000
FXUS61 KOKX 291430
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1030 AM EDT Sat Apr 29 2023
.SYNOPSIS...
A wave of low pressure along a warm front to our south approaches
today. It remains to our south this evening before dissipating. A
stronger low then impacts the region Sunday into Sunday night. The
low then meanders nearby on Monday, and an upper level trough
will remain over the area through the end of the week.
&&
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Updated probabilities and potential areas of moderate to
briefly heavy rainfall from late this morning into this
afternoon, to reflect timing with mid and upper shortwave moving
through the area in southwest flow, and llj, isentropic lift
and frontogenetic forcing to the NE of the approaching low will
serve to enhance rainfall rates during the periods of moderate
rainfall.
An area of low pressure along a warm front over the Mid
Atlantic states will approach from the south. It will remain to
our south tonight as it dissipates. At the same time, a low
level jet will slowly shift through much of the forecast area.
It`ll be a breezy day with easterly winds 15-25 mph with gusts
up to 30-35 mph for coastal areas and about 5-10 mph lighter
inland. The rain and onshore flow will hold high temperatures to
only 50-55.
More mid-level drying occurs for tonight, so lighter rainfall and
even some drizzle is expected. Winds should be strong enough to
prevent widespread fog with maybe the exception being well-inland.
Have gone with areas of fog in the forecast for the entire forecast
area.-- End Changed Discussion --
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
Light rain and drizzle remains likely Sunday morning, then chances
for rain increase during the afternoon. This will be in response to
a strengthening area of low pressure approaching us from the Mid-
Atlantic Region. It`s center or an attendant triple-point is
expected to pass through during Sunday night.
Rain during the afternoon into evening should be overall heavier
than today with even some chances of heavy rainfall. The core of a
low level jet ends up over the eastern half of the forecast area. At
the same time, PWATS increase to around 1.50 inches and
lift/frontogenetic from the low center itself plus large-scale lift
from a left-exit region of an upper jet streak should enhance
rainfall. Enough lift and elevated instability will be around for a
chance of a thunderstorm as well. There appears to be for now a
strong enough inversion aloft to prevent severe-level wind gusts, so
the main threat with convection should be any heavy downpours. HREF
mean implies the heaviest rainfall will be across NE NJ into the
Lower Hudson Valley and SE CT during this period. See the hydrology
section below for potential impacts.
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 afternoon
showers, primarily from the city to points north and west. Dry
weather follows for Monday night.
High temperatures for both Sunday and Monday mostly in the low 60s,
which is about 3-5 degrees below normal.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
The models were in good agreement in the extended, so the NBM was
followed for the fcst.
Upr trof will remain over the area thru the week. There are some
minor differences in the modeling wrt when the closed low exits,
with the GFS quicker than the ECMWF, but overall, cyclonic flow
aloft will keep temps blw average with chances for shwrs thru the
period. Regardless of where the center of the upr low is by the end
of the week, the cold pool aloft will keep steep lapse rates locked
in and the area primed for convective pcpn, particularly during the
daytime hours. Any strong dpva, especially Tue and Wed, could help
to enhance convection and produce some isold low topped tstms,
perhaps with some small hail.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
Low pressure will lift slowly north towards the area through
tonight. A stronger low will approach on Sunday.
MVFR to IFR conditions for most terminals lower to mainly IFR by
early afternoon. Any MVFR or VFR conditions for eastern terminals
(KBDR/KISP/KGON) lower to IFR by late this afternoon. LIFR possible
late this afternoon and into tonight for most terminals.
Light to moderate rain continues through much of the day, likely
lessening in intensity with drizzle by evening. Progression of
steadier rain and IFR cigs will be much slower for eastern
terminals, likely not until later this morning or afternoon. IFR or
lower continues through 18Z Sunday.
Gusty E winds continue through much of the day before slowly
weakening late this afternoon into the evening from SW to NE.
Another uptick in winds expected after 16Z Sunday.
LLWS develops after 00Z Sun and continues thru Sun morning.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments possible for changing flight categories and refining
timing of lowering to IFR or LIFR. Strong E winds through this
evening.
The haze forecast for all terminals today is MODERATE (YELLOW).
OUTLOOK FOR 12Z SUNDAY THROUGH WEDNESDAY...
Sunday: IFR or lower. Rain re-developing later Sun morning into
afternoon. Slight chance of thunderstorms late Sun/Sun eve. SE G20-
25 kt developing during the day, becoming S-SW wind gusts at night.
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.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
-- Changed Discussion --
No changes to the gale warning or small craft advisory at this
time.
Easterly winds are expected to gust to gale force today across
the ocean, NY Harbor, and south shore bays, with strong
advisory-level gusts just shy of 35 kt elsewhere. Seas on the
ocean are forecast to increase to 8 to 11 ft, peaking Saturday
afternoon into Sunday evening. Seas of 3 to 6 ft are expected
across LI Sound and the NY Harbor entrance. Winds and seas will
then begin to diminish tonight as an approaching low an
associated pressure gradient. SCA conds will continue into the
night for all waters.
A brief lull in stronger winds looks likely late tonight/early
Sunday morning before a SE-E flow increases late Sunday morning
through the evening. SCA gusts become likely on all waters, which
should continue into the evening. A strong low level inversion is
likely going to prevent stronger winds from reaching the surface. At
this time, gales look unlikely to occur, but wind gusts around 30 kt
are possible Sunday evening. Otherwise, SCA winds should continue on
the waters into Monday mainly on the ocean and possibly over eastern
LI Sound. SCA conds then continue on the ocean Monday night due to a
lingering swell that will keep seas elevated.
Although winds will be blw sca lvls on Tue, seas will linger aoa 5 ft
on the ocean. Seas will subside to blw sca lvls on the ocean by Wed
eve, with all areas blw sca lvls Thu and Fri.-- End Changed Discussion --
&&
.HYDROLOGY...
An additional 1.50 to 2.50 inches of rainfall is expected through
Sunday night. Based on flash flood guidance, there`s a chance of
minor nuisance flooding today - primarily in the more susceptible
areas of NE NJ. Based on observed upstream rainfall rates so far,
flash flooding seems unlikely. Rainfall intensity will be heavier
overall on Sunday, particularly in the afternoon and evening. There
will be a better chance for minor nuisance flooding during this
time. While flash flooding is not anticipated, cannot completely
rule it out. Once again, the better chances of any type of flooding
will be over the NE NJ urban areas and sensitive river basins.
No hydrologic impacts are expected Tue-Sat.
&&
.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 at this time appears to be for the south shore Back Bays and
SW CT coast along the Western Long Island Sound. Tides are
relatively low astronomically, so approximately 2 to 3 ft surge is
needed to bring water levels to minor flooding at these locations
Sunday evening.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 2 AM EDT Sunday for ANZ331-332-335-
340.
Gale Warning until 6 PM EDT this evening for ANZ338-345-350-
353-355.
&&
$$
SYNOPSIS...JC
NEAR TERM...JC/MET
SHORT TERM...JC
LONG TERM...12
AVIATION...MW
MARINE...12/JC/MET
HYDROLOGY...12/JC
TIDES/COASTAL FLOODING...