Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 221745
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
145 PM EDT Tue Aug 22 2017

.SYNOPSIS...
A cold front will approach today and pass early Wednesday. High
pressure then remains in control through the end of the week
with a much drier and cooler airmass.

&&

.NEAR TERM /THROUGH TONIGHT/...
Stratus has burned off for most coastal areas, but still
expecting cumulus development this afternoon. Could be an
isolated shower or thunderstorm in parts of the Lower Hudson
Valley during the first half of the afternoon, otherwise iso/sct
storms late this afternoon mainly west of the city. Shear and
CAPE values support the chance of strong gusts in TSTMs.

Highs in the lower 90s combined with dewpoints in the mid 70s
will combine for heat index values around 100 where the heat
advisory currently remains in effect for this afternoon.

Forcing increases this eve and tngt as the h3 jet gets closer,
however the existing convection may outrun the main forcing,
which could suppress additional development. High cape today
along with good shear balance, particularly wrn areas. There
will be svr chances with anything that pops in that environment.
As the night progresses, strong h85 winds around 50kt traverse
the cwa. Damaging winds possible in the stronger storms in this
environment.

Waves will get increasingly choppy this aftn as ssw winds
increase. A high rip current risk remains in effect for today.

&&

.SHORT TERM /WEDNESDAY/...
The actual cold front will be lagging behind and pass during the
day. The prefrontal trof however and preceding tstms are
progged to clear out most of the instability before the front
gets here. As a result, only low chances for tstms will remain
in the fcst until the fropa. The thermal trof will be exiting,
however, the hot air aloft should mix down early resulting in a
warm day, especially ern areas, but with less humidity. Because
of this, heat indices should be cooler than Tue. A blend of the
guidance was used for temps.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Canadian high pressure builds into the region Thursday through early
next week, providing dry and sunny conditions. Temperatures will
remain below normal as highs only reach the 70s to near 80 each day.

There could be some isolated showers/tstms on Sunday as an upper
trough moves through the Northeast. Most model guidance has the
upper level energy passing to the north of the CWA so have not
included in the current forecast, however this may change in
subsequent forecasts.

An area of low pressure may pass south of Long Island early next
week. While it should remain dry, an increasing easterly flow is
expected to develop.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
A cold front approaches the region late today and crosses
tonight.

South/Southwest winds will strengthen into the late afternoon.
Gusts of 20 to 25 knots expected for the afternoon/evening push,
with occasional gusts to 30 kt possible for LI and NYC/NJ metro
terminals.

Widespread showers/thunderstorms will track across Central NY/PA
late this afternoon, before weakening but likely working into
NYC/NJ terminals after 03Z with MVFR conditions. Gusty winds
possible in any stronger thunderstorm. Showers and
thunderstorms push east of the terminals overnight.

 ...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: S gusts 25-30 kt likely after 20z.

KLGA TAF Comments: S gusts 25-30 kt likely after 21z.

KEWR TAF Comments: SW gusts 20-25 kt likely and G25-30 kt
possible between 19-23z.

KTEB TAF Comments: S gusts 25 kt possible between 20-23z.

KHPN TAF Comments: Wind gusts could be stronger than forecast.

KISP TAF Comments: MVFR ceilings could prevail. S gusts 25 kt
likely after 22z.

.OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...
.Wednesday...Low prob of -shra/MVFR AM...mainly eastern
terminals. Becoming VFR in AM. W-NW G15KT possible.
.Wednesday night-Sunday...VFR.

&&

.MARINE...
Winds will increase today ahead of a strong cold front. The sca
remains on all waters for this aftn and tngt. On Wed, seas may
linger abv 5 ft on the ocean, especially during the mrng.
Elsewhere, wind and seas blw sca lvls.

Sub-advisory conditions are expected Wednesday night through the
weekend with tranquil weather.

&&

.HYDROLOGY...
Showers and thunderstorms today and tngt may cause minor
nuisance/urbanized flooding. No widespread hydrologic impacts
are forecast through the rest of the week.

&&

.TIDES/COASTAL FLOODING...
Tides are running high astronomically. Water levels will
approach minor flood levels across mainly the south shore bays
areas with tonight`s high tide, but are likely to remain just
below.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Heat Advisory until 6 PM EDT this evening for NYZ071>075-176-
     178.
     High Rip Current Risk until 9 PM EDT this evening for NYZ075-
     080-081-178-179.
NJ...Heat Advisory until 6 PM EDT this evening for NJZ004-006-
     104>108.
MARINE...Small Craft Advisory until 6 AM EDT Wednesday for ANZ330-335-
     338-340-345-350-353-355.

&&

$$
SYNOPSIS...BC/JMC
NEAR TERM...JMC/JC
SHORT TERM...JMC
LONG TERM...BC
AVIATION...CB
MARINE...BC/JMC
HYDROLOGY...BC/JMC
TIDES/COASTAL FLOODING...


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