Area Forecast Discussion
Issued by NWS Upton, NY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KOKX 262347
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
747 PM EDT Wed Jul 26 2017

.SYNOPSIS...
High pressure moves off the mid-Atlantic coast through Thursday. Low
pressure forms late Friday over Virginia and passes south of
Montauk Saturday Morning which likely brings rain to the region.
Canadian high pressure builds from the north late Saturday into
early next week.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
High and mid level clouds will continue to increase from the
west tonight. Minor updates have been made to reflect current
sky cover, temperature and dew point trends.

Otherwise, most should be able to see the International Space
Station (ISS) passing over at 8:57 EDT for 6 minutes from WSW to
NE this evening, brighter than Jupiter in the western sky.

Lows around 65 in the NY Metro - near 60 elsewhere (around 5
degrees below climo). Could have some valley fog towards
morning over the interior, but with the increase in high level
moisture, decided to not including it.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Weak frontal boundary sags down and over the region Thursday
evening. Have continued with low chance TSTMs with SPC lowering
the region to marginal after collaboration with Local NWS Offices.

Ensemble of NWP suggest about 1000 J/kg of MUCAPE and LI`s of -1
to -4 C of LI. Shear is only around 30 KT and most show
subsidence in the 850-700 hPa layer. Thus the lowering of POPs
and severe potential.

POPs increase overnight as front sags southeast. Instability
then has a synoptic support from the frontal passage and most
NWP supports scattered convection.

Upper 70s to around 80 based on consensus of MOS for highs and
around 70 for lows Thursday night using warmer NAM MOS based on
clouds and scatted precipitation.

There is a moderate risk of rip currents at area beaches.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
The long term period starts off with unsettled weather Friday,
Friday night and the first half of Saturday as low pressure passes
south of the forecast area.

At this time, looks like showers and thunderstorms will occur on
Friday. There is the potential that some rain could be heavy at
times.

the showers should transition to more of a stratiform rain event
Friday night into Saturday morning, once again with some rain
potentially being heavy, especially during the first half of Friday
night. Winds will increase, especially across Long Island and
southern CT, as the low intensifies Friday night and Saturday.  Gusts
into the 30 mph range is possibly, and can not rule out a few gusts
to 40 mph.

As of right now, average rainfall amounts for this event are
expected to range from 0.50-1.00 inches across the Lower Hudson
Valley and southern CT and from 1.00-1.70 across the Northeast NJ,
NYC and Long Island. Locally higher amounts will be possible. These
amounts are likely to change, as we fine tune the exact track of the
low.

The low moves east on Saturday. The rain comes to an end Saturday
morning as high pressure builds in from the north.

High pressure remains over the region through the first half of next
week, providing dry and seasonable conditions.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
High pressure slides offshore through tonight. A weakening cold
front approaches from the northwest on Thursday.

Mainly VFR through the TAF period. There is a low chance of
MVFR conditions late tonight into Thursday morning, especially
across the Lower Hudson Valley.

S-SE winds at 5-10 kt will become light and variable throughout
tonight. Winds then become S-SW at under 10 kt by mid-late
Thursday morning.

     NY Metro Enhanced Aviation Weather Support...

Detailed information, including hourly TAF wind component forecasts,
can be found at: http:/www.weather.gov/zny/n90

KJFK TAF Comments: Timing of onset of light and variable winds
could be off +/- 1-2 hours.

KLGA TAF Comments: Timing of onset of light and variable winds
could be off +/- 1-2 hours.

KEWR TAF Comments: Timing of onset of light and variable winds
could be off +/- 1-2 hours.

KTEB TAF Comments: Timing of onset of light and variable winds
could be off +/- 1-2 hours.

KHPN TAF Comments: Timing of onset of light and variable winds
could be off +/- 1-2 hours.

KISP TAF Comments: Timing of onset of light and variable winds
could be off +/- 1-2 hours.

.OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...
.Thursday afternoon-Thursday night...MVFR possible, with a
chance of showers and possibly a tstm.
.Friday-Saturday morning...MVFR or lower possible, with showers and
possibly a tstm. NE winds G20-30kt late Friday night into
Saturday, mainly at the coastal terminals.
.Saturday afternoon-Monday...VFR.

&&

.MARINE...
Tranquil into Friday. Winds and seas gradually build to
advisory levels Friday night and into Saturday night as low
pressure passes over the area waters. Expect a strengthening
N-NE flow, with the potential for gales Friday night into
Saturday. Winds will subside below advisory level on Sunday,
however it may not take until Monday for seas to fall back below
5 ft as high pressure builds in.

&&

.HYDROLOGY...
Heavy rainfall is possible Friday afternoon into the night
across the NY Metro and Long Island. Urban and poor drainage
flooding is possible.

&&

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

&&

$$
SYNOPSIS...Tongue
NEAR TERM...MD/Tongue
SHORT TERM...Tongue
LONG TERM...BC
AVIATION...Maloit/DW
MARINE...BC/Tongue
HYDROLOGY...BC



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.