NYC Office Forecast Discussion

000
FXUS61 KOKX 281333
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
933 AM EDT Mon Sep 28 2020

.SYNOPSIS...
High pressure remains over the Western Atlantic today. A slow
moving frontal system approaches from the Ohio Valley into
Tuesday, moving across the area Wednesday into Wednesday night.
Waves of low pressure will move along the frontal boundary,
bringing an extended period of unsettled conditions. A series of
reinforcing cold fronts will then follow at the end of the week
with high pressure returning next weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A slow moving cold front is located over the Ohio Valley with
high pressure over the Western Atlantic. The flow between these
two systems will pump warm and humid air across the region.

Any lingering patchy fog will continue to diminish leaving
mostly cloudy conditions. There may be some large breaks in the
clouds this afternoon for some brief partly cloudy conditions.
Not much lift for showers today other than a shortwave rotating
through from the SW. Have trimmed PoPs back and mainly confined
to areas north and west of NYC.

Highs will be in the 70s, except near 80 the normally warmer
portions of nern NJ.

There is a moderate risk of rip currents at the Atlantic Ocean
beaches today due to a building southerly swell and
strengthening onshore winds.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
No upr lvl forcing tngt, so fog and drizzle would be the main
threats. The NAM may be overdone with the drizzle threat,
especially with model depicting less depth to the llvl
moisture, so have left it out attm.

Upr trof approaches on Tue. It may be too far w during the day
to produce much rainfall. Best chances wrn areas, with ern areas
further from the forcing and more stable. It does look like the
upr trof gets close enough Tue ngt, and with the llvl jet
pumping pwats to around 2 inches, some locally hvy shwrs are
expected.

Remaining humid with continued sly winds.

Temps tngt thru Tue ngt close to the NBM with local adjustments.

There is a high risk of rip currents at the Atlantic Ocean
beaches on Tuesday due to a southerly swell and strengthening
onshore winds.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
An unsettled pattern through the end of the week continues to
become more likely as deterministic models and ensembles slowly
come into better agreement. Differences arise with timing of
specific features, but overall much needed rainfall is becoming
likely through early Thursday morning.

A longwave trough over the eastern CONUS with two separate
shortwaves, one within the northern stream and one in the southern
stream, will help draw up tropical moisture from the Atlantic and
Gulf of Mexico. The longwave trough will only slowly pivot towards
the east coast into Wednesday, but will send a cold front
towards the region. The cold front is likely to stall over or
just to our east late Wednesday into Wednesday night. At the
same time, the southern stream shortwave energy will quickly
lift northward.

The most significant rain is expected Wednesday night. Showers
should become widespread with a wave of low pressure Wednesday
night. Conditions should dry out Thursday morning as the energy
and low lift quickly to the northeast.

Dry conditions briefly return late Thursday morning through Friday
morning. A series of secondary cold fronts will move through the
region. The longwave trough will also remain in place across the
eastern states with its axis to our west. There are hints at another
vort max within the trough moving towards the region on Friday. This
energy may act upon the baroclinic zone just offshore to develop
another low pressure. Differences are quite high among the guidance
in its location and whether it develops offshore or closer to the
region. Have capped PoPs off at chance for the eastern half for now.

High pressure then builds into the weekend.

Above normal temperatures Wednesday will trend to near
seasonable levels Thursday and Friday. Below normal temperatures
are then expected next weekend.

&&

.AVIATION /13Z MONDAY THROUGH FRIDAY/...
High pressure remains over the Atlantic today. A slow moving
frontal system will begin to approach from the west tonight.

Flight categories are variable across the New York City metro
area, from MVFR to VFR. East of the New York metro conditions
were IFR. Conditions across the region will be improving to VFR
through this morning. Winds remain S around 10 kt, there could
be a few gusts 15-18 kt this afternoon at the NYC metros and
along the coast.

Cigs/vsby should lower again late tonight to MVFR and then IFR,
but exact timing is in question.

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

AMD likely to address fluctuations in flight cat.

.OUTLOOK FOR 12Z TUESDAY THROUGH FRIDAY...
.Tuesday...Chance of IFR/MVFR conditions. Patchy fog in the
morning into early afternoon. Showers likely and possibly a
tstm especially from mid afternoon on. S-SW winds G15-20 kt.
.Wednesday...IFR/MVFR with showers. Heavy rain possible at
times. SW winds G15-20kt into early evening.
.Thursday...Chance of MVFR/showers in the morning. VFR
thereafter. SW winds G20kt.
.Friday...Mainly VFR. Afternoon showers possible for KISP and
KGON.

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

&&

.MARINE...
A SCA remains in effect for ANZ350 and 353 today with seas in
the 4-5 ft range. This may need to be extended tngt, but
confidence was too low to extend now. Seas build on the ocean
Tuesday ahead of a slow moving cold front. Seas should then will
be around or just above 5 ft Tuesday night and continue to
build through Wednesday. Winds may also gust to around 25 kt
Tuesday night into Wednesday as the cold front nears the waters.
SCA conditions may also occur late Wednesday night into
Thursday on all waters as low pressure and the cold front move
across the waters. Ocean seas may remain elevated through
Friday, but winds should remain below 20 kt Thursday night into
Friday.

&&

.HYDROLOGY...
A slow moving frontal boundary and several waves of low pressure
will bring significant rainfall Tuesday into early Wednesday
and then again Wednesday night into early Thursday. Total
rainfall amounts average around 2 inches with locally higher
amounts possible. Due to dry antecedent conditions, the long
duration of the event, and high flash flood guidance, no
significant flooding is anticipated. Minor urban and poor
drainage flooding is the main threat.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 6 PM EDT this evening for ANZ350-
     353.

&&

$$
SYNOPSIS...JMC/DS
NEAR TERM...DS
SHORT TERM...JMC
LONG TERM...DS
AVIATION...MET
MARINE...JMC/DS
HYDROLOGY...DS

NWS OKX Office Area Forecast Discussion