Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 011429
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1029 AM EDT SUN MAY 1 2016

.SYNOPSIS...
A WARM FRONT APPROACHES FROM THE SOUTH THROUGH TONIGHT WITH WAVES
OF LOW PRESSURE RIDING ALONG IT. THE FRONT LIFTS INTO THE REGION
ON MONDAY...THEN SLIDES BACK TO THE SOUTH AND STALLS MONDAY
NIGHT. WAVES OF LOW PRESSURE THEN RIDE ALONG THIS STALLED FRONTAL
BOUNDARY THROUGH TUESDAY NIGHT. A COMPLEX STORM SYSTEM THEN
IMPACTS THE TRI-STATE FROM WEDNESDAY THROUGH SATURDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FORECAST MAINLY ON TRACK...WILL MAKE ADJUSTMENTS TO HOURLY GRIDS
BASED ON LATEST SFC OBS.

PERIODS OF RAIN WILL CONTINUE TO SPREAD OVER THE REGION TODAY.
SHOWALTER INDICES FALL DOWN TO BETWEEN 0 AND 2 THIS AFTERNOON OVER
MAINLY THE WESTERN 2/3 OF THE CWA...SO WILL KEEP SLIGHT CHANCE
OF THUNDER TO ACCOUNT FOR ANY ELEVATED STORMS.

HIGHS WILL TOP OFF IN THE UPPER 40S TO LOW 50S.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
A SERIES OF SHORTWAVES PASS BY THE AREA IN WSW-SW FLOW ALOFT
TONIGHT-TUESDAY NIGHT. THE RESULT WILL BE WAVES OF LOW PRESSURE
RIDING ALONG A FRONTAL BOUNDARY THAT WILL MAINLY LAY S OF THE
REGION...EXCEPT FOR POSSIBLY ON MONDAY...WHEN THERE IS NOW ENOUGH
SUPPORT IN THE VARIOUS NWP SOLUTIONS TO BELIEVE IT SHOULD PUSH
INTO THE REGION.

THE TIMING OF THESE WAVES...EVEN THIS CLOSE TO THE EVENT IS NOT
CERTAIN...BUT FOR NOW IT APPEARS THAT THEY WILL PRODUCE MORE
WIDESPREAD RAINFALL GENERALLY DURING THE DAY THAN AT NIGHT...SO
HAVE INTRODUCED FOG/DRIZZLE/LIGHT RAIN WHEN THERE ARE EXPECTED
LULLS IN PRECIPITATION. ALSO...SHOWALTER INDICES FOR THIS EVENING
AND AGAIN ON MONDAY ARE PROGGED TO GENERALLY -2 TO 2.

ON THE WHOLE GENERALLY EXPECT PERIODS OF LIGHT TO MODERATE
RAIN...WITH LULLS OF MAINLY PATCHY FOG/DRIZZLE THROUGH TUESDAY
NIGHT. A FEW RUMBLES OF THUNDER ARE ALSO POSSIBLE SUNDAY
EVENING...AND DURING THE DAY ON MONDAY.

FOR LOWS TONIGHT...A BLEND OF MAV/MET/ECS GUIDANCE WITH NAM AND
ECMWF 2-METER TEMPERATURES WAS USED. LOWS SHOULD BE WITHIN A FEW
DEGREES OF EITHER SIDE OF NORMAL. A BLEND OF MAV/MET/ECS
GUIDANCE...NAM 2-METER TEMPERATURES AND A MIX DOWN FROM 975-950
HPA PER BUFKIT SOUNDINGS WAS USED FOR HIGHS ON MONDAY. HIGHS
SHOULD BE A FEW DEGREES BELOW NORMAL. NOTE...IF THE WARM FRONT
DOES NOT MOVE INTO THE AREA...THEN HIGHS COULD END UP 5-10
DEGREES COOLER THAN CURRENTLY FORECAST...ESPECIALLY AREAS FROM
CENTRAL LONG ISLAND ON W-NW INTO NE NJ AND THE LOWER HUDSON
VALLEY.

A BLEND OF MAV/MET/ECS GUIDANCE AND NAM 2-METER TEMPERATURES WAS
USED FOR LOWS MONDAY NIGHT...WITH VALUES WITHIN A FEW DEGREES OF
EITHER SIDE OF NORMAL. FOR HIGHS ON TUESDAY A BLEND OF MAV/MET
GUIDANCE...NAM AND ECMWF 2-METER TEMPERATURES AND A MIX DOWN FROM
950-925 HPA WAS USED PER BUFKIT SOUNDINGS. HIGHS SHOULD BE AROUND
10 DEGREES BELOW NORMAL. FOR LOWS TUESDAY NIGHT...A BLEND OF
MEX/MEN/EKD/ECE/ECM/WPC GUIDANCE AND NAM AND ECMWF 2-METER
TEMPERATURES WAS USED. LOWS SHOULD BE NEAR NORMAL.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE MODELS HAVE COME INTO BETTER AGREEMENT WITH THE HANDLING OFF A
DEVELOPING CUTOFF LOW THAT WILL MOVE INTO THE GREAT LAKES REGION
ON WEDNESDAY...THEN TRACK TO THE MID ATLANTIC COAST BY
FRIDAY...WHERE IT WILL MEANDER THROUGH SATURDAY. THE RESULT WILL
BE ON AND OFF RAIN SHOWERS OVER THE REGION THROUGH THE PERIOD.

FOR TEMPERATURES WEDNESDAY-SATURDAY THE SUPER BLEND WAS
USED...WITH HIGHS SLIGHTLY BELOW NORMAL AND LOWS SLIGHTLY ABOVE
NORMAL.

IT SHOULD BE NOTED THAT THERE IS GREATER UNCERTAINTY THAN NORMAL
DUE TO A CUTOFF LOW BEING FORECAST...AS THE HANDLING OF THIS TYPE
OF FEATURE IS NOT THE GREATEST STRENGTH OF CURRENT NWP MODELS.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
A WARM FRONT APPROACHES FROM THE SOUTH THROUGH TONIGHT WITH A WAVE
OF LOW PRESSURE RIDING ALONG IT.

LIGHT ESE WINDS SLOWLY INCREASE TO AROUND 10 KT AT MOST TERMINALS
AS THEY BACK TO THE EAST.

A FEW GUSTS 16-19 KT POSSIBLE AT COASTAL LOCATIONS THIS AFTERNOON.

RAIN CONTINUES THROUGH THE AFTERNOON. VFR CONDITIONS TO
START...EVENTUALLY LOWERING TO IFR AFTER ABOUT 18Z...FROM WEST TO
EAST.

RAIN BECOMES LIGHT AND SPOTTY TONIGHT.

.OUTLOOK FOR 12Z MON THROUGH THU...
.MON-MON NIGHT...SUB-VFR IN SHOWERS AND DRIZZLE. FOG IN THE MORNING.
.TUE...RAIN WITH MVFR OR LOWER CONDS IN THE MORNING...THEN VFR.
.WED-THU...OCNL PERIODS OF MVFR OR LOWER CONDS IN SHOWERS AND
FOG/LOW CLOUDS.

&&

.MARINE...
MADE MINOR CHANGES THIS UPDATE TO REFLECT THE LATEST TRENDS IN
OBSERVATIONS AND GUIDANCE. THE FORECAST APPEARS ON TRACK.

ONSHORE WINDS INCREASE THIS AFTERNOON WITH SOME GUSTS UP TO AROUND
25 KT ON THE OCEAN WATERS AND SEAS UP TO RIGHT AROUND 5 FT. WINDS
DIMINISH TONIGHT...BUT SEAS ON THE COASTAL OCEAN WATERS PROBABLY
HOVER AROUND 5 FT FOR A GOOD PORTION OF THE NIGHT DUE TO SWELL.
WILL THEREFORE LEAVE SCA ON THE OCEAN UNCHANGED...LASTING FROM
THIS AFTERNOON THROUGH TONIGHT.

FOR THE OTHER WATERS...SUB-SCA CONDITIONS EXPECTED. NOT OUT OF THE
QUESTION FOR A GUST OR TWO UP TO 25 KT THIS AFTERNOON OVER THE
EASTERN SOUND OR BAYS...BUT NOT WORTH CONSIDERATION OF A SCA.

SUB-SCA CONDITIONS THEN EXPECTED ON MONDAY...BUT SEAS COULD CLIMB TO
5 FT ON THE OCEAN WATERS AT TIMES DUE TO A SWELL. NOT ENOUGH
CONFIDENCE TO EXTEND THE SCA AT THIS TIME.

THE REST OF THE FORECAST PERIOD WILL BE DOMINATED BY A BROAD AREA OF
LOW PRESSURE. WHILE WINDS LIKELY REMAIN BELOW SCA CRITERIA THROUGH
THIS TIME...SWELL MAY PUSH SEAS OVER 5 FT...PRIMARILY ON WEDNESDAY
AND THURSDAY.

&&

.HYDROLOGY...
AROUND 3/4 OF AN INCH OF RAIN IS FORECAST FROM LATE TONIGHT
THROUGH MONDAY...WITH LOCALLY HIGHER AMOUNTS POSSIBLE. ANOTHER
1/4-1/2 AN INCH OR SO OF RAIN IS POSSIBLE LATE MONDAY NIGHT-
TUESDAY EVENING. AT THIS TIME...THE MOST LIKELY IMPACT WOULD BE
PONDING OF WATER ON ROADWAYS IN THOSE AREAS THAT EXPERIENCE ANY
LOCALLY HEAVY RAINFALL.

MORE WIDESPREAD PRECIPITATION IS POSSIBLE WEDNESDAY-SATURDAY.
HOWEVER...THERE IS A LARGE AMOUNT OF UNCERTAINTY IN THE EXACT
LOCATION/TIMING/AMOUNT OF PRECIPITATION AT THIS TIME.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ350-353-355.

&&

$$
SYNOPSIS...MALOIT
NEAR TERM...MPS
SHORT TERM...MALOIT
LONG TERM...MALOIT
AVIATION...JC
MARINE...JC/MALOIT
HYDROLOGY...MALOIT



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