000
FXUS61 KOKX 062041
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
341 PM EST Wed Mar 6 2024
.SYNOPSIS...
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A frontal system and associated low pressure moves through this
evening into tonight. The low will exit east of the area
through Thursday night. High pressure briefly builds in for
Friday, then low pressure impacts the region over the weekend.
High pressure builds in behind the low next week.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
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A coastal low currently tracking northward off of the Carolina coast
will pass over the area this evening before a secondary low passes
overnight, then exiting northeast tomorrow. A 45-60 kt LLJ with the
approaching low will advect larger PWATs into the region with 12Z
guidance showing between 1.45 to 1.6 inches, with larger areas of
increased PWATs for eastern zones where the LLJ will be more
concentrated this evening and tonight. This exceeds the max moving
climatological average of 1.2 inches. We`ll also be inbetween jet
streaks with one to our northeast and another to our southwest which
may enhance synoptic lift. In the mid-levels, a shortwave will pass
this evening and tonight along with the surface low, aiding in
rainfall with positive vorticity advection.
Most 12Z guidance and the 12Z HREF has shifted things eastward from
prior projections. Rainfall will likely persist this evening into
tonight before tapering off as the low exits tomorrow morning, .
There will be two rounds of moderate-to-heavy rainfall. The first
round will likely pass over much of the area as rates increase from
a strengthening LLJ. The second round of moderate-to-heavy rain
overnight will be more concentrated over eastern zones (primarily
Suffolk county, New London county and Middlesex county). This is
being pulled farther east than prior projections due to an eastward
shift in the LLJ and will lead to higher event totals in eastern
sections. This area may need to be watched for training showers
overnight tonight if the LLJ jet is slower to move eastward of the
area.
Maximum rain rates will likely reach 0.25-0.5"/hr for western areas
and closer to 0.5"/hr for eastern areas with isolated pockets
possibly reaching 0.75"/hr as the LLJ strengthens and enhances
forcing early tonight. The 12Z HREF shows probabilities for rain
rates at least 0.5"/hr at 80-90% for New London county, ~50% for
parts of Suffolk, Middlesex, and New Haven counties. The timing of
the heaviest rainfall will be this evening into early tonight, in
line with the greatest forcing.
Event total rainfall will likely range from 1-2" with isolated 3"
totals possible. Higher totals are expected for eastern areas with
lower totals over western areas. A Flood Watch remains in effect
until 6am, with the primary concerns now concentrated farthest east
than previously.
Temperatures will remain very mild with the rainfall and warm, moist
airmass with lows in the mid-40s. Highs tomorrow will reach the
upper-40s to lower-50s before cooler air starts to filter in behind
the exiting low. Lows Thursday night will still be slightly above
seasonal averages in the upper-to-middle 30s.-- End Changed Discussion --
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
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Leftover drizzle or light rain is possible into the early
afternoon tomorrow as a coastal system exits to the east, with
rain tapering off west to east. High pressure centered over
northeast Canada noses in from northeast to southwest behind the
exiting low with winds shifting northwest in response. Winds
may become breezy Thursday afternoon before gradually weakening
late Thursday night. For Thursday night the clouds break up late
in the evening, with clearing from west to east later at night
with a drier north breeze. Cooler air does arrive with
temperatures still a few degrees above average, but noticeably
cooler late at night.-- End Changed Discussion --
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
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A transitory high ridges into the region from Labrador on Fri. This
will keep the cwa dry. Unless a bank of marine stratus develops and
advects swwd into the area, it will be mostly sunny as well. The
onshore component to the flow will modify temps across ern areas,
keeping highs cooler than the rest of the cwa. The NBM with local
adjustments was used.
Subtropical pacific tap of moisture seen on water vapor gets here on
Sat. This will produce ovc skies ahead of the next chances for rain.
As a deepening nrn stream trof interacts with this surge of
moisture, rain develops late Sat, ending Sun mrng. The pcpn is
mainly on the front end of this sys with a significant dry slot.
As the cold pool aloft moves in Sun ngt, pcpn chances transition to
shwrs. H85 gets to -8C so shsn possible. Similar setup on Mon with
steep lapse rates. Went abv the NBM and kept the whole area in at
least 20 pops for shra, with some ip possible as well, thru the day.
The models often do not handle this scenario well.
A ridge then builds across Tue and Wed keeping the area dry and
allowing for a warming trend.
The NBM was followed for temps Sat-Wed with a few local
adjustments.-- End Changed Discussion --
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
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Low pressure passes trough the area tonight, tracking offshore on
Thursday.
IFR or LIFR thru tonight. VLIFR possible at times.
Period of moderate to locally heavy rainfall this evening into the
first half of tonight. Likely a 3-6 hour window for heavy rainfall,
generally between 22z-03z for the NYC terminals, but could linger
several hours thereafter. After 6z, rain will start to taper off
from southwest to northeast. Some slow improvement is expected
toward 12z Thursday, with a return to VFR late Thu AM or early
afternoon.
NE/E flow up to 10 kt this evening becomes northerly tonight. G20-25
kt develop toward daybreak as speeds increase to between 10 and 15
kt thru Thursday.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments likely for changing flight categories.
Brief VLIFR conditions possible into early Thu AM.
Gusts may be more occasional on Thursday.
OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...
Thursday PM: Improving to VFR early. Winds N/NE G20-25kt.
Friday: VFR.
Saturday: Becoming MVFR or lower into the afternoon with rain.
Sunday: MVFR or lower with rain in the morning. Possible improvement
to VFR in the afternoon with gusty NW winds.
Monday: VFR. Blustery NW flow. G25-30 kt.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
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Small craft conditions will prevail on the ocean waters with mainly
4 to 6 ft seas this evening into tonight. Seas will climb
higher tonight into Thursday. Small craft gusts may be possible
Thursday morning on the non-ocean waters.
Seas will remain elevated on the ocean Fri, so the sca was extended
thru the day. Cond improve Fri ngt into early Sat, then winds and
seas increase late Sat thru Sun with low pres tracking thru the
region. There is a chance for a period of gales with the sys. It
remains windy on Mon with at least sca winds. Gales possible. Winds
gradually diminish on Tue.-- End Changed Discussion --
&&
.HYDROLOGY...
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WPC maintains a slight to marginal risk of excessive rainfall today
and tonight. A flood watch remains in effect. Widespread minor
flooding is expected for eastern areas while western areas it
may be more scattered, with some river flooding as well as more
significant flash flooding possible.
An additional 1 to 2 inches of rain could fall with the storm system
this weekend. Impacts with this event are still somewhat uncertain
as it will depend on where the heaviest rain falls with the
Wednesday/Wednesday night system.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
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As we head into the closest new supermoon of the year on March 10,
at least minor tidal flooding can be expected this weekend. The sys
over the weekend could enhance tides further. The ensemble spread
suggests moderate to isold major possible in spots, particularly
those typically most vulnerable.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Flood Watch through late tonight for CTZ005>012.
NY...Flood Watch through late tonight for NYZ068>075-078>081-
176>179.
NJ...Flood Watch through late tonight for NJZ002-004-006-103>108.
MARINE...Small Craft Advisory from 10 AM Thursday to midnight EST
Thursday night for ANZ331-335-338-340-345.
Small Craft Advisory from 10 AM Thursday to 6 PM EST Friday
for ANZ332.
Small Craft Advisory until 6 PM EST Friday for ANZ350-353-355.-- End Changed Discussion --
&&
$$
SYNOPSIS...JMC/BR
NEAR TERM...BR
SHORT TERM...BR
LONG TERM...JMC
AVIATION...DR
MARINE...JMC/BR
HYDROLOGY...JMC/BR
TIDES/COASTAL FLOODING...JMC