Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 300524
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
124 AM EDT TUE JUN 30 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 THIS MORNING/...
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 THIS MORNING THROUGH 6 PM 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 /06Z TUESDAY THROUGH SATURDAY/...
HI PRES DRIFTS OVER THE ATLC TODAY. A WARM FRONT APPROACHES FROM
THE S TNGT AND LIFTS THRU WED MRNG.

MAINLY VFR THRU AT LEAST 4Z WED. THERE COULD BE SOME POCKETS OF
FOG AT THE OUTLYING ARPTS THRU 12Z...BUT THE PROB WAS TOO LOW TO
INCLUDE IN THE TAFS. CHC FOR SHWRS MAINLY AFT 8Z IN THE EXTENDED
TAFS...BUT THERE COULD ALSO BE SOME STRATUS DURING THE SAME PERIOD
INVOF THE FRONT.

LGT WINDS THRU 12Z WITH SOME VARIABILITY IN DIRECTION...ALTHOUGH
IN GENERALLY PREVAILING AROUND 220-180 TRUE. WINDS BACK TO THE SE
DURING THE DAY AND FURTHER TO THE ESE TNGT.

.OUTLOOK FOR 06Z WEDNESDAY THROUGH SATURDAY...
.TUESDAY NIGHT-SATURDAY...MVFR OR LOWER POSSIBLE AT TIMES THROUGH
THE PERIOD IN SHRA AND POSSIBLE TSRA.

&&

.MARINE...
SCA WILL BE ALLOWED TO EXPIRE AT 06Z AS SEAS HAVE FALLEN BELOW 5
FT.

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 EARLY THIS MORNING FOR
     ANZ350.

&&

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



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