Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 121738
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
138 PM EDT SAT JUL 12 2014

.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFFSHORE THIS AFTERNOON AND EVENING. A
WARM FRONT MOVES NORTH OF THE REGION SUNDAY WITH ITS ASSOCIATED
COLD FRONT APPROACHING THE AREA FROM THE WEST. THE COLD FRONT
STALLS NEARBY THROUGH EARLY NEXT WEEK WITH WEAK AREAS OF LOW
PRESSURE FORMING ALONG IT. THE FRONT PUSHES TO THE EAST BY
WEDNESDAY WITH HIGH PRESSURE WILL BUILDING IN THURSDAY INTO
FRIDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FORECAST ON TRACK WITH MINOR UPDATES TO SKY/T/TD GRIDS TO MATCH
CURRENT TRENDS. HIGH TEMPERATURES NEAR AVERAGE FOR JULY 12...IN
THE LOW AND MIDDLE 80S.

HIGH PRESSURE WILL SHIFT SOUTH AND EAST OF LONG ISLAND THIS
AFTERNOON AND EVENING. OVERALL WEAK PRESSURE GRADIENT WILL REMAIN
ACROSS THE AREA WITH AFTERNOON SEA BREEZES EXPECTED TO DEVELOP.

WARMER AND MORE MOIST AIR WILL BEGIN TO BE ADVECTED IN AS MORE OF
A LOW LEVEL SOUTHWEST FLOW DEVELOPS. THIS WILL INCREASE
INSTABILITY AND MODELS INDICATE SURFACE TROUGH DEVELOPMENT TO THE
WEST OF THE REGION WITH DAYTIME HEATING. THIS MAY PROVIDE ENOUGH
CONVERGENCE FOR A SHOWER OR THUNDERSTORM ACROSS ORANGE COUNTY AND
WESTERN PASSAIC COUNTY...BUT POPS ARE JUST SLIGHT CHANCE.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
ANY CONVECTION EXPECTED TO QUICKLY DISSIPATE AFTER THE LOSS OF
DAYTIME HEATING AND THEREBY INSTABILITY SINCE ALOFT THE WEAK
HEIGHT GRADIENT PERSISTS. THIS LACK OF SYNOPTIC FORCING WILL KEEP
CONDITIONS DRY TONIGHT. THE ESTABLISHMENT OF SOUTHERLY FLOW WILL
BECOME MORE LOCKED INTO PLACE.

THIS WILL BEGIN THE TRANSITION TO MORE OF A HUMID AND WARM
AIRMASS. WE WILL SEE THIS REFLECTED IN NIGHT TIME TEMPERATURES
BEING SEVERAL DEGREES WARMER THAN THOSE OF THE PREVIOUS NIGHT DUE
TO ONSHORE FLOW AS WELL AS EXTRA CLOUDS.

ONE FEATURE TO NOTE THAT IS DRIVING THIS TRANSITION IS AN
UNUSUALLY DEEP CUTOFF LOW IN ONTARIO THAT WILL BE PUSHING SOUTH
INTO THE GREAT LAKES. ASSOCIATED WITH THIS WILL BE A DEEP TROUGH
AND STRONG UPPER LEVEL JET...BOTH OF WHICH WILL BE SLOWLY MOVING
SOUTH AND EAST TOWARDS THE REGION SUNDAY THROUGH MONDAY NIGHT. A
WARM FRONT AT THE SURFACE MOVES NORTH OF THE AREA SUNDAY AND THEN
AN ASSOCIATED COLD FRONT SLOWLY APPROACHES FROM THE
WEST...EVENTUALLY STALLING IN OUR REGION EARLY NEXT WEEK WITH
SMALL LOWS MOVING ALONG IT.

THE WEATHER WILL BECOME INCREASINGLY UNSETTLED WITH THE COLDER
TEMPERATURES ALOFT AND THE CONTINUED WARM AND MOIST AIR ADVECTION
NEAR THE SURFACE. SHOWERS AND THUNDERSTORMS WILL BECOME MORE
FREQUENT ACROSS WESTERN PARTS OF THE REGION SUNDAY AND WILL REACH
THE REST OF THE EASTERN PARTS OF THE REGION SUNDAY NIGHT INTO
MONDAY. CHANCES WILL BE INCREASING GOING THROUGH TIME.

THE BULK SHEAR 0-6 KM INCREASES TO AROUND 20-25 KT SUNDAY AND
SUNDAY NIGHT WITH SHEAR MORE AROUND 25-35 KT MONDAY THROUGH MONDAY
NIGHT. THIS WILL ALLOW FOR STRONGER THUNDERSTORMS TO FORM. THE
CONTINUED WARM AND MOIST AIR ADVECTION WILL ALLOW FOR A PERSISTENT
PWAT OF NEAR 2 INCHES...SO THIS WILL ENABLE THUNDERSTORMS TO
PRODUCE HEAVY RAIN. PARALLEL FLOW FROM LOW TO UPPER LEVELS WILL
ENABLE OF TRAINING OF CONVECTION...ALLOWING FOR MULTIPLE ROUNDS OF
SHOWERS AND THUNDERSTORMS TO MOVE ACROSS THE SAME AREA.

TEMPERATURES ARE FORECAST TO BE NEAR TO SLIGHTLY ABOVE NORMAL.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE COLD FRONT CONTINUES TO LINGER WITHIN THE LOCAL AREA THROUGH
TUESDAY NIGHT. AS A RESULT...EXPECT ROUNDS OF SHOWERS AND
THUNDERSTORMS CONTINUING THROUGH EARLY WEDNESDAY...AS WEAK LOWS
MOVE ALONG THE STALLED FRONT. DRIER AIR MOVES IN FOR LATER ON
WEDNESDAY AND THROUGH THE END OF THE WEEK.

HIGH TEMPERATURES WILL BE NEAR TO SLIGHTLY ABOVE NORMAL ON AVERAGE
ACROSS THE REGION TUESDAY AND THEN SLIGHTLY BELOW NORMAL ON
AVERAGE WEDNESDAY THROUGH FRIDAY.

LOW TEMPERATURES AT NIGHT ARE FORECAST TO BE SLIGHTLY ABOVE NORMAL
TUESDAY NIGHT AND TREND TO SLIGHTLY COOLER THAN NORMAL FOR THE
REMAINDER OF THE WEEK.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL REMAIN OFFSHORE THROUGH TONIGHT...THEN MOVE
FARTHER EAST ON SUNDAY AS A COLD FRONT APPROACHES.

SOUTH TO SOUTHWEST WINDS...GENERALLY 10 KT OR LESS...WILL INCREASE
EARLY THIS AFTERNOON. SEA BREEZES WILL ENHANCE THE WINDS ALONG THE
COAST...WITH SPEEDS AS HIGH AS 15 KT.

MVFR FOG DEVELOPMENT MORE LIKELY TONIGHT WITH A LIGHT ONSHORE FLOW.
FEW TO SCATTERED 005 KFT TO 010 KFT CLOUDS POSSIBLE. LOW CHANCE OF
IFR CEILINGS ALONG THE COAST AFTER 09Z.

ALL TERMINALS SHOULD RETURN TO VFR BY 14Z...HOWEVER CLOUDS WILL
GRADUALLY INCREASE THROUGH THE DAY. FOR THE 30 HOUR TAFS WEST OF
NYC...HAVE INCLUDED A PROB30 GROUP FOR THUNDER LATE IN THE DAY.

.OUTLOOK FOR 18Z SUNDAY THROUGH THURSDAY...
.SUNDAY AFTERNOON-WEDNESDAY...SCATTERED TO NUMEROUS SHRA/TSTMS.
STRONGER TSTMS DURING THIS TIME FRAME COULD PRODUCE PERIODS OF MVFR
OR LOWER CONDITIONS...LOCALLY HEAVY RAINFALL...AND GUSTY WINDS.
CONDITIONS IMPROVE LATE WEDNESDAY.
.THURSDAY...VFR.

&&

.MARINE...
LIGHT WINDS BECOME SOUTHERLY THIS AFTERNOON. CONDITIONS WILL
REMAIN TRANQUIL TODAY THROUGH SUNDAY. HOWEVER...LATE SUNDAY THE
SOUTHERLY WIND BEGINS TO INCREASE AND SEAS ON THE OCEAN WILL
LIKELY BUILD TO SMALL CRAFT LEVELS BY LATE SUNDAY NIGHT. THE
AMBROSE JET WILL INCREASE SUNDAY INTO SUNDAY EVENING AND SOME
GUSTS IN THE VICINITY MAY BE NEAR SMALL CRAFT LEVELS FOR SEVERAL
HOURS. THE STRONG SOUTHERLY FLOW CONTINUES AHEAD OF THE
APPROACHING COLD FRONT AND SEAS ON THE OCEAN CONTINUE AT SMALL
CRAFT LEVELS MONDAY INTO TUESDAY NIGHT. THE COLD FRONT MOVES
ACROSS THE WATERS LATE TUESDAY NIGHT INTO WEDNESDAY. BELOW SCA
CONDITIONS SHOULD RETURN BY WEDNESDAY NIGHT AS HIGH PRESSURE
BUILDS TOWARD THE WATERS THROUGH THURSDAY.

&&

.HYDROLOGY...
NO WIDESPREAD SIGNIFICANT HYDROLOGIC ISSUES EXPECTED THROUGH
SUNDAY MORNING.

THERE IS THE POTENTIAL FOR SIGNIFICANT RAINFALL FROM LATE SUNDAY
INTO EARLY WEDNESDAY. AT THIS TIME THERE IS TOO MUCH UNCERTAINTY TO
SPECIFY EXACT AMOUNTS OR SPECIFIC THREATS...OTHER THAN TO NOTE
FLOODING IS POSSIBLE IN AREAS THAT EXPERIENCE ROUNDS OF LOCALLY
HEAVY RAINFALL.

&&

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

&&

$$
SYNOPSIS...JM/DS
NEAR TERM...JM/DS
SHORT TERM...JM
LONG TERM...FIG
AVIATION...BC
MARINE...FIG/MET
HYDROLOGY...FIG/JM





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