000
FXUS61 KOKX 201447
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1047 AM EDT Wed Mar 20 2024
.SYNOPSIS...
A cold front passes through the region today. High pressure
then builds in its wake for Thursday and Friday and pushes
offshore by late Friday. Low pressure impacts the area Saturday
into Saturday night. High pressure then builds from southeast
Canada Sunday into early next week as the low slowly moves away
from the coast. Another frontal system may approach late
Tuesday.
&&
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Made some slight adjustments to temperatures, dewpoints, cloud
coverage and POPs to better match up with observed trends and
short term mesoscale forecasts.
Increasing chances of rain showers to the north and west of NYC
going into early this afternoon. Rain showers become likely
across much of the region late this afternoon into early this
evening.
Aloft, H5 closed low moves into New England this afternoon into
this evening. Attendant sfc low located in southern Quebec
heads east into the afternoon. A cold front approaches from
upstate New York and Pennsylvania this afternoon.
Another day of gusty winds ahead, increasing into this afternoon. It
will be warmer than Tuesday, under predominately WSW flow. Precip
chances begin increase midday into the afternoon as a cold front
works through the area and winds shift to the NW, remaining gusty
into this evening.
This cold front will quickly approach the CWA from west to east,
through the afternoon. Gusty southerly flow will strengthen in
advance of this frontal system--though there may be a few hours
into early afternoon where the gusts subside with a weakness in
the pressure field. BUFKIT model soundings are depicting
35-45kts at the top of the mixed layer, while the HRRR max gust
potential and HREF ensemble mean gusts show a widespread
30-35kts. Strongest winds look to be just ahead of, and behind,
the passage of the frontal system from about 20Z (west) to 00Z
(east). Gusty NW winds will remain into this evening post front,
though will be in the 20-25kt range.
Precipitation associated with the front will be mainly in the form
of rain showers. Several 00Z HREF members depict a more
organized band of precip pushing across LoHud and southern CT,
so have slightly higher amounts here. Would also not be
surprised given cold pool aloft that some graupel/small hail
may mix in with the showers across elevated surfaces in CT and
the LoHud Valley. Precip amounts overall are light, with less
than 0.1" across the board. With CAA behind the front, some snow
showers may briefly mix in at the end across higher elevations
NW of NYC, but do not expect any accumulation, at this point.
Finally, temperatures today will be warmer than on Tuesday, given
increased WAA with the prefrontal SW flow. Forecast high
temperatures will range mostly from the upper 40s to mid 50s.-- End Changed Discussion --
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
The frontal system then heads east on Thursday and high pressure
builds in from the OH Valley and moves overhead by Friday morning.
The high slides offshore by Friday night. Thus, both days look dry.
With ample CAA at the start of the period under continued gusty NW
flow, high temperatures will be below normal both days. Friday may
be a few degrees warmer, as return southerly flow takes hold by the
afternoon and cloud cover increases in advance of the next system.
Wind chills each night will be in the upper teens to low 20s given
the elevated winds and cold air mass..
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
There has not been too much change with the forecast thinking
for the upcoming weekend into early next week. Another
significant rainfall event is becoming more likely Saturday
into Saturday night. This is due to a low pressure over the
southeast and Middle Atlantic sending subtropical moisture
northward and interacting with a frontal system slowly moving
over the northeast.
*Key Points*
*Widespread rain is expected Saturday into the first half of
Saturday night.
*The rain may be moderate to locally heavy at times with
potential of 1-2 inches. Current model consensus favors Long
Island and Southern Connecticut with the highest rain totals,
but this could change in subsequent forecasts.
*The latest NBM probability for greater than 1 inch of rain in a
24 hour period ranges from 40 percent west of the city to
around 60 percent across Long Island and SE CT.
*The latest NBM probability for greater than 2 inches of rain in
a 24 hour period is not insignificant, generally 15-25 percent
along and west of the Hudson River and 30 to 40 percent east.
*Minor flooding appears to be the greatest threat at this time,
but it is too early to determine if there will be any impacts
to rivers and streams.
*The rain should begin tapering off from west to east late
Saturday night.
*Breezy conditions are likely Saturday, but strongest winds
(gusts 25-35 mph) may occur Saturday night into Sunday,
especially near the coast.
The main southern stream shortwave is likely to remain near the
southeast on Sunday as the progressive northern stream picks up
the deep moisture and shifts it offshore. The guidance has
become better aligned for Sunday into early next week, but there
are still questions with the evolution of the southern stream
becoming a cut-off low over the western Atlantic. There have
been several models indicating the cut-off meandering nearby or
even retrograding closer to the region. This could help send
some rain back into eastern portions of the area. However, there
are also many pieces of guidance signaling the cut-off will be
far enough east with little impact to the region. While this is
a occurring, a strong surface high will settle over southeast
Canada and ridge down over the region. The high may serve to
keep any precip offshore, especially if the stronger high
solutions verify. Due to the large amount of uncertainty with
this time period, have followed the NBM PoPs. The overall trend
however is for lowering PoPs into Sunday and then mainly dry
conditions Monday. Another shortwave may lift across the Great
Lakes next Tuesday, which could send a frontal system towards
the area. The system may have trough reaching the region,
especially if the cut-off low is still close enough to the
coast.
Temperatures this weekend into early next week look to be near
or slightly below normal.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
A cold front passes across the terminals this afternoon and
evening.
Mainly VFR through the TAF period. Scattered showers this
afternoon may bring brief MVFR conditions. One or two showers
could contain pea sized hail. There may also be some ice
pellets or wet snow mixed in well NW of the NYC terminals with a
few of these showers. The showers will taper off from west to
east early in the evening.
Mainly WSW flow for the rest of this morning at 10-15 kt with
occasional gusts around 20 kt possible. The wind direction becomes
less certain this afternoon, especially near the coast. Winds may
shift to the S and weaken briefly. This will be short-lived as winds
will quickly become W-WNW behind the cold front passage 20-23z. Wind
speeds and gusts then increase, becoming 15-20 kt with gusts around
30 kt this evening. A few gusts could reach 35 kt. There may be some
slight weakening late tonight, but gusts still average around 25 kt
into Thursday morning.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
WNW winds possible before 16z possible, but should remain south of
310 magnetic. Winds could become S at KLGA 18-21z.
Timing of wind shift to the WNW-NW this evening may be off by
1-2 hours. A peak gust 35-40 kt also possible this evening.
OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...
Thursday: VFR. NW winds 15 kt with gusts around 25 kt.
Friday: VFR through early evening. MVFR or lower possible overnight
with chances for rain near coast and rain/snow inland.
Saturday: IFR and rain. SE wind gusts 20-25 kt during the day
city east, becoming N all areas with gusts 25-30 kt at night.
Sunday: Mainly VFR. Chance of rain. N wind gusts 20-25 kt.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
-- Changed Discussion --
After collaboration with neighboring offices, a Gale warning has
been issued for the ocean waters, NY Harbor and
south shore back bays from this afternoon through early Thursday
given the trend up in >34kt wind gusts being realized. As a
strong cold front passes through, there will be a period of westerly
gusts that may approach 40 kts for a brief period near 00Z tonight.
Winds should begin to subside overnight into early Thursday.
Elsewhere on the LI Sound, SCA has been extended into Thursday
afternoon based in the higher likelihood of >25kt gusts occurring
along with the elevated seas near 5ft.
Model soundings indicate some potential for 35 kt gusts on the
Long Island Sound as well as Eastern Long Island bays tonight,
but it seemed from wind gusts forecast that the 35 kt would be
more occasional. These marine areas thus have SCA instead of
gale warning for the short term marine hazard for tonight.
Small craft conditions subside Thursday night as the pressure
gradient relaxes. Lighter winds will result in sub small craft
conditions Friday. SCA conditions are possible Saturday,
especially on the ocean. A strong N-NE flow develops Saturday
night behind a departing low pressure system leading to
widespread wind gusts 25-30 kt. There is even potential for gale
gusts on the ocean. These conditions will likely persist into
Sunday.-- End Changed Discussion --
&&
.HYDROLOGY...
No hydrologic impacts are expected through Friday. 1-2 inches
of rain is possible late Friday night into Saturday night. Minor
flooding appears to be the main threat at this time. Flash
flood guidance has recovered some over the past week and soil
moisture has decreased a bit. There remains uncertainty with the
placement of the heaviest rainfall axis, but current model
consensus hints at Long Island and southern Connecticut seeing
the highest rainfall amounts. It is too early to determine if
any impacts to rivers/streams will occur with this rainfall.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 6 PM this evening to 5 PM EDT
Thursday for ANZ331-332-335-340.
Gale Warning from 6 PM this evening to 6 AM EDT Thursday for
ANZ338-345-350-353-355.
Small Craft Advisory until 6 PM EDT this evening for ANZ350-
353-355.
&&
$$
SYNOPSIS...DBR/DS
NEAR TERM...JM/DBR
SHORT TERM...DBR
LONG TERM...DS
AVIATION...JC/DS
MARINE...JM/DBR/DS
HYDROLOGY...DBR/DS