Area Forecast Discussion
Issued by NWS Upton, NY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KOKX 300231
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1031 PM EDT MON JUN 29 2015

.SYNOPSIS...
AS LOW PRESSURE MOVES INTO THE CANADIAN MARITIMES THROUGH
TONIGHT...HIGH PRESSURE WILL BUILD INTO THE NORTHEAST. ANOTHER LOW
WILL MOVE THROUGH THE EASTERN GREAT LAKES ON TUESDAY WITH ITS WARM
FRONT APPROACHING FROM THE SOUTH. IT MOVES THROUGH WEDNESDAY. AS A
COLD FRONT MOVES SLOWLY SOUTHEAST ACROSS THE REGION WEDNESDAY
NIGHT...IT WILL BECOME NEARLY STATIONARY SOUTH OF THE AREA
THURSDAY THROUGH MONDAY AS A SERIES OF LOW PRESSURE SYSTEMS MOVE
EAST ALONG THE FRONT.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
WINDS CONTINUE TO DIMINISH WITH LOSS OF DIURNAL HEATING AND WITH
GRADIENT SLACKENING AS HIGH PRES BUILDS IN FROM THE EAST. WITH
CLEARING SKIES AND LIGHT WINDS...RADIATIONAL COOLING WILL ALLOW
FOR RELATIVELY COOLER TEMPS IN THE INTERIOR AND RURAL SECTIONS OF
THE REGION. LOWS WILL BOTTOM OUT IN THE MID 50S TO UPPER 60S.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/...
THE HIGH PRESSURE WILL STILL BE PREVALENT TUESDAY WITH THE RIDGE
OFFSHORE. CLOUDS WILL INCREASE FROM THE WEST DURING THE DAY WITH
AN INCREASING CHANCE OF SHOWERS MAINLY WEST OF NYC TOWARDS THE
LATTER PORTION OF THE DAY. MORE SUN EXPECTED FARTHER EAST THAN
THE PREVIOUS DAY AND DESPITE A SE FLOW...TEMPS ALOFT AT 850MB WARM
A FEW DEGREES COMPARED TO THE PREVIOUS DAY AS WELL. AS A
RESULT...HIGH TEMPS WILL BE A FEW DEGREES WARMER AS WELL. HIGHS
RANGE FROM THE LOW TO MID 80S.

FOR TUESDAY NIGHT AND WEDNESDAY...A LOW WILL BE DEVELOPING IN THE
OHIO VALLEY INTO THE EASTERN GREAT LAKES. ITS ASSOCIATED WARM
FRONT WILL BE APPROACHING FROM THE SOUTHWEST. IT WILL MAKE SLOW
PROGRESS AND NOT MOVE THROUGH UNTIL DURING THE DAY WEDNESDAY. THE
CHANCES FOR SHOWERS AND ISOLATED THUNDERSTORMS BECOMES MORE
WIDESPREAD TUESDAY NIGHT. INSTABILITY AT THE SURFACE INCREASES LATE
TUESDAY NIGHT AND WEDNESDAY...MAKING FOR A RELATIVELY HIGHER
CHANCE OF THUNDERSTORMS. SHOWERS WILL BE LIKELY LATE TUESDAY NIGHT
AND WEDNESDAY WITH SCATTERED EMBEDDED THUNDERSTORMS FROM TIME TO
TIME.

MORE OF SYNOPTIC FORCING CONVEYED BY MODELS WITH SHARPENING
SHORTWAVE EARLY WEDNESDAY TRAVERSING THE REGION AND ASSOCIATED
UPPER LEVEL SOUTHERLY JET STREAK. THIS WILL HELP ADVECT IN GREATER
MOISTURE WITH MORE SOUTHERLY FLOW THROUGH THE ATMOSPHERE.

LOWS TUESDAY NIGHT CONVEYED THE WARMER SIDE OF GUIDANCE WITH
VALUES RANGING FROM THE LOW TO UPPER 60S. TOOK COOLER SIDE OF
GUIDANCE FOR HIGHS WEDNESDAY WITH A RANGE FROM THE UPPER 70S TO
LOWER 80S.

THERE IS A MODERATE RISK OF RIP CURRENTS AT OCEAN BEACHES ON
TUESDAY.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
FORECAST UNCERTAINTY REGARDING TIMING AND LOCATION OF RAIN WILL
REMAIN HIGH LEADING TO A LOW CONFIDENCE LONG TERM FORECAST.

WHAT WE KNOW...MEAN POSITIONS OF THE UPPER LVL RIDGE ACROSS THE
WESTERN U.S. AND EASTERN U.S. WILL NOT CHANGE MUCH. SHORT WAVES WILL
CONTINUE TO DEVELOP AND ROTATE AROUND THE POLAR VORTEX JUST NORTH OF
HUDSON BAY CANADA. AS EACH SHORT WAVE DROPS FAR ENOUGH SE...IT WILL
BRING INCREASES CHANCES OF SHOWERS AND TSTMS.

WHAT WE DONT KNOW...THE SPECIFIC TRACKS...INTENSITY AND TIMING OF
THE APPROACHING SHORT WAVES.

WED NIGHT...WX CONDITIONS ARE FCST TO IMPROVE WITH THE SLOW PASSAGE
OF A COLD FRONT MVG SE ACROSS THE REGION...BRINGING A TEMPORARY END
TO A ROUND OF SHOWERS AND TSTMS.

THU THROUGH THU NIGHT...THIS FCST DEPENDS ON HOW FAR SOUTH THE FRONT
MAKES IT AS A WAVE OF LOW PRES DEVELOPS ALONG IT AND MVS EAST.
INCLUDED A CHC OF TSTMS MAINLY THU AFTN AND EVE WITH THE APPROACH OF
THIS LOW AND AN UPPER LVL SHORT WAVE.

FRI...POTENTIAL FOR A FAIR WX DAY AS SUBSIDENCE BEHIND THE EXITING
LOW ALONG WITH HIGH PRES TO THE NORTH MAY HOLD MOST SHOWERS SOUTH
AND WEST OF THE REGION.

SAT...INCREASING CHC FOR SHOWERS AND TSTMS WITH THE APPROACH OF THE
NEXT LOW WITH MAX CHANCES DURG THE AFTN AND EVE.

SUNDAY...POTENTIAL FOR A FAIR WX DAY AS SUBSIDENCE BEHIND THE
EXITING LOW PASSES ACROSS THE REGION.

&&

.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
VFR THROUGH THE TAF PERIOD AS HIGH PRESSURE BUILDS
TONIGHT. LOW PRESSURE AND A WARM FRONT APPROACH TUESDAY.

W/SW WIND FLOW LIGHTENS TONIGHT AS IT BACKS TO THE SSW-SW. S/SE
WINDS INCREASE TUE MORNING BECOMING 9-15 KT IN THE AFTERNOON.

THERE IS A CHANCE FOR SHRA AND ISO TSRA TOMORROW
AFTERNOON...MAINLY WEST OF THE NYC METRO.

.OUTLOOK FOR 00Z WEDNESDAY THROUGH SATURDAY...
.TUESDAY NIGHT-SATURDAY...MVFR OR LOWER POSSIBLE AT TIMES THROUGH
THE PERIOD IN SHRA AND POSSIBLE TSRA.

&&

.MARINE...
SEAS REMAIN UP AROUND 5 FT AT 44017...SO WILL CONTINUE SMALL
CRAFT ADVISORY FOR ANZ350 UNTIL 2 AM.

SUB SCA CONDITIONS WITH A WEAK PRESSURE GRADIENT EXPECTED TUE
INTO WED. NON OCEAN WATERS STAY BELOW SCA.

WED NIGHT THRU THU MORNING...SEAS WILL GRADUALLY SUBSIDE
BELOW SMALL CRAFT ADVISORY LVLS OF 5 FT BY THU AFTN.

THU AFTN THRU SATURDAY...CHANCE OF TSTMS MAINLY DURING THU AND SAT
AFTN AND EVENINGS WITH THE APPROACH OF LOW PRES SYSTEMS MOVING EAST
ALONG A NEARLY STATIONARY FRONT JUST SOUTH OF THE COASTAL WATERS.
WINDS AND SEAS ARE FORECAST TO REMAIN BELOW SMALL CRAFT ADVISORY
LVLS OUTSIDE OF TSTMS.

&&

.HYDROLOGY...
NO WIDESPREAD SIGNIFICANT RAINFALL IS EXPECTED THROUGH TUE.

TUE NIGHT THROUGH WED AFTN...PW VALUES 1.5 TO 1.75 INCHES WILL
ENABLE ANY SHOWERS OR THUNDERSTORMS TO PRODUCE LOCALLY HEAVY RAIN.
THE FORECAST BASIN AVG OF RAIN IS AROUND A HALF INCH BUT RAIN
AMOUNTS COULD BE HIGHER LOCALLY UP TO 1 INCH APPROXIMATELY...POSSIBLY
HIGHER.

THIS COULD CAUSE AT LEAST MINOR URBAN/POOR DRAINAGE
FLOODING...AND GIVEN EXPECTED ANTECEDENT CONDITIONS...POSSIBLY
LOCALIZED FLASH FLOODING.

THU AFTN THRU EVE AND SAT AFTN THRU EVE...AS LOW PRES
SYSTEMS MOVE EAST ALONG A COLD FRONT...THERE IS A CHC OF 1/2-3/4-
INCH RAIN WITH ISOLATED HIGHER AMOUNTS ASSOCIATED WITH HEAVIER
SHOWERS AND TSTMS. MINOR URBAN FLOODING IS POSSIBLE. THERE IS A
LOW PROB OF FLASH FLOODING.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT TUESDAY FOR ANZ350.

&&

$$
SYNOPSIS...GC/JM
NEAR TERM...MPS
SHORT TERM...JM
LONG TERM...GC
AVIATION...DS
MARINE...GC/JM/MPS
HYDROLOGY...GC/JM


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.