000
FXUS61 KOKX 252043
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
443 PM EDT Sun Jun 25 2023
.SYNOPSIS...
A weak trough remains near the region tonight before another
trough of low pressure approaches from the west on Monday. A
slow moving frontal system will impact the area through mid-
to-late week. Weak high pressure tries to move in Friday before
another frontal system approaches from the west impacting the
region through the weekend.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Diurnally driven showers and thunderstorms will continue into
this evening before weakening with the loss of daytime heating.
Initial storms were quite slow moving and resulted in several
reports of flash flooding in northeast New Jersey. Storm motion
has now increased somewhat and there has been a general downward
trend in convection, but with a moist atmospheric profile in
place minor poor drainage flooding in low lying areas will
remain possible with any additional storms into this evening.
The best chances will continue to be across the Lower Hudson
Valley and northeast New Jersey.
While the ongoing convection is expected to weaken after
sunset, precipitation chances continue through the overnight
hours as shortwave energy lingers across the region. Overall
conditions should be more dry than wet, but can`t rule out
additional pop up showers/storms during this period, especially
towards daybreak Monday.
With little change in the airmass from the previous few nights,
patchy fog is once again expected to develop from east to west
tonight. Winds just above the surface are stronger than the past
couple nights which could disrupt fog development, although
more widespread and/or dense development can`t be ruled out. As
with previous nights, the best chances remain along the coast.
Overnight lows will again remain in the mid to upper 60s.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
Monday is expected to be an active weather day as a vertically
stacked low over Michigan slowly moves east during the day.
Energy out ahead of this feature will combine with jet energy
rounding the base of the upper trough and a developing surface
trough to spark convection during the afternoon and evening
hours.
A few unorganized showers and thunderstorms could be ongoing to
start the day, but those should give way to the potential for
more organized convection as the day wears on. By late
afternoon, CAPE is expected to climb to 1000-1500 J/kg west of
NYC along with bulk shear of 30-35 kts. SPC continues to place
the NYC Metro, northeast New Jersey, western Long Island, and
portions of the Lower Hudson Valley in a slight risk for severe
weather, with the remainder of the region in a marginal risk.
The greatest threat with any strong to severe storms would be
the potential for damaging winds, although an isolated tornado
can`t be ruled out north and west of NYC. In addition to the
potential for severe thunderstorms, a flash flood threat also
remains, with WPC including northeast New Jersey in a slight
risk of excessive rainfall.
While the ingredients are in place to support the development
of strong to severe storms, the exact evolution of the
convection remains uncertain. Some of today`s 12Z high
resolution model runs indicate the potential for multiple rounds
of convection, possibly beginning as early as 15-16Z over
western portions of the area. Any early convection may limit
the available instability later in the afternoon/evening. In
addition, the timing of the primary convection looks to be on
the late side - after 21Z and possibly after 00Z, at which
point diurnal support would be waning. For areas east of NYC,
another mitigating factor is the general south to southeast
flow, which introduces more of a marine influence and could
help suppress any eastward moving convection.
While the potential for severe weather diminishes overnight,
shower and thunderstorm chances will linger across the region as
the upper low draws closer. The combination of lingering shower
activity and overall higher winds should preclude any fog
development Monday night.
Temperatures on Monday are expected to rise into the upper 70s
to lower 80s, near to slightly below normal for late June.
Overnight lows will fall into the mid to upper 60s.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
The unsettled pattern will continue through the long term, with
the only chance of a brief reprieve and perhaps more intervals
of sunshine overall towards Fri / Sat. Shower and thunderstorm
coverage will be numerous to widespread on Tuesday with a
possible moderate to heavy downpour with WPC giving the city and
interior areas a Marginal risk for excessive rainfall. The risk
for flooding from any moderate or heavy downpours will depend
on how waterlogged the soils get over the next few days. PWATs
sit around 1.6-1.7" based on the 12Z GFS, the 6Z ECMWF getting
close to 1.8" and the 12Z NAM giving upwards of 2.1" on Tuesday.
Aside from the risk for heavier rain, thunderstorms may pose
their own risks. The latest 12Z NAM is putting out 2500-2800
J/kg of MUCAPE with Bulk Sfc-500mb shear of 40- 50 kts and mid-
level lapse rates between 6 and 7C/km. The SPC currently has us
under a Marginal Risk for severe weather on Tuesday.
Coverage of showers and storms may start lessen on Wednesday as
the deeper moisture axis starts shifting to the east and north
as a front and triple point pass overhead or nearby. However,
the upper trough and closed low will only slowly move overhead
into Thursday. Shower and scattered t-storm activity remains
possible, especially in the afternoon and evening. The trough
and associated frontal system may start to shift to the east on
Friday with weak high pressure trying to settle, but confidence
how this evolves is still quite low. 700mb RH values from
deterministic models would suggest some moments of sun in
between periods of clouds on Friday.
Look for daily max temps to average below normal with a good
deal of daytime cloud cover anticipated on average throughout
the period. There may be a day towards Fri or Sat where daytime
temps may get closer to normal. Night minimums should average
close to normal with higher humidity due to a persistent
southerly flow and a good chance of night time cloud cover.
Mainly used NBM for temperatures.
Late Saturday into Sunday another frontal system will approach
us from the west increasing southerly flow and thereby
increasing available moisture and keeping temperatures warm.
&&
.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
A low pressure trough remains nearby.
Generally VFR this evening. Showers and thunderstorms mainly
north and west of NYC terminals into early evening with
potential MVFR. A repeat of fog...some dense..and low stratus
with IFR/LIFR conditions appears likely for tonight. Timing
highly uncertain but most likely after midnight.
S winds 5-10 kt expected this evening, diminishing tonight and
then backing SE overnight.
More significant potential for TSRA on Monday with a few rounds
TSRA w/ heavy rain and gusty winds possible. MVFR/IFR likely
with any thunderstorm.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments likely for changing flight categories due to stratus
redevelopment across coastal terminals tonight.
OUTLOOK FOR 21Z MONDAY THROUGH FRIDAY...
Monday: Showers. Chance of tstms with gusty winds and from the
NYC metros north/west/south, especially afternoon/evening. MVFR
cond expected, IFR possible.
Tuesday and Wednesday: Showers. Tstms with gusty winds and hail
possible, especially afternoon/evening. MVFR cond expected, IFR
possible. Tuesday S winds G20-25kt.
Thursday: Chance of showers and a slight chance of tstms. MVFR
or lower possible at times.
Friday: Becoming VFR.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
Fog has lingered over the eastern ocean waters for much of the
day and is expected to expand westward across most of the
waters again tonight. The primary exception to this will be NY
Harbor. The fog could once again become dense.
Otherwise, both winds and seas are expected to remain below SCA
criteria through the day on Monday before increasing Monday
night on increasingly southerly flow. By Tuesday, seas on the
ocean will increase to 5-6 feet, and are expected to remain
elevated into Wednesday night before decreasing during the day
on Thursday. Winds will also increase to around 25 kt on the
ocean on Tuesday.
&&
.HYDROLOGY...
Minor flooding of low lying and poor drainage areas will remain
possible in any heavier showers this evening across the Lower
Hudson Valley and northeast New Jersey.
There is a continued risk of minor flooding and localized flash
flooding mainly late Monday into Tuesday in showers and
thunderstorms. WPC continues to carry a slight risk of excessive
rainfall across northeast New Jersey on Monday and a marginal
risk across the remainder of the area, with a marginal risk for
the entire region on Tuesday.
Hydrologic impacts are also possible Wednesday into Thursday,
but may be dependent on where the heaviest rainfall occurs
through Tuesday. WPC currently has a marginal risk of excessive
rainfall NW of the NYC metro.
&&
.TIDES/COASTAL FLOODING...
-- Changed Discussion --
The moderate risk of rip current development continues for all ocean
beaches through Monday, with an upgrade to a high risk on Tuesday.
The rip current risk is being driven mainly due to south to
southeasterly swells.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...FEB/BR
NEAR TERM...FEB
SHORT TERM...FEB
LONG TERM...BR
AVIATION...IRD
MARINE...FEB
HYDROLOGY...FEB/DS
TIDES/COASTAL FLOODING...