000
FXUS61 KOKX 261950
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
350 PM EDT Wed Apr 26 2023
.SYNOPSIS...
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A weak area of low pressure and associated cold front moves
across the region tonight into Thursday morning, with the front
stalling and remaining in the vicinity through Thursday night. High
pressure exits offshore on Friday as a frontal system
approaches from the west, moving through the region Saturday. A
second area of low pressure develops in the Southeast this
weekend, impacting the region into early next week.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
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A line of showers will over central New York and eastern
Pennsylvania will make its way into western portions of the
forecast area this evening in association with a weak cold
front. A weak area of low pressure is expected to form along the
frontal boundary later tonight. The upper level low north of the
Great Lakes will weaken overnight. This will allow upper level
troughing to take place over the Northeast U.S.
Did add a slight chance for thunder, mainly for Orange County
for early this evening as there is some instability at the
surface in most models, with up to a couple of hundred J/kg. It
is not totally out of the question to see some small hail in
this area, with up to 100 J/kg of CAPE in the -10 to -30 C range
noted in the SPC analysis. However, with weak forcing, the
chance would be low that any showers or thunderstorms would
create a strong enough updraft for hail.
With an easterly to southeasterly flow over much of the area, a
more stable air mass is in place, and thus much of the rest of
the forecast area should only see showers. Lows will be near
normal for this time of year thanks to cloud cover preventing
radiational cooling. Lows will be in the 40s.-- End Changed Discussion --
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
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Showers will continue as the cold front slowly moves through
Thursday morning. However the chances should lower during the
day as the system loses upper level support with the trough
flattening out and then upper level ridging starting to move
into the area from the west. Showers are possible for Long
Island through Thursday morning as the front becomes stationary
and remains nearby through at least Thursday night.
Dry conditions are expected Thursday night with weak high
pressure over the Northeast U.S. Similar low temperatures
expected Thursday night as compared to Wednesday night.-- End Changed Discussion --
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
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An active spring pattern sets up in the long term period, with
multiple rounds of rain expected.
The front half of Friday remains dry, with weak high pressure
retreating across New England into Canada as a mid-level shortwave
and surface low approach from the south and west with a developing
frontal wave along the coast into Saturday. Increasing cloud cover
Friday afternoon should give way to scattered to numerous rain
showers Friday night into the day on Saturday. Have increased POPs
since the last forecast as stronger moisture transport seems
apparent for the Friday-Saturday system with PWATs 75% to 90% of
climatological average. WPC has also included us under a marginal
risk for excessive rainfall for Saturday.
Meanwhile, a more potent disturbance dives south across the Central
US. Ensembles continue to signal a deepening area of low pressure
along the East Coast Sunday into Monday as the trough becomes
negatively tilted.
Conditions may dry Saturday night into much of the day on Sunday as
one system departs and the second is a bit slow to approach. Global
models are still not in agreement on just how long this lull in wet
weather will last before the next system, so timing of POPs may
change once models find a consensus.
Late Sunday into Monday morning a shortwave exits the mid-Atlantic
coast and lifts up the east coast into New England around an already
major closed low to our northwest. This will likely enhance the
influx of moisture with most global deterministic models agreeing on
maximum PWATS of 1.4-1.6" Monday morning. SPC`s sounding climatology
has a max moving average of 1.5" and a 90th percentile around
1.2" for PWATs. This greater availability in moisture could
allow for moderate to heavy rainfall at times Sunday night into
Monday, with timing still subject to change. A strong jet over
the region could also signal greater divergence aloft allowing
for a greater chance for rain coverage. WPC has given our region
a marginal risk for excessive rainfall on Sunday for their day
5 outlook. A strong LLJ could also signal the potential for some
gusty winds overnight Sunday into Monday.
The storm itself exits by Tuesday, though the upper low lingers
nearby into the middle of next week, maintaining the chance for
showers and cloud cover.
The persistent onshore flow and wet weather will keep temperatures
through the period below normals for the time of year. Other than
previously noted, national blended guidance was followed with subtle
adjustments.-- End Changed Discussion --
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
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A weak area of low pressure will move across the area tonight
into Thursday morning.
Mainly VFR through the event but there could be a period of
MVFR/IFR with showers later tonight into the morning hours. For
the time, just carried a TEMPO group after 12Z.
SE winds around 10 kt at the coast late this afternoon/early
this evening, otherwise 10 kt or less through Thursday. Some
locations may just go light and variable overnight. Winds may
vary significantly in direction on Thursday due to the close
proximity of a surface trough, but will be less than 10 kt
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Winds may vary by 10-20 degrees this afternoon. KLGA 200-210 for
a short period this afternoon.
Chance of MVFR or lower overnight in any showers, especially
after 06Z.
OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...
Thursday Afternoon: Mainly VFR. Slight chance of a shower east
of NYC terminals in the afternoon.
Friday-Friday Night: VFR during the day, then MVFR or lower possible
in increasing chance of showers at night. E wind gusts 15-20 kt at
night.
Saturday: MVFR or lower in rain. E wind gusts 20-30 kt.
Sunday: MVFR or lower in rain. SE wind gusts 20-30 kt.
Monday: Chance of MVFR or lower in rain in the morning,
improving to VFR. W wind gusts 20-25 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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Winds and seas remain below SCA criteria through Thursday night
with a weak pressure gradient over the waters.
Low pressure passing through the waters late Friday into Saturday
will lead to an increasing easterly flow.
SCA conds return this weekend as ocean seas build to 5 ft by early
Saturday morning, and remain elevated into early next week. E gusts
20-25 kt develop on most waters on Saturday, potentially continuing
through the remainder of the weekend as another area of low pressure
approaches and moves through into early next week.-- End Changed Discussion --
&&
.HYDROLOGY...
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No hydrologic impacts are expected with showers today into
Thursday with a quarter of an inch or less of rain expected with
rain showers into Thursday morning.
Rainfall expected on Saturday and Sunday could be moderate to
potentially heavy at times. Exact hydrologic impacts are still
uncertain at this time.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JP/BR
NEAR TERM...JP
SHORT TERM...JP
LONG TERM...BR
AVIATION...DW
MARINE...JP/BR
HYDROLOGY...JP/BR