Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus61 kokx 150726 
afdokx

Area forecast discussion
National Weather Service New York New York
326 am EDT sun Sep 15 2019

Synopsis...
a weak cold front moves offshore this morning followed by high
pressure returning through Sunday night. Another weak cold front
moves through late Monday. High pressure then returns thereafter
and remains in control through the end of next week.

&&

Near term /through tonight/...
showers associated with a weak cold front working through the region
are generally confided to eastern Long Island and just offshore
of the Long Island coast. These showers will continue working
south and east of the area through sunrise as the cold front
moves offshore. The flow behind the front is weak, so it may
take a bit longer for drier air to advect into the area this
morning. Patchy fog and lingering clouds may hang on until
better mixing commences after sunrise.

High pressure will settle over the area today. There is not much
change to the air mass behind the front with just a slight
lowering of dew points into the upper 50s and lower 60s. In
fact, it will be a few degrees warmer today compared to Saturday
as temperatures reach the upper 70s to near 80s degrees.

Cyclonic flow aloft and approaching shortwave energy will gradually
increase clouds tonight, especially late for interior locations.
Lows temperatures range from the upper 50s inland to the lower and
middle 60s most elsewhere.

There is a moderate risk of rip current development at the ocean
beaches through this evening.

&&

Short term /Monday through Monday night/...
shortwave energy over southern Ontario and southern Quebec is
progged to dive southward around the periphery of a longwave trough
centered over the Canadian Maritimes on Monday. This shortwave
energy moves into northern New England by Monday afternoon and then
off the New England coast Monday night. The shortwave energy will
aid in sending a weak cold front into the region on Monday, which
quickly passes south by Monday evening. Weak lift and limited
moisture continue to be indicated by the models and this makes sense
given the northwest flow aloft. A slight chance pop for showers remains in
the forecast from the morning inland to the afternoon and evening
near the coast. Highs range from the low 70s inland to the middle
and upper 70s near the coast. If clouds end up thicker or more
widespread ahead of the shortwave energy and front, then highs near
the coast may have to be lowered in subsequent forecasts.

High pressure quickly returns behind the front Monday night.
Northerly flow behind the front dries out any lingering moisture
with skies becoming mostly clear through the night. Lows will range
from around 50 degrees across the interior to the upper 50s and low
60s closer to the coast.

There is a moderate risk of rip current development at the ocean
beaches on Monday.

&&

Long term /Tuesday through Saturday/...
longwave trough over the Canadian Maritimes will be slow to move
east into the North Atlantic Tuesday into Wednesday. However,
heights aloft gradually rise and a ridging aloft and at the surface
is indicated by the deterministic models and ensemble means to
dominate the synoptic pattern through the beginning of next weekend.

Dry weather is expected through the long term. High pressure
centered to the north may promote chances of stratus and drizzle for
coastal sections Wednesday night through Thursday night. The
models are still not indicating this potential. However, will
need to monitor trends to see if this changes in future runs
since the location of the high to our north would promote an
extended period of onshore flow that would enhance these
chances. The onshore flow would also limit the mixing height, so
expecting highs at or slightly below normal through Thursday.
Winds become more offshore for Friday and Saturday, so high
temperatures above normal are expected both days.

&&

Aviation /07z Sunday through Thursday/...
a cold front slowly approaches the region from the west overnight.
The cold front then pushes east of the region on Sunday.

Generally VFR conditions in and around the city terminals to
start with MVFR to IFR at outlying terminals. Ceilings at the
city terminals are expected to lower to MVFR for a period late
tonight, before the entire region improves to VFR within a few
hours of daybreak. The best chance of showers through the
remainder of the overnight period will be at kjfk/kisp/kgon.

Light winds turn more SW as the night progresses, then shift to
west/northwest around daybreak. North/northwest winds in the morning back to the west/SW
in the afternoon, with late day seabreezes likely for coastal
terminals (quicker across CT terminals). Speeds remain 10 kt or
less.

Outlook for 06z Monday through Thursday...
Sunday night...VFR.
Monday...mainly VFR, slight chance for showers.
Tuesday-Thursday...VFR.

&&

Marine...
winds remain rather light today with a weakening pressure gradient
and high pressure returning. Ocean seas hover near 4 initially
but should subside to about 3 ft through the day. Winds and seas
will then remain below Small Craft Advisory levels through Monday.

Offshore flow strengthens a bit Monday night into Tuesday morning
before weakening again Tuesday afternoon. Sustained winds may
approach 15 kt on the ocean during this time, but gusts remain below
25 kt on all waters. Sub-Small Craft Advisory conditions continue through Wednesday,
then winds pick up once again Wednesday night into Thursday with the
pressure gradient tightening. Winds should remain below advisory
criteria during this period, but ocean swells could increase to 5 ft
in association with Humberto and remain elevated through Thursday
night.

&&

Hydrology...
no significant hydrologic impacts are currently anticipated
through the end of the week.

&&

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...jc/ds
near term...ds
short term...ds

National Weather Service Glossary of Abbreviations