Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 182130
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
530 PM EDT SAT APR 18 2015

.SYNOPSIS...
A COLD FRONT WILL CROSS THE TRI-STATE THROUGH EARLY THIS
EVENING....FOLLOWED BY HIGH PRESSURE BUILDING TO THE NORTH INTO
SUNDAY MORNING. THIS HIGH SLIDES TO THE EAST INTO SUNDAY
NIGHT...ALLOWING A WARM FRONT TO APPROACH FROM THE SOUTH SUNDAY
NIGHT AND MONDAY...LIKELY MOVING THROUGH SOMETIME LATE
MONDAY OR MONDAY NIGHT. A COLD FRONT PASSES TUESDAY. A SERIES OF
WEAK COLD FRONTS AND/OR TROUGHS OF LOW PRESSURE WILL MOVE THROUGH
DURING THE MID TO LATE WEEK PERIOD.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
DEEP LAYERED RIDGING BUILDS IN FROM THE WEST TONIGHT. ASSOCIATED
SUBSIDENCE AND DOWNSLOPE FLOW SHOULD KEEP THINGS DRY AND PROMOTE
MINIMAL CLOUD COVER TONIGHT.

LOWS TONIGHT WERE BASED ON A BLEND OF MAV/MET/ECS GUIDANCE AND
SHOULD BE A FEW TO FIVE DEGREES ABOVE NORMAL. IT IS UNCERTAIN
HOWEVER...EXACTLY HOW MUCH DECOUPLING WILL OCCUR DURING THE
OVERNIGHT HOURS...ESPECIALLY OVER WESTERN ZONES. IF MORE
DECOUPLING OCCURS THEN CURRENTLY EXPECTED - THEN WOULD NEED TO
LOWER LOWS WHERE THIS OCCURS BY 5 DEGREES OR SO.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
DEEP LAYERED RIDGING CONTINUES TO BUILD OVER THE AREA
SUNDAY...WITH ITS RIDGE AXIS LOCATED NEAR THE HUDSON RIVER BY
AROUND 00Z MONDAY. COULD SEE A FEW HIGH CLOUDS BUILD IN OVER
WESTERN ZONES IN THE AFTERNOON AS A RESULT...OTHERWISE THERE
SHOULD BE LITTLE IF ANY IN THE WAY OF CLOUD COVER SUNDAY.

HIGHS ON SUNDAY WERE BASED ON A BLEND OF MIXING DOWN FROM 900-875
HPA PER BUFKIT SOUNDINGS WITH NAM 2-METER TEMPERATURES AND A BLEND
OF MAV...MET AND ECS GUIDANCE. HIGHS SHOULD BE NEAR TO SLIGHTLY
BELOW NORMAL.

HAVE KEPT THINGS DRY THROUGH SUNDAY EVENING DUE TO SUBSIDENCE
UNDER DEPARTING RIDGE. SHOULD THEN HAVE SUFFICIENT WARM
ADVECTION/ISENTROPIC UPGLIDE LATE SUNDAY NIGHT TO WARRANT POPS
FROM CHANCE EASTERN ZONES (SLIGHT CHANCE FAR E NEW LONDON COUNTY)
TO CATEGORICAL OVER ROUGHLY THE WESTERN 1/4 OF THE CWA AFTER 6Z.

WITH A 45-55 KT LOW LEVEL JET FORECAST TO IMPINGE ON THE CWA BY
LATE SUNDAY NIGHT...SHOULD SEE SOME MODERATE...TO POSSIBLY LOCALLY
HEAVY RAINFALL IN AREAS WITH CATEGORICAL POPS LATE SUNDAY NIGHT.

FOR NOW...BELIEVE MARINE INVERSION WILL KEEP MOST IF NOT ALL OF
THE LOW LEVEL JET ALOFT SUNDAY NIGHT...WITH STRONGEST WINDS NEAR
THE COAST. GUSTS SHOULD BE 25 MPH OR LESS...WITH LITTLE IF ANY
GUSTING OVER N INTERIOR ZONES.

FOR LOWS SUNDAY NIGHT USED A BLEND OF MAV/MET/ECS GUIDANCE WITH
NAM 2-METER TEMPERATURES...WITH NEAR NORMAL TEMPERATURES
FORECASTED.WOULD EXPECT A NON-DIURNAL TEMPERATURE TREND...ESPECIALLY
AFTER MIDNIGHT GIVEN DEVELOPING STRONG LOW LEVEL WARM ADVECTION
THEN.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
THIS MEDIUM RANGE PERIOD WILL FEATURE A FULL LATITUDE TROUGH...
UPPER LEVEL LOW WHICH SLOWLY TRAVERSES FROM THE GREAT LAKES REGION
ACROSS THE NORTHEAST. SPLIT FLOW OUT WEST...AND EVENTUAL PACIFIC NW
ENERGY SHOULD KICK THIS UPPER LOW OVER THE NORTHEAST OUT BY NEXT
WEEKEND.

AT THE SURFACE...WARM FRONT APPROACHES MONDAY...WITH A WEAK WAVE OF
LOW PRESSURE...TRIPLE POINT NEARING THE AREA. WITH THE MAIN SFC LOW
FAR TO THE WEST CLOSER TO THE UPPER TROUGH...WARM FRONT MAY HAVE A
HARD TIME MOVING THROUGH UNTIL RIGHT BEFORE THE COLD FRONTAL
PASSAGE...WHICH LOOKS TO OCCUR EARLY TUESDAY.

THE AREA WILL REMAIN BETWEEN HIGH PRESSURE TO THE SOUTH AND LOW
PRESSURE TO THE NORTH THROUGH WEDNESDAY. ANOTHER COLD FRONT
APPROACHES WED NIGHT AND MOVES THROUGH THURSDAY...AS UPPER ENERGY
ROUNDS THE BASE OF THE LOW.

AS FOR SENSIBLE WEATHER...RAIN MOVES IN AHEAD OF THE WARM FRONT/SFC
WAVE. STRENGTHENING LOW LEVEL JET WILL RESULT IN MODERATE TO
POSSIBLY HEAVY RAIN FOR A TIME MONDAY...WITH PLENTY OF LIFT OVER THE
COOLER AIR AT THE SFC. ATLANTIC AND GULF MOISTURE IS TAPPED WITH
THIS SYSTEM...SO WOULD EXPECT SIGNIFICANT RAINFALL.

ELEVATED INSTABILITY NOTED AS WELL LATE MONDAY AND MONDAY NIGHT.
WILL ADD IN ISOLATED THUNDER AND PATCHY FOG AS THE WARM FRONT SITS
NEARBY.

THEREAFTER...GENERALLY DRY WEATHER RETURNS...ALTHOUGH HARD TO LEAVE
OUT POPS LATE IN THE WEEK DUE TO PRESENCE OF UPPER LOW/COLD POOL.
BEST CHANCE THOUGH FOR ADDITIONAL RAIN LOOKS TO BE WED NIGHT INTO
EARLY THURSDAY AHEAD OF THE COLD FRONT.

TEMPS SHOULD REMAIN SLIGHTLY BELOW NORMAL MONDAY PER MOS...ASSUMING
WARM FRONT REMAINS SOUTH. SEASONABLE TEMPS ARE EXPECTED
TUESDAY...WITH A GRADUAL COOLING TREND THEREAFTER. FOLLOWED
MEX/GRIDDED MOS AND WPC NUMBERS THROUGH MUCH OF THIS TIME FRAME.

&&

.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
A COLD FRONT PASSES THROUGH THIS EVENING FOLLOWED BY HIGH PRESSURE
BUILDING OVER THE TERMINALS INTO SUNDAY MORNING.

VFR THRU THE TAF PERIOD. W-WNW WINDS 10 TO 15 KT THIS AFTERNOON WITH
GUSTS 20 TO 25 KT AWAY FROM THE COAST. S-SW SEA BREEZES AT
KJFK/KLGA/KISP/KBDR/KGON. WINDS WILL SHIFT TO THE NW THIS EVENING
WITH COLD FRONT PASSAGE WITH GUSTS AROUND 20 KT CONTINUING.

WINDS WILL SHIFT TO THE NW THIS EVENING WITH GUSTS AROUND 20 KT.
GUSTS END BY 06Z...WITH WINDS VEERING TO THE NE. NE WINDS CONTINUE
SUNDAY MORNING.

.OUTLOOK FOR 18Z SUNDAY THROUGH THURSDAY...
.SUN...VFR. WINDS BECOMING SE IN THE AFTERNOON WITH G15-20KT
POSSIBLE.
.SUN NIGHT...MVFR/IFR IN RAIN. LLWS DEVELOPING LATE. ESE G20-25KT
LATE.
.MON...MVFR/IFR. RAIN. LLWS EARLY. INCREASING ESE SFC WIND.
G30KT.
.TUE...MVFR BECOMING VFR.  WEST G25KT.
.WED-THU...MVFR POSSIBLE IN CHANCE OF SHOWERS.

&&

.MARINE...
GUSTS TO AROUND 20 KT THIS EVENING...WITH POSSIBLY SOME ISOLATED
GUSTS TO 25 KT...THEN WINDS DIMINISH TO AROUND 15 KT OR LESS ON
ALL WATERS OVERNIGHT...AND REMAIN SO THROUGH SUNDAY EVENING.
WINDS INCREASE LATE SUNDAY NIGHT OUT OF THE E. AT THIS TIME...NOT
CONFIDENT ENOUGH IN GUSTS TO 25 KT TO PUT IN THE FORECAST...BUT
CANNOT RULE OUT. HOWEVER...WINDS SHOULD BE STRONG ENOUGH TO BRING
SEAS ON THE COASTAL OCEAN WATERS TO SCA LEVELS LATE SUNDAY NIGHT.
HAVE HOISTED AN SCA THERE STARTING AT MIDNIGHT SUNDAY NIGHT AS A
RESULT.

BY MONDAY...EXPECT CONDITIONS TO DETERIORATE QUICKLY AHEAD OF A
FRONTAL SYSTEM...AND HAVE SCA FOR COASTAL OCEAN WATERS ON MONDAY
AS RESULT.

EXPECT E/SE WINDS TO INCREASE RAPIDLY MONDAY MORNING...WITH
BUILDING SEAS THE RESULT. IN FACT...A FEW GALE GUSTS ARE POSSIBLE
MONDAY. THE WINDS DIMINISH LATE IN THE DAY AND AT NIGHT AS THE
FRONT NEARS.

A COLD FRONT WILL PASS ACROSS THE WATERS TUESDAY...AND WINDS ARE
EXPECTED TO SHIFT TO THE WEST BEHIND THE FRONT. ELEVATED OCEAN SEAS
WILL TAKE SOME TIME TO SUBSIDE THROUGH TUESDAY.

HIGH PRESSURE BUILDS WELL TO THE SOUTH TUESDAY AND WEDNESDAY.
ANOTHER FRONT APPROACHES WED NIGHT INTO THURSDAY. WINDS INCREASE
AHEAD OF AND BEHIND THE FRONT.

FOR THE NON OCEAN WATERS...SCA CONDITIONS ARE EXPECTED MONDAY...THEN
SUB SCA IS FORECAST THROUGH THURSDAY.

&&

.FIRE WEATHER...
ACROSS LONG ISLAND AND CSTL CT...CONDITIONS HAVE IMPROVED DUE TO
SEA BREEZE DEVELOPMENT.

FOR THE REMAINDER OF THE CWA...DRY WEATHER...MINIMUM RH 20-30
PERCENT...AND WINDS GUSTING TO 25-30 MPH WILL LEAD TO ELEVATED
POTENTIAL FOR FIRE GROWTH/SPREAD THROUGH EARLY THIS EVENING. GUSTS
MAY BRIEFLY STRENGTHEN AFTER THE COLD FRONTAL PASSAGE AS WELL. A
RED FLAG WARNING IS IN EFFECT THROUGH 8 PM.

&&

.HYDROLOGY...
THERE IS THE POTENTIAL FOR SIGNIFICANT RAINFALL WITH
AN APPROACHING FRONTAL SYSTEM FROM LATE SUNDAY NIGHT INTO MONDAY
NIGHT. STORM TOTAL RAINFALL WITH THIS SYSTEM IS EXPECTED TO BE IN
THE 1 TO 2 INCH RANGE. LOCALIZED HIGHER AMOUNTS WILL BE POSSIBLE.
THIS COULD CAUSE POSSIBLE MINOR FLOODING OF URBAN AND POOR
DRAINAGE AREAS.

FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEB SITE.

&&

.TIDES/COASTAL FLOODING...
INCREASING E/SE FLOW MONDAY MAY RESULT IN LOCAL TO WIDESPREAD MINOR
COASTAL FLOODING. ASTRONOMICAL HIGH TIDES WILL BE RUNNING HIGH
FOLLOWING A NEW MOON. IN SOME CASES...DEPARTURES OF ONLY HALF A FOOT
ABOVE NORMAL ARE NEEDED. STORM SURGE COULD PRODUCE WATERS LEVELS 1
TO 1 1/2 FT ABOVE NORMAL.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR CTZ005>007.
NY...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR NYZ067>074.
NJ...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR NJZ002-004-
     006-103>108.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT SUNDAY NIGHT TO 6 PM EDT
     MONDAY FOR ANZ350-353-355.

&&

$$
SYNOPSIS...MALOIT/PW
NEAR TERM...MALOIT/PW
SHORT TERM...MALOIT
LONG TERM...PW
AVIATION...DS
MARINE...MALOIT/PW
FIRE WEATHER...PW
HYDROLOGY...MALOIT/PW
TIDES/COASTAL FLOODING...PW



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