Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus61 kokx 180819 
afdokx

Area forecast discussion
National Weather Service New York New York
419 am EDT Wed Sep 18 2019

Synopsis...
high pressure will dominate the weather pattern through the
weekend. A cold front may cross the region early next week.

&&

Near term /until 6 PM this evening/...
Canadian high pressure builds over New England today. NE flow
around the high has been advecting low level moisture from the
Atlantic towards the area. There is also shortwave energy diving
south around an upper trough over the western Atlantic. The
main challenge for today will be the degree of cloud cover. The
low level moisture likely gets trapped beneath a subsidence
inversion around 4-5 kft, especially across portions of Long
Island and southeast Connecticut. Scattered-broken stratocu
develops/spreads southwestward in the morning and could persist
through around 18z. Hrrr and rap forecast soundings indicate
the moisture diminishes in the afternoon, but the GFS and NAM
are a bit slower with this idea. The shortwave energy shifts
south late in the day. This should help clear any of the
remaining scattered-broken clouds with mostly clear conditions by early
evening.

High temperatures today will be a few degrees below normal in the
upper 60s to lower 70s.

There is a high risk of rip currents at Atlantic Ocean beaches due
to long period swells from distant Hurricane Humberto.

&&

Short term /6 PM this evening through 6 PM Thursday/...
skies will continue to clear tonight as the high pressure slowly
builds over the tri-state. A weak pressure gradient remains in
place near the coast, so winds may not fully decouple here.
Otherwise, good radiational cooling conditions are forecast
resulting in temperatures dropping into the lower to middle 40s.
The rest of the area will see lows in the upper 40s and lower
50s.

Ridging continues to build aloft on Thursday as western Atlantic
troughing continues to amplify. Surface high pressure will lie over
the region with mostly clear skies and temperatures in the upper 60s
to lower 70s.

There is a high risk of rip currents at Atlantic Ocean beaches
on Thursday due to long period swells from distant Hurricane
Humberto.

&&

Long term /Thursday night through Tuesday/...
large upper level ridge across the eastern US will keep the extended
period dry through the weekend. High pressure at the surface will
result in plenty of sunshine, light winds and warmer than normal
temperatures.

With a dry airmass in place, and light winds overnight lows
Thursday into Friday morning will drop into the 40s for the
interior and in The Pine Barrens of Long Island with coastal
locations remaining in the 50s. With better mixing in place on
Friday, highs will rise into the 70s to near 80.

High pressure will slowly slide off the southeast coast on Saturday,
allowing winds to turn more southwesterly. This will allow for
temperatures rise higher through the weekend. These highs will be 10-
12 degrees above normal for this time of the year.

Hurricane Humberto is forecast to slowly continue tracking northeast
through the weekend. Indirect impacts will include dangerous rip
currents and rough surf at Atlantic Ocean beaches. There is
potential for high surf of 5 to 8 feet Thursday night into
Friday as swells arrive. Refer to the National Hurricane Center
for official forecast information on Humberto. Conditions at the
beaches should improve by late Saturday.

The next chance of precipitation will be on Monday and Monday night
associated with an approaching cold front. High pressure will follow
behind the frontal passage for Tuesday.

&&

Aviation /08z Wednesday through Sunday/...
VFR through the taf period as high pressure continues to build
in from the north today and hurricane huberto tracks well
offshore over the western Atlantic. This will keep the area
under a prolonged period of north to northeast flow.

Winds will generally be NE through the forecast period. Wind
speeds will be under 10 kt overnight, then the NE flow
increases to 10 to 15 kt this morning, closer to 15 kt along
the coast. Gusts 15 to 20 kt develop this morning with
occasional higher gusts possible, especially this afternoon.

..NY Metro enhanced aviation weather support...

Detailed information, including hourly taf wind component fcsts,
can be found at:
http://www.Weather.Gov/zny/n90

Kjfk taf comments: no unscheduled amendments expected.

The afternoon kjfk haze potential forecast is green, which implies
slant range visibility p6sm outside of cloud.

Klga taf comments: no unscheduled amendments expected.

The afternoon klga haze potential forecast is green, which implies
slant range visibility p6sm outside of cloud.

Kewr taf comments: no unscheduled amendments expected.

The afternoon kewr haze potential forecast is green, which implies
slant range visibility p6sm outside of cloud.

Kteb taf comments: no unscheduled amendments expected.

Khpn taf comments: no unscheduled amendments.

Kisp taf comments: no unscheduled amendments expected.

Outlook for 06z Thursday through Sunday...
Wednesday night through Sunday...VFR.

&&

Marine...
Small Craft Advisory on the ocean waters through Thursday night.

Seas will continue to build today to 5-7 ft and these seas should
continue into at least Thursday night in response to long period
swells from distant Hurricane Humberto. In addition, wind gusts
could be around 25 kt this afternoon and evening offshore on the
ocean waters. Otherwise, winds will fall below Small Craft Advisory levels into
Thursday night.

Winds will remain below Small Craft Advisory levels through Sunday. Rough seas will
continue into Friday, and possibly Saturday as long period
swells continue from Hurricane Humberto. Seas gradually subside
below Small Craft Advisory Saturday into Saturday night.

&&

Hydrology...
no significant hydrologic impacts through the weekend.

&&

Equipment...
NYC National oceanic and atmospheric administration weather radio station kwo35 (162.55 mhz) remains off
the air.

&&

Okx watches/warnings/advisories...
CT...none.
New York...high rip current risk through Friday evening for nyz075-080-
081-178-179.
New Jersey...none.
Marine...Small Craft Advisory until 6 am EDT Friday for anz350-353-355.

&&

$$
Synopsis...cb/ds
near term...ds
short term...ds
long term...cumulonimbus

National Weather Service Glossary of Abbreviations