Area Forecast Discussion
Issued by NWS Upton, NY

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121
FXUS61 KOKX 201928
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
328 PM EDT Mon Aug 20 2018

.SYNOPSIS...
High pressure centered off the Canadian maritimes will move
farther northeast through Tuesday ahead of an approaching low
pressure system. A warm front is expected to move through late
Tuesday, followed by a cold frontal passage on Wednesday. High
pressure then builds in through the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
A weak vorticity maximum will continue to allow for occasional
light showers and drizzle through the early part of the evening,
before subsidence increases in its wake tonight. Although shower
chances will decrease thereafter, a low level inversion and
lingering moisture in onshore flow will lead to mostly cloudy
conditions overnight, and near climatological normal
temperatures.

There is a moderate risk of rip currents at the Atlantic Ocean
beaches for the remainder of today.

&&

.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
Forcing for ascent will gradually increase into Tuesday as a
series of upper disturbances pass through and a warm front
slowly approaches the area. Moisture will initially be greatest
in the low levels, leading to similar conditions as Monday with
occasional light rain and drizzle. Temperatures will be cooler
than normal due to the combination of onshore flow and cloud
cover. As the warm front moves through late Tuesday, slantwise
instability may support a few isolated heavier showers, though
the best chance of rain and any thunderstorms will largely be
Tuesday night as the upper trough and attendant cold front
approach the region, leading to increasing deep-layer
instability. Heavy rain will certainly possible amidst PWAT
values increasing to well over 2 inches, and modest flow that
will be parallel to the approaching front, perhaps supporting
the eventual development of a disorganized line of convection.

For Tuesday, the risk for rip currents at Atlantic Ocean beaches
will be moderate with winds becoming more E-SE and easterly
swell.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
The cdfnt will slowly pass thru the region on Wed. The upr sys
will be lagging resulting in the slow passage. A worked over
airmass is likely to mitigate any svr threat. The modeling also
shows the high pwat air e of the region, mitigating the flood
threat as well. Timing of the upr trof appears to be Thu mrng,
so some flattening due to the steep lapse rates but subsidence
in the aftn. If the upr sys slows, there could be an isold shwr
or tstm. Thereafter, dry wx thru Sun. Mainly clr Fri and Sat,
then some increasing clouds on Sun as a waa pattern begins. Mon
looks to be much warmer attm, with temps approaching 90. There
cold be some tstms depending on whether a weak front to the n
drops thru. For now, the fcst was kept dry with the most
likely focus across the mountains to the n of the cwa. The NBM
was used for temps, but the numbers in subsequent fcsts may need
to be adjusted upward for Mon.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
A weak frontal boundary remains nearly stationary across the
Mid Atlantic states through tonight, meanwhile, high pressure
noses in from the north. The high retreats Tuesday as a warm
front begins to approach from the south. The warm front moves
into the region Tuesday Night.

MVFR ceilings expected to gradually lift to VFR with SCT MVFR
cigs for evening push. Widespread MVFR conditions expected to
re-develop late tonight into morning push, with IFR conditions
possible for coastal terminals. MVFR conditions likely continue
through the day. Potential for IFR cigs for coastal terminals
for Tue evening push. SHRA/sparse tsra likely hold off until
after 00z Tue eve.

NE winds of 8 to 12 kt, expected to veer to the E late this
afternoon/evening while diminishing to less than 10 kt. NE
winds less than 10 kt Tues morning, become E/ESE Tue afternoon.

   ...NY Metro Enhanced Aviation Weather Support...

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

KJFK TAF Comments: VFR cigs likely for evening push, before
returning to MVFR late tonight into morning push.

KLGA TAF Comments: VFR cigs likely for evening push, before
returning to MVFR late tonight into morning push.

KEWR TAF Comments: VFR cigs likely for evening push, before
returning to MVFR late tonight into morning push.

KTEB TAF Comments: VFR cigs likely for evening push, before
returning to MVFR late tonight into morning push.

KHPN TAF Comments: VFR cigs likely for evening push, before
returning to MVFR late tonight into morning push. Low prob of
IFR for morning push.

KISP TAF Comments: VFR cigs likely for evening push, before
returning to MVFR late tonight into morning push. Low prob of
IFR for morning push.

.OUTLOOK FOR 18Z TUESDAY THROUGH SATURDAY...
.Tue aft...MVFR cigs. Spotty MVFR possible in -dz. E/ESE winds
10kt or less.
.Tue Night-Wed...MVFR/IFR conditions likely developing Tue Eve
and continue through Wed morning push. Shra/tsra development
likely after 00z Tue eve. Improvement to VFR late Wed.
.Thu-Sat...VFR.

&&

.MARINE...
Extended the SCA for the ocean waters east of Moriches Inlet
until 8 pm, where seas have remained around 5 ft. Otherwise,
SCA conditions fall tonight and remain below SCA conditions are
forecast through Tuesday.

Wind and seas will likely hit sca lvls on Wed, especially on the
ocean, invof a cdfnt. 5 ft seas may linger for at least a part
of Thu, then conditions on all waters will remain blw sca lvls
thru the weekend.

&&

.HYDROLOGY...
No hydrologic impacts are expected through Tue.

Showers and thunderstorms, some with heavy rain, may be possible
Tuesday night into Wednesday morning with the passing of a
frontal system. PWATs increase to over 2 inches and deep layer
SW flow, could result in the potential for urban and poor
drainage flooding from NYC north/west. Flash flood potential is
not out of the question with low FFG values especially over NE
NJ, but does not look widespread.

No hydrologic impacts are expected Thu-Mon.

&&

.EQUIPMENT...
NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) remains off
the air for an extended period of time.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ350.

&&

$$
SYNOPSIS...JMC/MD
NEAR TERM...MD
SHORT TERM...MD
LONG TERM...JMC
AVIATION...NV
MARINE...JMC/MD
HYDROLOGY...JMC/MD
EQUIPMENT...



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