000
FXUS61 KOKX 271325
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
925 AM EDT Thu Apr 27 2023
.SYNOPSIS...
A weak area of low pressure and associated cold front move
across the region into this morning, with the front stalling
and remaining in the vicinity through tonight. 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.
&&
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
A nearby mid-level shortwave and weak surface boundary help to
instigate scattered shower activity through this morning, and
potentially into the afternoon.
A batch of light rain is moving eastward through southern
Connecticut this morning with scattered showers elsewhere so
PoPs were adjusted accordingly. Otherwise, forecast remains on
track with only minor adjustments to temperatures and dew
points.
Intermittent showers continue through the morning as the weak
boundary meanders near or over the region. Rain chances begin
to lower as the system loses upper level support early this
afternoon, but weak forcing may not allow a complete dry out,
though the bulk of the rain falls by 15z. Total rainfall should
stay under a quarter of an inch, with most under a tenth.
Heights rise later today as the shortwave exits and ridging builds
aloft. The associated subsidence should help to try and break down
the cloud cover late in the day.
Temperatures remain seasonably cool for late April given the wet
weather, cloud cover, and easterly flow. Temperatures will sit in
the 50s for much of the region, with highs struggling to hit 60
outside the urban metro, or about 5 to 10 degrees below normals.
Dry conditions are expected tonight with weak high pressure
over the Northeast. Blended in MAV/MET data for lows given the
light winds and relatively clear skies.-- End Changed Discussion --
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
The region doesn`t remain dry for long. Into late week, a
second, more potent, shortwave swings east, with associated low
pressure tracking into the Ohio Valley on Friday. A 1025 mb
surface high over New England retreats offshore as the low
approaches, and the E/SE flow begins to increase Friday with the
tightening pressure gradient.
Cloud deck gradually builds and lowers through the day, giving
way to rain by Friday night. The center of the primary surface
low passes northwest and tracks through the Great Lakes, with a
secondary developing along the coast and meandering near the
region through Saturday.
Hi-res CAMs indicate the rain should develop in the late
afternoon or early evening Friday across the western half of the
area, spreading north and east into the evening and overnight,
and continuing through much of the day Saturday. The showers
begin to lighten and taper Saturday eve, but conditions may not
entirely dry out overnight into Sunday.
The LLJ strengthens overhead on Saturday as the low approaches,
with 40-50 kt winds progged at 925 mb (~2 kft) on BUFKIT
soundings. This likely leads to a few gusts topping 30-40 mph
during the day, adding to the raw feel of the day.
Total QPF from this system looks to range between 0.5 and 1.5
inches. WPC continues to outline a marginal risk region-wide for
excessive rainfall on Saturday. On one hand the relatively dry
conditions this month lends this rainfall the opportunity to be
more beneficial than anything else. On the other, the potential
for moderate, to locally heavy, rain at times, means nuisance
flooding is certainly possible at times, particularly in the
vulnerable urban locales.
Temperatures will be mildest on Friday prior to the wet weather,
with highs for most in the lower 60s. Cooler conditions can be
expected on Saturday with overcast skies and period of rain,
temperatures largely stay in the lower to middle 50s. Blended
guidance was generally followed for this period.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Weak low/triple point will be in the vicinity on Sunday with a
stronger low center approaching us from the Mid-Atlantic as an
associated shortwave energizes the system. Rain becomes likely
generally SW to NE through the forecast area as the day progresses
with rain continuing through the evening before tapering off late at
night. Although the core of a low level jet might end up just off to
our east, rainfall is expected to be moderate, and potentially heavy
at times across the entire area - mainly late in the day into the
night. PWATS will still be 1.25-1.50 inches and lift from the low
center itself plus large-scale lift from a left-exit region of an
upper jet streak should enhance rainfall. Have added in an isolated
thunderstorm for the eastern zones Sunday night as the low center
shifts through along with some CAPE and potential llj lift.
The low pressure center lifts NE on Monday, however a closed 500mb
low will remain over the Great Lakes Region. With the cyclonic flow
aloft stretching over to here, there will be a chance of showers,
primarily inland. The closed low aloft slowly drifts east through
Wednesday with generally low chances of showers through much of the
period.
NBM was used for temperatures. Highs will be around or slightly
below normal for Sunday and Monday, then 5-10 degrees below normal
for Tuesday and Wednesday
&&
.AVIATION /13Z THURSDAY THROUGH MONDAY/...
Weak low pressure slowly moves through the region today.
Mostly VFR to MVFR and -shra during the remainder of the
morning push. Rain chances diminish not too long thereafter,
but with still a slight chance of a shower through at least the
daytime hours. MVFR should prevail through early afternoon, but
VFR might prevail before sundown. VFR otherwise returns early
this evening and probably prevails through tonight.
Winds under 10 kt through the TAF period, mainly SE through this
evening before backing more E to NE.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
VFR potentially prevails through the remainder of the morning
push without TEMPO MVFR. Chance that VFR even prevails all day,
otherwise timing of MVFR onset and ending may be off by a few
hours.
OUTLOOK FOR 012Z FRIDAY THROUGH MONDAY...
Friday-Friday Night: Mainly VFR during the day, then MVFR or lower
with increasing chances of rain at night. Rain becomes likely late
at night for NYC terminals and terminals to the north and west. ESE-
E wind gusts 15-20 kt.
Saturday: Rain with MVFR or lower. E wind gusts near 20-25 kt.
Sunday and Sunday night: MVFR or lower. Rain, mostly in the
afternoon and night. SE wind gusts 20-25 kt at night.
Monday: MVFR possible with a chance of rain showers. Wind direction
switches from more SE to eventually more WSW. Wind gusts 20-25 kt.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
Winds and seas remain below SCA criteria through tonight.
Low pressure passing through the waters will lead to increasing
easterly flow late Friday into Saturday. SCA conds return as
ocean seas build to 5 ft by early Saturday morning, and remain
elevated into early next week. E gusts around 25 kt develop on
all waters early Saturday, with gales possible for a time
Saturday afternoon.
Seas on the ocean remain elevated on Sunday with a SE swell, so SCA
conds will continue through the rest of the weekend. Winds ramp up
Sunday night with a low pressure center approaching from the Mid-
Atlantic with SCA probably on all waters, with winds probably still
gusting to 25 kt on Monday on the backside of the storm.
&&
.HYDROLOGY...
A storm system brings a widespread half inch to inch and a half
of rainfall late Friday through Saturday. With moderate to locally
heavy rain at times, nuisance flooding will be possible,
particularly in vulnerable urban locales.
An additional inch to inch and a half of rainfall is possible during
Sunday into Sunday night. Again, mainly minor/nuisance flooding
would be the extent of hydrologic impacts.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JC/DR
NEAR TERM...DR/MW
SHORT TERM...DR
LONG TERM...JC
AVIATION...BC/JC
MARINE...JC/DR
HYDROLOGY...JC/DR