Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
358 am EDT Thursday Aug 21 2014
high pressure remains centered to the north and east of the area
through tonight. Meanwhile...waves of low pressure aloft move
across the region Tod day and tonight. An upper level disturbance
will track through the area on Friday as high pressure builds down
from eastern Canada. The high will continue to build southward
into the region on Saturday...and remain anchored over the area
through the beginning of next week.
Near term /until 6 PM this evening/...
showers will continue to move through the area this morning in
response to an upper level trough that will slowly move toward the
region while at the surface...high pressure remains centered to
the northeast of the area. Brief moderate to heavy rain can be
expected with some of these showers. Bulk of the activity will
remain over NE New Jersey...lower Hudson Valley and into NYC. These areas
may also see an isolated thunderstorm as mucap across these
locations will be highest...a few hundred to just over 1000 j/kg.
With a lack of a significant lifting mechanism...not looking for
anything strong or severe.
Cloud cover will help to keep temperatures slightly below normal
for the most part. Generally highs will be in the upper 70s to
Short term /6 PM this evening through 6 PM Friday/...
the chance for showers continues tonight as the closed upper low
associated with the trough moves into New England and a shortwave
moves around its base. With the loss of daytime
heating...the chance for thunderstorms decreases...and thus just
plain showers are in the forecast. Southwesterly flow off the
ocean early tonight will allow for a moist airmass. Dewpoints
will rise into the middle 60s. Winds shift more to the northeast
late tonight...and dewpoints will come back down to the lower 60s
by daybreak Friday. This northeasterly flow will then mean an even
cooler day on Friday as compared to Thursday...with highs
generally in the lower to middle 70s. Some upper 70s for the NYC
High pressure from the northeast will nose into the area
Friday...allowing the chances for showers to end from east to
west on Friday.
Long term /Friday night through Wednesday/...
solid model consensus through Tuesday. Hipres builds into the area then
strengthens as the upper ridge translates eastward. On Wednesday...the European model (ecmwf)
brings a cold front close...but the GFS keeps the feature off the local
map. Have sided with the slower GFS solution as this fits a fast model
bias at this time range.
A maritime polar airmass is locked in Friday night into the first part of
Sat. Virtually no lift in the moist layer...so have only forecast
sprinkles. The clouds begin to clear in the afternoon from NE to SW as
strong subsidence kicks in.
Dry with light winds sun-Wednesday courtesy of the high. Some cirrus at
Temperatures blw normal Sat...then a gradual warming trend takes place
sun-Tuesday as heights increase.
Aviation /07z Thursday through Monday/...
weak high pressure remains over the area.
With the exception of possible IFR conditions in fog at
kgon...generally expect VFR conditions through the morning and
afternoon hours. There will be isolated to scattered showers...and
any shower could reduce ceilings or visibilities to MVFR briefly. Best
chance for showers across NYC metropolitan and north and west.
Possible higher coverage of showers tonight as an upper level
disturbance moves through. Best chance NYC metropolitan and north and west.
Light winds become southeast or south 5 to 10 kts during the daytime.
..NY metropolitan enhanced aviation weather support...
Detailed information...including hourly taf wind component forecasts can
be found at: http://www.Erh.NOAA.Gov/zny/n90 (lower case)
Kjfk fcster comments: light and variable winds will become southeast
later this morning.
Klga fcster comments: a light east to northeast wind is expected to
become southeast before noon. Timing could be off an hour or two.
Kewr fcster comments: light winds become southeast late this
morning...just to the right of 130 magnetic.
The afternoon kewr haze potential forecast is green...which implies
slant range visibility 7sm or greater outside of cloud.
Kteb fcster comments: no unscheduled amendments expected.
Khpn fcster comments: no unscheduled amendments expected.
Kisp fcster comments: no unscheduled amendments expected.
Outlook for 06z Friday through Monday...
tonight...VFR...although MVFR ceilings/visibilities are possible in scattered
there will be a chance for showers today as an upper level
disturbance moves toward the area. An isolated thunderstorm is
possible across the western sound and Harbor. Winds and seas
should remain below Small Craft Advisory criteria...but may approach Small Craft Advisory criteria
briefly in any thunderstorm. The chances for showers continue into
tonight and Friday...with chances diminishing throughout the day
Friday. Winds and waves continue to remain below Small Craft Advisory for tonight
Winds will approach Small Craft Advisory levels Friday night...then diminish during the day
on Sat. Seas on the ocean will build to around 4 feet late Friday
night...then linger through most of Sat before subsiding. A Small Craft Advisory may be
needed especially on the ocean Friday night and Sat. Otherwise...winds
and seas will be blw Small Craft Advisory levels sun-at least Tuesday.
a few thunderstorms are possible on Thursday across the lower Hudson
Valley and interior NE New Jersey and into NYC. Any storms will have the
potential to produce locally heavy rain...but basin averaged
totals are forecast to remain light...as any thunderstorms should
be isolated. Trace amounts of precipitation are possible Friday night into Sat.
It will then remain dry through the beginning of next week.