000
FXUS61 KOKX 171142
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
742 AM EDT Sun Sep 17 2023
.SYNOPSIS...
High pressure to the north and west will gradually weaken today.
A cold front will approach tonight and move through on Monday as
low pressure passes to the south and east late Monday into Monday
night. High pressure builds in for Tuesday and remains over the
area through Thursday night, then moves off the northeast coast
Friday and remains into next weekend. Meanwhile, low pressure
will approach from the south Saturday.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Forecast is on track with minor changes needed. Previous
discussion follows.
Upper level ridge pushes east of the area today while an upper
trough approaches from the mid-West. At the surface, high
pressure will weaken over the area, allowing a cold front to
approach late in the afternoon. Out ahead of the front, a light
south to southwesterly flow develops, allowing for warm
advection. Temperatures are expected to be slightly warmer than
Saturday, with an increase in humidity level, more noticeable by
the mid to late afternoon hours.
Any showers will hold off until the afternoon, and even then,
mainly for areas west of the Hudson River. There continues to be
uncertainty in track and strength of the low, but current
consensus among the models show eastern areas receive the bulk
of the rainfall. Will have to continue to monitor model guidance
as the ECMWF continues to show a stronger low closer to the
coast, which would mean more in the way of rainfall for all
areas.
Model guidance continues to indicate some surface based CAPE,
especially with the closest approach of the low, so continue
mention of slight chance thunder as its only a few hundred J/kg.
There continues to be a low threat for flooding with this
system. There is a tropical connection in the Gulf of Mexico,
dew points rise into the 60s tonight, and PWAT values rise to
1.50"-1.75". Finally, low level winds are less than 30 kt,
indicating potentially slow moving storms. The Weather
Prediction Center has placed the easter 2/3 of the area (mainly
southern Connecticut and central and eastern Long Island) in a
marginal risk for excessive rainfall.
The cold front moves through Monday with Canadian high pressure
building in behind it, bringing and end to the rainfall. Dry
weather and seasonable temperatures are expected on Tuesday.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
Showers overspread the tri-state from west to east overnight
tonight as the cold front advances. The upper trough will aid in
cyclogenesis off the mid-Atlantic coast late tonight, with then
heads northeast.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Most of the low term period will be tranquil as an upper level
building ridge to the west Tuesday night tracks slowly eastward and
moves east and weakens late in the week into the upcoming weekend.
Meanwhile, surface high pressure remains across the eastern Great
Lakes and into the mid Atlantic region, moving off the northeast
coast late in the week. There is uncertainty as to when and where a
closed and nearly cutoff low across the southeastern states Friday
will track into next weekend. With high pressure off the coast
remaining in place the low will be slow to move north into the high.
Dry weather is expected into early Saturday, and showers may begin
to move into the southern sections late Saturday into Sunday. With
the uncertainty and being day 7/8, have used the NBM probabilities.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
Weak high pressure remains over the area through late this
afternoon. A cold front begins to approach from the west as a
wave of low pressure moves into the mid Atlantic region from the
southeastern states tonight.
VFR through late afternoon with showers developing 21Z.
Conditions continue to lower, becoming MVFR early evening, and
then IFR late tonight, with timing uncertain and low confidence.
Possible that conditions remain MVFR late tonight.
Winds light, becoming SW less than 10 kt this morning, and
southerly during the afternoon at the coast terminals as sea
breezes develop. Winds SW along the coast this evening and
overnight, and light and variable inland tonight.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
No unscheduled AMD expected through this afternoon. Sea breeze
development may be off +/- an hour. Low confidence and timing
uncertain with the lowering conditions to MVFR this evening, to
IFR late tonight, and may be later than forecast.
OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY...
Monday: MVFR, chance IFR especially in the morning, with
showers.
Monday night: Showers ending, becoming VFR.
Tuesday through Thursday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Sub-SCA conditions are expected today through the first half of
Monday night. SCA conditions for at least the ocean waters
appears to return late Monday night into Tuesday in wake of
departing coastal low pressure. Marginal SCA gusts possible all
waters during this time as well.
Lingering 5 foot seas on the ocean waters east of Moriches Inlet are
possible into early Tuesday evening as low pressure departs to the
northeast and high pressure builds to the west. High pressure
remains in control Tuesday night through Thursday night. Winds
remain below SCA levels across the forecast waters Tuesday night
through Thursday night. East to southeast swells from distant
Tropical Storm Nigel could bring SCA seas to the ocean waters
Thursday into Thursday night.
Monitor https:/www.weather.gov/okx/tropical or
https:/www.nhc.noaa.gov for the latest NHC forecasts on Tropical
Storm Nigel.
&&
.HYDROLOGY...
No hydrologic impacts through this weekend.
Total rainfall forecast is 0.50" to 0.75" west of the Hudson
River, and 0.75" to just over 1.00" for Long Island/CT, with
locally higher amounts of 1.50"-2.00" possible. Heavy rain will
be possible at times presenting a minor urban and poor drainage
flood threat. Rainfall rates should generally be below 1"/hr in
a mostly stratiform environment.
Otherwise, no hydrologic problems expected through next week.
&&
.TIDES/COASTAL FLOODING...
There is a moderate rip current risk for Sunday and Monday with
a mix of 1-2 ft swells.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JP
NEAR TERM...JP
SHORT TERM...JP
LONG TERM...MET
AVIATION...MET
MARINE...JP/MET
HYDROLOGY...JP/MET
TIDES/COASTAL FLOODING...