000
FXUS61 KOKX 202343
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
743 PM EDT Tue Jun 20 2023
.SYNOPSIS...
High pressure over northern New England remains nearly
stationary into Wednesday before slowly shifting offshore
Wednesday night into Thursday. A frontal system over the
southeast US slowly moves north Thursday into the weekend.
This frontal system will continue to affect the forecast area
through the weekend, weakening as it does so. A cold front
approaches from the west late Monday.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
-- Changed Discussion --
The forecast is generally on track with minor changes needed.
Showers over central Connecticut and western portions of the
mid Hudson Valley are moving south into portions of the Lower
Hudson Valley and inland southern Connecticut, where there is a
slight chance in the forecast currently. While they will
generally be light and weaken as they head south, a shower or
two may be associated with some briefly heavy rain.
A weak surface trough will linger near the interior this
evening, supporting a low chance for a shower. Most of the
showers should remain north of the area and any lingering
activity will dissipate after sunset.
The persistent upper trough that has been over the region
recently will move offshore tonight. Heights will rise aloft as
a rex block settles over the eastern states. Strong ridging
will build across the Great Lakes and northeast over an upper
low over the southeast and Middle Atlantic states. High pressure
will also remain anchored over northern New England tonight.
Dry conditions are expected with mostly cloudy skies. There will
be a good amount of high clouds streaming north from the upper
low to our south. These clouds may be thinner further inland as
subsidence from the building ridge tries to dry out the upper
levels. Model soundings also indicate a thin layer of moisture
beneath an inversion around 1-2 kft. The strengthening low level
flow may also bring some lower level stratocu or stratus, but
do not anticipate this to be widespread at this time.
Lows should be in the lower 50s inland and middle to upper 50s
most elsewhere. The NYC metro will fall into the low 60s.-- End Changed Discussion --
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
The blocking pattern will persist aloft through the middle of
the week. The core of the upper ridge will remain over
southeast Canada and northern New England, with the upper low
only meandering a bit N- NNW Wednesday into Wednesday night.
High pressure at the surface will largely remain over Northern
England on Wednesday and only start to shift offshore Wednesday
night. The high pressure both aloft and the surface will create
subsidence and prevent any precipitation from making it this far
north from the upper low on Wednesday. There will be a varying
amount of high clouds through the day with some stratocu,
especially closer to the coast. Skies may end up partly to
mostly sunny further inland where the high clouds struggle to
make headway north into the stronger ridging/subsidence. Fairly
strong onshore flow is expected with an easterly flow 10-15 mph
with gusts 20-25 mph. The strongest winds look to occur closer
to the coast where a few gusts up to 30 mph are possible. Highs
will continue below normal for this time of year in the lower to
middle 70s.
A warm front and potentially a weak frontal wave start approaching
from the Middle Atlantic Wednesday night. Model guidance differs
in the speed of this system owing to uncertainty in amount of
ridging/subsidence over the northeast and New England. Have
continued to side with slightly slower progression which only
introduces chance PoPs to the southern half of the area early
Thursday morning. Middle level dry air will have to be overcome
to see measurable rain, which largely looks to hold off until
close to day break near the coast. The steadiest of the rain
likely occurs during the day on Thursday, especially well
inland.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
The long term will continue to be characterized by a blocky
pattern atypical of mid-June for this part of the country. A
cutoff low over the Southeast US slowly drifts north as a cutoff
high develops over southeast Canada and pushes east. This
cutoff low and associated frontal system slowly weakens as it
heads toward the forecast area. Outside of Wednesday, much of
the rest of the week can be expected to be unsettled with this
type of pattern in place.
Thursday is expected to be relatively cool thanks to a continued
easterly flow and the possibility of rain cooled air as the cutoff
low and its surface reflection along with the frontal boundaries
head north. Northeastern areas may be warmer than southwestern areas
as these areas will be closer to the high, and therefore, less in
the way of rain and clouds are expected. Highs will be in the lower
to middle 70s. However, some models indicated parts of the forecast
area may not climb above the upper 60s to around 70.
There is some uncertainty rain amounts for Thursday due to
uncertainties in the strength of the high, especially between
the ECMWF and NAM. Both of these models show a period of
moderate rainfall to move through the area, but there are
differences in timing, with the ECMWF bringing in the more
moderate precipitation earlier than the NAM as the high is
modeled to be weaker and the associated warm front closer to the
region than the NAM. The NAM is 6-12 hours slower than the
ECMWF. The GFS is an outlier with not much in the way of any
precipitation at all. With a warm front in the vicinity, would
tend to lean towards the other models as this will be a lifting
mechanism for precipitation.
Later in the week, as the high continues to push east and the
cutoff low heads into the mid-West, a southerly flow develops,
allowing for temperatures to warm to more seasonable, but
slightly below normal levels, for this time of year. The
southerly flow will also allow for an increase in humidity
levels as dew points rise into the middle to upper 60s from
Friday through the beginning of next week. The upper low weakens
into a trough late Friday night into Saturday that remains to
the west of the area through then, and looks to be around
through the weekend.
The approach of a cold front from the west at the beginning of
next week will aid in pushing the upper trough associated with
the blocked pattern east of the area, but chances for
precipitation will continue until this front moves through the
area which does not look to occur until Tuesday or later.
The increase in humidity and the warmer temperatures will allow
for more in the way of instability, and thus thunderstorms to
develop during the afternoon and early evening hours from Friday
onward.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
Mostly VFR as high pressure remains to the north. There could be
MVFR cigs after midnight east of the city, especially KGON.
E-SE winds either side of 10 kt should diminish this eve and
back more to the E this evening and ENE overnight. ENE flow
should then increase to 10-15G20kt after about 13Z Wed, highest
along the coast.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Uncertainty in how much low stratus redevelopment could occur
late tonight. TEMPO MVFR conds possible 10Z-13Z.
OUTLOOK FOR 00Z THURSDAY THROUGH SATURDAY...
Wednesday night: VFR in the evening. Chance of showers/MVFR
cond after midnight. E-NE winds 10-15G20kt.
Thursday: Showers likely. MVFR or lower cond possible at times.
E winds G15-20 kt daytime/early evening.
Friday: Chance of showers/TSTMs/MVFR conds.
Saturday and Sunday: Showers likely with MVFR or lower cond at
times. Tstms also possible, mainly afternoon into evening. S
winds G15-20kt afternoon/evening.-- End Changed Discussion --
&&
.MARINE...
Sub-SCA conditions will continue on the waters through
tonight. An increasing easterly flow is then expected Wednesday
with winds increasing to around 25 kt on the ocean waters and
the NY Harbor. This increasing flow will also build seas to 5 to
6 ft through the day. Winds may settle closer to 20 kt on the
ocean Wednesday night, but seas will remain elevated. Have
extended the SCA on the ocean through 6 am Thursday and also
started the zone east of Moriches Inlet at 6 am Wednesday as
seas look to build faster than previously anticipated. Have also
added the NY harbor to the SCA from 1 pm to 8 pm Wednesday.
Winds on the non-ocean waters are expected to remain below SCA
levels through Wednesday night.
Persistent easterly flow will allow waves to build to 5 to 7 ft
on Thursday. Waves then diminish Thursday afternoon, falling
below 5 ft by late Thursday night into early Friday morning.
Gusts of 25 to 30 kt are also expected across the western and
central ocean zone Thursday morning as the pressure gradient
increases between a departing high and weak low to the southeast.
Winds diminish by Thursday afternoon.
Winds and waves are expected to remain below SCA levels from Friday
onward.
&&
.HYDROLOGY...
No hydrologic concerns through Wednesday night.
The Weather Prediction Center has placed western sections of the
forecast area (the Lower Hudson Valley and northeast New Jersey)
in a marginal risk of excessive rainfall for Friday and
Saturday. As a more humid air mass works into the region, PWAT
values may rise to 1.75" to just over 2.00". Any locations in
the aforementioned areas could see up to 2.00" of rainfall in a
short period of time. However, there is a great deal of
uncertainty as to certain features that would be the focus of
the development for thunderstorms, such as the upper low, its
surface reflections, and frontal boundaries. Therefore, 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.
&&
.TIDES/COASTAL FLOODING...
There is a high risk of rip current development for all ocean
beaches on Wednesday and Thursday.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...High Rip Current Risk from Wednesday morning through Wednesday
evening for NYZ075-080-081-178-179.
NJ...None.
MARINE...Small Craft Advisory from 1 PM to 8 PM EDT Wednesday for
ANZ338.
Small Craft Advisory from 8 AM Wednesday to 6 AM EDT Thursday
for ANZ350-353-355.
&&
$$
SYNOPSIS...JP/DS
NEAR TERM...JP/DS
SHORT TERM...DS
LONG TERM...JP
AVIATION...JC
MARINE...JP/DS
HYDROLOGY...JP/DS
TIDES/COASTAL FLOODING...