Scientific Forecaster Discussion
fxus61 kokx 220544
Area forecast discussion
National Weather Service New York New York
144 am EDT Fri Sep 22 2017
Tropical Storm Jose will remain nearly stationary southeast of
Long Island for the next several days, become Post-tropical on
Friday if not sooner, then dissipate this weekend. High pressure
build late Friday into Saturday then remains over the region
into early next week. Hurricane Maria is expected to pass
offshore of the East Coast and the move farther offshore mid to
late next week as a cold front approaches. The cold front moves
through late Wednesday night into Thursday morning. High
pressure builds in behind the front Thursday. Please refer to
National Hurricane Center products for more details on Jose and
Near term /until 6 am this morning/...
forecast is generally on track. Pcpn moving in from the east
slightly faster so have adjusted timing of increasing pops a
Otherwise...ts Jose will remain stationary well southeast of eastern
Long Island. The tightest pressure gradient between Jose and the
building high will reside across the Twin Forks of Long Island
and southeast Connecticut tonight, where wind gusts 25-30 mph
are still possible tonight. Mid deck shield progressing
westward across Li and CT, with a few bands of showers moving
through southeast CT and eastern Long Island periodically overnight.
Areas from NYC and north/west should remain dry.
Lows tonight will range from the lower/mid 60s along the coast
and in NYC Metro, to 55-60 inland.
Short term /6 am this morning through 6 PM Saturday/...
with better daytime mixing winds out east should be a little
stronger, with gusts 30-35 mph through much of the day.
Otherwise sct-numerous morning showers over Long Island and
southern CT should diminish in coverage through the afternoon.
High temps on Fri should be a little lower than those of today,
ranging from the lower/mid 70s across most of CT/Long Island,
to the lower 80s in NYC/NE New Jersey.
Skies should gradually clear from west to east Fri night,
becoming mostly clear form NYC north/west and ptcldy over
western Long Island/CT, but remaining overcast out east. Lows
Fri night should have similar range to those expected for
tonight, from the mid 50s to mid 60s.
Dangerous rip currents will continue at the ocean beaches on
Long term /Saturday night through Thursday/...
weakening Post-tropical Jose lingers about 200-300 miles
offshore of Montauk Saturday and becomes a remnant low Sunday,
then dissipates. As Jose is expected to drift slightly westward
a few showers may brush the far eastern areas, mainly
southeastern Connecticut and the Twin Forks of Long Island,
Saturday morning. Meanwhile an upper ridge and surface high will
be building into the northeast Saturday and remain across the
region into early next week.
The upper ridge and surface high weaken Tuesday into Wednesday
as a northern stream long wave trough digs into Great Lakes and
northern plains into Thursday. Meanwhile Maria will be moving
offshore of the East Coast. There are timing difference with the
timing of a cold front expected to move through Wednesday night
into early Thursday at this time. The upper trough and surface
cold front is expected to move Maria farther offshore mid to
late next week. Please refer to National Hurricane Center
products for more details on Maria. Once again there will be
increasing beach hazards with building surf and the possibility
of dangerous rip currents in advance of Maria. There is also
uncertainty with how much precipitation will accompany both
Maria and the cold front. At this time will be keeping
probabilities at slight chance to low end chance.
Aviation /06z Friday through Tuesday/...
Tropical Storm Jose will meander off the southern New England
Generally VFR. Kgon may see a periods of MVFR through the taf
period, especially in areas of showers.
Occasional gusts to 20 kt this morning, possibly 30 kt at kgon.
Gusts increase and become more widespread after sunrise. Expect
gusts between 20-30 kt, with the highest across the eastern
Outlook for 06z Saturday through Tuesday...
Friday night...VFR. Gusts gradually subsiding.
Saturday-Tuesday...VFR. Wind becoming north-NE 10-20 kt. A few
higher gusts possible.
Small Craft Advisory conds will continue for the ocean and the eastern waters late
tonight into Fri morning as winds increase, continuing all day
Fri. This should also bring Small Craft Advisory conditions for the South Shore
bays. Most places will gusts to 25-30 kt, but think a small
portion of the easternmost ocean zone southeast of Montauk could see a
brief period of minimal tropical storm conditions or close to it
Fri morning. In collaboration with NHC and box decided to stick
with Small Craft Advisory for the zone but mention the window for stronger
Long period easterly swells will likely continue on the ocean
waters into the weekend.
Saturday winds across the eastern ocean waters may be around small
craft as gusty winds from weakening Jose impact there area. There is
uncertainty as to the strength and westward extent of the gusty
winds. Then winds will be below small craft levels through the
middle of next week. Across the remainder of the waters winds and
gusts remain below small craft levels. Rough seas and swells will be
affecting the ocean waters with small craft seas expected Saturday
no hydrologic problems anticipated through the middle of next
ts Jose will remain nearly stationary a couple hundred miles southeast
of eastern Long Island, with ekman forcing keeping elevated
water levels along the coast despite offshore winds.
This will have water levels peaking with the Friday morning
high tide cycle, resulting in widespread minor coastal flooding
in the South Shore bays of western Li and NYC and localized
minor elsewhere. There is a low probability of localized
moderate coastal flooding along the South Shore back bays of
Long Island Fri am.
Water levels should gradually drop Friday night into the
weekend, with any minor flooding localized to the most
vulnerable South Shore Bay locales Friday night.
Rough surf will also continue into the weekend, but dune
erosion from this point on should be localized.
New York...high rip current risk through this evening for nyz075-080-081-
Coastal flood advisory from 9 am this morning to 1 PM EDT
Saturday for nyz075-080-178-179.
Marine...Small Craft Advisory until 6 am EDT Saturday for anz330-340-
Small Craft Advisory from 6 am this morning to 6 PM EDT this
evening for anz345.