558
FXUS61 KOKX 011947
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
347 PM EDT Thu May 1 2025
.SYNOPSIS...
-- Changed Discussion --
A warm front approaches tonight and lifts through Friday morning. A
cold front to the west gradually draws closer Friday night into
Saturday. A large cut-off low pressure system will bring unsettled
conditions to the area from the weekend through at least mid-week.-- End Changed Discussion --
&&
.NEAR TERM /THROUGH FRIDAY/...
-- Changed Discussion --
The stretch of nice spring weather begins to break down as a warm
front approaches from the west and south tonight. The first half of
the evening should manage to be dry. However, as warm air comes in
over the top of the boundary layer look for clouds to lower with
rain / showers developing from southwest to northeast later in the
evening and into the overnight further east. Have gone with low end
likely PoPs across a portion of the area (mainly further east), with
a period of chance PoPs most elsewhere. As the warm front gets close
with some extra lift, there is the slight chance of a rumble of
thunder (mainly for western most sections from very late in the
evening until just after midnight) as there is just a hint of
elevated instability as per some BUFKIT forecast soundings. Later at
night as the low level winds continue to veer gradually look for
some patchy to perhaps some areas of fog. This would be mainly
towards and after 08z as the sfc warm front gets on our doorstep.
Once the area of showers tapers off and gets to the east, this is
when the chances for fog go up, more so approaching daybreak.
Temperatures should average just above average with clouds and
an onshore flow.
On Friday NWP remains confident in getting the warm front through
and getting sfc winds around to more of a SW direction for the mid
to late morning. This should allow for the sky to brighten and more
in the way of sunshine towards midday and the afternoon as the
region gets purely in the warm sector. Temperatures should get well
above normal inland and not quite as warm along the coast, but still
above normal for the most part. Lower and middle 80s can be expected
inland to the N and NW, with 70s in most places, and a few 60s
across the east end of LI and portions of SE Southern CT. Guidance
does indicate some instability, with a few hundred Joules of CAPE.
However, the better forcing will still reside well west of the area
and forecast sounding are suggestive of a weak cap in place. Thus,
have kept mainly slight chance to chance PoPs the further west one
goes Friday afternoon and evening with the slight chance of a few
thunderstorms. Coverage at this time looks limited with SPC placing
mainly the western portions of the area in a marginal risk of severe
weather for this reason. CAMs thus far are not too suggestive of any
meaningful coverage in terms of convection during Friday as the
afternoon and evening.-- End Changed Discussion --
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/...
-- Changed Discussion --
The same line of thinking carries over into Friday night. With a
cold front remaining back to the west the higher PoPs and convective
chances will to the west. But still cannot rule out that some shower
/ thunderstorm activity gets in some during the night. With this
said, much if not all of the night remains dry. On a SW synoptic
flow temperatures will remain above normal with lows mainly in the
middle 50s to middle 60s. Some patchy fog cannot be ruled out late
Friday night where any showers occur earlier in the night, but this
should may be the exception rather than the rule.
On Saturday the cold front will progress further east. The morning
should remain primarily dry on a S to SW flow out ahead of the
front. Partial sunshine should help temperatures warm to around 80
inland and west, to mainly the lower and middle 70s and the upper
60s getting further east and closer to the coast. SPC has placed
much of the area in a marginal risk of severe weather. A southerly
wind off the colder water should limit severe chances further east.
However from around the NYC metro and west where there will be less
marine air to ingest into any developing convection and thus any
storms could produce strong gusty winds and brief heavy rainfall. An
early look at some of the CAMs shows more coverage across the area
due to increased forcing from the approaching cold front. The
greatest chance of showers and thunderstorms will be further west
and northwest, and later in the day.-- End Changed Discussion --
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
-- Changed Discussion --
The extended period will be dominated by a large cut-off low
pressure system which will bring periods of rain, possibly with
embedded thunderstorms, from the weekend through at least the middle
of next week.
By Saturday night, a digging trough over the Midwest is expected to
completely cut off from the main flow and meander generally in place
over the Ohio Valley through much of the period before eventually
being reintroduced to the flow sometime mid-to-late week. During
this time, we will be positioned downstream of this trough and our
weather will be dominated by the surface frontal system that will be
placed just west of the area.
Additionally, a surface high pressure over the Western Atlantic
combined with the surface low pressure to our west will allow for a
continuous S/SE flow through the timeframe. This will advect a
continuous stream of moisture from the sub-tropical Atlantic,
resulting in overcast skies and periods of rain through the period.
When it is not raining, there may be ample enough low level moisture
to produce drizzle and/or fog, especially at night.
With the upper trough just to the west, there may be enough
instability each afternoon and evening for there to be isolated to
embedded thunderstorms, especially in any more organized convection
that forms, mainly for the western portions of the area.
Due to the inherent uncertain nature of a spinning but nearly
stationary cut off low pressure system, it remains especially
difficult to pinpoint any periods of more persistent or heavier
rainfall or thunderstorms. At this time, global models seem to
suggest that the Sunday night - Tuesday night timeframe may have the
best combination of moisture and lift to allow for a more widespread
steadier to locally heavy rainfall, but this may change in future
runs. WPC has the area in a marginal risk for excessive rainfall
during this timeframe.
Models also suggest that a widespread 2-3 inches of rainfall is
possible for much of the area, especially for western areas which
may be more favorable for convection at any given time. Locally
upwards of 4 inches isn`t ruled out, though this accumulated
rainfall is over the entire extended period, generally from Saturday
night through Wednesday.
The low pressure is expected to move out of the area sometime
Wednesday night through Friday morning. Despite ample cloud cover
and rainfall, temperatures through the timeframe should be fairly
seasonable to slightly below average, with highs each day generally
in the 60s, possibly a bit warmer for the NYC metro. Lows each night
will remain in the 50s, courtesy of the ample amounts of moisture.-- End Changed Discussion --
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
High pressure north of the area will move off the coast this
afternoon. A warm front then approaches tonight, lifting north
of the terminals Friday morning.
VFR conditions will prevail into this evening before conditions
deteriorate with the approach of the warm front. MVFR conditions
are expected to develop around midnight at the NYC metro
terminals, followed by IFR after 06Z and LIFR possible towards
daybreak at some locations. Scattered showers are also possible
overnight ahead of the approaching front, along with an isolated
thunderstorm. VFR conditions will return between 12-15Z at the
metro terminals as the warm front pushes north.
SE winds around 10 kt will continue through this afternoon.
Winds then diminish to around 5 kt overnight before returning
out of the S after the warm frontal passage Friday morning.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of both the deterioration to sub-VFR conditions overnight
and improvement back to VFR Friday morning could be off by 1-2
hours.
.OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...
Friday: VFR. Showers/tstms possible in the afternoon and at
night. S winds G15-20kt in the afternoon.
Saturday: MVFR or lower cond possible with chance of
showers/tstms. S winds G15-20kt.
Sunday: MVFR or lower cond possible with chance of showers/tstms.
Monday: MVFR or lower cond possible with chance of showers/tstms.
E-NE winds G20-25kt.
Tuesday: MVFR or lower cond possible with chance of
showers/tstms. S winds G15-20kt.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
-- Changed Discussion --
A SE flow turns more S tonight, and then increases some into Friday.
Small craft conditions start to become more likely during the
afternoon out on the ocean waters with marginal small craft seas and
gusts approaching 25 kt. More widespread small craft conditions will
be likely for the ocean into Friday evening on a S to SW wind. Ocean
seas should get closer to 4 ft towards Saturday morning as sub
advisory conditions continue on the non-ocean waters. After a brief
break from advisory level conditions during Saturday morning, by
later Saturday afternoon small craft conditions should return. Small
craft conditions are also possible for the south shore and eastern
bays of Long Island by late in the day.
SCA conditions are possible through Saturday night before waves
subside and gusts largely drop below SCA thresholds for Sunday.
Increasingly S/SE flow on Monday may allow for near SCA gusts for
all the waters and wave heights on the ocean nearing 5 feet once
again.-- End Changed Discussion --
&&
.FIRE WEATHER...
-- Changed Discussion --
A special weather statement for an elevated risk of fire spread
continues until 7 pm for NE NJ zones. With an onshore flow RH is
expected to climb into this evening, bringing an end to any risk
of fire spread.-- End Changed Discussion --
&&
.HYDROLOGY...
-- Changed Discussion --
Long duration rainfall this weekend through midweek will likely
result in a widespread 2-3 inches of rainfall, possibly locally
higher in any thunderstorms. WPC has the area in a marginal risk for
excessive rainfall Sunday through Tuesday. While flash flooding
isn`t expected, minor urban or poor drainage flooding is possible at
any point Saturday night through Wednesday.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 4 PM Friday to 6 AM EDT Saturday for
ANZ350-353.
Small Craft Advisory from 4 PM Friday to midnight EDT Friday
night for ANZ355.-- End Changed Discussion --
&&
$$
SYNOPSIS...JE/MW
NEAR TERM...JE
SHORT TERM...JE
LONG TERM...MW
AVIATION...FEB
MARINE...JE/MW
FIRE WEATHER...
HYDROLOGY...JE/MW