000
FXUS61 KOKX 192343
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
743 PM EDT Thu Oct 19 2023
.SYNOPSIS...
High pressure off the East Coast moves further out into the
western Atlantic Ocean tonight as a frontal system approaches
from the west. A secondary area of low pressure develops along
the DelMarVa Friday into Friday night and deepens through Saturday
night while tracking into New England. The low departs to the
northeast Sunday as high pressure builds in from the west and
settles over the region early next week. A frontal boundary
approaches late next week.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Only minor adjustments were made to account for current observations
and trends. Overall, the forecast remains on track.
Deepening H5 trough axis centered over the Midwest gradually tracks
east as an associated northern stream frontal system tracks through
the Great Lakes into tonight. This will push surface high
pressure further out into the western Atlantic and allow for
increasing cloud cover before rain develops overnight.
Meanwhile, a convergent band of cloud cover and spotty showers
that has stubbornly persisted across portions of eastern LI and
into southern CT much of the day is finally beginning to dissipate.
A dry evening is expected regionwide before the clouds thicken
tonight.
Rain chances increase overnight as moisture streams north ahead
of the incoming trough. Showers should move in from south to north
toward daybreak, overspreading much of the region into the
morning. Temperatures bottom out in the 50s.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/...
As the trough swings east and the primary low moves through the
Great Lakes, a secondary area of low pressure begins to develop
off the Mid Atlantic coast, tracking north and east through
Saturday.
There remains some guidance differences as to the exact
track of the associated features, and thus, coverage and
placement of the rain. Occasional showers are likely much of
Friday with large scale ascent ahead of the trough axis. BUFKIT
soundings indicate the possibility of a few embedded thunderstorms,
particularly in the afternoon through the evening with several
hundred joules of elevated CAPE present. Periodic breaks in the
rain are likely before a final round moves through Saturday morning
and afternoon as the upper level low with the northern stream
system tracks across the region and merges over New England. The
bulk of the day may end up dry, or at least less wet than
Friday, especially for western areas.
Overall, QPF averages around an inch regionwide, with perhaps a few
locales picking up closer to two. The rain should fall primarily
light to moderate through the event, falling over a long enough
period of time to mitigate most flooding concerns. The typical
urban and poor drainage areas may experience minor issues should
a thunderstorm or locally heavy rain moves through.
Tight pressure gradient on the backside will increase surface flow.
Westerly gusts 20 to 25 mph are likely by late Saturday. Followed
a blend of CONSAll and NBM for this update.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Sunday a large, broad upper-level trough is situated overhead with a
possible mid-level shortwave tracking through as the trough exits on
Sunday night/Monday morning. At the surface, a low-pressure system
will continue to exit northeast towards the Canadian Maritimes. As
high pressure inches in from the west.
As the system exits and a shortwave tracks through, some lingering
precip (mainly for interior areas) may still be possible on Sunday
particularly for interior areas. Chances for now look low and mainly
isolated or light. Cloud cover will remain partly to mostly cloudy
on Sunday because of this, as well.
A strong pressure gradient will exist for much of the day on Sunday
as the system departs, leaving strong and gusty NW winds with peak
gusts in the afternoon 25-30 mph. Winds will gradually subside as
the pressure gradient weakens and high pressure builds overnight
Sunday into Monday morning. The strong winds and a broad trough will
help cooler air to filter into the region. Highs on Sunday will be
in the low-50s for northwestern interior areas while south and
southeastern coastal areas will reach the upper-50s.
Surface high pressure builds Monday through Wednesday with a large
ridge over much of the eastern United States. HIgh pressure will
keep sunny skies around early next week. Temperatures will gradually
increase each afternoon with heights rising. HIghs will be in the
mid/upper-50s Monday, low-60s Tuesday, then into the mid/upper-60s
on Wednesday.
Clear skies and light winds may allow for strong radiational cooling
Sunday and Monday night. Temperatures could drop into the upper-30s
to mid-40s Sunday night. Monday night may see further cooling with
coastal areas in the mid-40s and interior locations in the mid-30s.
Patchy areas of frost will be possible Monday night for some
interior locations.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
High pressure will continue to drift east of the region tonight
as a low pressure system approaches from the west on Friday.
VFR expected through much of the overnight. Cigs lower after 6Z,
becoming MVFR for most areas by 12Z. Some localized spots of IFR
are possible by Friday morning. Rain expected in the morning for
much of the NYC and nearby terminals. Low chance for thunder,
but not enough confidence to include in the TAF at this time.
Exact timing and placement of rain is a bit uncertain. Rain
expected to become more scattered SHRA by late morning/afternoon
with some slight improvements of cigs. Brief VFR possible for
the NYC terminals 20Z-00Z. KGON may stay VFR through much of the
day Friday.
S winds through tonight, backing to the SE Friday morning and
remaining thru 00Z Sat. Wind then may become variable after 00Z
Saturday as a low develops somewhere overhead or in the
vicinity.
....NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of category changes due to cigs may be off by an hour.
Fair amount of uncertainty in placement of rain Friday morning.
Embedded TSRA possible Friday morning, but too low confidence
to include in the TAFs.
OUTLOOK FOR 00Z SATURDAY THROUGH TUESDAY...
Friday night through Saturday: MVFR or lower with rain. Improvement
to VFR possible after 18Z Saturday.
Sunday: MVFR possible with CIGS around 3000 ft. W to NW wind gusts
25-30 kt.
Monday: VFR with gusty NW flow.
Tuesday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
A south to north oriented line of weak showers across portions of
the ocean off Fire Island and Long Island`s south shore bays
may produce a funnel cloud or weak waterspout. Marine Weather
Statement is in effect for these areas for this potential into
late afternoon. Otherwise, with a weak pressure gradient across
the waters tonight, winds and seas remain below advisory levels
across the forecast waters.
Increasing flow into Saturday as low pressure approaches and
moves through the waters. Westerly wind gusts begin to exceed 25
kts on all waters Saturday afternoon into evening, with ocean
seas building to around 5 ft during this time as well. The
pressure gradient over the area waters tightens on Sunday,
bringing the best chance for gales to the ocean waters. While
the chances for gales are lower on the non- ocean waters, can
not rule out a few gust to gale force. Winds and seas will then
gradually diminish Sunday night, with the non-ocean waters
falling below SCA conditions, however the ocean will continue to
see seas at or above 5ft through Sunday night. The seas on the
ocean waters are forecast to fall below SCA levels Monday
morning. By Monday afternoon or early evening, sub-SCA
conditions are then expected on all the waters and should remain
below SCA levels through Wednesday.
&&
.HYDROLOGY...
Rainfall between 0.75 and 1.5 inches is expected from late tonight
through Saturday, with most of the rainfall occurring Friday into
Friday night. Locally heavy downpours with any embedded
thunderstorms could produce nuisance flooding of urban and poor
drainage areas.
There are no hydrologic concerns Sunday through next week.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...BR/DR
NEAR TERM...BR/DR
SHORT TERM...DR
LONG TERM...BR
AVIATION...MW
MARINE...BR/DR
HYDROLOGY...BR/DR