000
FXUS61 KOKX 292358
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
758 PM EDT Sat Apr 29 2023
.SYNOPSIS...
A weak wave of low pressure off the Delmarva dissipates this
evening. Deepening low pressure over the southeastern states
tonight tracks northeast and over the region Sunday afternoon,
and to the north Sunday night. The low then meanders over the
Great Lakes Monday before slowing moving over the northeast
through the middle of the week. The low should move off the New
England coast Thursday into Friday, but a surface trough may
linger into next Saturday.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
No major changes made with this update. Still seeing some mainly
light returns on both TDWRs and regional radar mosaics with
light rain/drizzle occurring across the area. This rain is in
association with overrunning from a weak low off the Delmarva
and high pressure to the northeast. The low should slowly
weaken this evening with associated lift weakening through
tonight. The depth of the low level moisture should also
decrease. Still there is a chance at some light rain and drizzle
overnight. There is also a chance that the rain/drizzle ends
for a brief period late tonight/early Sunday morning.
Winds will continue to lighten through tonight, and areas of
fog become likely, however dense fog is not expected. With the
easterly flow, clouds, and precipitation, temperatures will drop
only a few degrees.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
A large upper closed low remains over the Great Lakes region
Sunday into Sunday night as a shortwave moves into the southern
portion of the upper low and tracks from the Gulf coast states
Sunday morning and into New England by Sunday night.
Precipitation will once again increase across the region from
the southwest to northeast as surface low pressure also moves
over the area by late Sunday afternoon. Rain will be mostly
light through the morning, and then with increased upper lift as
the low moves over the area rainfall will increase by mid to
late afternoon into the evening. And with elevated Cape
increasing to 200 to 300 J/kg there will be a chance of a few
thunderstorms across the entire area. Rainfall rates will be
increased, and with precipitable waters vales increasing to one
and a half increases briefly moderate to heavy rainfall is
possible. Rainfall is expected to remain below flash flood
guidance and headwater flood guidance, so no watches have been
issued. However, nuisance flooding will be possible. With the
low level jet moving across from east of New York City into
Connecticut the heaviest rain may be more across these regions.
The shortwave and surface low move rather quickly to the north
Sunday evening and the rain quickly ends south to north.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
No major changes made to the long term with unsettled weather
continuing through the upcoming week.
The low pressure that impacts the area late Sunday and Sunday night
will continue to interact with a large closed upper low over the
Great Lakes on Monday. The system becomes vertically stacked and
will gradually shift over the northeast Tuesday into Wednesday. A
general consensus of the latest guidance has the large upper low
pushing east of the area Thursday into Friday.
Monday should start out dry, but there is a chance for an afternoon
shower, mainly NW of the NYC metro. Shower chances increase late
Monday night into Tuesday. This is due to potential of more
organized energy and positive vorticity advection occurring as the
upper low nears. There also appears to be a bit higher probability
Tuesday morning NW of NYC with the aforementioned energy. Chances
persist into Tuesday afternoon with steepening lapse rates from the
cold pocket aloft and some limited daytime heating. Similar
conditions are expected Wednesday. Some low topped convection cannot
be ruled out given the pattern. An isolated thunderstorm is possible
each afternoon with small hail given low freezing levels (around 5
kft). Since this still 4-5 days out, have left mention out of the
forecast for now. Probabilities of showers decrease a bit for the
end of the week with the departing upper low. However, a lingering
surface trough may still be enough to support a few afternoon
showers.
The main theme here is that each day will not be a wash out, but
there may be showers at times each afternoon. Temperatures will be
below normal for the first week of May. Some slight moderation is
possible at the end of the week, but still could end up below
normal.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
Low pressure will lift slowly north towards the area through
tonight. A stronger low will approach on Sunday.
IFR conditions or less at all terminals through much if not all
of the TAF period. LIFR cigs will be possible this evening and
into the overnight at most terminals. Patchy fog overnight is
possible as well.
Light rain or drizzle is expected into the early morning on
Sunday. Another batch of moderate to locally heavy rainfall
moves into the area after 14-16Z Sunday. Some isolated embedded
thunderstorms are are also expected 18Z. Exact timing and
coverage remains somewhat uncertain. Will cover this threat with
a PROB30.
Any gusty winds gradually weakening this evening from SW to NE.
Another uptick in winds expected after 16Z Sunday with gusts
upwards of 25-30kt. Winds will generally be from the E through
late Sunday, then winds start to veer towards the SW late in the
TAF period.
Have pushed back the timing of the LLWS until late
morning/early afternoon on Sunday
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
High confidence of IFR or less through much of the TAF period.
Occasional wind gusts on Sunday may be higher than forecast.
Timing of convection on Sunday remains uncertain.
OUTLOOK FOR 00Z MONDAY THROUGH THURSDAY...
Sunday Night: IFR or lower to start, then improvement expected
after midnight. Any leftover precipitation comes to an end.
Winds shift to the SW.
Monday: VFR. Slight chance of afternoon rain showers with MVFR.
SW wind gusts near 20-25 kt.
Tuesday: VFR. Chance of afternoon rain showers with MVFR. SW wind
gusts 15-20kt.
Wednesday: VFR. Chance of afternoon rain showers with MVFR. W/NW
gusts 15-20kt.
Thursday: Mainly VFR. Chance of MVFR or lower in any rain
showers.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
The gale warning east of Moriches Inlet has been replaced with
an SCA. The SCA on the ocean waters will be in effect through
at least Sunday night, mainly for seas, as wind diminish this
evening, and then increase during Sunday, before diminishing
again Sunday evening. There is a low chance that winds east of
Moriches Inlet briefly reach gale force Sunday afternoon.
Across the remainder of the waters a SCA is in effect until
midnight across western Long Island Sound, and the south shore
bays and New York Harbor, and through tonight for eastern Long
Island Sound, and the eastern bays. Once these advisories expire
small craft gusts will be likely again from about midday Sunday
into Sunday evening, and another advisory will be needed.
SCA conditions will likely continue on the waters Monday morning.
Winds should fall below SCA levels by late morning/early afternoon.
However, seas will remain elevated above 5 ft through Tuesday night
due to lingering swells. Seas will subside below 5 ft on the ocean
on Wednesday. Otherwise, conditions will remain below SCA levels
through late in the week.
&&
.HYDROLOGY...
Rainfall of 1.5 to as much as locally 3.25 inches has fallen
through Saturday mid afternoon, and an addition 1 to 1.75, with
locally up to 2 inches across Connecticut, is possible from
Saturday evening through Sunday evening. Minor nuisance flooding
will be possible once again Sunday afternoon into Sunday
evening across poor drainage and urban areas.
No hydrologic impacts are expected next week.
&&
.TIDES/COASTAL FLOODING...
A strong SE flow due to a deepening low pressure on Sunday may
bring Sunday evening high tide levels to minor flood benchmarks.
The main concern continues to be for the south shore Back Bays
of southern Nassau and southern Queens, western Great South Bay
along southwest Suffolk, and SW CT coast along the Western Long
Island Sound. Astronomical tides low, so approximately 2 to 3 ft
surge is needed to bring water levels to minor flooding at
these locations Sunday evening.
Have issued a coastal flood statement for southern Nassau,
southern Queens, southwest Suffolk, and coastal Fairfield as a
consensus of the latest guidance brings water levels to just
touching minor flooding benchmarks. A few of the more vulnerable
locations could see a few tenths above minor, but a widespread
minor flooding is not expected at this time. Elsewhere, water
levels should remain below minor flooding during the Sunday
evening high tide.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 6 AM EDT Sunday for ANZ331-332-340.
Small Craft Advisory until midnight EDT tonight for ANZ335-338-
345.
Small Craft Advisory until 6 AM EDT Monday for ANZ350-353-355.
&&
$$
SYNOPSIS...DS/MET
NEAR TERM...DS/MET
SHORT TERM...MET
LONG TERM...DS
AVIATION...BC
MARINE...DS/MET
HYDROLOGY...DS/MET
TIDES/COASTAL FLOODING...