Discussion on 2023-04-25

000
FXUS61 KOKX 251530
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1130 AM EDT Tue Apr 25 2023

.SYNOPSIS...
-- Changed Discussion --A surface trough develops across the area today and then
weakens this evening. Weak high pressure builds over the area
tonight into Wednesday morning, before giving way to an
approaching weak cold front. The front moves slowly through the
area Wednesday night into Thursday morning, followed by high
pressure building in from the west. Low pressure passes near the
region late Friday into Saturday, with another low potentially
impacting the region late this weekend into the beginning of
next week.-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --Latest radar imagery shows some light returns across the Lower
Hudson Valley and northern NJ, which are either sprinkles
and/or light showers. Latest CAMs indicate potential for this to
continue and work east this afternoon in conjunction with the
upper low and surface trough. Any rainfall will be very light
and brief.

A large closed low will remain centered just north of the Great
Lakes through today as a vort max rotates into upstate New York
this afternoon. Temperatures will be near seasonal levels and
leaned toward the MOS guidance for the highs.-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
The upper closed low remains to the north of the Great Lakes
tonight, and slowly weakens, becoming an open negative trough
through Wednesday. Meanwhile surface high pressure builds over
the area tonight and moves offshore Wednesday. For tonight,
after initial clearing behind the weak low, temperatures will
drop, nearing the mid and upper 30s across the interior and the
lower 40s along the coast. Mid and upper level clouds will be
increasing late tonight as another weak low begins to approach
from the west. Temperatures may then fall more slowly late
tonight, or hold steady. With temperatures marginal, and
possible only for 2 to 3 hours, and clouds moving in, any frost
that may develop will not be widespread enough for an advisory,
so will hold off on issuing one at this time.

With near zonal flow additional upper energy quickly moves into
the area Wednesday and tracks through the area into early
Thursday. Again, any forcing is weak, and precipitable water
increasing slightly, up to 3/4 inches at times. Will carry only
chance probabilities Wednesday into Wednesday night. There is a
chance that the upper energy will be farther south, along with a
weak surface wave, and the better chances of precipitation may
end up along the coast, and south.

High pressure then begins to build toward the area for
Thursday.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
An active long term period with troughing for much of the
period and a series of disturbances moving through in the flow.

A relatively weak shortwave passes through into the start of
the weekend, bringing the chance for rain showers Friday night
and Saturday. Global guidance differs on the exact placement of
the surface low that develops, with implications on how much
rain is able to develop over the area. Much of Friday and
Saturday at the least appear overcast, with moistening
conditions in easterly flow.

Meanwhile, a more potent disturbance dives south across the
Central US. This system has the potential to be a soaker, with
ensemble means signaling several inches of liquid possible this
weekend into early next week as surface low pressure attempts to
rapidly deepen as it reaches the Eastern Seaboard and the
trough becomes negatively tilted. This would allow moderate to
heavy rain to fall much of Sunday and Monday. Given inherent
uncertainty at this stage, capped PoPs at 70% and winds at 30 kt
for this update.

Persistent onshore flow and wet weather will keep temperatures
through the period near or slightly below normals for the time
of year. Other than previously noted, national blended guidance
was followed with subtle adjustments.

&&

.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
High pressure slowly builds in from the west during the TAF
period. VFR forecast.

Light NW winds around 5 kt or less this morning increases to
near 10 kt after 15z. The flow backs more W to SW in the
afternoon along the coast, but stays WNW or NW for inland
terminals. Flow becomes lgt and vrb tonight as high pressure
builds overhead. Winds turn S or SE on Wednesday with the high
shifting offshore, speeds remain under 10 kt.

A widely scattered shower is possible this afternoon, though
coverage is expected to be low. Cigs remain at or above 5 kft
today.

 ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...

A few gusts around 15 kt possible for NYC terminals this afternoon.

Wind direction will be near 310 magnetic at times today, though
largely left of it after 16z.

Brief rain shower cannot be ruled out this afternoon.

OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...

Wednesday: VFR. A chance of rain showers in the afternoon into
the night with MVFR possible.

Thursday: VFR. Possible rain showers and MVFR, mainly east of NYC
terminals during the day.

Friday: Mainly VFR. E wind gusts 15-20 kt.

Friday Night-Saturday: Increasing chances of rain showers.
Possible MVFR or lower at times. E wind gusts 20-25 kt.

Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90

&&

.MARINE...
-- Changed Discussion --Winds and seas remain below small craft advisory levels
through Thursday as high pressure builds toward the waters
through tonight. A weak front then moves through the waters
Wednesday night into early Thursday.

Low pressure passing near the waters late Friday into Saturday
will lead to increasing easterly flow. Wind gusts of 25-30 kt
are possible on all waters and ocean seas build to 5 ft during
this time.

Another area of low pressure may impact the waters late this
weekend, bringing the chance for widespread SCA conds, with
gales possible for a period as well.-- End Changed Discussion --

&&

.HYDROLOGY...
Deepening low pressure may impact the region late this weekend,
bringing the potential for several inches of rainfall across
the region. Hydrological impacts are possible during this time
period.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --CT...None.
NY...None.
NJ...None.
MARINE...None.-- End Changed Discussion --

&&

$$

UPDATE...DW