043
FXUS61 KOKX 170603
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
203 AM EDT Mon Mar 17 2025
.SYNOPSIS...
A strong cold front approaches overnight and pushes across into
Monday, pushing offshore Monday evening. High pressure takes
over thereafter and remains into Wednesday. A fast moving
frontal system moves across the area Thursday into Thursday
night. High pressure begins to build back into the area on
Friday and should remain in control next weekend.
&&
.NEAR TERM /THROUGH TODAY/...
A line of convection across NJ and upstate NY along a
prefrontal trough will continue to weaken as it pushes east.
Strong onshore flow will push stable maritime air a bit inland
and along the coast as the this convection pushes east. The
latest SPC mesoanalysis indicates the axis of higher PWATs goes
right into the eastern half of the CWA for a good portion of the
overnight and nudges a bit further east towards daybreak.
The prefrontal trough and associated cold front moves across
overnight. There will still be showers and embedded elevated
thunder with the aforementioned weakening convective line, but
it appears a resurgence of showers will occur from southwest to
northeast across the area with strengthening LLJ in combination
with increasing upper divergence from a an approaching jet
streak to our northwest. This will likely induce a weak wave
along the frontal boundary, which will increase convergence and
lift overnight.
Moderate to locally heavy showers are expected to increase in
coverage for the overnight and predawn hours. PWATs range
anywhere to around 1.4 to 1.5 inches supporting potential for
some locally heavy downpours, especially for the eastern half to
2/3rds of the area. Still think a few rumbles of thunder are
possible, but elevated instability is minimal overnight. SPC
mesoanalysis has indicated a marginal ridge of CAPE nosing
into NE NJ and close to the NYC metro. Thus, continuing with
slight chance and iso thunder. The heaviest rain shifts east of
the NYC metro for the predawn hours, with a steadier stratiform
rain from the city on NW.
Peak hourly rainfall rates from 0.25 to 0.50 inches per hour
seem most likely, although a few downpours will have a few
higher instantaneous rates associated with them. MRMS is
currently supporting peak rates of 0.40 to 0.50 in the heavier
bands over the ocean moving north-northeast. The main concern
overnight into early Monday will be from minor urban and poor
drainage flooding. Eastern Long Island and southeast Connecticut
stand the best shot at seeing a longer duration of heavier
downpours, so cannot completely rule out a localized instance of
flash flooding here and will continue to monitor latest radar
and MRMS QPE and Flash trends. Rainfall totals around 1.5" to
2.50" overall are forecast, highest across eastern portions of
the area. Locally higher amounts cannot be ruled out where the
heaviest downpours occur.
Following the exit of the line of rain with the surface trough
by Monday morning, periods of spotty showers could continue
across the area into Monday afternoon before the cold front
officially passes later on Monday, leading to drier air finally
advecting in under a NW wind by evening.
Southerly winds this evening into the first half of tonight
could gusts up to 30-35 mph, locally up to 40 mph. Winds will
subside overnight as the pressure gradient relaxes and low level
jet shifts east of the area. The inversion influence by the
onshore flow and slightly cooler boundary layer after sunset
should also help limit peak wind gusts to just below advisory
levels.
Low temperatures tonight will remain mild and well-above
average in the low to mid 50. Highs on Monday will continue
above normal in the mid-50s to near 60 with any colder air
arriving late and Monday night.
&&
.SHORT TERM /TONIGHT/...
Surface high pressure takes over tomorrow night as an upper-level
trough centers itself over the area. Clouds will begin to clear
west to east due an exiting cold front. Much colder air will
fall in line behind the front tomorrow night. Low are expected
to drop into the 30s, with a few near or just below freezing in
the far interior. While much colder than the previous night,
these lows are are quite seasonal for this time of year.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Key Points:
* Dry conditions will prevail Tuesday into Thursday morning and then
again next weekend with temperatures mainly above average.
* Showers become likely late Thursday and Thursday night along a
fast moving frontal system.
* Breezy and cooler conditions briefly return Friday.
The modeling has remained relatively consistent over the last few
days with the overall pattern progression into next weekend.
The upper trough that slowly moves overhead on Monday will slide
offshore Tuesday morning. This is in response to a build upper
ridge. The upper low is still expected to get trapped beneath the
ridge over the western Atlantic into Wednesday. This will not
directly impact our weather, but could enhance subsidence with the
ridging aloft later Tuesday and Wednesday. The upper ridging pushes
offshore on Thursday ahead of the next upper level trough, which
likely lifts over the area Thursday night into Friday. The ensemble
means then indicate a mostly zonal flow for next weekend.
Surface high pressure will be in control Tuesday and Wednesday
before moving offshore on Thursday. The aforementioned upper trough
will send a fast moving frontal system across the area late Thursday
into Thursday night. The latest model consensus indicates most of
the daytime Thursday will be dry with just a chance of showers late
in the afternoon. The cold front sweeps across the area Thursday
night with the likelihood of showers. Low pressure may develop along
the front as it passes to our east and help add more lift and
moisture for the continuation of showers into early Friday morning.
Guidance has come into better agreement with this scenario, but
differ on the intensity of the low. The progressive pattern would
favor the low to quickly push off the New England coast Friday
morning. The NBM probabilities for greater than an inch of rain in a
12 or 24 hour period Thursday into Thursday night remain low and
under 10 percent, consistent with the speed of the system. The
potential of low pressure on the front may bring a possibility of
some wet snow flakes mixing in well inland as the system pulls away
and draws colder air southward.
Breezy and cooler conditions are expected on Friday under strong
cold advection and a W-NW flow. Temperatures look to remain in the
mid and upper 40s for highs which are slightly below average for
March 21st. Winds will likely gust 25-35 mph. The pressure gradient
should relax Friday night with high pressure returning for the
remainder of the weekend. Have kept the forecast dry next weekend
with a mainly zonal flow aloft.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
Cold front approaches form the west, moving thru the area later
this morning as a wave of low pressure develops along it. The
frontal wave and cold front passes east in the afternoon.
Conditions vary across the region, with most either IFR or MVFR
as of 6Z Mon. KHPN and other coastal sites occasionally LIFR or
lower. Bands of showers are filling in from the south, bringing
several hours of IFR vsby in moderate to locally heavy rain
early this morning, especially E of the NYC metros. S winds
gusting up to 25-30 kt and LLWS (S flow 50-60 kt at FL020)
persist through most of the overnight with this activity.
Showers gradually taper off through the mid to late morning,
but conditions could remain IFR/LIFR as winds diminish and
become variable with slow passage of the front and wave of low
pressure. Improvement will be slow to occur, with MVFR from
late morning into early afternoon at the NYC metros hanging on
through the rest of the day. IFR cond may last at KBDR/KISP into
late afternoon and at KGON through the period.
As the cold front and frontal wave move into the region, winds
and gusts diminish later this morning, and likely go variable
less than 10 kt. As the front passes east into the afternoon,
winds shift to the W and then NW-N, gusting to 20-25 kt by late
day. Speeds lower tonight into Tuesday morning.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Unscheduled AMD likely to address changes in flight categories
and timing of rain and wind shifts.
.OUTLOOK FOR 06Z TUESDAY THROUGH FRIDAY...
Late tonight: VFR at the NYC terminals and west, MVFR/IFR east
early in the evening, becoming VFR throughout. NW-N winds
G20-25kt.
Tuesday and Wednesday: VFR.
Thursday: IFR/LIFR cigs possible in the morning mainly E of the
NYC metros. Chance of showers with MVFR cond possible. S winds
10-15 kt with G20-25 kt, winds shifting W during the evening.
Friday: VFR at the NYC terminals and west, MVFR/IFR east with
showers ending late in the day, becoming VFR throughout. NW
wind 15-20 kt with G20-30kt.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
A strong cold front impacts the waters into Monday. Some fog for
the ocean waters will translate east and northeast overnight
with the heavier shower activity moving in, overall
visibilities should remain above 1 nm.
S winds should increase overnight as a stronger low level jet
passes over the waters. While a strong inversion will be in
place, winds beneath may approach gales on the ocean and the
eastern Sound. For this reason a gale warning is in effect into
early Monday morning. A Small Craft Advisory remains in effect
elsewhere through tonight. SCA conditions will continue on the
ocean through Monday night due to elevated seas.
Winds on all waters should remain below SCA levels Tuesday through
much of Thursday. Ocean seas will remain elevated at or above 5 ft
during this period mainly due to lingering SE swells. The next chance
for SCA winds will be Thursday night behind a cold front passage.
There is also potential for gales on the waters on Friday under a
strong NW flow and cold advection over the warmer waters. Seas will
remain elevated to end the week.
&&
.HYDROLOGY...
Rainfall of 1.5-2.5 inches expected into early Monday, with the
higher amts across eastern Long Island and SE CT.
Nuisance flooding is the main concern.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 6 AM EDT early this morning for
ANZ331-335-338-345.
Gale Warning until 6 AM EDT early this morning for ANZ332-350-
353-355.
Small Craft Advisory until 8 AM EDT this morning for ANZ340.
&&
$$
SYNOPSIS...BR/DS
NEAR TERM...JE/BR
SHORT TERM...BR
LONG TERM...DS
AVIATION...BG/DR
MARINE...BR/DS
HYDROLOGY...BR/DS
NWS OKX Office Area Forecast Discussion
