000
FXUS61 KOKX 221630
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1230 PM EDT Thu Jun 22 2023
.SYNOPSIS...
High pressure over the Gulf of Maine slides into the open Atlantic
today ahead of an approaching warm front. The front lifts through
the region Friday. A series of frontal systems will then move across
the area this weekend into the middle of next week bringing
unsettled weather conditions.
&&
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Areas of drizzle and light rain continue this morning
intermittently, with many ASOS sights no longer reporting
drizzle. CAMs have backed off rain chances for later today. They
remain in the forecast, particularly for eastern areas with
enough forcing later this afternoon, but have adjusted POPs
accordingly. Temperatures have also been running warmer as a
result, so have blended in some HRRR to allow for a warmer
consensus on high temperatures today. Even so, highs are still
close to on track.
Upper ridging gradually weakens across southern Canada and New
England today, while an anomalous and large closed upper low
spins across the southeastern US/Tennessee River Valley with a
sheared out vort axis rotating around it up the coast. Deep
southerly flow ahead of this low will have the weak low
pressure wave and warm front riding up the Mid Atlantic coast.
The approaching frontogenetic zone and easterly jet will allow for
a band of stratiform rain to develop, though competing factors
are leading to some uncertainty in rainfall amounts. In favor of
moderate to locally heavy rain is a relatively strong LLJ for
June (35-40 kt at 925 mb), PWATs increasing to 1 1/2 to 2", and
increasing warm rain processes as warm cloud layer deepens to
10-12 kft. If heavier rain is to develop, best consensus
appears to be across LI and possibly into SW CT (with
orographics) into this afternoon. Elsewhere, generally a light rainfall
today. Likely see a lull in the steadiest of the showers by
late afternoon or evening as forcing wanes, though increasing
low level moisture may allow for areas of drizzle or light rain
at times. Patchy fog may also develop this evening, and could
linger overnight as the warm front begins to move in.
Breezy conditions are expected to resume later this morning and
persist through the afternoon as the pressure gradient tightens
between the high to the north and approaching Mid Atlantic wave.
Gusts generally up to 25 mph, and up to 30 mph along the coast.
Winds gradually subside late this afternoon and into the evening
the high pushes further into the Atlantic.
The rain, clouds, and onshore flow will make for an unseasonably
cool June day, with highs in the mid 60s, or 15 to 20 degrees
below normals. Temperatures largely remain where they are
overnight into early Friday morning. There is potential for the
next shortwave to approach overnight, which could instigate
additional shower activity close to daybreak Friday.-- End Changed Discussion --
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
The closed upper low tracks into the Ohio Valley on Friday,
while at the surface, a warm front lifts through the region
early in the day, stalling nearby in New England.
The day likely begins on the showery side as the warm front
moves through. Dew points rise into the upper 60 to near 70 with
southerly flow developing post fropa in the morning. Coverage
showers and thunderstorms likely becomes more scattered in nature
by the afternoon, before expand into the overnight period with
increasing forcing. The moist air mass and efficient warm cloud
processes will allow heavy downpours to be possible with any
convection, and WPC has the region outlined with a marginal risk
for excessive rainfall.
Temperatures will be a bit milder than Thursday with the region
lying in the warm sector, though still below normal values for
late June. Highs top out in the mid 70s for most, and remain
mild overnight into Saturday morning. Stuck close to the
superblend of guidance for this update.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
No significant changes to the forecast thinking for Saturday
into the middle of next week. The weather pattern will remain
unsettled and the NBM was followed closely this period.
A slow moving upper trough and its associated energy move
towards New England this weekend. The trough will likely weaken
as it approaches, but will help draw in deep moisture, which
can be traced to the Gulf of Mexico. Models continue to show
PWAT values between 1.75" and 2.00". There will be a surface
focus in the form of several frontal boundaries providing
convergence and lift along with some support aloft from the
approaching trough. These systems will combine to develop
showers and some thunderstorms this weekend, with the greatest
probabilities occurring on Saturday. Instability looks a bit
higher from the NYC metro on N and W, which is where potential
exists for a bit more coverage of thunderstorms. Loss of daytime
heating should slowly diminish showers and storms Saturday
evening into Saturday night. The frontal boundary associated
with the upper trough starts to push offshore late Saturday
night into Sunday, but a surface trough could hang back over the
area Sunday afternoon and evening. This should again support
development of showers and a few thunderstorms in the afternoon
and evening. WPC has a marginal risk for excessive rainfall
highlighted on Saturday and Sunday from the NYC metro on north
and west. The main concern is minor urban and poor drainage
flooding, but localized flash flooding cannot be ruled out. It
will be humid this weekend, but highs should be close to
seasonable levels in the upper 70s and low 80s.
The upper trough lifts away from the area on Monday as it gets
absorbed into yet another larger trough that approaches from the
Great Lakes. This renewed troughing will bring another frontal
system and a continued unsettled conditions into the middle of
the week. The upper trough is progged to slowly move eastward
Monday and Tuesday and possibly lift over New England by the
middle of the week. The guidance differs on how quickly this
will occur given that this is about a week out. However,
confidence is increasing that at least diurnal showers and
possible thunderstorms will occur each day, mainly in the
afternoon and evening. The higher probabilities are currently
indicated on Monday and Tuesday afternoons given the focus from
the next frontal boundary and upper trough. Coverage may be
greatest from around the Hudson River corridor on west Monday
and then the entire area Tuesday with the closer proximity of
the upper trough. This pattern supports potential of minor urban
and poor drainage flooding and localized flash flooding.
Temperatures continue near normal levels early next week with
continued higher humidities.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
A warm front and associated wave of low pressure approach from
the south through tonight. The front lifts across the terminals
on Friday.
Occasional light rain will continue across the terminals,
allowing for MVFR conditions to continue for most terminals.
Expecting rain to become more steady with further lowering of
ceilings to IFR during the mid to late afternoon. Visibilities
are expected to remain VFR to MVFR.
The rain becomes lighter mid to late afternoon and should
transition to areas of drizzle this evening. IFR then prevails
through tonight and there is potential for LIFR conditions.
There is also a chance for fog of 1/4sm-1/2sm overnight, but
confidence is too low in its timing and extent to include in the
TAF.
NE winds 10-15 kt will have gusts becoming more frequent for
NYC and coastal terminals. Gusts will end by the start of
evening with winds weakening in the evening. Wind speeds
generally fall to around 10 kt or less towards 00z Friday. Winds
continue to weaken tonight as the wind direction becomes more
east early Friday morning.
An isolated thunderstorm is possible early Friday morning.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments likely for timing of lowering flight categories.
Development of IFR this afternoon could be off by 1-2 hours.
Gusts could be occasional.
The afternoon KJFK and KLGA haze potential forecast is
RED...which implies slant range visibility less than 4sm outside
of cloud.
The afternoon KEWR haze potential forecast is YELLOW...which
implies slant range visibility 4-6SM outside of cloud.
OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...
Friday-Saturday: Showers and MVFR likely. IFR possible. Chance
of thunderstorms, mainly each afternoon/evening with highest
chance NYC metro on NW.
Sunday-Monday: Showers likely, mainly in the afternoon and
evening. Chance of thunderstorms with highest chance NYC
metros north/west each afternoon and evening. MVFR conditions
possible.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
SCA gusts (25 to 30 kt) should resume on all waters later this
morning and into the afternoon, with easterly gradient
tightening between a Mid Atlantic low and departing New England
high. SCA conds continue for all waters into this evening. Ideal
fetch for seas of 3 to 4 ft on LI Sound and 6 to 9 ft on the
ocean. Winds gradually subside below SCA this evening, with
ocean seas following suit by early Friday morning.
Winds and seas look to remain below SCA levels Friday and this
weekend. Winds could begin to approach 25 kt on the ocean waters
late Monday into Monday night as southerly flow increases with
the approach of the next frontal system. Sea may also build
close to 5 ft.
&&
.HYDROLOGY...
A widespread 1/4 to 3/4" of rainfall is likely to fall today
across much of LI and SW CT, with up to 1/2" of rain elsewhere.
The probability of 1"/3 hr is low in this stratiform rain
environment, and with antecedent dry conditions, not expecting
any flooding concerns even if higher amounts are realized.
Locally heavy downpours are possible on Friday, and may lead to
minor flooding of urban and poor drainage areas. The Weather
Prediction Center has placed the entire forecast area in a
marginal risk of excessive rainfall.
The Weather Prediction Center has placed the western sections
of the forecast area (the Lower Hudson Valley and northeast New
Jersey) in a marginal risk for excessive rainfall this weekend
Saturday and Sunday. The main concern is from minor urban and
poor drainage flooding, but localized flash flooding cannot be
ruled out. Even areas outside of the aforementioned locations
may see heavy rainfall, but at this time, the potential is lower
than where there is currently a marginal risk.
Locally heavy rainfall remains possible early next week and minor
flooding could occur. Hydrologic impacts early next week may be
determined by the extent of the rainfall Friday into this
weekend.
&&
.TIDES/COASTAL FLOODING...
There is a high risk of rip current development for all ocean
beaches today with building easterly wind swell. Breaking surf
likely builds to 5 to 7 ft with a strong e to w longshore
component, which will likely also enhance beach erosion.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...High Rip Current Risk until 8 PM EDT this evening for NYZ075-
080-081-178-179.
NJ...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ331-
332-335-338-340-345.
Small Craft Advisory until 8 AM EDT Friday for ANZ350-353-355.
&&
$$
SYNOPSIS...DR/DS
NEAR TERM...BR/DR
SHORT TERM...DR
LONG TERM...DS
AVIATION...JM/DS
MARINE...DR/DS
HYDROLOGY...DR/DS
TIDES/COASTAL FLOODING...