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Area forecast discussion 
National Weather Service New York New York
421 am EDT sun Jul 24 2016

Synopsis...
high pressure builds in from the west today and moves offshore
tonight. A cold front approaches on Monday and moves through the
region Monday night. High pressure returns on Tuesday and moves
offshore Wednesday into Thursday. A slow moving frontal system
approaches the region Friday, possibly affecting the region
through the weekend.

&&

Near term /until 6 PM this evening/...
high pressure builds in from the west today with an airmass that
is not quite as hot as the one on Saturday. Highs will top off in
the low to mid 90s across NYC and NE NJ, and in the upper 80s to
around 90 elsewhere. With dewpoints ranging from 55-60 for most
areas, and into the low 60s near the coasts, heat indices will
range from 90-95.

Light west-northwest winds will give way to afternoon seabreezes. Winds turn
S at 10-15 mph, possibly gusting to 20 miles per hour in NYC.

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

&&

Short term /6 PM this evening through Tuesday/...
high pressure moves offshore this evening. SW flow develops, and
with increasing humidity levels, it will be warm and muggy
tonight with lows in the mid to upper 70s in/around NYC and in the
upper 60s to low 70s elsewhere. With the increase in low level
moisture, can expect patchy fog as well.

The hottest airmass of the seas builds into the region on Monday.
Surface dewpoints will climb into the lower 70s. With highs in the
upper 90s across NYC and most of NE NJ, the heat index will range
from 105-110. An excessive heat watch remains in effect for those
areas. For the lower Hudson Valley, Long Island, and southern CT,
highs will top off in the low to mid 90s, and the heat index will
range from 100-105. A heat advisory has been issued for those
areas.

A cold front approaches during the day Monday. Scattered showers
and thunderstorms will develop over far northwest zones and spread east
during the afternoon and evening. MUCAPE values will range from
2000-3000 j/kg. Inverted-v forecast sounding indicate potential
for gusty and potentially damaging winds. Pwats will be over 2",
and heavy rainfall is possible as well.

Cold front moves offshore late Monday night and showers and
thunderstorms will taper off. High pressure builds in from the
west on Tuesday with slightly cooler and less humid conditions.
Highs will top off in the low to mid 90s in/around NYC and in the
upper 80s to low 90s elsewhere. Dewpoints will be in the low 60s.
Heat indices will be in the low to mid 90s.

&&

Long term /Tuesday night through Saturday/...
models in fairly good agreement with the region lying between a
closed low over northern Ontario/Quebec and heat ridge across the
southern US for mid week. This low will eventually pivot
northeastward on Friday...but be replaced by a trough digging into
the Great Lakes this weekend. The result will be an active upper
flow through the region...with a series of weak shortwaves/vorts
moving through during the period.

At the surface...weak high pressure moves offshore Wed into Thu,
with a slow moving cold front approaching the region from the northwest
Fri. Very warm conditions will continue for the mid to late
week...with high generally about 5 degrees above seasonable...well
into the 80s to lower 90s. As moisture gradually increases and
shortwave energy increases aloft...increasing potential for
diurnal shra/tstm activity away from the coast Thu and moreso Fri.

Uncertainty on how far south this front makes it heading into the
weekend as troughing digs into the Great Lakes. SW upper flow
ahead of the trough will also have potential for a southern
frontal system to track close to the region. Overall low
confidence on sensible weather details for the weekend...but
potentially unsettled with seasonable warm temps and humid
conditions.

&&

Aviation /08z Sunday through Thursday/...
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. Southerly
sea breeze development likely for klga and khpn late this
afternoon. For kewr and kteb westerly gusts into the mid teens
possible this afternoon...impeding any sea breeze development
until late in the day. Winds subside and return to the S/SW this
evening.

Outlook for 06z Monday through Thursday...
late tonight...VFR. Low prob of sparse 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.
Tuesday-Wednesday...VFR.
Thursday...mainly VFR, except MVFR or lower possible in
scattered late day/evening thunderstorms.

&&

Marine...
high pressure builds in from the west today and then moves
offshore tonight. A light west-northwest flow will give way to afternoon sea
breezes, turning winds S 5-10 knots. For ocean waters, S winds will
range from 10-20 knots. Winds diminish tonight. Patchy fog develops
tonight as humidity levels rise.

A cold front approaches on Monday. Scattered showers and
thunderstorms will develop in the afternoon and continue into
Monday night. High pressure returns for Tuesday.

Winds and seas will overall remain below Small Craft Advisory criteria during the
period, and then will continue through Thursday with a weak
pressure gradient as the high builds east.

&&

Hydrology...
no rain is forecast through Monday morning.

There is the potential for 1/4 to 1/2 inch of rainfall, with
locally higher amounts, possibly 1 inch or more, in showers and
thunderstorms Monday and Monday night.

Dry weather returns for Tuesday and Wednesday. There is the
potential for additional showers and thunderstorms, mainly across
the interior and during the afternoons and evenings Thursday and
Friday. This threat may continue into the weekend.

&&

Okx watches/warnings/advisories...
CT...heat advisory from 11 am to 6 PM EDT Monday for ctz005>012.
New York...heat advisory from 11 am to 6 PM EDT Monday for nyz067>071-
078>081-177-179.
Excessive heat watch from Monday morning through Monday
afternoon for nyz072>075-176-178.
New Jersey...heat advisory from 11 am to 6 PM EDT Monday for njz002.
Excessive heat watch from Monday morning through Monday
afternoon for njz004-006-103>108.
Marine...none.

&&

$$
Synopsis...mps/NV
near term...mps
short term...mps
long term...Nevada
aviation...Nevada
marine...mps/NV
hydrology...mps/NV

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