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Area forecast discussion 
National Weather Service New York New York
612 am EDT Tuesday Aug 4 2015

Synopsis...
a slow moving cold front will approach overnight then stall
across the area today. The cold front moves offshore Wednesday as
weak high pressure builds into the area. Weak high pressure builds
into the area on Thursday. Several waves of low pressure may
impact the area Friday into Saturday. High pressure returns for
the second half of the weekend.

&&

Near term /until 9 am this morning/...
forecast going rather as expected. High cape/instability and dynamics
in the form of a pronounced jet streak produced a massive severe
storm that is moving along the North Shore.

Expect the activity is east of CT and Long Island by 900 am.

&&

Short term /9 am this morning through 6 PM Wednesday/...
expecting mostly dry into the early afternoon...then isolated thunderstorms
develop in response to heating. Ncar ensemble supports isolated
convection at best with focus in the Hudson Valley. Have kept it
at isolated all locations as have been too busy with severe to
fully analyze nwp yet.

Dry...less humid and near normal for Wednesday.

Blended MOS used for temperatures.

There is a high risk for the development of rip currents at the
ocean beaches today. A rip current statement is in effect.

&&

Long term /Wednesday night through Monday/...
upper level trough over the region Wednesday night lifts into
southeast Canada on Thursday with weak ridging at the surface and
aloft. Upper level vorticity/energy currently over The Rockies will
slowly slide east into the Ohio Valley by Thursday. The strength of
this energy will be key to the development and track of low pressure
across the middle-Atlantic and northeast Thursday night into Saturday.

The latest 00z models offer slightly more confidence that there will
be low pressure impacting the area sometime on Friday into at least
the first portion of Saturday. The details are still very much in
question...but a widespread significant rainfall is possible Friday
into Saturday morning.

The 00z GFS is the flatest and slowest as it does not really develop
the low until Friday night as a second piece of energy amplifies
behind the main one. The 00z European model (ecmwf) is the strongest with this energy
and develops the low across the middle Atlantic on Friday and moves it
just south and east of Long Island into Saturday morning. The 00z
gefs are a bit faster...with the mean low track and timing similar
to the 00z European model (ecmwf).

Have continued with likely probability of precipitation on Friday...and have increased probability of precipitation
to likely Friday night. Probability of precipitation then decrease to chance during the day
on Saturday. As timing becomes clearer...expect adjustments to the
timing of probability of precipitation.

The low lifts northeast of the area Saturday night into Sunday
morning with weak high pressure returning on Sunday with dry
conditions.

Temperatures will be near to slightly below seasonable levels during
the period. Friday and Saturday will likely be the coolest as
temperatures struggle to get out of the 70s.

&&

Aviation /09z Tuesday through Saturday/...
a cold front continues to slowly approach from the west.

Thunder has moved east of isp...so just kgon left to be impacted
by thunder. Another line of showers now over the city terminals
should move east by 11z.

Otherwise...expect S-SW winds of 5-10 knots at knyc terminals and 5 knots
or less along with VFR conditions.

After frontal passage...winds shift to the west-SW and increase to
8-12 knots. Gradient tightens this afternoon. Local sea breezes
possible at coastal terminals.

Additional isolated to scattered showers and thunderstorms will be
possible late in the afternoon. Will leave out of the taf for now
with low confidence of coverage and timing.

..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: afternoon seabreezes likely today. Timing of
gusts may be off by +/- 1 hour today. Amendments may be needed for
any convection this afternoon.

Klga fcster comments: timing of gusts may be off by +/- 1 hour
today. Amendments may be needed for any convection this afternoon.

Kewr fcster comments: timing of gusts may be off by +/- 1 hour
today. Amendments may be needed for any convection this afternoon.

The afternoon kewr haze potential forecast is green...which implies
slant range visibility 7sm or greater outside of cloud.

Kteb fcster comments: timing of gusts may be off by +/- 1 hour
today. Amendments may be needed for any convection this afternoon.

Khpn fcster comments: timing of gusts may be off by +/- 1 hour
today. Amendments may be needed for any convection this afternoon.

Kisp fcster comments: afternoon seabreezes likely today. Timing of
gusts may be off by +/- 1 hour today. Amendments may be needed for
any convection this afternoon.

Outlook for 09z Wednesday through Sat...
Tuesday night...slight chance for thunderstorms mainly coastal terminals in the
evening. Becoming VFR overnight. SW flow becoming northwest overnight.
Wed-Thu...VFR. Generally west flow.
Friday...MVFR or lower in rain. Winds becoming NE.
Sat...MVFR or lower possible in rain. NE winds.

&&

Marine...
ocean seas build due to the increase in these winds. A Small
Craft Advisory remains in effect on the ocean waters through early
Tuesday evening.

Ocean seas will be subsiding tonight...but 5 feet seas may linger
on the eastern ocean until Wednesday morning. Weak high pressure
passes over the waters on Wednesday with sub Small Craft Advisory conditions
expected. Several waves of low pressure may pass over the waters
for the end of the week. Occasional Small Craft Advisory conditions are possible on
Friday...especially on the ocean.

Weak high pressure will move over the waters on Thursday with low
pressure on Friday into Saturday. Sub Small Craft Advisory conditions are expected
Thursday into Friday...with seas building to around 5 feet on Saturday
on the ocean.

&&

Hydrology...
a widespread significant rainfall is possible Friday into Saturday.
However...uncertainty exists in where and when the heaviest of the
rain will fall. Antecedent dry conditions should limit flooding
potential. However...any heavier rainfall that do develops would
have the potential for localized flooding.

&&

Equipment...
tewr terminal Doppler radar remains unavailable.

&&

Okx watches/warnings/advisories...
CT...none.
New York...high rip current risk through this evening for nyz075-080-081-
178-179.
New Jersey...none.
Marine...Small Craft Advisory until 8 PM EDT this evening for anz350-
353-355.

&&

$$
Synopsis...tongue
near term...tongue
short term...tongue
long term...ds
aviation...British Columbia
marine...tongue
hydrology...tongue
equipment...

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