Scientific Forecaster Discussion
fxus61 kokx 221337
Area forecast discussion
National Weather Service New York New York
937 am EDT Fri Sep 22 2017
Post tropical cyclone Jose will meander and weaken to
the southeast of Long Island through Saturday, as high pressure
slowly builds in from the west. The high continues to build into
the area for the rest of the weekend, then remains over the area
through much of next week as Hurricane Maria tracks well offshore
of the East Coast. A cold front passes through the region
Thursday. Please refer to National Hurricane Center products for
more details on Jose and Maria.
Near term /until 6 PM this evening/...
updated forecast to account for mostly clear skies across the
area this morning. Clouds though should work in from the east
across Li and southern CT as the day progresses.
Could see some lingering showers over far eastern zones,
otherwise it will be dry. It will be mostly sunny/partly cloudy
west and partly to mostly cloudy east. All this in response to
Jose as it slowly weakens to the southeast of Long Island.
850 temperatures are rather warm for this time of year, 15-16c,
however, low level mixing is limited to 975-925 hpa, so highs
will only be from the mid 70s to around 80. It will be a few
degrees cooler over far eastern zones, where cloud cover will
limit temperatures to upper 60s to lower 70s.
Long period swells from Jose will continue to produce dangerous
rip currents and pounding surf at Atlantic beaches into this
Short term /6 PM this evening through 6 PM Saturday/...
Post tropical cyclone Jose continues to slowly weaken tonight
and Saturday to the southeast of Long Island. Any lingering
showers over far eastern Long Island should come to an end this
evening. Cloud cover will gradually decrease from west to east through
Lows tonight will be around 10 degrees above normal. With less
cloud cover, should mix uniformly to around 925 hpa. As a
result, it should be about 5-10 degrees warmer on Saturday than
today, with highs mainly from around 80 to mid 80s, except upper
80s in NYC and urban NE New Jersey.
Swells form Jose should continue to produce a high risk of rip
currents on Saturday.
Long term /Saturday night through Thursday/...
a anomalous upper air pattern will feature a longwave trough over
the western states, and a highly amplified ridge across the east.
Hurricane Maria will track slowly north then northeast through the
weak in a weakness in the ridge provided by Post-tropical cyclone
Jose. The latter of which remains nearly stationary through the
weekend before working slow east early next week. Refer to the
latest advisories from the National Hurricane Center for forecast
information on Jose and Maria.
Warm heights aloft and subsidence will result in an unseasonably
warm week with mainly dry conditions. The warmest days look to be
Sunday and Monday with readings in the 80s for most locations. There
is a low chance of showers for the mid week period as moisture works
in ahead of Maria and the upper ridge begins to break down with the
approach of an upper trough over the upper Midwest and Great Lakes.
Due to long period swells from both Jose and Maria, there will be a
prolonged period of rough surf at the ocean beaches.
Aviation /14z 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.
Gusts today between 20-30 kt, with the highest across the
eastern terminals. Gusts diminish after 00z.
New York Metro enhanced aviation weather support...
Detailed information, including hourly taf wind component forecasts,
can be found at: http:/www.Weather.Gov/zny/n90
Kjfk taf comments: occasional wind gusts may be higher than
The afternoon kjfk haze potential forecast is yellow...which implies
slant range visibility 4-6sm outside of cloud.
Klga taf comments: occasional wind gusts may be higher than
The afternoon klga haze potential forecast is yellow...which implies
slant range visibility 4-6sm outside of cloud.
Kewr taf comments: occasional wind gusts may be higher than
The afternoon kewr haze potential forecast is green...which implies
slant range visibility 7sm or greater outside of cloud.
Kteb taf comments: occasional wind gusts may be higher than
Khpn taf comments: occasional wind gusts may be higher than
Kisp taf comments: occasional wind gusts may be higher than
Outlook for 12z Saturday through Tuesday...
Friday night...VFR. Gusts gradually subsiding.
Saturday-Tuesday...VFR. Wind becoming north-NE 10-20 kt. A few
higher gusts possible.
a combination of winds gusting to 25 to 30 knots (occasionally 35
kt over the coastal ocean waters east of Moriches inlet) and
swells from Jose will produce small craft conditions over all
waters except NY Harbor and west Long Island Sound today. Gusts
should subside to below 25 knots on the South Shore bays, by this
evening, so limit the Small Craft Advisory there to just today. Sub-Small Craft Advisory
conditions are expected on west Long Island Sound and New York Harbor
today, with gusts to around 20 kt.
Gusts to small craft levels continue on the coastal ocean waters
(with still some spotty gusts to around gale force possible east
of Moriches inlet) and on the eastern sound and bays of Long
Island tonight, so have continued the Small Craft Advisory there. Sub-small craft
conditions should exist to tonight on New York Harbor,W Long Island
Sound and the South Shore bays and remain so on Saturday.
On Saturday, while the winds should diminish below Small Craft Advisory levels on
all waters by afternoon, seas on the coastal ocean waters will
remain above Small Craft Advisory levels through the day. As a result, have
extended the Small Craft Advisory for east Long Island Sound and the eastern bays
through midday Saturday and on the coastal ocean waters through
the day on Saturday.
Small craft level seas should linger through Saturday night on
the coastal ocean waters, but winds on all waters should be
around 10 kt or less Saturday night.
A weak flow Sunday into Monday will give way to strengthening NE
winds during the mid week period as the pressure gradient tightens
between Hurricane Maria and high pressure over the area. Winds
though look to remain below Small Craft Advisory. Seas will gradually build through
the period due to long period swells from Maria with small craft seas
expected through the mid week.
little if any precipitation is expected through the middle of
next week, as a result no significant hydrologic impacts are
forecast through then.
Post tropical cyclone 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
This will have water levels peaking with the Friday morning
high tide cycle, resulting in widespread minor coastal flooding
in the South Shore bays from Brooklyn through southwestern
Suffolk County, so have a coastal flood advisory in effect
there. Water levels also could come close to reaching minor
coastal flood benchmarks for Hudson County and Staten Island
during todays high tide so have a coastal flood statement for
Water levels should gradually drop Friday night into the
weekend. Historically, guidance is to fast to bring down water
levels in the Back Shore bays when there is a persistent
onshore long period swell, so have continued the coastal flood
advisory from Brooklyn through southwest Suffolk County through
tonights high tide. There is some potential that there could be
some very , localized minor flooding at the most vulnerable
South Shore Bay locales Saturday morning. This threat can be
addressed with a coastal flood statement if it looks like this
threat will be realized.
Rough surf will also continue into the weekend, but dune
erosion from this point on should be localized.
New York...high rip current risk until 7 PM EDT this evening for nyz075-
Coastal flood advisory until 4 am EDT Saturday for nyz075-080-
Marine...Small Craft Advisory until noon EDT Saturday for anz330-340.
Small Craft Advisory until 6 PM EDT Saturday for anz350-353-
Small Craft Advisory until 6 PM EDT this evening for anz345.