Area Forecast Discussion
Issued by NWS Upton, NY
FXUS61 KOKX 311555
Area Forecast Discussion
National Weather Service New York NY
1155 AM EDT WED AUG 31 2016
A cold front slowly approaches from the Eastern Great Lakes today,
pushing through late tonight into early Thursday morning. A large high
pressure system then builds into the region through early next
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Updated to account for some isolated showers across eastern LI/SE
CT. SPC mesoanalysis indicating MU CAPES of 500 to 1000 J/KG
across much of the area with a weak fine line triggering a few
showers across the aforementioned area.
Clouds continue to erode across coastal sections with plenty of
mid level clouds across interior SE NY and southern CT. This
should hold true for much of the day
Precipitation was breaking out well ahead of the front,
approaching northern portions of the Lower Hudson Valley.
Based on this there is a chance of showers/isolated thunderstorms
across the northern and western zones by early late morning/early
A cold front will slowly approach the area today as an upper
level trough digs into the Great Lakes and the Ohio Valley. The
front was moving into the eastern Great lakes region through lower
Michigan. The bulk of the precipitation looks to hold off until
mid afternoon for areas north and west of New York City.
Temperatures today will be a couple of degrees warmer than
yesterday with a continued southerly flow, in the middle to upper
80s. Humidity levels will also be rather high as dew points climb
into the upper 60s. Some isolated areas may even see some lower
70s dew points.
There is a high risk of rip currents at Atlantic Ocean beaches on
today due to continued long period se swells from Gaston.
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
The chance for precipitation will increase tonight as the cold front
continues its approach toward the area. Precipitation will mainly be
in the form of showers, however, a rumble of thunder is not out of
the question, as lifted indices are in the 0 to -2 range, so
continued the slight chance for thunderstorms. The front should move
through late tonight into Thursday morning. Chances for rain will
continue though as the trough axis remains to our west on Thursday.
However, chances for rain will be on the decrease and begin to end
from northwest to southeast as surface high pressure builds in.
Clouds and a wind shift to the north will mean cooler temperatures
for Thursday, upper 70s to lower 80s.
Rainfall amounts should average between a quarter and a third of an
inch, with locally higher amounts in any thunderstorms. Models do
develop an area of low pressure along the front over the Virginias
and move it northeast, near/over our area overnight. 00Z NAM is an
outlier with the strength. It therefore has more in the way of
rainfall. Because it is an outlier, thinking is that the rainfall
amounts are overdone. Even if it the NAM does turn out to be
correct, the heaviest of the rain would fall north and west of
the low, and thus north and west of our area.
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A broad area of low pressure along with a surface cold front will be
exiting the eastern forecast zones Thursday evening as an upper
trough remains over the northeast and into the mid Atlantic region
with an embedded shortwave moving off the northeast coast. With the
slightly slower progression of the upper trough and surface low will
have chance probabilities across southeastern Connecticut and
eastern Long Island.
Friday through Saturday the upper trough moves east while a strong
ridge builds to the west and northwest with another ridge building
into the central and western Atlantic. Late Friday into Saturday the
upper trough will begin to interact with TD9 as the trough moves off
the northeast coast. The eventual track will be dependent on the
interaction with the trough and the ridge building to the west and
the other over the Atlantic. Refer to the National Hurricane center
forecasts and advisories for further details on TD9.
At the surface a large Canadian high builds to the north and a
cooler northeast flow develops behind the cold front. The high
weakens to the north and another high builds over the southeastern
states Sunday into Monday as the strong upper ridge builds into the
mid Atlantic and northeast. With a return flow setting up Monday and
Tuesday will see temperatures and humidity increasing.
The forecast will be dependent of the interaction of the tropical
system`s interaction with the upper trough and uncertainties remain
Saturday into the beginning of next week.
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
A cold front approaches from the northwest today, then crosses the
Mainly VFR through the TAF period, with possible exception of
patchy MVFR conditions with showers/isolated thunderstorms ahead
of/behind a cold front tonight into Thursday morning. Confidence
in timing and placement of any thunderstorms is too low to reflect
Seabreezes this afternoon for all but KSWF. Winds veer to the SW then W
with the front tonight.
...NY Metro Enhanced Aviation Weather Support...
Detailed information, including hourly TAF wind component forecasts,
can be found at: http:/www.weather.gov/zny/n90
KJFK TAF Comments: Gusts to 20 kt possible after 20z.
KLGA TAF Comments: Seabreeze development expected between 19z and
21z. Gusts 15-20 kt possible after 20z.
KEWR TAF Comments: Seabreeze development expected between 20z and
The afternoon KEWR haze potential forecast is GREEN...which implies
slant range visibility 7SM or greater outside of cloud.
KTEB TAF Comments: Sea breeze development possible between 20z and
KHPN TAF Comments: Sea breeze development possible between 20z and
KISP TAF Comments: Sea breeze development expected between 17z and
.Outlook for 12Z Thursday through Sunday...
.Thursday...MVFR or lower possible in showers.
.Thursday night-Friday night...VFR.
.Saturday-Sunday...Most likely VFR. Very low chance of a strong
low passing SE of Long Island brining impacts.
Winds and waves should remain below SCA criteria for the short
term period. A persistent SE swell from distant Hurricane Gaston
will keep seas around 4 ft over the coastal ocean waters through
tonight and 3 to 4 ft on Thursday, with rough conditions likely at
Ocean seas will remain elevated into Thursday due to swells
generated by Gaston.
Thursday night into Friday night winds and seas are expected to
remain below small craft advisory levels as a cold front moves east
of the forecast waters Thursday evening and high pressure builds to
the north. However, lingering long period swells of 2-3 ft from
Gaston are expected to continue into Friday night.
Then the winds and seas forecast become uncertain for the weekend
and into the beginning of next week and will depend on the future
track and intensity of TD9 as it moves from the Gulf of Mexico into
the Atlantic. The forecast does not include any direct wind impacts,
but does include ocean waves building to over SCA criteria Saturday
and continuing through Monday. In addition, depending on the track
of TD9 wind gusts across the ocean waters may be around small craft
levels Saturday and Sunday.
Refer to the National Hurricane center forecasts and advisories for
further details on TD9.
Between a quarter and a third of an inch of rainfall is forecast.
Flooding is not a concern with these amounts.
Dry weather expected from late Thursday night into the beginning of
Moderate to severe drought conditions continue. The next local
drought statement updated is scheduled for September 1st.
NY...High Rip Current Risk until 8 PM EDT this evening for NYZ075-