Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 260547
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
147 AM EDT SUN APR 26 2015

.SYNOPSIS...
A LARGE UPPER LEVEL LOW PRESSURE SYSTEM WILL PERSIST OVER THE
NORTHEASTERN UNITED STATES INTO EARLY NEXT WEEK. HIGH PRESSURE
BUILDS ACROSS THE REGION TUESDAY NIGHT INTO WEDNESDAY.
MEANWHILE...LOW PRESSURE OVER THE GULF COAST STATES WILL TRACK TO
THE MID ATLANTIC COAST BY THURSDAY AND CONTINUING NORTHEAST INTO
THE ATLANTIC THROUGH THE END OF THE WEEK. AN UPPER LEVEL
DISTURBANCE MAY IMPACT THE AREA ON SATURDAY.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
FORECAST IS ON TRACK. AFTER COLLAB WITH BOX...SOME CONCERN WITH
REGARD TO TEMPS OVERNIGHT DUE TO HIGH CLOUDS ENCROACHING FROM THE
SOUTH/SOUTHWEST AND MID LEVEL CLOUDS PIVOTING SOUTHWARD ACROSS
NEW ENGLAND. ANY ADDITIONAL CLOUD COVER MAY PREVENT TEMPS FROM
FALLING QUITE AS LOW AS CURRENT FCST. HOWEVER...LATEST HOURLY
GUIDANCE DOES SUGGEST CLEARING OCCURS. LIGHT NORTH FLOW COULD LEAD
TO THE COOL TEMPS THAT ARE ALREADY IN THE FORECAST. AS
SUCH...FROST ADVISORY REMAINS IN EFFECT.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
ELONGATED UPPER TROUGH OVER NORTHERN NEW ENGLAND BEGINS TO PIVOT
SOUTH INTO CENTRAL NEW ENGLAND ON SUNDAY...WITH WEAK SURFACE
TROUGH REFLECTION DEVELOPING ALONG THE COASTAL PLAIN.

DAYTIME INSTABILITY...STEEPENING MID LEVEL LAPSE RATES...AND
CONVERGENCE ALONG SURFACE TROUGH SHOULD ALLOW FOR SCT-BKN AFT/EVE
INSTABILITY CU AND ISO-SCT SHOWER DEVELOPING OFF THE HIGHER TERRAIN
AND SINKING S/SE. HIGHEST COVERAGE WILL LIKELY BE ACROSS CT IN
VICINITY OF SURFACE TROUGH. GUSTY WINDS POSSIBLE WITH ANY SHOWERS
WITH INVERTED V SOUNDING. HIGHS GENERALLY IN THE UPPER 50S TO LOWER
60S.

UPPER TROUGH CONTINUES TO SINK SE OVER THE REGION SUNDAY NIGHT.
DIMINISHING SURFACE INSTABILITY AND CONVERGENCE SHOULD END ANY
SHOWER ACTIVITY...BUT MID-DECK SHIELD ASSOCIATED WITH TROUGH APPEARS
TO SINK SOUTH OVER THE REGION. THIS SHOULD KEEP TEMPS SEVERAL
DEGREES MILDER SUNDAY NIGHT.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
A BLOCKY PATTERN LOOKS TO DOMINATE THE FIRST HALF OF NEXT WEEK
ACROSS THE CONUS. A LARGE PERSISTENT CUTOFF LOW PRESSURE SYSTEM IS
FORECAST TO PLAGUE THE NORTHEAST US THROUGH TUESDAY WHICH WILL
RESULT IN GENERALLY MOSTLY CLOUDY CONDITIONS AND SCT SHOWERS
MON/MON NIGHT AS SPOKES OF VORTICITY WITHIN THE CYCLONIC FLOW
ROTATE THROUGH THE AREA.

THIS CUTOFF FINALLY EXITS ON TUE WITH RIDGING BRIEFLY BUILDING IN
TUE NIGHT AND WED. DRY CONDS AND PARTLY CLOUDY SKIES ARE EXPECTED.

MODEL GUIDANCE REMAINS DIVERGENT WITH HOW QUICKLY THE RIDGE AXIS
MOVES THROUGH AND THE NEXT TROUGH APPROACHES. GFS IS FASTER THAN THE
EC. WHAT BOTH MODELS DO AGREE ON IS THE PHASING OF A NRN STREAM
SHORTWAVE WITH A CUTOFF LOW OVER THE SOUTHERN PLAINS RESULTING IN A
DEEP TROUGH THROUGH THE MISSISSIPPI VALLEY TUE NIGHT. THE SFC LOW
ASSOCIATED WITH THE CUTOFF TRACKS THROUGH THE GULF COAST STATES TO
OFF THE NORTH CAROLINA COAST ON THU AND CONTINUES ON A NE TRACK
THROUGH FRI. HOWEVER DUE TO THE DIFFERENCES ALOFT THE EC IS
STRONGER...SLOWER AND CLOSER TO THE COAST...BUT CONTINUES TO REMAIN
WELL S OF THE FORECAST AREA. HAVE KEPT SCHC POPS ACROSS THE AREA THU
AS SEVERAL SHORTWAVES DIVE DOWN FROM THE N DURING THIS TIME.
HOWEVER...DUE TO THE UNCERTAINTY IN THE PATTERN EARLIER IN THE
FORECAST...THIS IS VERY LOW CONFIDENCE.

TEMPERATURES WILL BE NEAR TO SLIGHTLY BELOW NORMAL LEVELS THROUGH
THE PERIOD.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
HIGH PRESSURE REESTABLISHES ITSELF FROM THE NW THROUGH THE
MORNING HOURS BEFORE ANOTHER THERMAL TROF SETS UP ACROSS THE
AREA IN THE AFTERNOON. THE HIGH THEN BUILDS BACK IN SUN NIGHT.

THIS WILL RESULT IN A N/NE FLOW AT LESS THAN 10 KT OVERNIGHT...
WHICH THEN BACKS AROUND THE THE W/SW BY AFTERNOON. SEABREEZES ARE
LIKELY AT THE COASTAL TERMINALS...DEVELOPING AS EARLY AS 15Z
ALONG THE CT COAST. KEWR AND KLGA MAY SEABREEZE LATE. WINDS ARE
LIKELY TO VARY AS THE TROUGH SETS UP IN THE AFTERNOON.

.OUTLOOK FOR 06Z MONDAY THROUGH THU...
.SUN NIGHT...VFR..
.MON-MON NIGHT...POSSIBLE MVFR WITH SHOWERS.
.TUE-WED NIGHT...VFR.
.THU...POSSIBLE MVFR WITH SHOWERS.

&&

.MARINE...
A WEAK PRES GRADIENT WILL KEEP SUB-ADVSY CONDS ACROSS THE WATERS
THROUGH MUCH OF THE PERIOD.

MARGINAL NW GUSTS ARE POSSIBLE LATE MON NIGHT INTO TUE ON THE
EASTERN OCEAN WATERS AS THE GRADIENT TIGHTENS.

&&

.HYDROLOGY...
SIGNIFICANT PRECIPITATION IS NOT EXPECTED THROUGH NEXT WEEK.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...FROST ADVISORY UNTIL 8 AM EDT THIS MORNING FOR CTZ005>008-
     010>012.
NY...FROST ADVISORY UNTIL 8 AM EDT THIS MORNING FOR NYZ067>070-079-
     081.
NJ...FROST ADVISORY UNTIL 8 AM EDT THIS MORNING FOR NJZ002-004-103-
     105-107.
MARINE...NONE.

&&

$$


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