137
FXUS61 KOKX 160819
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
419 AM EDT Fri May 16 2025

.SYNOPSIS...
Multiple surface troughs move through today and Saturday, followed
by a cold frontal passage Saturday night. A secondary cold front
moves through Sunday afternoon and Sunday night. Low pressure
lingers in New England and into the Canadian Maritimes through
Monday as high pressure pushes in. High pressure remains in
control Tuesday into Tuesday night. Another frontal system impacts
the area Wednesday into Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
The upper level trough can now be seen to our east on latest
satellite imagery. Heights may briefly rise aloft heading into the
early morning hours. At the surface, a very weak pressure gradient
is leading to calm to light winds. This and the moisture available
from several days on onshore flow has resulted in fog around the
area. With the fog being locally dense, have issued an SPS through
13z.

The convection forecast today and Saturday continues to be very
tricky. There will be multiple chances for showers and thunderstorms
with different forcing mechanisms. The first chance will be with any
activity that moves into our area this morning from the potential
decaying MCS/broken line from the west. CAMs are not all that
excited about this feature, but can not rule out some of this making
it into far western portions of our area. Radar trends upstream will
be monitored as this activity nears. Will have a better idea once,
if at all, convection starts to enter western PA.

As we head into the afternoon, shortwave energy approaches and
instability increases as we warm to the upper 70s with mid 60s
dewpoints. Some showers and thunderstorms likely spark just west and
move towards the area. Highest chances are once again north and west
of NYC, but can not rule out a shower or thunderstorm anywhere. Some
organized convection is possible with this afternoon activity given
increased instability and shear along with better curvature in the
low levels on model hodographs. At this time the main hazard would
be isolated damaging wind gusts or large hail, again mainly north
and west of NYC. This activity will decrease heading into tonight.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
The upper level low continues approaching on Saturday with shortwave
energy ejecting out ahead of it. Similar forecast challenges in the
morning hours as there may be some sort of approaching convection
left over from what happens in the Ohio Valley and Great Lakes
region tonight. Then, once again, the area destabilizes ahead of a
cold front. While CAMs are not overly excited about this either,
there is potential for more widespread convection over the area
Sunday afternoon given stronger forcing, instability(MLCAPE
approaching 2000 J/kg) and shear(0-6km bulk shear around 40kt).
This will also lead to more widespread chances of storms
reaching severe thresholds. The SPC has placed the western half
of the area in a slight risk. As of right now, the main threat
is damaging wind gusts. Model hodographs will have to be watched
as there is some indication of favorable low level shear and an
isolated tornado can not be ruled out. Latest Nam3km and HRRR
show around 150 m2/s2 of effective inflow layer SRH.

The cold front moves through Saturday night and then a secondary cold
front moves through Sunday and Sunday night. PoPs lower
significantly, but there will be additional slight chances of
showers across the interior Sunday afternoon with the upper low
above us.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Mostly sunny skies take over as high pressure centered over or near
Hudson Bay in Canada gradually noses into the area Monday into
Tuesday night, keeping the area dry. To our northeast, low pressure
will continue to exit into New England and into the Canadian
Maritimes through. This will lead to breezy W/WNW winds from an
increased pressure gradient through Monday.

A frontal system from the Great Plains then moves into the Ohio or
Tennessee River Valleys on Tuesday, moving through or in the
vicinity of our region Wednesday into Thursday. Expecting showers
during this timeframe. Too soon to call chances for thunderstorms.
Model guidance still varies with timing, magnitude, and track of
this frontal system. Have gone with chance POPs Wednesday into
Thursday as a result.

Temperatures look to cool each day in the long-term period,
especially towards Wednesday and Thursday with clouds and rain
limiting any heating. Highs on Monday will be in the upper 60s to
lower 70s and by Thursday, with will be in the upper 50s to lower
60s. Overnight lows will range from the middle 40s to lower 50s.

&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
A surface trough approaches and moves through from the west today.

Expecting IFR or lower through daybreak today. Improvement to MVFR
this afternoon, but with potential showers. A passing thunderstorm
is possible, mainly for the NYC terminals, but the chances for this
are decreasing. Improvement to VFR for some terminals late in the
day such as the metro terminals and KSWF. Conditions deteriorate
once again for all terminals to IFR or lower tonight.

Light and variable winds through daybreak becoming southerly at 10
kt or less for today and continue into tonight with outlying
terminals becoming light and variable again.

 ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...

Timing of IFR onset could be off by an hour or two for KTEB and
KLGA. Timing of improving categories on Friday may also be off by an
hour or two.

.OUTLOOK FOR 06Z SATURDAY THROUGH TUESDAY...

Friday night: IFR or lower.

Saturday: IFR to start, improving to MVFR mid-morning, then becoming
VFR in the afternoon with showers likely, and a chance of
thunderstorms with MVFR.

Sunday: Mainly VFR. Slight chance of showers inland. W winds G20-
25kt.

Monday - Tuesday: VFR. Monday NW winds G20-25kt.

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

&&

.MARINE...
Dense fog on all waters is expected to continue through late
morning. Fog will then return tonight, potentially becoming dense
again.

Winds and waves remain below SCA criteria through Sunday for the
most part. There looks to be brief potential for 25 kt gusts
Sunday afternoon, mainly for NY Harbor, western Sound and
western Ocean. During this time, seas on the ocean could also
approach 5 ft. Outside of this, there is potential for showers
and thunderstorms each day, with potential for severe
thunderstorms Saturday afternoon. Winds and seas will be locally
higher in any storms.

Winds are expected to remain below SCA criteria for Monday. However,
there is a low to medium chance of 25 kt wind gusts over the ocean
waters with low pressure over the Gulf of Maine creating an
increased pressure gradient. Thereafter winds and waves should
remain below SCA criteria due to lack of any strong pressure
gradient across the waters.

&&

.HYDROLOGY...
There are no hydrologic concerns through the end of next week.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Dense Fog Advisory until 11 AM EDT this morning for ANZ331-332-
     335-338-340-345-350-353-355.

&&

$$

SYNOPSIS...JP/JT
NEAR TERM...JT
SHORT TERM...JT
LONG TERM...JP
AVIATION...JP
MARINE...JP/JT
HYDROLOGY...JP/JT