Area Forecast Discussion
Issued by NWS Upton, NY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KOKX 250240
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1040 PM EDT Mon Jul 24 2017

.SYNOPSIS...
High pressure builds north of the area this evening, while
another frontal wave passes just south of Long Island late
tonight into Tuesday. High pressure then builds into the area
Tuesday night into Wednesday before moving offshore Wednesday
night ahead of a cold front to the west. The cold front will
slowly approach the area through late week before passing to the
east on Friday. Brief high pressure builds across the area
again before a surface low passes to the south early next week.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Forecast generally on track, with only minor adjustments to
reflect latest observations.

Otherwise, Conditions have dried out across the area as low
pressure passes to the south and east of southern New England.
In its wake, high pressure builds across New England with
Northeasterly winds.

An approaching upper trough over the Great Lakes tonight aids
the development of a frontal wave near the Delmarva that passes
just south of LI. Based on latest guidance, it appears the low
will pass far enough south to spare the region anything more
than showers, with the best chance for measurable rain across
LI.

Overnight lows will range from the mid 50s inland, to the lower
60s at the coast. This about 5 to 10 degrees below normal.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Low pressure passes to the south and east in the morning with
lingering showers possible into the afternoon as the upper
trough moves across the area. A continued N/NE flow will result
in mostly cloudy conditions with temperatures in the 60s to
lower 70s. This is well below normal by about 10-15 degrees.

There could be some late day clearing with subsidence on the
backside of the upper trough and high pressure building in from
the west. High temperatures could be warmer than forecast
across wester sections if this clearing happens earlier in the
day.

Another unseasonably cool night is on tap for Tuesday night with
continued clearing.

There remains a high risk of rip currents at ocean beaches
through Tuesday.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Initially zonal flow will give way to a blocking pattern as high
pressure builds across the western US and the western Atlantic,
placing the Northeast in an unsettled pattern dominated by multiple
low pressure systems. Wednesday will be one of the quieter days in
the extended as high pressure builds across the area, eventually
moving offshore overnight. Given the prolonged period of
northeasterly flow, there is a low chance of some morning clouds and
drizzle, although lower dew points suggest anything ongoing will
likely dissipate quickly. Temperatures will be a few degrees below
normal. By Thursday, the area returns to a more southerly flow ahead
of a slow moving cold front, with a chance of afternoon showers and
thunderstorms, especially to the north and west of the NYC metro.
High temperatures will still be a few degrees cooler than
climatological normals, though there will be a marked increase in
humidity amidst moist advection which in turn will lead to low
temperatures closer to normal. By Thursday night into Friday, the
front will slowly move through the area bringing the greatest
possibility of showers and thunderstorms to the area before drying
out as high pressure builds eastward on Saturday into early next
week. There is a little bit more uncertainty towards the weekend
depending on the placement of a coastal low, which is currently
forecast to pass well to the south but subsequent forecasts will
need to be monitored.

&&

.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
A stationary frontal boundary across southern New Jersey to well
south of Long Island will move south as a cold front overnight
as low pressure moves along the boundary. High pressure begins
to build to the north during Tuesday.

Ceilings will be MVFR, 1500 to 2500 feet, overnight through
Tuesday morning, then gradually improve to VFR. There will be
local areas where ceilings lower to IFR outside of the NYC metro
terminals. Also, areas of MVFR fog are possible late tonight at
the outlying terminals.

Winds will be generally NE to near E, anywhere from 030 to 080
true, 10 kts or less.

.OUTLOOK FOR 00Z WEDNESDAY THROUGH SATURDAY...
.Tuesday night-Wednesday...VFR.
.Thursday-Friday night...MVFR to locally IFR with a chance of showers
and isolated thunderstorms.
.Saturday...VFR.

&&

.MARINE...
Another wave of low pressure then passes off the Delmarva late
tonight into Tuesday. This will keep a NE flow over the waters
with seas slow to come down. SCA conditions are likely to linger
on the ocean through at least Tuesday, primarily for seas.

Easterly flow continues into Wednesday before gradually diminishing
as high pressure builds across the area. Southerly flow will briefly
allow seas to build ahead of a cold front that will pass through the
area Thursday night into Friday, though seas should remain below SCA
levels. High pressure builds again through early next week which
will keep winds and seas low.

&&

.HYDROLOGY...
Light rainfall overnight, mainly along the coast, is not
forecast to pose any hydrologic issues.

Additional rainfall is possible Thursday through Friday night.
Hydrologic impacts are not expected at this time.

&&

.TIDES/COASTAL FLOODING...
With the new moon that occurred early yesterday morning and the
current easterly flow, tides are running astronomically high.
Tidal departures of 1/2 to 1 ft departures are needed tonight.

A coastal flood advisory has been issued for the south shore
back bays of Nassau and Queens for tonight with statements
across the NY Harbor and Western LI Sound for more localized
flooding.

Thereafter, any minor coastal flooding is forecast to be
localized into Tuesday.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...High Rip Current Risk through Tuesday evening for NYZ075-080-
     081-178-179.
     Coastal Flood Advisory until 11 PM EDT this evening for NYZ178-
     179.
NJ...None.
MARINE...Small Craft Advisory until 6 PM EDT Tuesday for ANZ350-353-355.

&&

$$
SYNOPSIS...MD/DW
NEAR TERM...BC/DW
SHORT TERM...DW
LONG TERM...MD
AVIATION...MET
MARINE...BC/MD/DW
HYDROLOGY...MD/DW
TIDES/COASTAL FLOODING...



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.