000
FXUS61 KOKX 310909
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
509 AM EDT Sun Mar 31 2024
.SYNOPSIS...
Weak high pressure settles in on Sunday. Another low pressure
approaches from the west Sunday night, passing to the south on
Monday. A stalled front south of the area Monday night into
midweek will have lows developing along it. The relatively
strongest low develops in the mid-Atlantic along it towards
midweek. This low traverses south of Long Island Wednesday night
and eventually more in the vicinity of New England offshore
waters Thursday night. High pressure stays west of the area with
low continuing to track slowly east Friday into Saturday.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Weak high pressure takes hold again for Sunday morning and
afternoon. Clouds leftover from an exiting low to the east may keep
hold under weak high pressure. Currently have partly cloudy skies
forecasted for the morning and afternoon. Afternoon highs will only
be slightly above seasonal in the upper-50s to lower-60s.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
Another wave of low pressure swings by Sunday night into Monday.
Clouds become overcast Sunday evening. A band of strong 850mb warm
air advection frontogenetic forcing approaches the area Monday
morning and afternoon. It has a northwest to southeast orientation
to it and will likely lead to higher rain totals with periods of
moderate to heavy rain. In addition, the area is located under the
left exit region of an upper-level jet streak. Totals will range
between 0.10" to 0.5" with the higher totals concentrated in NE NJ,
NYC metro and LI. PWATs will reach around 0.9" during the peak
period of forcing which is around the 90th percentile for this time
of year per SPC`s Sounding Climatology page. Should the band of
stronger forcing shift north or south, the area of heavier rainfall
and higher totals will shift with it. This too will be a fast
system, with much of the rain ending by early afternoon. As a
result, flood benchmarks will not be reached.
Temperatures will remain above normal Sunday night due to the cloud
cover, but with the easterly flow and rain Monday, temperatures will
budge little. Highs Monday will be around 50, which is several
degrees below normal.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
-- Changed Discussion --
Long wave ridge in the midlevels will be starting place for the
local region Monday night into Tuesday. The upper level jet pattern
will be zonal. The 250mb jet streak SW to NE Pacific into Mexico
extends northeast to South Central US and then branches into
Great Lakes as well as Carolinas.
The upper level jet pattern becomes more active towards the middle
of the week coinciding with a diving strong mid level shortwave
from South Central Canada. Left front quad of the jet gets closest
to the area for late Tuesday night into early Wednesday. This
cutoff low approaches the area Wednesday and eventually moves
into the Northeast Thursday into Friday, gradually making its
way east to the NW Atlantic going into next weekend.
At the surface, there will be a stalled front south of Long Island
with multiple lows developing and traveling along it Monday night
into the middle of the week. The low Tuesday night into Wednesday
looks to be the stronger one according to the consensus of forecast
model guidance. This low eventually moves northeast of the area
going into latter half of this week.
Rain is in the forecast Monday night through Thursday. Conditions
then trend drier Thursday night with dry conditions expected Friday
into Saturday. Potentially the rain could be heavy at times
especially for midweek. Elevated instability will present a
slight chance of thunderstorms as well around the middle of this
week, particularly near the coast. Wintry precipitation remains
possible as well for the interior while for the coast this
precipitation will be mainly plain rain.
Temperatures average below normal overall during the long term.
Forecast highs stay in the 40s Tuesday, Wednesday and Thursday.
Forecast highs trend higher Friday into next weekend and get
relatively closer to normal values. Winds will become quite
gusty Tuesday night through Thursday night but at this time,
forecast values are below wind advisory thresholds.
More detailed analysis focused on the low pressure storm system
for mid to late week as well as surface winds is discussed
below.
The main feature at the surface will be the origin of cyclogenesis
Tuesday night and its subsequent evolution through mid to late week.
The models have a general consensus of depicting this low to move
northeast from the Mid-Atlantic towards New England going from mid
to late week and then slowly moving the low farther offshore.
Models have exhibited large differences from each other as well as
from the same model but from an earlier run. The low position and
movement has widely varying depictions amongst large scale
numerical weather prediction models of the GFS, ECMWF, and
Canadian models for Thursday.
An example of a significant change is within the ECMWF model which
has trended relatively weaker with this storm system for the middle
of the week. The rainfall within a 24 hour period according to the
grand ensemble still has differences between extremes amounting to
near 2.5 inches which is a half inch less than where the differences
were looking at the same grand ensemble the previous night. The same
grand ensemble also continues to convey the possibility of
measurable snow especially for interior areas.
Regarding winds, there is forecast to be an extended period of
easterly winds, building fetch and seas. There will be some minor
coastal flooding heading into midweek. See tides/coastal flooding
section for more details. Winds are forecast to become more
northeast to north Wednesday night and then northwest Thursday into
the start of next weekend. Highest forecast gusts are forecast in
the Tuesday night through Thursday night time period, with
gusts along the coast getting near 35 to 40 mph.-- End Changed Discussion --
&&
.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
High pressure takes hold today before another low approaches Monday
morning.
VFR through Sunday. Light rain is almost clear of the area.
ceilings drop Monday morning ahead of rain later Monday morning,
becoming MVFR. Increasing NW flow after 12z becomes WNW-W Sunday
afternoon, 10-15 kt. Occasional gusts up to 20 kt are possible late
morning into the afternoon. Winds weaken again, likely becoming
variable Sunday night into MOnday morning.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Occasional gusts up to 20 kt possible on Sunday.
OUTLOOK FOR 09Z MONDAY THROUGH THURSDAY...
Monday: MVFR-IFR in rain, especially in the morning and early
afternoon.
Tuesday: IFR in rain. E-ENE gusts 20-25 kt.
Wednesday: IFR in rain. E-NE gusts 25-35 kt possible. The rain could
be mixed with wet snow well inland late.
Thursday: MVFR or lower with showers possible, possibly mixed with
snow inland. NW gusts 25-35 kt.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
Winds and waves will remain below SCA criteria through Monday.
Winds and waves will trend higher Monday night but are forecast
to stay below SCA criteria.
SCA conditions become more likely Tuesday and especially going
through the midweek period. There will be potential for gales
Tuesday night through Thursday night.
&&
.HYDROLOGY...
A brief period of moderate to heavy rainfall is possible Monday
morning with totals of 0.25"-0.5" for NE NJ, NYC metro and LI. The
rain quickly exits Monday afternoon, so flood benchmarks will not be
reached.
An extended forecast period of rainfall is forecast Monday night
through Thursday. It will not rain the entire timeframe but the
bulk of the rainfall can be expected Tuesday through Wednesday
night. Heavy rainfall will be possible at times but exact
rainfall amounts cannot be determined at this time due to low
confidence. Poor drainage and low lying could very well
experience some minor flooding with an overall marginal flood
threat.
&&
.TIDES/COASTAL FLOODING...
-- Changed Discussion --
Astronomically, by the middle of this week, we will be past the
halfway point between the full and the new moon cycles. There
will thus be an increase in the tidal levels around high tide.
This combined with a long period and increasing easterly flow
early to mid week will lead to more fetch and piling of water.
For some shorelines particularly across the lower NY Harbor,
South Shore Bays and Western Long Island for late Tuesday night
into Wednesday around the times of high tide, minor coastal
flooding will be possible.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JM/BR
NEAR TERM...BR
SHORT TERM...BR
LONG TERM...JM
AVIATION...BR
MARINE...JM/BR
HYDROLOGY...JM/BR
TIDES/COASTAL FLOODING...JM