Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus61 kokx 172051 
afdokx

Area forecast discussion
National Weather Service New York New York
351 PM EST Wed Jan 17 2018

Synopsis...
low pressure moves into the Canadian Maritimes tonight. High
pressure builds in through Thursday. The local area will be
between low pressure to the north and high pressure to the south
on Friday, both of which depart to the east over the weekend. A
warm front will slowly lift to the north on Monday, then a cold
front will pass through on Tuesday.

&&

Near term /until 6 am Thursday morning/...
decreasing cloud cover tonight as the low pulls away to the
northeast.

Cold temperatures will return for tonight with lows falling into the
teens for the outlying areas, while temperatures in and around New
York City will be around 20 degrees.

&&

Short term /6 am Thursday morning through Thursday night/...
a closed low remains southeast of Long Island on Thursday as ridging builds
into the area. Mostly sunny with temperatures in the low 30s, about
5 degrees below normal. West-northwest winds 10-15 kt, with the strongest
winds along the coast.

Shortwave trough passes through dry Thursday night. Lows drop
down into the teens to low 20s.

&&

Long term /Friday through Wednesday/...
nwp is in relatively good agreement with the overall 500 mb pattern
across North America through the period. There are some differences
in timing and strength with a fairly strong system moving through
the Great Lakes and northeast during the first half of next week,
which will hopefully be worked out over the next few days.

A split flow will reside over the Continental U.S. At the start of the long
term. After a shortwave trough passes through New England early
Fri morning, the 500 mb flow will flatten in response to another
northern stream trough diving across central and eastern Canada.
Zonal flow will generally prevail through the weekend, with an
amplifying ridge developing Sun night/Mon as an upper level
trough cuts off in The Rockies and continues into the Central
Plains. This system will continue NE through the Great Lakes and
northeast Tue night into Wed.

At the sfc, dry weather will dominate through the weekend
although a brisk westerly flow will develop on Sat due to a
tightening pressure gradient between low pres to the north and
high pres to the south. A leading warm front will approach our
area late Sun night into Mon, and its progress may be delayed by
high pressure to the NE. There could be some spotty wintry
precip inland late Sun night into Mon morning, otherwise light
rain into Mon evening. Followed slower model trend with a cold
front trailing from the Great Lakes low, with it moving through
on Tue. We could be setting up for a moderate to locally heavy
rain event during this time as the low taps Atlantic moisture
via a strengthening llj, with both it and difluent flow aloft
likely providing enhanced lift, and a possible triple point low
passing nearby and concentrating low level convergence.

&&

Aviation /20z Wednesday through Monday/...
precipitation will gradually taper off from west to east, with an
hour or two of haze possible after precipitation ends.
Otherwise, a slow return to VFR is expected this evening.

As conditions improve, winds will begin to strengthen from the
west-northwest-NW, with gusts around 20 kt. Gusts may continue a few hours
into the overnight before diminishing, only to strengthen again
after sunrise on Thursday.

New York 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: timing of VFR conditions may be off by +/- 1
to 2 hours.

Klga taf comments: timing of VFR conditions may be off by +/- 1
to 2 hours.

Kewr taf comments: timing of VFR conditions may be off by +/- 1
to 2 hours.

Kteb taf comments: timing of VFR conditions may be off by +/- 1
to 2 hours.

Khpn taf comments: timing of VFR conditions may be off by +/- 1
to 2 hours.

Kisp taf comments: timing of VFR conditions may be off by +/- 1
to 2 hours.

Outlook for 18z Thursday through Monday...
Thursday-Thursday night...VFR. West-northwest winds g20kt on Thursday.
Friday...VFR. West-SW winds g15-20kt possible.
Saturday-Sunday...VFR.
Monday...MVFR or lower possible in -shra, mainly late.

&&

Marine...
pressure gradient over the waters will allow winds and seas to
remain at Small Craft Advisory levels. Winds on the ocean waters will have gusts up
to 25 kt and seas 4 to 6 feet, therefore have kept Small Craft Advisory through 6 PM
Thursday.

There is a possibility that the Small Craft Advisory will have to be extended for the
far eastern waters for both winds and seas into Thursday night,
but confidence is too low at this time.

Marginal Small Craft Advisory conds are possible on the ocean waters Fri. Small Craft Advisory conds
are also likely Sat into Sat evening on the ocean as a moderate west
flow develops between low pressure passing well to the north and
high pressure building to the south. Tranquil conds on all waters
then expected through Sun night.

&&

Hydrology...
no significant hydrologic impacts are expected through at least
the upcoming weekend.

A frontal system passing through Mon night into Tue has potential to
bring over an inch of rain during that time. Mainly nuisance
urban/poor drainage impacts expected attm.

&&

Equipment...
NYC National oceanic and atmospheric administration weather radio station kwo-35 (162.55 mhz) is off the
air for an extended period of time.

The Riverhead (rvh) National oceanic and atmospheric administration weather radio station wxm-80 (162.475)
is emitting a loud buzzing noise that is currently being
assessed by technicians.

&&

Okx watches/warnings/advisories...
CT...none.
New York...none.
New Jersey...none.
Marine...Small Craft Advisory until 6 PM EST Thursday for anz350-353-
355.

&&

$$
Synopsis...cb/24
near term...cumulonimbus
short term...cumulonimbus

National Weather Service Glossary of Abbreviations