713
FXUS61 KOKX 281123
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
723 AM EDT Sun Apr 28 2024

.SYNOPSIS...
A warm front will remain nearby through this afternoon. A weak
trough moves through tonight, with high pressure briefly
building in Monday. A back door cold front moves through Monday
night followed by another frontal system for late Tuesday. The
frontal system exits the area on Wednesday as high pressure
builds in for Thursday and Friday. Another frontal system then
approaches for Saturday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Two different areas of scattered showers continue early this
morning. One is pushing off the east end and the other is more
of a broken line extending from upstate NY down into Western
Long Island. There is around 100 to 250 J/kg of MUCAPE from
western Long Island north and west, so one or two rumbles of
thunder are possible in any heavier shower. These showers should
begin to diminish in coverage through 8 am and likely end
shortly thereafter.

Otherwise, a warm front will remain nearby through the day. SW
flow should give temperatures a boost compared to recent days.
There will also be some clearing late morning into the
afternoon. Even with mostly cloudy skies, the air mass is much
warmer with 850 mb temps 11 to 13C (compared to 3 to 6C Saturday
afternoon). The spread of high temperatures has been reduced,
but the NBM deterministic and MOS output still lie at or below
the 25th percentile, especially for NE NJ and the NYC metro.
These outputs have typically been running too cool in similar
setups, so will continue to side with the NBM 50th percentile,
which yields highs in the upper 70s to around 80 for NE NJ,
portions of the NYC metro and Lower Hudson Valley. Highs could
end up a few degrees higher, especially in the normally warmer
locations. Onshore component of the wind across Long Island and
Connecticut will prevent temperatures from rising as much, but
should still reach the 60s to around 70 away from the immediate
shore.

Another shortwave passes to the north late in the afternoon
and evening. Some vorticity energy dives southeastward around
the periphery of the high amplitude ridging aloft, helping to
push a weak surface trough across the area. Several CAMs are
signaling isolated-scattered convection, first across the Lower
Hudson Valley just before sunset, and then potentially the rest
of the area around our just after 00z. Model soundings are
showing an average of 250-500 J/kg of MUCAPE. The NAM hints at
some capping aloft, so will only mention slight chance of
thunder for now. Brief downpours are possible, but no severe
weather is expected out of this activity. Any convection the
first half of the night quickly diminishes with dry conditions
prevailing after midnight. It will be much milder with lows in
the 50s to potentially low 60s in NE NJ and NYC metro.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
The high amplitude middle and upper level ridging will
continue over the eastern seaboard on Monday. The passage of
the weak surface trough will leave behind a NW-N flow and a bit
deeper mixing on Monday. Weak high pressure will remain over the
region. There is still uncertainty with how high max temperatures
will reach mainly due to timing of a back door front and any
lingering cloud cover. The deeper mixing and NW flow should
allow for temperatures to reach summerlike levels based on
conditions being favorable for quick warming during the first
half of the day. Models also tend to run too cool in early
season warmth, similar to this setup. The NBM deterministic and
MOS guidance continues to run close to the 25th percentile.
Given the aforementioned setup, have gone close to the NBM 50th
percentile resulting in highs in the upper 70s and low 80s
across CT, Lower Hudson Valley, and Long Island. Highs in NE NJ
and the NYC metro are generally in the middle 80s. The potential
continues to be there for temperatures to reach the upper 80s
and possibly make a run at 90 in NE NJ potentially at Central
Park. See climate section for records for April 29th.

The back door cold front moves through Monday evening into
Monday night from northeast to southwest. Easterly flow
develops which could set the stage for a few showers, but for
now will leave the forecast mainly dry. Think low cloud
development is more probable especially as the front works its
way east of the area.

The ridge axis will begin to shift to the east on Tuesday as
a shortwave axis approaches from the west. A wave of low
pressure will develop along the front to our west Tuesday and
then slowly slide east across the region Tuesday night. Chances
for showers begin to increase Tuesday afternoon and especially
Tuesday night. There may even be a few thunderstorms with
instability aloft. Not anticipating strong convection at this
time with the stable surface and easterly flow. Highs on Tuesday
will be cooler ranging from the upper 50s and low 60s east to
the upper 60s and lower 70s west.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
*Key Points*

*Near to slightly below normal temperatures to start the period
 followed by a slight warmup for the week`s end into next
 weekend.

*Mainly dry conditions expected with a few chances of showers and
 thunderstorms as multiple frontal systems impact the area
 during the period.

Decent model agreement on a shortwave heading east of the
forecast area on Wednesday AM as the trough axis shifts
offshore. Upper ridging then builds back into the north east
becoming a bit more amplified by the weekend. At the surface,
weak sfc low and attendant fronts continue to head offshore on
Wednesday. Shower chances remain for at least the first half of
the day until the aforementioned trough axis clears the area.
Clouds will be slow to clear, but should become partly cloudy
everywhere by late afternoon.

Surface high pressure then returns for Thursday and Friday, and
it should remain mostly dry during this period under the large
scale subsidence. Another upper low then ejects out of the
Northern Plains and heads into Canada late Friday into Saturday.
An accompanying frontal system with this low then impacts the
area late Friday into Saturday with additional chances of
showers and possibly some thunder.

&&

.AVIATION /11Z SUNDAY THROUGH THURSDAY/...
A warm front remains near the terminals.

Widespread MVFR will continue for the next few hours, until
14-16Z or so; then some improvement to VFR. -RA activity has
shifted east of the terminals attm, and will continue to be
vicinity for KSIP/KBDR/KGON.

Another round of showers after 00Z Monday, with low probability of
thunder for KSWF and KHPN. Not enough confidence to put in TAFs attm
but bears watching.

S winds remain rather light through the TAF period. A shift more to
the SSW or SW is expected later this morning with continued
veering to the WSW late this evening.


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

Improvement to VFR on Sunday may be off by a few hours. Timing of
showers this evening may be an hour or two off.

OUTLOOK FOR 06Z 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.

Thursday: VFR. Light winds.

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

&&

.MARINE...
Winds and seas will remain below advisory levels through middle
to late next week under a weak pressure gradient regime.

&&

.HYDROLOGY...
No hydrologic concerns through the end of next week.

&&

.CLIMATE...
Here are the record high temperatures for April 29th

EWR: 91/1974
BDR: 86/2017
NYC: 89/1974
LGA: 88/2017*
JFK: 85/2017
ISP: 85/2017

*Also occurred in previous years

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.

&&

$$

SYNOPSIS...DBR/DS
NEAR TERM...DS
SHORT TERM...DS
LONG TERM...DBR
AVIATION...DBR
MARINE...DBR/DS
HYDROLOGY...DBR/DS
CLIMATE...