339
FXUS61 KOKX 070110
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
910 PM EDT Tue Aug 6 2024
.SYNOPSIS...
A nearly stationary front remains in the vicinity through
tonight as waves of low pressure track along the boundary. The
front pushes slowly south as a cold front Wednesday and
Wednesday night. The front then lifts back into the area
Thursday into Friday, followed by a cold frontal passage on
Saturday. Tropical moisture associated with tropical cyclone
Debby will interact with both of these boundaries.
Please refer to the latest official forecast on Debby from the
National Hurricane Center.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
-- Changed Discussion --
Severe Thunderstorm Watch was cancelled as the strongest of the
cells have weakened, and likely remain below severe criteria for
the rest of the evening. A flood watch remains in effect for
the entire region until Noon EDT Wednesday.
Rounds of moderate to heavy rain continues to track eastward
along the nearly stationary boundary lying across northern New
Jersey into Long Island. Only minor updates were made for the
on-going weather.
A frontal boundary, through northern New Jersey into the Long
Island Sound will remain in the vicinity through tonight as
waves of low pressure track along this boundary, with the
potential for a few stronger thunderstorms with damaging winds
and heavy rainfall. There is some uncertainty regarding how long
the front will remain in the vicinity tonight as a ridge begins
to move into the eastern Great Lakes and surface high pressure
builds to the north. The building high pushes the front south as
a cold front during Wednesday.
With a moisture laden atmospheric column in place, with
precipitable water values rising to as high as 2.5 inches this
evening, any stronger storms have the potential to produce
torrential downpours. Also, storms will be training along the
boundary, with additional waves of low pressure, and multiple
rounds of heavy rainfall remain possible into the overnight and
possibly into early Wednesday morning. Stronger storms may also
produce damaging wind gusts this evening across western
sections, west of NYC, with the threat diminishing as CAPE and
instability lower, and as low level lapse rates become less
favorable.-- End Changed Discussion --
&&
.SHORT TERM /WEDNESDAY NIGHT/...
High pressure continues to build east through southern Canada
Wednesday night, and push the cold front slowly farther to the
south. However, there remains uncertainty as to how far south
the front will be pushed before moving back north as a warm
front. So, will continue to have a chance of precipitation
across the region, with the higher probabilities to the south.
And with a more stable airmass thunderstorms are not expected at
this time.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Key Points:
* Potential remains for a moderate to high impact flooding event
late Thursday into Saturday as multiple frontal systems interact
with tropical moisture associated with Debby.
* The future track of Debby, and larger scale weather systems
influencing the storm`s track, will play a big part in how this
portion of the forecast unfolds. Refer to the latest official
forecasts from the National Hurricane Center.
Not much change with the 00Z globals as the GFS continues to linger
the circulation of Debby too long over the Southeast and then shear
it out when finally moving northeast late Friday into the the first
half of this weekend. However, the ECMWF/Canadian while quicker are
becoming similar in that the low becomes absorbed into the mid
latitude cold front approaching from the west.
Even before the actual circulation of Debby (no matter what its
classification) approaches, we may have to deal with a tropical
predecessor heavy rainfall event on Friday as a leading warm front
approaches from the south, with good southerly moisture transport
and possibly enhanced lift via weakly coupled jet streaks, one
departing over New England Thursday and and another riding up the
coast Friday. In addition, a cold front associated with an
amplifying upper trough and cut off low across the Great Lakes and
Ohio Valley states sends a strong cold front across the area on
Saturday, interacting with the tropical moisture and producing
another potential round of heavy rain. Deterministic/ensemble QPF`s
continue to bear this out, showing up to an additional 3 inches
rainfall through the weekend somewhere over the CWA or in areas just
north and west. There has been a westward shift in the axis of
precipitation as is reflected in WPC`s moderate just west of the
forecast area for day 4, which just clips western Orange County.
All the above are still highly uncertain and subject to changes in
the future track and status of Debby as the circulation eventually
comes northward.
Daytime highs should run below normal through Sat, then rebound
closer to normal for Sunday and Monday as rain chances decrease.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
A cold front stalls nearby tonight as a frontal wave tracks along
it.
Declining conditions this evening with showers and thunderstorms
around through tonight. Cigs and vsbys likely prevail MVFR at
most terminals by 3Z or sooner. IFR conditions are then likely
to develop thereafter, especially across the Lower Hudson
Valley and CT terminals, working south across the NYC and LI
terminals into early Wednesday morning. Showers and storms taper
Wednesday AM, becoming mostly dry by noon with gradually
improving cigs to VFR toward 21Z Wed.
Winds will be finicky with the nearby front, becoming E/NE
around 10 kt early this evening, persisting thru Wed. However,
multiple frontal waves tracking along the front across the area
tonight could result in significant variability in wind
direction.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments likely through tonight for changing flight categories
with showers and thunderstorms.
IFR possible at times into Wednesday morning.
Winds may vary significantly in direction overnight as multiple
waves of low pressure move across the area. Low confidence in
wind direction.
OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY...
Wednesday Night and Thursday: MVFR or lower in SHRA.
Friday: MVFR/IFR in SHRA. SE gust 20-25kt possible.
Saturday: MVFR/IFR in RA/SHRA. E to NE gusts 20-25kt possible.
Sunday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
A nearly stationary front remains in the vicinity of the
forecast waters through tonight, and then moves south as a cold
front Wednesday and Wednesday night. With a weak pressure
gradient remaining across the forecast waters tonight through
Wednesday night winds and seas will remain below SCA levels.
There is quite a bit of uncertainty for the end of the week due
to the future track of Debby. Long period southerly swells may
start arriving Thursday into Friday, but at this time seas are
kept right around 4 ft. Seas should increase above 5 ft Fri
night, and if the circulation center of Debby passes to the
west, gale force wind gusts may be possible late Fri night into
Sat, but the current forecast calls for 25 to 30 kt on the ocean
waters at this time. The forecast could significantly change,
so please refer to latest forecast information from the NHC as a
starting point.
&&
.HYDROLOGY...
A Flood Watch remains in effect for the entire region until Noon
EDT Wednesday, as a nearly stationary front remains in the
vicinity tonight before pushing slowly south Wednesday and
Wednesday night. WPC continues with a moderate risk of
excessive rainfall through tonight for NE NJ, NYC metro, and
western Long Island, and has maintained a slight risk for the
rest of the forecast area. Moderate to locally heavy rainfall
remains possible at least through tonight with rainfall rates as
high as 2"/hour, which leads to the potential of localized to
scattered instances of flash flooding, especially for the more
urban locales. There remains a chance that locally heavy
rainfall continues into a portion of Wednesday morning.
Currently rainfall of 2 to 3 inches is possible, with the
highest amounts across the southern areas, and local amounts of
3 to 5 inches.
Another round of heavy rainfall is possible late this week into
the weekend, first from Thu night into Fri as a warm front
lifting northward into the area interacts with tropical moisture
well in advance of Debby. However, there is a great deal of
uncertainty with this time frame and how far south high pressure
builds in from the northeast. Then again from Fri night into
Sat if the circulation of Debby passes close by. PWATs of over
2"+ are expected with this feature. Again, there is a great deal
of uncertainty with this as well.
&&
.TIDES/COASTAL FLOODING...
A high rip current risk continues into early this evening per
RCMOS and NWPS guidance. This is due to southerly swells of
around 4 feet. A moderate risk is forecast for Wednesday and
Thursday as swells start to diminish late tonight.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...Flood Watch through Wednesday morning for CTZ005>012.
NY...Flood Watch through Wednesday morning for NYZ067>075-078>081-
176>179.
NJ...Flood Watch through Wednesday morning for NJZ002-004-006-
103>108.
MARINE...None.-- End Changed Discussion --
&&
$$
SYNOPSIS...JP/MET
NEAR TERM...DR/MET
SHORT TERM...MET
LONG TERM...JP
AVIATION...DR
MARINE...JP/MET
HYDROLOGY...JP/MET
TIDES/COASTAL FLOODING...