000
FXUS61 KOKX 162304
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
704 PM EDT Mon Oct 16 2023
.SYNOPSIS...
After one trough passage this evening, another one approaches
Tuesday and moves across Tuesday night. High pressure across
the area for the middle part of the week will give way to a
frontal system that will impact the area Friday into Saturday.
Low pressure that forms along the front will lift to the north
and east of the area Saturday through Sunday. High pressure will
follow early next week.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
-- Changed Discussion --
Still some spotty shower activity moving north to south across
the area associated with deep-layered cyclonic flow and cold air
aloft. These will likely dissipate over the next couple of hours
as low-levels stabilize. Otherwise, mainly dry conditions are
expected for tonight.
The upper level trough axis shifts southeast of the area this
evening. While moisture will remain limited, any enhancement to
lift as diagnosed from positive vorticity advection will trend
down this evening. Clouds will also vary in coverage through the
night.
Lows tonight a combination of MOS and NBM, ranging from the lower
40s to lower 50s. With ground level saturation overnight into
early Tuesday, expecting quite a bit of dew.-- End Changed Discussion --
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Another trough approaches from the north and west Tuesday but will
not be as strong. This is conveyed from the geopotential height
tendency increasing with time during the day. The mid level positive
vorticity quantity exhibited by forecast models is less than that
shown on the previous day. The trough axis moves across with its
relative cold pool late Tuesday night into early Wednesday morning.
CAMs with their reflectivity forecast depict less coverage of echoes
across the local region compared to the previous day. Likewise, in
the POPs forecast, have mostly slight chance across the area with a
little higher chance for Orange County NY.
Cyclonic flow aloft will keep clouds abundant Tuesday through
Tuesday night, mitigating sensible heat transfer and radiational
cooling. Forecast model 850mb temperatures are slightly lower than
the previous day. Tuesday`s forecast high temperatures are likewise
a few degrees less than the previous day, ranging from the upper 50s
to lower 60s using a blend of MAV, MET, and NBM. For low
temperatures Tuesday night, same blend of forecast model data used
with similar lows as the previous night, lower 40s to lower 50s.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
High pressure over the area on Wednesday retreats offshore ahead of
an approaching frontal system. However, global models are in less
agreement than they were 24h ago with the evolution of the
amplifying upper trough east of the Mississippi River Valley at the
end of the week. While it still looks wet as the frontal system
approaches the area Friday into Saturday, there is disagreement with
the amount of amplification of the longwave trough (due to digging
jet energy on backside) and placement of the upper and secondary
surface lows. Does the secondary form far enough offshore like the
12Z ECMWF to keep Saturday mainly dry, or farther northwest and
wetter like the GFS across the northern Mid Atlantic on Saturday?
There still does remain some agreement for a period of warm conveyor
belt rains riding up the eastern seaboard Friday into Friday night.
So the greatest uncertainty at this time is the duration of the rain
heading into Saturday and how quickly the area drys out. Behind the
system, gusty west winds will follow with drier, cooler conditions
for Sunday into Monday.
Near normal temperatures on Wednesday will warm up to several
degrees above normal for highs Thursday and Friday, with lows
considerably warmer due to cloud cover and southerly flow. It cools
down a bit Saturday, but moreso Sunday into Monday behind the
departing system.
As a side note, confidence remains high that there will be at least
some rainfall into Saturday, which would mark the 7th consecutive
weekend of rainfall at Central Park.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
Low pressure continues moving across the Canadian Maritimes into
tonight. High pressure begins building over the northeast on
Tuesday.
VFR. A few sprinkles or light showers are possible into this
evening.
CAMs with their forecasts of reflectivity decrease in coverage by
mid to late evening. Expecting any brief light rain showers or
sprinkles to taper off during the evening with dry conditions
expected overnight.
NW-N winds 10-15kt this afternoon will begin to diminish below 10 kt
this evening. A light NNW-N flow then prevails overnight, with most
outlying terminals becoming light and variable. Light NW winds 10 kt
or less are expected on Tuesday.
....NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Wind direction may vary 20-30 degrees from forecast at times this
afternoon and early evening.
An occasional gust 15-18 kt is possible through 22z.
OUTLOOK FOR 18Z TUESDAY THROUGH SATURDAY...
Tuesday Afternoon through Thursday: VFR.
Friday: Mainly VFR early, then chance of MVFR and showers late.
Showers likely with MVFR or lower possible at night. S-SE wind gusts
20 kt late day and at night.
Saturday: MVFR or lower in showers early. VFR possible in the
afternoon. S-SE wind gusts 20 kt becoming W in the afternoon.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Weak ambient pressure gradient across the waters through Tuesday
night will allow for conditions to remain below SCA thresholds.
Seas are forecast to stay below 4 ft on the ocean with 2 ft or
less for non-ocean waters. Any wind gusts stay at or below 20
kt.
High pressure over the waters on Wednesday retreats out into the
western Atlantic ahead of a frontal system impacting the waters
Friday into Saturday. A strengthening southerly flow at the end of
the week will result in building seas with the potential for SCA
conditions late Friday into Saturday, especially for the ocean
waters. There is also a low chance for gales on Sunday on the
backside of the system.
&&
.HYDROLOGY...
Less than a tenth of an inch is forecast with showers through
Tuesday night.
No hydrologic problems are expected.
&&
.TIDES/COASTAL FLOODING...
More northerly flow tonight and slightly less total water levels
forecast for sites during high tide Tuesday will likely keep
water levels below minor coastal flood benchmarks.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JM/DW
NEAR TERM...JM/DW
SHORT TERM...JM
LONG TERM...DW
AVIATION...DS
MARINE...JM/DW
HYDROLOGY...JM/DW
TIDES/COASTAL FLOODING...