506
FXUS61 KOKX 052022
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
422 PM EDT Mon May 5 2025
.SYNOPSIS...
-- Changed Discussion --
A weak frontal boundary will remain in close proximity to the
area through Tuesday with high pressure tracking across the
Canadian Maritimes. At the same time, a broad area of low
pressure over the Ohio Valley will track slowly east. Between
the two, bands of rain will work in off the ocean. The front
gradually lifts back the north on Tuesday, while low pressure
approaches from the west. Weak low pressure will then slide
northeast through the area on Wednesday. A cold front will
approach from the northwest on Thursday and stall nearby
Thursday night as low pressure develops along it over the Mid
Atlantic region. Coastal low pressure will track over or just
southeast of the region Friday into early Saturday, before
heading up the New England coast. Another cold front will
approach from the northwest on Sunday.-- End Changed Discussion --
&&
.NEAR TERM /THROUGH TUESDAY/...
-- Changed Discussion --
System thus far has underperformed the last 24h and guidance and
the CAMs continue to struggle with the rain bands rotating in
off the ocean. Latest consenus has shifted the axis of heaviest
rain a bit farther east, emphasizing eastern LI and much of
southern CT as the likely recipients. An easterly LLJ of 40kt
will lift across the area this evening, enhancing orographic
lift with to 3 inches of rainfall still possible across the
inland areas of CT, minus slightly lower amounts in the CT
River Valley. The Lower Hudson Valley, NYC, and NE NJ can expect
an additional quarter to one-inch, possibly up to 1.5 inches
across some of the higher elevations north and west.
Latest CAMs take the current area of rain and lift it north
through early this evening. There will likely be a break in the
action before another band moves in from the south. The focus
is mainly from NYC and east. Instability remains marginal and
will gradually increase overnight into Tuesday as the precipitation
takes on a more convective look.
SPC HREF PMM hourly and three-hourly amounts remain below FFG
through tonight with storm total amounts as high as 3 to 5
inches across the higher elevations in CT. Based on performance
thus far and uncertainty with the band placement, these amounts
are likely to be localized. As for the latest NBM, probability
for more than an inch of rainfall is 60 to 80 percent.
WPC maintains a slight risk of excessive rainfall across the
area through the overnight, so can`t completely rule out
isolated flash flooding. Once again though, emphasis on location
would be across interior CT.
Easterly winds will veer around to the SE tonight with mild
conditions. Lows will be in the mid and upper 50s. Then onshore
flow and high dew point air will also result in fog, some of
which could be locally dense.
On Tuesday, a bit more instability is expected, especially west
of the NYC metro in the afternoon with the potential for some
partial clearing. However, there still looks to be enough of a
marine influence to keep it more elevated and unlikely to
reach severe limits. With the upper low approaching, impulses
will move in from the south with additional bands/pockets of
rain, but looking less organized than what is expected tonight.
Localized amounts up to an inch will be possibly with potential
training of cells in a deep-layered southerly flow. Minor
nuisance flooding will continue to be possible.
Highs Wednesday will be warmer in the mid 60s to around 70. This
closer to normal.-- End Changed Discussion --
&&
.SHORT TERM /TUESDAY NIGHT/...
-- Changed Discussion --
Widely scattered to scattered showers can be expected Tuesday
night with emphasis to the west of NYC early in the evening
where the airmass will be most unstable. The upper low will
near the area by daybreak Wednesday. Expect some additional fog
with a southerly flow and high dew point air in place. Lows
will be in the 50s, which is about 5 to 10 degrees above
normal.-- End Changed Discussion --
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --
Good model agreement in persistent cutoff upper low to the SW of the
area the last few days shearing NE through the region on Wed, ahead
of a digging northern stream trough sliding from Ontario into
Quebec. This trough will slide into the NE US for late week, with
good agreement in another closed low developing at its based in the
to the SW the region Thu Night/Friday and then pivoting ne through
Saturday.
At the surface, the stalled frontal system over the region should
lift ne thru the area Wed into Wed eve, with drying conditions Wed
Night into Thu AM. Cold pool aloft plus daytime heating should
generate enough instability for sct to numerous shra/tstms late Wed
AM into Wed eve ahead/along surface wave/frontal trough,
particularly N&NW of NYC.
Drying conds in wake of the departing low appears short lived, as
the next cold front approaches the region Thu aft/eve. Isolated aft
shra/tsra activity possible in this weakly unstable environment.
Good agreement in sfc cyclogenesis over the Mid Atlantic region
along the cold front on Thu Night into Friday as the digging
northern stream trough phases with southern jet and closes off at
its base across the Central Appalachians. Resultant strengthening
coastal low pressure will bring increasing likelihood of overrunning
rain Thu Night into Fri AM, with potential for a period of moderate
to heavy rain Fri into Sat AM with deep layered lift and convergence
of Gulf/sub-tropical moisture feed over the region as low pressure
tracks over or se of the region.
Improving conditions Sat aft/night in wake of low pressure and
closed low. Subsequent shortwave likely crosses with cold frontal
passage Sun/aft eve, with seasonable conditions to follow for early
next week with Canadian high pressure building into its wake and
gradually rising heights.
Temps near to slightly above seasonable for Wed/Thu, falling to a
few to several degrees below seasonable Fri/Sat with low pressure
affecting the area, then moderating back to slightly above
seasonable for Sun into early next week.-- End Changed Discussion --
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
-- Changed Discussion --
Frontal boundary remains stalled within the region through the
TAF period.
Mainly IFR to LIFR forecast with low clouds, fog, and periods of
rain expected through the TAF period. Some terminals could see
brief VLIFR (mainly overnight and for outlying areas) or MVFR
conditions at times. MVFR conditions would likely come in
improvements in visibility with lighter rain or a respite from
the rain (though any moderate to briefly heavy rain would be
associated with lower visibility, keeping it in the IFR to LIFR
range).
Winds are easterly around 10 kt. Gusts, mainly for the
sound terminals (KLGA, KBDR and KGON). Occasional gusts 15 to
20 kt elsewhere, diminishing this evening. Southeasterly flow
expected Tuesday at around 10 kt.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Categories will fluctuate between LIFR and MVFR through the
TAF period.
.OUTLOOK FOR 18Z TUESDAY THROUGH SATURDAY...
Tuesday afternoon and night: Rain/showers and IFR. Possible
thunderstorms. SE gusts around 10 kt, with gusts up to 15 kt.
Wednesday: Chance of MVFR or lower with and a chance of showers
and slight chance of thunderstorms.
Thursday: MVFR possible with a chance of showers, mainly at
night.
Friday: MVFR possible with a chance of showers. A slight chance
of thunderstorms.
Saturday: Mainly VFR, except MVFR or lower possible in slight
chance of showers.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
-- Changed Discussion --
Marginal SCA conditions for seas around 5 ft will continue
through the day Tuesday in an E/SE flow. This may need to be
extended into Tuesday night, but confidence is low at this
time.
Marginal 4-5 ft ocean seas possible Wed into Wed night in mainly a
residual E/SE swell, with sub SCA conditions likely on Thu under a
weak pressure gradient.
Next potential for SCA conditions Fri/Sat on all waters with coastal
low pressure. Low prob for gales on the ocean in E/SE flow ahead of
the low if stronger coastal development evolves.-- End Changed Discussion --
&&
.HYDROLOGY...
-- Changed Discussion --
An additional 1 to 3 inches of rainfall is expected through
Tuesday with the upper end forecast across interior CT due to
an easterly LLJ this evening. Localized higher amounts are
possible. WPC has the area under slight risk of excessive
rainfall with isolated flash flooding possible.
There is the potential for a period of moderate to heavy
stratiform rain for Fri into Sat AM. NBM probability of 1" in 24
hr is at 20%, with less than 10% prob of 2" in 24 hr.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...None.
NY...None.
NJ...None.
MARINE...Dense Fog Advisory until 8 PM EDT this evening for ANZ350-353-
355.
Small Craft Advisory until 6 PM EDT Tuesday for ANZ350-353.
Small Craft Advisory until 6 PM EDT Tuesday for ANZ355.-- End Changed Discussion --
&&
$$
SYNOPSIS...NV/DW
NEAR TERM...DW
SHORT TERM...DW
LONG TERM...NV
AVIATION...JP
MARINE...NV/DW
HYDROLOGY...NV/DW