378
FXUS61 KOKX 161434
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1034 AM EDT Mon Sep 16 2024
.SYNOPSIS...
High pressure over the area will gradually retreat north on
Tuesday. A frontal system will then slowly approach from the
southwest through mid week as the high drifts east out into the
Atlantic. Low pressure may linger nearby Thursday along a cold
front. The front will move across on Friday, followed by high
pressure building from southeast Canada for the weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
Forecast mostly on track. Some low clouds have developed and
are drifting westward across parts of Long Island and NYC. These
should dissipate with continued heating/mixing later this
morning.
With deep layered ridging aloft and a large dome of high
pressure at the surface, expect the dry weather to continue with
mainly sunny to partly cloudy skies. The winds once again will
be light and variable to begin the day, but with solar
insolation, winds toward late morning and mid day will become
more ENE at around 5 to 10 mph, with SE-S sea breezes close to
the coast. Temperatures should be at seasonable levels for mid
September.
For tonight, upper level ridging begins to slowly break down.
More in the way of high clouds attempts to work in as low
pressure off the SE coast begins to work NW. Partly cloudy to
mostly cloudy skies are expected tonight with a light E-NE flow
in place. With a bit more moisture in the lower levels there
should be a reasonable chance to see some low stratus / patchy
fog in many of the lower lying rural locations as in previous
nights as of late. Temperatures should average close to normal
in outlying areas, and a bit above normal in the more urban
areas.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Surface high pressure will gradually begin to wane in strength
on Tuesday. A southerly component to the flow aloft begins to
get established during the afternoon as the region gets on the
outer edge of the northeast quadrant of a closed low getting
into the Lower Appalachians. The mid levels may moisten up
enough to produce more in the way of mid level clouds,
especially as the day progress. Thus a partly cloudy to mostly
cloudy day from NE to SW across the region appears most likely.
With more mid and upper level clouds compared to lower level
clouds, expect the clouds to mainly filter out varying amounts
of sun. Temperatures will once again run right around seasonable
levels. Dew point readings should edge up in the 60s,
especially along the coast as the day proceeds.
The high slowly drifts east through mid-week. At the same time,
low pressure over the Carolinas will slowly trek northwestward
toward the Ohio Valley through mid-week. The associated frontal
system will approach from the southwest and will begin to
impact the region Tuesday night.
The low and frontal system get caught under the upper level
ridging over the eastern US from mid to late week and a
prolonged period of some unsettled weather is possible as weak
flow under the ridge will mean slow movement of these features.
Right now, it looks like the most likely period of rain is
overnight or early Wednesday morning through Wednesday night.
There is a deep moisture feed from the tropics and training
possible. Dewpoints rise well into the 60s Wednesday into
Thursday and PW around 2 inches are seen in most of the
guidance. Of course, this is all dependent on certain mesoscale
features that cannot be resolved at this point, but there is a
low chance right now of flooding, and the Weather Prediction
Center has placed the forecast area in a marginal risk of
excessive rainfall Wednesday into Thursday. With the previously
mentioned uncertainty, stuck close to the NBM and did not go any
higher than chance PoP. However, models have trended a little
slower on the system`s arrival, so have kept chance PoP out of
the forecast until late Tue night.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
Mid level trough remains over the region Thursday through Friday
and weakens Saturday. Mid level ridging eventually takes over
to close out the weekend.
At the surface, low pressure may still be not too far away to
the south of Long Island Thursday into Thursday night. Chances
for showers will remain in the forecast.
A back door cold front moves across Friday, keeping shower
chances in the forecast. However PoP should be more in the
slight chance range since moisture becomes more limited as low
to the south weakens and moves farther away.
For Friday night into the weekend, dry conditions return as high
pressure builds in from the north. Clouds may very well linger
around to start but will be on a decreasing trend.
Temperatures favored the 50th NBM percentile as the pressure
gradient between low pressure to the south and high pressure
to the north remains, giving NE flow much of the time during the
long term. Gusty conditions expected along the coast as well.
NBM 50th percentile showed lower temperature for eastern half of
the region and along the coast compared to NBM. The
temperatures are expected to be below normal during the day.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
High pressure will become centered off the New England coast
through early Tuesday.
VFR conditions are expected through much of the period. MVFR to
IFR stratus/fog potential late tonight into early Tuesday,
mainly outside the NYC metro terminals.
A light NE flow will become ESE-SE late this morning into the
afternoon, mainly 10 kt or less. Winds weaken tonight and back
to the NE.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of ESE-SE wind development could be off by 1-2 hours.
MVFR to IFR stratus and/or fog possible late tonight into early
Tue morning.
OUTLOOK FOR 12Z TUESDAY THROUGH FRIDAY...
Tuesday: Chance of MVFR or lower conditions with low clouds/fog
early Tuesday morning and late Tuesday night, otherwise VFR.
Wednesday through Friday: Chance of showers with MVFR or lower
conditions possible especially with any low clouds/fog. ENE
winds 10-15G20kt, mainly at the coastal terminals during the
day into early eve.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Ocean seas are already at 5 ft at buoy 44025 just south of the
coastal waters as relatively long period 3-4 ft SE swell
interacts with 2-3 ft wind waves in E flow. Meanwhile seas at
44079 SE of Montauk are running at 3-4 ft. SCA already in effect
beginning late tonight through 8 PM Tue may need to start sooner
on the ocean waters if the trend for more frequent 5-ft seas at
44025 continues.
More widespread 5 ft seas on the ocean waters are expected
Wednesday through Fri night on a persistent E flow. Wind gusts
on the non ocean waters could also reach 25 kt at times Fri
into Fri night.
&&
.HYDROLOGY...
No issues expected. An extended period of rain is possible from
Tuesday night through Wednesday night with a tropical feed and
training possible. There is still some uncertainty with regards
to the amount of rain we may see. The Weather Prediction Center
has placed the area under a marginal risk for excessive rainfall
on Wednesday. One factor against flooding would be the
antecedent dry conditions over the last week.
&&
.TIDES/COASTAL FLOODING...
With an approaching full moon on the 17th, astronomical high tides
will be rising into much of this week, with total water levels
rising as well as continuous E flow builds seas and allows for
some piling of water. While some of the guidance is showing
water levels increasing, there is a general consensus of keeping
them below minor coastal flooding benchmarks for the most part,
although Stevens NYHOPS suggests minor flooding for the south
shore bays and the western Sound toward late Tue into Wed.
There is a moderate risk of rip current development at the ocean
beaches today with an E flow developing. The risk should
increase to high on Tue.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 5 AM to 8 PM EDT Tuesday for ANZ350-
353-355.
&&
$$
SYNOPSIS...BG/JM/BR
NEAR TERM...BG/BR
SHORT TERM...BR
LONG TERM...JM
AVIATION...JM/DS
MARINE...BG/JM/BR
HYDROLOGY...JM/BR
TIDES/COASTAL FLOODING...