Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus61 kokx 170834 
afdokx

Area forecast discussion
National Weather Service New York New York
434 am EDT Tue Sep 17 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/...
surface high pressure will remain centered north of the region
through the day while aloft a trough lingers over the northeast with
a ridge to the west over the Ohio Valley. This will result in a dry
day with plenty of sunshine. Highs will be near normal, in the mid
70s.

There is a moderate risk of rip currents at Atlantic Ocean
beaches today.

&&

Short term /6 PM this evening through 6 PM Wednesday/...
while high pressure will remain in control at the surface, a
combination of onshore flow and a shortwave rounding the base of the
upper trough will lead to increasing clouds overnight, with partly
to mostly cloudy conditions expected through much of the day on
Wednesday. This will result in a potentially tricky temperature
forecast across the eastern half of the area tonight, as initially
clear skies will allow for some radiational cooling before clouds
increase. For now, think the thicker cloud cover will move in late
enough that temperatures will be able to fall off quickly this
evening before remaining nearly steady towards daybreak. This will
result in lows ranging from the mid to upper 40s in typically cooler
outlying locations to around 60 in New York City. Temperatures on
Wednesday will then remain several degrees below normal with a good
deal of cloud cover and persistent northeast flow.

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

&&

Long term /Wednesday night through Monday/...
the long term pattern will be characterized by a pseudo-Omega
block. The tri-state will be on the NE side of eastern US upper
ridging between deep western US troughing and amplifying western
Atlantic troughing. The upper ridge axis will settle over the
eastern US on Saturday and then gradually slide offshore on Sunday
as the western US trough translates east. This trough should help
send a cold front towards the region early next week.

Dry weather is forecast through the weekend. There is quite a bit of
model spread on the amplitude of the upper trough early next week.
This will be important to the degree of moisture and lift along the
potential cold front for precipitation. A slight chance of showers
has been included on Monday.

Lingering moisture trapped beneath a strong subsidence inversion
will diminish Wednesday evening with partly cloudy skies anticipated
by midnight. Canadian high pressure builds over New England
Wednesday night with an autumn feel to the air. Once the clouds
clear, excellent radiational cooling conditions will be present. The
coolest night since Spring is likely as temperatures drop into the
lower 40s inland and Long Island Pine barrens with upper 40s and low
50s most elsewhere. The NYC Metro should fall into the middle 50s.
The high pressure remains over the northeast coast on Thursday with
highs in the upper 60s to lower 70s. Another cool night is expected
Thursday night, but temperatures may be a few degrees higher than
Wednesday night due to some modification of the air mass. The core
of the surface high will shift the south and west Friday, centering
more over the middle Atlantic and southeast. This allows for
continued modification of the air mass with temperatures reaching
near to slightly above normal levels in the middle and upper 70s.
The warming trend will continue into the weekend and possibly next
Monday as the ridge moves over the East Coast/western Atlantic.
Highs should reach the upper 70s to middle 80s, warmest away from
the immediate coast.

Hurricane Humberto will stay well out to sea late this week/early
weekend. The only indirect impacts will be dangerous rip/longshore
currents and rough surf at Atlantic Ocean beaches. Potential exists
for high surf and associated beach erosion issues into early weekend
as well as energetic east/southeast swells arrive. Refer to the National
Hurricane Center for official forecast information on Humberto.

&&

Aviation /09z Tuesday through Saturday/...
high pressure builds in from the north through Tuesday evening.

VFR through the taf period.

Winds increase to around 10 kt Tuesday morning, after 12z, and
become northeast, 020 to 040. Gusts to around 15-17 kt are
likely at kewr, kjfk, and kisp, with more occasional gusts at
klga. Winds and gusts diminish around sunset, 23z Tuesday.

..NY 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: no unscheduled amendments expected.

The afternoon kjfk haze potential forecast is green...which implies
slant range visibility 7sm or greater outside of cloud.

Klga taf comments: no unscheduled amendments expected.

The afternoon klga haze potential forecast is green...which implies
slant range visibility 7sm or greater outside of cloud.

Kewr taf comments: no unscheduled amendments expected.

The afternoon kewr haze potential forecast is green...which implies
slant range visibility 7sm or greater outside of cloud.

Kteb taf comments: no unscheduled amendments expected.

Khpn taf comments: no unscheduled amendments expected.

Kisp taf comments: no unscheduled amendments expected.

Outlook for 00z Wednesday through Saturday...
Tuesday night through Saturday...generally VFR. There is a low
chance for some MVFR stratus Wednesday morning at the coastal
terminals.

&&

Marine...
winds and seas will remain below Small Craft Advisory criteria today. Seas could
approach 5 ft beginning early Wednesday morning in response to long
period swells from distant Hurricane Humberto. In addition, wind
gusts could approach Small Craft Advisory criteria for a period Wednesday afternoon
east of Moriches Inlet as the pressure gradient tightens between
Hurricane Humberto and high pressure building south out of Canada.

Winds Wednesday night through Saturday will generally remain below
sca, but potential for some marginal Small Craft Advisory gusts on the eastern ocean
waters into Thursday morning.

Elevated seas will continue Wednesday night through Saturday with a
combination of long period swells from Humberto and easterly wind
waves. Seas may build to 7 to 9 ft by late week/early weekend as
most energetic swells arrive.

&&

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...none.
New Jersey...none.
Marine...none.

&&

$$
Synopsis...Feb/ds
near term...Feb
short term...Feb

National Weather Service Glossary of Abbreviations