945
FXUS61 KOKX 161933
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
333 PM EDT Sun Mar 16 2025
.SYNOPSIS...
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A strong cold front approaches this evening, moving across the
region on Monday and 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.-- End Changed Discussion --
&&
.NEAR TERM /THROUGH MONDAY/...
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Key Points:
* 1.5-2.5" of total rainfall expected this evening into
tomorrow, most of which will fall with a strong line of rain
this evening into tonight. Highest totals east. Isolated
higher totals possible. A few rumbles of thunder are
possible.
* Moderate to heavy rainfall along a slow moving line of rain
tonight may lead to minor, nuisance flooding.
* Breezy southerly winds continue this evening until the line
of rain passes tonight.
* Showers will be more spotty tomorrow before cold front
passes.
We`re mostly socked in with cloud cover early this evening with some
breaks of sun for far eastern locations. Temperatures are sitting
much higher today thanks to the passage of a warm front. This has
left us with strong southerly flow. Any breaks in cloud cover should
fill in later this evening as southerly flow and a strengthening LLJ
aloft advects in more moisture up the East Coast.
A prefrontal trough situated ahead of the cold front moves into the
region later this evening into tonight. At the same time a longwave
trough to our west approaches. As it does so, it stretches in
latitude and narrows in longitude. The prefrontal surface trough
arrives just before it with plenty of positive vorticity advection.
A strong 60-70kt LLJ accompanies it along with a tongue of higher
PWATs which will range anywhere from 1.3-1.6 inches. We`ll also be
located under the right entrance region of a jet streak through
tonight into tomorrow morning.
Given all of the mentioned factors, rain showers will be likely late
this evening into tonight. Isolated thunderstorms could occur across
the western half of the area, but instability drops quickly further
east due to the marine layer. The rain will arrive as a line that is
expected to slow its advance tonight across eastern zones before
eventually exiting tomorrow morning. After examining model
soundings, the Corfidi Upshear vector at times is 10kts or less,
which could indicate the line of showers backbuilding as they
advance east. Most models have PWATs right at or exceeding our max
moving average for this time of year, according to SPC`s Sounding
Climatology Page. Tall, skinny sounding profiles with a warm cloud
layer around 3km in depth could indicate some efficient rain makers
tonight. WPC has us under a Marginal Risk for Excessive Rainfall.
Examining 12Z HREF, it appears we have good probabilities for
quarter to half inch per hour rainfall rates. Probabilities drop
off after that, but rain rates closer to 0.75-1.0"/hr can not
be ruled out, though they may remain isolated if they occur.
This could cause some minor flooding issues for eastern areas as
the line of advancing rain slows before exiting late tonight
into daybreak tomorrow. For now, expecting only isolated
instances of minor, nuisance flooding from stronger showers
embedded in the line of advancing rain tonight. Widespread flash
flooding is not something we are expecting with this. The areas
of primary risk will be Suffolk county in NY and Middlesex and
New London counties in CT.
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.
This evening through tonight and into tomorrow, total rainfall is
expected to be 1.25" to 2.50". Isolated higher rain totals can not
be ruled out in stronger showers. Areas east will see the highest
totals. Areas west will see the lowest totals.
Southerly winds this evening into early tonight could gusts up to 30-
35 mph, eventually subsiding late tonight into tomorrow morning.
Some 12Z guidance brings in gusts higher than this, likely
influenced by the development of a strong LLJ, but have opted not to
include higher gusts due to a strong inversion that may prevent a
lot of this from mixing down.
Given strong southerly flow amid widespread rainfall, low
temperatures tonight will remain mild and well-above average in the
mid-50s to upper-40s. Highs tomorrow will again warm into the mid-
50s to near 60 prior to the frontal passage.-- End Changed Discussion --
&&
.SHORT TERM /MONDAY NIGHT/...
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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.-- End Changed Discussion --
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
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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.-- End Changed Discussion --
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
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Low pressure and a cold front approach from the west into this
evening with the cold front moving into the terminals late tonight
into Monday morning as a wave of low pressure develops on the front.
The frontal wave and cold front move east early Monday afternoon.
Conditions vary across the region with IFR/LIFR across Long Island
into coastal New York City, and MVFR most other locations, and even
local VFR inland. Conditions will be lowering back to widespread
IFR/LIFR late afternoon into early this evening, and remain IFR/LIFR
through tonight with showers developing this evening, with a period
of moderate to heavy rainfall. There is also a chance of thunder
from about 02Z to 07Z at the NYC metro terminals, however, chances
and confidence are low, and have not included in the forecast.
Showers gradually come to an end Monday morning into the afternoon
with VFR late Monday afternoon.
Southerly winds, with gusts 25 to 30 kt, continue through this
evening, with a few peak gusts to around 35 kt possible along the
coast this afternoon. As the cold front and frontal wave move into
the region, winds and gusts will diminish, and may for a time
evening become light and variable. Timing of the diminishing winds
is uncertain. As the front passes east, winds sift to the west and
then NW/N, becoming gusty late Monday.
LLWS continues with S winds at 2kft 50-60 kt into late tonight, and
ends from west to east 05Z to 13Z.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Unscheduled AMD likely through the TAF period to address changes in
flight categories and timing of rain, and wind shifts.
.OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY...
Monday afternoon: Generally MVFR with showers ending west to east,
then becoming VFR, except at KGON where IFR and showers continue
into late afternoon, ending early evening. NW/N winds G15-20 kt late
afternoon/early evening.
Tuesday and Wednesday: VFR.
Wednesday night and Thursday morning: IFR/LIFR cigs possible
especially along the coast.
Thursday afternoon and night: Chance of showers with MVFR cond
possible. S winds 10-15 kt with G20-25 kt, winds shifting to W
during the evening.
Friday: VFR at the NYC terminals and west, MVFR/IFR east with
showers ending late in the day, then becoming VFR. NW wind 15-20 kt
G20-30 kt.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
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A Small Craft Advisory is issued on the bays, harbor and LI Sound
through early Monday morning for winds. A Gale Warning will go up
tonight until early tomorrow morning for the chance of gale-force
winds. A Small Craft Advisory may need to be issued on ocean
waters following the Gale Warning through Monday night for
waves.
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.-- End Changed Discussion --
&&
.HYDROLOGY...
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1.5"-2.5" of total rainfall is expected this evening into the day
tomorrow, most of which will fall with a strong line of showers and
embedded isolated thunderstorms this evening into tonight. The
highest rain totals will be over the counties of Suffolk, Middlesex,
and New London. These areas may also be at the highest risk of minor
nuisance flooding, but not a significant concern for dangerous
flash flooding. WPC has the entire area under a Marginal Risk
for Excessive Rainfall. Rainfall rates will likely be
0.25"-0.50"/hr, but isolated rainfall rates up to 1.0"/hr can
not be ruled out.
No hydrologic impacts are expected Tuesday into next weekend.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 6 AM EDT Monday for ANZ331-335-338-
345.
Gale Warning from 8 PM this evening to 6 AM EDT Monday for
ANZ332-350-353-355.
Small Craft Advisory until 8 AM EDT Monday for ANZ340.-- End Changed Discussion --
&&
$$
SYNOPSIS...BR/DS
NEAR TERM...BR
SHORT TERM...BR
LONG TERM...DS
AVIATION...MET
MARINE...BR/DS
HYDROLOGY...BR/DS