Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
956 PM EDT sun Mar 16 2014
low pressure passes well south and east of the area late tonight
into Monday. High pressure moves in from the north Monday
night into Tuesday and moves east of the region Wednesday into early
Thursday. High pressure returns briefly for the end of the week
before another low pressure system potentially affects the region
Friday night into Saturday. Polar high pressure builds back into
the region to end the weekend.
Near term /until 6 am Monday morning/...
00z okx radiosonde observation data indicates very dry air in the lowest 7kft with
ice saturation above in the middle and high level cloud deck. High
resolution model guidance...including the hrrr...rap...Stony Brook
WRF as well as the 18z GFS and NAM agree with keeping this dry air
in place to limit any substantial snow from reaching the surface
across southern zones. With the best forcing staying well south of
the region...do not expect sufficient saturation of this dry layer.
Have removed probability of precipitation except portions of Staten Island and South
Shore of Long Island where slight chance of light snow exists
overnight. Included mention of flurries for rest of Long
Island...NYC...and portions of metropolitan NE New Jersey. Have also removed all
mention of accumulation as well.
The other change in this update was to raise low temperatures a
few degrees...especially across southern zones since minimal
evaporative cooling is now expected with only flurries or very
light snow falling. Temperatures should still fall into the teens
across the interior and low and middle 20s closer to the coast
with increasing northerly flow overnight.
Short term /6 am Monday morning through Monday night/...
any lingering flurries tapers off early Monday morning. High pressure
will build in from the north. It will be cold...with highs only in
the lower to middle 30s and lows in the teens and 20s. Conditions
will also become breezy...especially across Long Island and NYC
where winds could gust to 30 miles per hour.
Long term /Tuesday through Sunday/...
the theme for the long term continues to be an active Pacific
flow...with multiple shortwaves and associated middle week and weekend
lows impacting the area.
Split upper flow on Tuesday with polar high pressure builds into the
region...and southern stream energy staying well to the south. As
expected operational NAM has converged with the majority
flat/progressive solution. Temperatures will run several degrees below
seasonable Tuesday with polar high overhead.
Next Pacific shortwave to watch...currently in the eastern
Pacific...will make its way onshore late tonight/Monday morning.
General agreement exists in this amplifying energy working into the
central plain by Tuesday and then interacting with northern stream
energy and lifting sliding through the northeast Wednesday night through
Friday. At the surface resultant strong low pressure tracks from the
Central Plains into Great Lakes Tuesday/Wednesday and then NE through
Ontario/Quebec on Wednesday night/Thursday night. Some uncertainty continues in
strength/timing/track of low pressure...due to model differences in
amplification/nature of this shortwave predicated on degree of
interaction with northern shortwave energy. Although these
differences exist...for our region...majority of
ensemble/operational guidance continue to signal a fairly quick
hitting precipitation event ahead/along the trailing cold front during the
Wednesday after into early Thursday morning time frame. The can continues to be a
low probability solution...bringing a sub-tropical wave up the coast
Tuesday night/Wed. So...with increased confidence in event have
trended probability of precipitation higher...peaking at low likely on Wednesday night. With
progressive nature of event...looks to be a light to moderate precipitation
event. Storm track and thermal profiles indicate a mainly rain
event...but if precipitation starts early enough Wednesday morning could have a
brief start as a wintry mix across northwest zones. On the flip side...with
offshore flow and March sunshine...with only modest cold air advection on
Thursday...temperatures could rise to above seasonable levels in wake of system
(lower to middle 50s).
Models continue in decent agreement with brief ridging and dry
weather with slightly above seasonable temperatures for Thursday night/Fri.
Models signaling yet another Pacific shortwave...entering the Pacific northwest on
Wednesday...and then tracking through the northern US during the late week
and approaching the NE for Saturday. Quite a bit of uncertainty
exists in the amplification of this shortwave as it interacts with
northern stream energy...manifesting in track and intensity
differences with the resultant low. So low predictability exists in
p-type and quantitative precipitation forecast details at this point...but signal are there for the
next potential Friday night/Sat measurable precipitation event for the region.
In the wake of this system...signs point to a return to a polar
airmass under NE troughing.
Aviation /02z Monday through Friday/...
Canadian high pressure builds in through early Monday evening...as
a storm system tracks well to the south and east of Long Island.
VFR through the taf period.
Now appears that most if not all snow will fall S of Long
Island/NYC/NE New Jersey terminals...so have removed all snow from tafs.
Still small chance of light snow/flurries city/Long Island
terminals - but should be of no aviation impact...if it even
Northwest-north winds veer to the north-northeast by 06z and increase to around 15 knots by
07z with gusts 20-25 knots from 11z - 20z Monday. Winds NE 10kt or
less by Monday evening.
Outlook for 00z Tuesday through Friday...
Monday night-Tuesday night...VFR.
Wednesday-Wednesday night...MVFR or lower possible in -ra...
possibly a wintry mix in the morning inland.
low pressure will develop off the southeast coast and track well
south and east of the waters. Winds will increase tonight...with
Small Craft Advisory conditions late tonight through Monday. There is a
possibility that a few gale gusts or a brief period of gales could
be reached late tonight/Monday morning. Winds come down Monday
night...but waves may stay up above 5 feet.
Marginal Small Craft Advisory ocean seas possible Tuesday...mainly from easterly
Increasing chance for Small Craft Advisory seas late Tuesday night and more so on
Wednesday with strengthening east flow ahead of approaching frontal
system. Brief period of Small Craft Advisory winds possible ahead of a cold frontal
passage Wednesday evening with S/southeast low level jet...and then on westerly
flow behind the cold front.
no significant precipitation is currently expected for the coming
the National oceanic and atmospheric administration weather radio transmitter that serves the New York City
metropolitan area remains out of service due to radio frequency
interference with the U.S Coast Guard transmitter.
For more information see the following public information
statement (all lower case):
Marine...Small Craft Advisory from 1 am to 6 PM EDT Monday for anz338-