed Jul 15 2015 11:14AM EDT