000
FXUS61 KOKX 241326
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
926 AM EDT Thu Aug 24 2023
.SYNOPSIS...
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Low pressure and its associated warm front approach into
tonight. The warm front slowly pushes through Friday, followed
by a cold front Friday night. A slow moving frontal system
slides east early Saturday, followed by a Canadian cold front
moving through late Saturday. Canadian high pressure builds in
for Sunday and east on Monday. A frontal system will approach
Monday Night, slowly crossing through Tuesday into Tuesday
Night. Another Canadian cold front crosses on Wednesday.-- End Changed Discussion --
&&
.NEAR TERM /THROUGH TONIGHT/...
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High pressure continues to move further offshore this morning.
Mid level deck also is expanding eastward across the region and
low level clouds are beginning to advect northward as moisture
starts to increase. This warm advection pattern will continue
through the day. The chance for showers remains, especially
along and west of the Hudson River corridor late morning into
the afternoon. May also start to see some showers further east
late as surface ridging relaxes with the high further offshore.
Max temps will only get into the lower and middle 70s today.
Shower activity will likely increase for the evening as the
elevated warm front starts to slide in from the west. Therefore
shower activity will become more widespread into the overnight.
PW values will get to 1 3/4 and 2 inches. Also with some
elevated instability some showers have the potential to become
locally heavy with the potential for some embedded convection,
more so after 4-6z. Look for efficient warm rain processes in
any heavier pockets of rain with warm cloud layer to around 13
to 14 kft towards early Fri AM. Thus, most of the ingredients
for localized heavy rainfall are in place for the late night and
into early Fri morning. With warmer and more humid air on a SSE
flow look for temperatures to hold steady Thu night, warmer
than previous nights as dew point readings rise into the upper
60s towards early Fri AM.-- End Changed Discussion --
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
During Friday morning the more widespread shower activity will
likely be pivoting through as the warm front pushes into the area at
and just above the sfc. One thing of note is the 0-1, and 0-3 km
helicity and hodographs on the fcst soundings. If convection does
form right along the warm front into Friday morning there may be
some rotation associated with any thunderstorms. There remains
uncertainty among NWP with regard to the degree of instability
closer to the sfc and any lingering convection and the proximity of
the warm front that would provide added helicity to any associated
convection. The guidance will have to be closely monitored getting
closer to Fri AM with regard to any spin up potential with any t-
storms that may develop. Rainfall rates in the heaviest shower
activity will likely be on the order of three quarters of an inch
per hour, with maximum rainfall rates of up to 1 inch or more per
hour not out of the question.
Into Fri afternoon and evening with lingering instability and the
region in the warm sector, look for scattered shower and
thunderstorm activity. There remains uncertainty if there will be a
dominant focus mechanism for convection, until the cold front slowly
pushes through either Fri evening or later Fri night. Have continued
with a chance of showers and a slight chance of thunderstorms for
this time frame, along with a heavy rain mention further east into
the day Friday. By early Sat AM on the back side the cold front look
for the winds to become more NW. Shower coverage overall should
decrease towards early Sat AM, although some guidance is suggestive
of the front temporarily stalling which would keep shower chances
lingering into Sat AM. QPF Amounts look to be on the order of
mainly 3/4 to 1 inch. Locally higher amounts of 1.5 inches or more
are possible where any locally heavy downpours take place. See the
Hydrology section for more details.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Good model agreement in persistent mean NE troughing continuing
through the period as one trough develops for the weekend and a
second deeper trough approaches for Tue/Wed. Meanwhile, the
anomalously strong Central and Southern US subtropical ridge will
gradually weaken and retrograde to the SW US through the weekend.
The first shortwave, associated with a closed low currently over
Alberta, will track around the northern periphery of the Central US
subtropical ridge Thu Night/Fri and dig through the Great Lakes into
NE US Fri night into Sat. At the surface, this will have a broad
surface wave/cold front pushing through the region Friday night into
early Saturday morning with associated shower/embedded tstm activity
sliding offshore.
Cyclonic flow on Saturday, and lingering weak surface troughing
across northern and eastern areas will likely have considerable
cloud cover lingering, and could spark an isolated instability
shra/tsra Sat aft, or with a cold frontal passage late Sat/Sat eve.
Temps should run near seasonable upper 70s to lower 80s with
offshore flow.
Model in better agreement with the orientation/strength and
progressiveness of the trough axis and associated closed over New
England for the weekend, increasing confidence in a fairly strong
Canadian cold front approaching late Sat and likely crossing Sat
night. Gusty NW winds likely in the wake of the passage with an
early autumn-like airmass advecting into the region for Sun/Mon.
Temps will be running a few degrees below seasonable (mid to upper
70s) for late August with low humidity levels.
General consensus in the next in a series of shortwaves digging an
upper trough into the upper Mississippi River Valley and Great Lakes
Monday night into Tuesday, with a resultant frontal system sliding
towards the region Monday night and slowly through the region
Tue/Tue Night. This pattern and model consensus points to TC
Franklin staying well offshore. Monitor
https:/www.weather.gov/okx/tropical for the latest NHC forecasts on
this tropical system and others. Signals though, are looking better
for possible enhanced/predecessor rainfall development somewhere
along the front from northern Mid Atlantic to southern New England
during the Mon Night to Tue Night timeframe. A lot of inherent
uncertainty on this type of phenomenon, especially this far out, and
will be dependent on timing/track of Franklin and trough axis/front
particulars.
Higher confidence in energetic swells from Franklin likely building
to the coast late Monday into Tuesday and continuing into mid week,
bringing increasing potential for dangerous rip currents and high
surf.
&&
.AVIATION /13Z THURSDAY THROUGH MONDAY/...
A warm front approaches from the west this afternoon into tonight.
An associated low pressure system gradually crosses the region
Friday into Friday Night.
Isolated showers develop across western terminals this morning. This
activity should become more widespread for western terminals
(including NYC/NJ metro) this afternoon with conditions likely
coming down to MVFR. For the eastern terminals, mainly VFR
conditions are expected today, with brief MVFR possible in late
afternoon/evening shower activity.
Widespread shower activity and MVFR conditions develop from w
to e tonight, after 04-06z and continue thru Fri AM push.
Isolated tsra threat, mainly across western terminals, late
tonight into Fri AM (between 08z and 15z) as warm front nears.
S/SE winds at 5-8 kt this morning, increasing to 10-15g20kt by late
morning for coastal terminals, and continuing into tonight.
Peak gusts to 25 kt for NYC and eastern terminals.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
VFR for AM push, MVFR conds w/SHRA likely for PM push. Timing of
onset of gusts may be off by 1 to 2 hrs. Peak gusts to 25 kt
possible.
OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...
Friday: MVFR/IFR conds in widespread showers and embedded tsra
through Friday morning for western terminals, and into Friday
aft/eve for eastern terminals. Isolated shra/tsra threat for
western terminals for Fri PM push. S/SE gusts 20-25 kt into
Friday AM push, diminishing and veering S/SW late morning into
afternoon.
Friday Night: Isolated Shra/Tsra threat, mainly east late.
Saturday: VFR, early AM isolated shower/tstm threat across
eastern terminals. Isolated shower threat across northern
terminals in PM.
Sunday and Monday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
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SE winds slowly increase today with gusts on the western waters
approaching 20 kt late today. Winds approach small craft
criteria late tonight, especially for the western ocean waters
with ocean seas building to around 4 ft. Small craft conditions
are expected for the majority of the waters Friday, and perhaps
into a portion of Friday evening. Small craft advisories have
been issued for all waters, except for the western most
nearshore waters of the NY Harbor and Western LI Sound. But
small crafts may eventually be needed for these zones as well
with marginal small craft wind gusts currently being forecast.
Any small craft conditions should come to an end Friday night
from west to east with a cold front slowly sliding through.
Residual SCA southerly wind swell on the ocean should gradually
subside below SCA on Saturday, although marginal SCA conds may be
extended into Sat Night with gusty NW flow in wake of cold frontal
passage. Thereafter, sub SCA conditions favored for Sun into Mon
morning on all waters (although ocean seas may run 3-4 ft in long
period SE swell), with high pressure building in.
Energetic SE swells likely build in from tropical cyclone Franklin
late Monday into Tuesday, likely bringing a return of SCA conditions
on the ocean.-- End Changed Discussion --
&&
.HYDROLOGY...
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Showers will become more widespread tonight into Friday morning
with some embedded thunderstorms possible. Locally heavy
rainfall is possible with the main concern from minor urban and
poor drainage flooding late tonight into early Friday morning.
This risk may continue into Friday afternoon for eastern CT and
eastern LI. An isolated flash flood occurrence or two cannot be
ruled out.
No widespread hydrological concerns for Saturday through Monday.
Low predictability on heavy rain threat along a slow moving frontal
system Monday night into Tuesday night of next week.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
The risk of rip current development increases from low to moderate
for all beaches this afternoon, with strengthening SE/S winds and
building southerly wind waves this afternoon and this evening.
A high rip current risk is likely Friday into Saturday with 5 ft+
southerly wind waves.
Swells from tropical cyclone Franklin will likely build late Monday
into Tuesday, continuing into midweek, increasing likelihood for
high surf and dangerous rip currents.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 3 AM to 6 PM EDT Friday for ANZ331-
332-340-345-350.
Small Craft Advisory from midnight tonight to 6 PM EDT Friday
for ANZ353-355.
&&
$$
SYNOPSIS...JE/NV
NEAR TERM...JE/DS
SHORT TERM...JE
LONG TERM...NV
AVIATION...NV
MARINE...JE/NV
HYDROLOGY...JE/NV
TIDES/COASTAL FLOODING...