Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service New York New York
1154 am EDT Friday Aug 29 2014

high pressure builds across New England today...then slides
offshore tonight and Saturday. A low pressure trough will
approach from the west Sunday and then slowly move across the area
Sunday night into Monday. Weak high pressure will then briefly
follow Monday night before a cold front moves through Tuesday
night. High pressure will return for the middle of next week.


Near term /until 6 PM this evening/...
upgraded eastern Suffolk County to a high risk of rips for today.
Reports out of Montauk indicate 3-5 feet surf with dangerous rips.
Moderate risk remains on track for the rest of the oceanfront
with mainly 2-4 feet waves.

As upper trough continues to depart out to sea...heights will rise
as the subtropical Bermuda high and northern stream ridge phase
along the East Coast today. Satellite indicates mainly sky clear. Some
cirrus across western New York state may get in late this afternoon.

Northerly winds will veer around to the southeast with seabreeze development
likely at the coast. Forecast soundings indicate mixing around
850 mb...with temperatures around 10c at this level which will yield highs
in the middle to upper 70s across the area.


Short term /6 PM this evening through 6 PM Saturday/...
deep layered ridging will remain over the area through Sat with 500 mb
heights around 590 dam. Surface high slides offshore tonight with an
onshore flow remaining through Sat. 850 mb temperatures will rise to around
13c Sat afternoon which will result in temperatures a few degrees
higher as compared to today...but the onshore flow will keep
highs near normal levels.

Outlying locations should decouple from the flow tonight under
mostly clear skies. Low temperatures are a bit tricky however since the
opaqueness of the high clouds will determine how much radiational
cooling will occur as well as weak warm air advection occurring. Lows tonight are
still forecast to be below normal...however a few degrees warmer
than Thursday night.

One other thing that is troubling is the amount of low level
moisture the models are indicating early Sat morning. Despite the
onshore flow...feel that they are overdoing the amount of moisture
becoming trapped under the subsidence inversion and do not foresee
broken low clouds around 12z. Do however feel that few-scattered could be
around which has been included in the forecast.


Long term /Saturday night through Thursday/...
a warm...muggy period as high pressure both aloft and at the surface
builds east across the western Atlantic. This will keep the
tri-state area under a moist S/SW flow with a series of frontal
systems to impact the area. The first of which is a trough or
weak warm front that approaches sun and passes trough Sun night into
Monday. Increasing deep-layer shear and precipitable water values around 2 inches
raises some concern for heavy rainfall potential. Decent westerly
flow aloft and the orientation of the front does not support
training of cells...thus any flooding will likely be localized.

Weak high pressure follows late Monday into early Tuesday before a
weakening cold front approaches with another round of convection Tuesday
aft/eve. At this time...environment looks to feature MDT-high
cape...but weak shear.

Expect above normal temperature with highs inland in the middle to
upper 80s...and low to middle 80s at the coast during this period. Lows
will be in the middle 60s to around 70. Some drier and slightly cooler
air works in behind the front on Wednesday.


Aviation /16z Friday through Tuesday/...
high pressure will move slowly east across the area today then
move offshore on Saturday.

VFR weather will prevail through Saturday.

Winds...light NE winds of 5-10 knots will become southeast at the same speeds
this afternoon...except at kjfk where winds could be a bit higher
this afternoon. Winds begin to subside after sunset.

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: timing of sea breeze may be off by +/- 1-2
hours from forecast.

Klga fcster comments: timing of sea breeze may be off by +/- 1-2
hours from forecast.

Kewr fcster comments: timing of sea breeze may be off by +/- 1-2
hours from forecast.

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

Kteb fcster comments: timing of sea breeze may be off by +/- 1-2
hours from forecast.

Khpn fcster comments: timing of sea breeze may be off by +/- 1-2
hours from forecast.

Kisp fcster comments: timing of sea breeze may be off by +/- 1-2
hours from forecast.

Outlook for 12z Sat through Tuesday...
Sun-Tue...mainly VFR. Possible MVFR conditions with potential
showers and thunderstorms Sun afternoon through Tuesday.


sub-advsy conds expected to prevail on all waters through Sat
with high pressure building across New England and then offshore.

A prolonged period of S/SW winds will be featured from Sat night
into Tuesday as a series of weak frontal systems approach from the west.
There is the potential for seas on the ocean to reach Small Craft Advisory criteria
sun after though Monday morning.


no rainfall through Sat. Scattered showers and thunderstorms late
Sunday and Monday may produce heavy downpours...with potential for
localized urban/poor drainage flooding.


Okx watches/warnings/advisories...
New York...none.
New Jersey...none.


near term...jmc/24
short term...24
long term...dw

National Weather Service Glossary of Abbreviations