Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 210753
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
353 AM EDT Sat Oct 21 2017

.SYNOPSIS...
Mild weather continues through the weekend. A cold front brings
rain to the region on Tuesday that may linger into Wednesday as
temperatures cool. High pressure builds back in by late in the
week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Mild and dry weather continues with high pressure over the
region.

With temps so anomalous - we`ve gone with the warmer GFS/ECMWF
MOS Blend. This places all locals well into the 70s with KEWR
getting into the lower 80s. While we`ll be 15 degrees above
normal - it`s still below record values (except perhaps KISP`s
76 which was set last year).

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
Cirrus starts to increase on Sunday and we`re partly to mostly
cloudy on Monday as warm advection increases aloft. Max temps
lower slightly due to the cloud cover, but still well above
seasonable.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Well, it sure appears that it will actually rain! Analysis of
the 00Z GEFS suggests cold FROPA consensus timing is focused on
Tuesday Evening in the local area as a rather potent cyclone
occludes over the Great Lakes. Note that the ECMWF deterministic
run suggest a slightly slower and prolonged passage.

The GFS BUFR wind data has impressed me with the narrow cold
frontal rain band. Standardized anomalies and the ensemble
situational awareness table indicate +3 Standard Deviation in
the 925 hPa southerly winds in the GEFS with the deterministic
GFS run getting up to +5 or more. Thus, the threat for at least
wind advisory (Gust 40+ KT) criteria is increasing - especially
for Long Island and Southern CT.

Did remove the thunder from the forecast as there`s no cape and
it all indices do not support it.

Beyond Tuesday night, uncertainty is high as for how much, if
any rain we get Wednesday. the majority of the GEFS members keep
the rain offshore. The local forecast is trending this
direction.

Temperatures average above normal through the period with
Thursday being closest to normal.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
VFR through the TAF period as high pressure builds in from the
west overnight, then begins to move offshore later today.

Light and variable winds become S/SW less than 10 kt in the
afternoon.

.OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY...
.Sunday...VFR.
.Sunday night-Monday...MVFR/IFR possible in stratus and fog.
.Tuesday...MVFR possible in showers. S wind G20-30 KT at coast.
LLWS possible.
.Wednesday...VFR. A chance of showers with areas of MVFR,
especially early.

&&

.MARINE...
Sub-advsy conds will prevail on the waters into at least Mon night.
The pressure gradient will begin to tighten late Mon night between
high pressure to the east and strengthening low pressure to the
west. SCA conds are expected to develop on Tue, with gale force
winds possible late Tue and Tue night as there is the potential for
a 50-60kt LLJ at 950mb. There is uncertainty with the strength and
track of the low, so wind forecast does not reflect this potential
yet, but have increased the gusts from previous forecast. Will also
mention the gale potential in the HWO. Winds begin to subside Tue
night, although the GFS is faster than the EC, so may be bringing
them down a bit too quick. Seas will likely remain above SCA
levels on the ocean waters through Wed night.

&&

.HYDROLOGY...
No hydrologic problems are expected the next 7 days. Rain with cold
frontal passage late Tuesday should average near 1".

&&

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

&&

$$
SYNOPSIS...Tongue
NEAR TERM...Tongue
SHORT TERM...Tongue
LONG TERM...Tongue
AVIATION...24
MARINE...24
HYDROLOGY...Tongue


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