Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 131556

Area Forecast Discussion
National Weather Service New York NY
1156 AM EDT Sun Aug 13 2017

High pressure builds in today and shifts offshore on Monday. Weak
low pressure passes to the south Monday night. A cold front then
approaches from the north Tuesday before sliding to the south
Tuesday night. Weak high pressure will then be in place for
Wednesday. A series of fronts may impact the late week period.


Major update to reflect new information reported from local
beaches. Southerly swells of around 9 seconds and 3-5 ft surf is
resulting in strong rip current activity across the Nassau and
Suffolk County beaches. The SRF and coastal hazard messages have
been updated to reflect the high risk of rip currents for the
ocean beaches. There is still moderate potential for rip
currents at the city beaches as well.

Surface high pressure builds in today and the flow aloft
becomes more zonal. Mostly sunny, and with forecast 850mb temps
around 14C plus a downslope flow for most spots, went closer to
the warmest guidance for high temperatures.


High pressure center shifts towards the forecast area tonight with
mostly clear conditions and light to calm winds. This setup will
allow for good radiational cooling away from the city. Lows in some
of the outlying suburbs will be in the mid to upper 50s.

High pressure shifts offshore for Monday and it looks like another
mostly sunny day. Winds will become onshore, but on the light side.
This will probably result in slightly cooler highs for some coastal
spots as compared to today, but inland spots should reach or
slightly exceed today`s highs with 850mb temps at 14-15C.

A weak low pressure wave then passes us to the south Monday night.
The rain shield should be too far south of us, so will continue with
a dry forecast through the night.


A shortwave approaches the Northeast on Tuesday, and this will help
push a weak cold front towards us. The front could reach the Lower
Hudson Valley by day`s end, and this is where the best overall lift
will be. Will therefore go with isolated afternoon and early evening
showers/TSTMs here. The rest of the tri state area should remain
dry. With 850mb temps 15-16C, highs 85-90 for most spots. A
relatively weak northern stream ridge builds into the area Tuesday
night-Wednesday night, so it should be dry then.

Zonal flow then sets up over the area Thursday-Saturday, with the
models differing on the timing of shortwave troughs and ridges
embedded in the flow. The result should be a period of unsettled
weather, that will probably end up more dry than wet for most
people, depending on exactly where a surface frontal boundary ends
up stalling out relative to the region. For now bring in slight
chance pops to mainly western areas late Thursday, then chance pops
throughout Thursday night-Saturday.


High pressure builds in through tonight and offshore Monday. VFR
conditions are forecast, although before 18Z, there is a low
chance of occasional broken MVFR cigs N/W of city terminals.

The NW flow 5-10 kt will continue into this evening and drop in
speed before veering N late then SE after 12Z Mon.

There is a low potential that a sea breeze develops today along
the immediate south coasts. This would bring winds at KJFK to
180 around 17-19Z.

.Tuesday...VFR. Low and sparse potential for showers and tstms NW of
NY/NJ metro in the afternoon.
.Tuesday night-Thursday...VFR.


Seas will build to around 5 ft on the ern ocean today. The sca has
therefore been continued. Elsewhere, winds and seas will remain blw
sca lvls, so the advy was cancelled for anz355. Seas will subside
overnight, then winds and seas will remain blw sca lvls on all
waters Mon-Fri.


No hydrologic impacts are expected through Saturday.


NY...High Rip Current Risk until 8 PM EDT this evening for NYZ080-
MARINE...Small Craft Advisory for hazardous seas until 2 AM EDT Monday
     for ANZ350-353.


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