000
FXUS61 KOKX 280010
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
810 PM EDT Sat Apr 27 2024
.SYNOPSIS...
High pressure continues to slide offshore tonight, with a warm
front approaching tonight and moving north on Sunday. A weak
trough moves through Sunday Night, with high pressure briefly
building in Monday morning. A back door cold front moves through
Monday afternoon into Monday evening. A frontal system approaches
from the west and moves through the area Tuesday afternoon and
night. High pressure then builds in for the middle of the week
before another frontal system potentially affects the area to
close out the week.
&&
.NEAR TERM /UNTIL 7 AM SUNDAY MORNING/...
-- Changed Discussion --
Initial band of showers has nearly dissipated in the dry air
across the region. Over time though the airmass moistens and
and additional showers ahead of an approaching warm front will
increase in coverage.
Otherwise, the upper ridge axis continues to nudge into the
region tonight. At the same time, good agreement in shortwave
energy shearing through Ontario and into western Quebec tonight.
At the surface, the high pressure, centered just S/SE of the
area, will slide farther SE tonight. Meanwhile, weak low
pressure tracks NE through Ontario into Quebec tonight with
associated weakening warm front approaching tonight and lifting
NE of the area Sunday AM.
Models continue in good agreement in a period of showers late this
evening into the overnight ahead/along warm front in response to
approaching left front quad of ULJ streak, shortwave energy rounding
ridge axis and theta-e advection of 1 1/2 to 2 std PWAT airmass.
Lift and moisture is modest with instability lacking, so shower
activity should be generally light to moderate. Highest prob across
interior and eastern areas around periphery of ridge axis.
WAA and cloud cover will have temps noticeably milder then the last
few nights, with lows generally in the 40s.-- End Changed Discussion --
&&
.SHORT TERM /7 AM SUNDAY MORNING THROUGH MONDAY/...
Upper ridge axis remains fairly stationary just to the west of
the region Sunday thru Monday, while a northern stream shortwave
digs into SE Canada. Weak shortwave forcing rounding the upper
ridge slides east Sunday morning, with another train of
vorts/weak shortwave approaching late Sun and tracking across
northern and eastern portions of the region Sunday night.
At the surface, warm front dissipates overhead or lifts north
Sun AM, ending shower threat. Weak surface troughing appears to
linger over the area, with more distinct pre-frontal approaching
late in the day and crossing Sunday Night. Ahead of this, the
region becomes warm sectored Sunday with temps moderating to
above seasonable levels with strong waa aloft, but still model
spread on max temps dependent on cloud cover, seabreeze timing,
and depth of mixing. Interestingly, deterministic NBM temps
(bias corrected and MAE weighted model blend) are generally
running close to the 10th-25th percentile of the NBM ensemble
spread (raw model and MOS inputs). Will lean towards a blend of
deterministic and 50th percentile of NBM, with potential for
temps to be several degrees warmer than forecast across NYC/NJ
metro and interior with breaks in cloud cover and remaining
north and west of the synoptically enhanced seabreeze along the
coast. There appears to be an opportunity for a period of partly
to mostly sunny skies between the Sun AM strato-cu dissipating
and ahead of increasing high/mid deck in mid-late aft.
Pre-frontal trough approaches late Sunday and passes thru Sunday
night. Not a tremendous amount of forcing, but combo of vorts moving
through aloft and surface trough moving through in a 2 to 2 1/2 std
PWAT airmass (weakly unstable across far western areas) support
potential for scattered showers. Low prob for a thunderstorm
Sun eve across far NW areas of the region
The passage of the surface trough Sunday night leaves behind a deep
W/NW flow Monday morning, which should allow for rapid drying and
deep mixing to at least 850mb (temps of 13-14C). Still quite a bit
of spread on how high max temperatures could reach based on
timing of a backdoor cold front in the afternoon. Once again,
deterministic NBM temps are generally running close to the
10th-25th percentile of the NBM ensemble spread. Based on
favorable heating conditions for at least the first half of the
day will ride closer to 50th percentile. This supports potential
for summerlike conditions (warmest day so far this Spring) with
widespread temps in the lower to mid 80s. Potential for temps
to be a few degrees warmer than forecast if cold frontal timing
is slower, with a few spots making a run at record highs for the
day (mid to upper 80s).
Backdoor cold front could spark an isolated shra or trsa late
Mon/Mon eve across western portions of the Tri-State with some
weak instability and moisture pooling.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
*Key Points*
*Cooler conditions Tuesday and Wednesday, but still above normal. A
slight warmup then for week`s end.
*Mainly dry conditions expected with a few chances of showers and
thunderstorms as multiple frontal systems impact the area during
the period.
Upper ridging along the eastern seaboard weakens while moving out
into the Atlantic on Tuesday. At the same time, a weakening frontal
system on the backside of the ridge moves into the area with a
chance of showers, possibly a thunderstorms Tuesday afternoon/night.
Not expecting strong and/or severe convection with weak instability
and an easterly flow. Ridge then is forecast to amplify over the
eastern third of the country Wednesday into Thursday, more so than
what we saw 24 hours ago.
Mainly dry conditions during this time once any lingering rain exits
the area Wednesday morning. Another upper trough then lifts north
out of the intermountain west Wednesday into Thursday, then up into
the Great Lakes Friday into Saturday. This will send another
weakening frontal into the area to close out the week.
As for temperatures, an easterly flow on Tuesday following a
backdoor cold front will return highs closer to normal. The trend in
the NBM and much of the 12Z guidance has been cooler for that day. A
gradual warmup can then be expected for the rest of the week with
temperatures 3 to 5 degrees above normal along the coast, but to 5
to 10 degrees inland. Chance of rain and cloud cover Saturday knocks
temps down a bit.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
High pressure shifts east as a warm front approaches tonight,
remaining in the vicinity through Sunday evening.
VFR this evening becoming MVFR late tonight, generally after
08Z-09Z, mainly because of lowering cigs. There is a low chance
of seeing vsbys come down below 6 SM, except perhaps for KGON,
and that is only for a brief time. Showers increase in
coverage after 03Z, falling intermittently thru about 14Z
before drying out with slow improvement to VFR into the early
afternoon. High end IFR cigs possible at times in the early
morning hours, especially at KSWF, KHPN, KBDR, and KGON, but
can`t be ruled out elsewhere.
S winds diminish this evening and remain rather light through
the rest of the TAF period. A shift more to the SSW or SW is
expected at most terminals Sunday morning.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of MVFR conditions tonight may be off by a couple of
hours.
IFR cigs possible Sunday AM.
Improvement to VFR on Sunday may be off by a few hours.
OUTLOOK FOR 00Z MONDAY THROUGH THURSDAY...
Sunday night: VFR with a light SW flow.
Monday: VFR. Winds under 10 kt.
Tuesday: MVFR or lower possible with afternoon showers and isolated
thunderstorms.
Wednesday: VFR. Winds under 10 kt.For the first half of the
night,
Thursday: VFR. Light winds.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Winds and seas will remain below advisory levels through the
weekend under a weak pressure gradient regime. Coastal jet thru
this will bring marginal SCA wind gusts (20- 25kt) near the
entrance to the NY Harbor.
Much of next week looks to be below sub-SCA with a weak flow across
the waters. Potential fog development due to warmer air moving
over the colder waters (SSTs near 50F) early next week, but
still too early for any specific details on timing and extent.
&&
.HYDROLOGY...
No hydrologic concerns through the end of next week.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...NV/DW
NEAR TERM...NV/DW
SHORT TERM...NV
LONG TERM...DW
AVIATION...JP
MARINE...NV/DW
HYDROLOGY...NV/DW