Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
121 PM EDT Wednesday Aug 27 2014
a cold front approaches today and passes through this evening. High
pressure builds in behind the front through Friday before shifting
offshore for the weekend. Another frontal system impacts the area
late in the weekend into early next week.
Near term /until 6 PM this evening/...
a cold front will move to a position near the northwest portion of the
County Warning Area late this afternoon. Isolated/scattered showers and thunderstorms
right ahead of the front this afternoon...limited to north and
west of the city. Thunderstorms probably not severe with middle level lapse
rate being the limiting factor...however strong gusts still a
possibility with any thunderstorm.
850mb temperatures of 17c...a moderate west to SW boundary layer flow
hindering sea breezes to a degree...and mostly sunny/partly cloudy
conditions should allow highs over parts of NE New Jersey/city/lower Hudson
Valley reach the lower 90s. Highs in the middle and upper 80s expected
for most other spots. Surface dewpoints will result in heat indices
within a degree or two of the ambient temperature.
Short term /6 PM this evening through Thursday night/...
the cold front moves through mainly during the evening hours. Still
enough cape for isolated/scattered showers during the first half of
the evening...then activity drops off near midnight with
stabilization and the frontal passage. Strong wind gusts still
possible during the early evening.
High pressure builds back in behind the front on Thursday with a
sunny sky. A northerly flow will bring a less muggy airmass and less
of a spread among high temperatures across the area. A blend of
NAM/MOS guidance looked good with highs closer to normal. Dry
weather continues Thursday night with cooler than normal lows.
Long term /Friday through Wednesday/...
upper level ridging builds to the East Coast to start the
weekend...then gradually flattens to end the weekend into early
next week as a deep trough over The Rockies gradually slides east
into the Great Lakes. This northern stream trough may interact with
a bit of southern stream energy as it slides through the NE early
Fair and dry conditions expected Friday into Sat as Canadian
high pressure slides offshore. Temperatures should moderate from slightly
below to slightly above seasonable Friday into Sat.
Models still with a bit of timing/interaction issues with
approaching shortwave energies for sun into Monday...but overall theme
is an approaching frontal system sun...which gradually passes
through the region Sun night into Monday. With approaching shortwave
energies and increasing warmth and southern moisture ahead of the
front...an increasing chance for rain showers/thunderstorms and rain exists across NYC and
points to the west/northwest sun after into evening...translating east Sun night
into Monday. Very warm and humid conds likely sun into Monday in deep S/SW
flow...with temperatures running several degrees above seasonable.
A continuation of very warm temperatures and diurnal convection possible
through the midweek.
Aviation /18z Wednesday through Monday/...
a weak pre frontal surface trough extended from Cape Cod southwest
into central New Jersey. A cold through upstate New York will pass
through the terminals from 03z northwest to 08z east. The front
will come through mainly dry...however there is a low chance of
scattered showers. A rumble of thunder is possible north and west of
the New York terminals this evening.
VFR. South to southwest wind around 10 knots ahead of the front shifts
to the west and northwest behind the front around 10 knots. Gusts
develop up to 19 knots during Thursday morning.
New York 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: no unscheduled amendments expected.
Klga fcster comments: no unscheduled amendments expected.
Kewr fcster comments: no unscheduled amendments expected.
Kteb fcster comments: no unscheduled amendments expected.
Khpn fcster comments: no unscheduled amendments expected.
Kisp fcster comments: no unscheduled amendments expected.
Outlook for 18z Thursday through Monday...
Sun-Mon...VFR. A chance of MVFR conditions in showers and
thunderstorms from Sun afternoon through Monday.
seas on the ocean will build and become rough this afternoon as
an increasing long period southeast swell from Cristobal moves into the
waters. Rough conditions will then continue through at least
Thursday...and probably into Thursday night. A Small Craft Advisory
for hazardous seas is in effect for the ocean zones from 2 PM today
through Thursday afternoon.
Refer to the latest forecast from the National Hurricane Center on
the track of Cristobal.
High pressure builds across the waters Friday and then east over the
weekend. A prolonged period of southerly flow Sat into sun may produce
marginal Small Craft Advisory seas late sun into Monday.
a few tenths of an inch of rainfall is possible late this afternoon
into tonight with a chance of higher amounts in isolated
No widespread significant rainfall is forecast Thursday through early
Gulf moisture advects into the region sun into Monday. Scattered convection
during this time would produce heavy downpours...with potential for
localized urban/poor drainage flooding.
widespread 4 feet waves and dangerous rip currents have been
reported. Conditions will only get worse through Thursday morning...before
the swell retreats into the North Atlantic. As a result...have issued
a high surf advisory through Thursday. Although waves may fall just short of
the 7 feet criteria into the early evening...in this case the advisory
includes the dangerous rip threat as well...which is why the
product has been issued to include this afternoon.
New York...high surf advisory until 10 PM EDT Thursday for nyz075-080-081-
Marine...Small Craft Advisory for hazardous seas until 6 PM EDT
Thursday for anz350-353-355.