NYC Office Forecast Discussion

306
FXUS61 KOKX 011832
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
232 PM EDT Thu Oct 1 2020

.SYNOPSIS...
A cold front stalls across the area today with a frontal wave
developing tonight passing near or just east of the area on
Friday. High pressure builds in from the west for Saturday and
Sunday, then moves northeast of the region Sunday night. Low
pressure moves through the area Monday and Monday night. High
pressure returns for Tuesday into early Wednesday. There is a
chance of a storm passing north of the area Wednesday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Forecast is on track with only minor updates to reflect current
observations and trends.

The long wave trough over the Great Lakes region continues the
southwesterly upper level flow. These winds keep the environment
relatively moist with precipitable water values around 0.85
inches. But with no lift to speak of, rain chances will be near
zero through this evening. The moisture should allow for mid
level cloud cover as 850-700 RH values hover around 75-80%. Near
the surface, southwest winds promote mild temperatures.
Afternoon highs are expected to reach the mid 70s.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Rain chances increase this evening. A shortwave impulse
embedded within the overall flow enters southern New York late
tonight into the overnight hours. The wave deepens a surface low
over Lake Erie and strengthens the trailing cold front. These
features act as the lifting mechanism for the overnight
showers. Since moisture locally isn`t that high to start with as
PWATs remain around 0.90 inches, models are indicating that the
highest rainfall amounts will be less than 0.10 inches. These
totals are expected to be focused around the Lower Hudson Valley
and northeast New Jersey with decreasing amounts the further to
are from the lows center.

The cold front itself pushes through the forecast area Friday.
High temperatures will struggle to reach the mid 60s in the
afternoon and will probable feel chiller thanks to the 10 mph
northwest wind.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Most of the long term forecast will be dominated by a high amplitude
longwave upper pattern, as a ridge remains in place across the
western states and a trough across the central and eastern states.
With a deeper shortwave moving through the longwave trough Monday
the upper pattern becomes more progressive with the eastern trough
weakening, and the western ridge moving into the intermountain
region and western plains, until Wednesday as another high amplitude
shortwave moves into the upper trough. This will keep the eastern
states below seasonal normals for temperatures through the extended
period.

With the shortwave Monday leaned toward the Canadian and ECMWF and
WPC guidance, which all have a deep low tracking through the region,
while the GFS is much more progressive and has high pressure over
the region by Monday.

With the more progressive flow into the middle of next week high
pressure briefly builds to the south Tuesday into Wednesday before
another deep low potentially impacts the region Wednesday.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
A wave of low pressure along a nearly stalled frontal boundary
will track just east of the area late tonight into Friday
morning.

Mainly a VFR forecast with a low chance of MVFR with any showers
late tonight into Friday morning.

W-SW winds around 10 kt diminish to less than 10 kt this evening
and veer to the NW by daybreak.

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

Winds will likely vary by 20 to 30 degrees this afternoon with
a frontal boundary stalled across the area. A few gusts of 15-18
kt are also possible.

.OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...
.Friday Afternoon-Sunday...VFR.
.Sunday Night-Monday...MVFR with a chance of rain.
.Tuesday...Mainly VFR. An isolated shower is possible.

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

&&

.MARINE...
SCA conditions will linger on the ocean waters today with seas 5
to 6 feet gradually diminishing into the afternoon.

Winds and seas likely remain below SCA levels across the forecast
waters Friday through Sunday night. With a storm moving into the
waters Monday there is the potential for SCA gusts across the
waters, and ocean seas may approach 5 feet. However, there is
uncertainty as to the strength and track of the storm.

&&

.HYDROLOGY...
A low pressure system may impact the region Sunday night through
Monday night with the potential for a significant rainfall.
However, there is high uncertainty as to the strength and track of
the low which would affect potential rainfall.

&&

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

&&

$$

SYNOPSIS...MET/DW
NEAR TERM...DJ/MW
SHORT TERM...DJ
LONG TERM...MET
AVIATION...DW
MARINE...DJ
HYDROLOGY...DJ/MET/DW

NWS OKX Office Area Forecast Discussion