Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 240517

Area Forecast Discussion
National Weather Service New York NY
117 AM EDT SUN JUL 24 2016

A weak cold front has moved across and this will be followed by
high pressure going into Sunday. A warm front will move through
Monday morning. A weak cold front approaches the area Monday and
crosses Monday night. High pressure returns for Tuesday and
Wednesday. A series of waves of low pressure pass through the
region Thursday and Friday, with a cold front passing through
Friday night.


The cold front has moved across much of the region. It will pass
through the ocean marine zones over the next 1-2 hours. Flow is
switching to a more northerly flow and will become lighter with
the decrease in pressure gradient overnight. This will advect in
a relatively drier airmass into the region. Temperatures and
dewpoints were adjusted to better match observed trends.

Skies will clear out overnight. Min temperatures range from the
lower 60s across interior rural areas to upper 70s for much of


Behind the cold front, day time high temperatures are forecast
around 6 to 8 degrees cooler than highs Saturday. With dew point
temperatures forecast mainly 55-60 degrees, heat index values are
forecast to remain below 95 degrees. Therefore, a heat advisory
will not be issued for Sunday.

Morning light NW winds will be replaced with afternoon sea breezes,
the strongest in the NY bight with S winds 10-15 kt aft 19z/3 pm.

For Sunday night, as high pressure moves offshore, a warm front will
approach from the SW. Low lvl warm air advection will cause an
increase in clouds along with some patchy fog in suburban and rural

There is a moderate risk for rip currents along the Atlantic
Ocean beaches for Sunday.


By the start of the extended period an upper ridge will be moving
off the northeast coast as a shortwave moves through the nearly
zonal flow, passing through the Great Lakes Monday into Monday
night. An associated weak surface low moves through the Great Lakes
with a cold front passing through Monday night. Temperatures and
dewpoints will be increasing Monday as the region comes under the
influence of a hot and humid airmass as a warm front passes Monday
morning. With the shortwave passing showers and thunderstorms will
be possible early Monday. The area destabilizes and by the afternoon
CAPE increases to around 1000 J/KG and lifted indices will be around
-3. There is a potential for heavy rain and gusty winds with the
convection Monday afternoon and will include in the forecast.
Depending on timing and the possibility of earlier convection
destabilization may become limited.
Regardless, with the hot and humid conditions, heat indices will be
near 105 by the afternoon for most of northeastern New Jersey and
into NYC. So an excessive heat watch has been posted.

Tuesday and Wednesday will remain warm however drier air moves in
behind the cold front. With the shortwave not very deep and passing
to the north, the cold front does not moves too far south and
becomes nearly stationary south of Long Island. Waves of low
pressure are forecast to move along this boundary Thursday and
Friday with a back door cold front pushing through as high pressure
builds to the north. Timing if the backdoor cold front is uncertain
and may not moves through until Saturday. However, at this time will
have Saturday dry.


High pressure builds into the area today and offshore tonight.
VFR expected through the TAF period.

Light northerly winds back to a more westerly direction by late
morning. Sea breezes develop in the afternoon for coastal
terminals...possibly to 15 kt at KJFK in the late aft. Seabreeze
development likely for KLGA and KHPN late afternoon. For KEWR,
KTEB deep mixing may allow for westerly gusts into the mid teens
this afternoon...with late day sea breeze development possible.

Winds subside and return to the s/sw this evening.

.Late Sunday Night...VFR. Low prob of spare shra/tsra coverage.
Mvfr br possible towards daybreak for outlying terminals.
.Monday-Monday Night...Mainly VFR, except MVFR or lower possible
in scattered late day/evening thunderstorms.
.Thursday...Mainly VFR, except MVFR or lower possible in
scattered late day/evening thunderstorms.


Winds and seas will further lower overnight as high pressure
begins to build in from the north and west.

Wind speeds and sea heights are forecast to remain below Small
Craft Advisory levels through Sunday night.

Afternoon sea breezes likely on Sunday, and have to monitor
potential for locally strong onshore flow from Sandy Hook to Fire
Island Inlet Sunday afternoon.

With a weak pressure gradient force across the forecast waters
Monday through Thursday, winds and seas are expected to remain below
small craft advisory levels. A cold front is forecast to pass
through the waters Monday night with thunderstorms possible.
The front will remain south of the waters with waves of low pressure
moving along the front Thursday into Friday. A backdoor front moves
through Friday night.


No rain is forecast through Sunday night.

There is the potential for 1/4 to 1/2 inch of rainfall, with locally
up to one inch, in showers and thunderstorms Monday and Monday night.

Dry weather returns for Tuesday and Wednesday. Then there is the
potential for additional showers and thunderstorms, mainly during
the afternoons and evenings Thursday and Friday.


NY...Excessive Heat Watch from Monday morning through Monday
     afternoon for NYZ072>075-176-178.
NJ...Excessive Heat Watch from Monday morning through Monday
     afternoon for NJZ004-006-103>108.


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