Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
109 PM EST Monday Mar 2 2015
high pressure builds in from the west this afternoon and tonight.
The high drifts over...then east of the region on Tuesday. Low
pressure will track well north of the area Tuesday night and
Wednesday...with a warm front lifting towards the area Tuesday
night...followed by a cold front Wednesday. Another wave of low
pressure may affect the region Wednesday night into Thursday. High
pressure will then build in for the remainder of the week.
Near term /through tonight/...
extended scattered flurries over CT and The Forks region for the next
hour or two...then as a shortwave aloft exits...negative vorticity advection and
subsidence should dry things out over there. The afternoon should
be partly cloudy/mostly sunny with highs mostly in the middle and
upper 30s. Northwest winds will produce wind chills in the 20s.
A period of clear skies this evening...then high clouds ahead of the
next system begin to filter in late tonight.
Temperatures a blend of guidance tonight. Winds this evening may limit the
initial drop off after dark...particularly coasts and city. As winds
diminish overnight...the increasing middle clouds are expected at this time
to keep temperatures from completely bottoming out.
Short term /Tuesday/...
the Gulf begins to open up and hi pressure over the County Warning Area drifts
offshore. Result is increasing Theta-E over the region with snow
developing from SW to NE after 18z. The NAM/GFS/ECMWF all have
similar timing. Temperature profiles indicate the column is generally cold
enough for all snow through 00z. The NAM does warm things slightly
faster aloft...so some sleet mixing in would be possible across
Staten Island into New Jersey in the 22-00z time period should this faster
With a locally MDT burst of snow at the onset...will forecast around
an inch of snow western zones for late in the afternoon.
Temperatures blw climatology with a blend of guidance used. The onshore southerly
flow will keep temperatures nearly steady as the day ends.
Long term /Tuesday night through Sunday/...
main focus will be prolonged period of unsettled weather Tuesday
night through Thursday.
Models in decent agreement with a couple of northern stream
shortwaves phasing and digging down the Front Range of The Rockies
into northern plains early this week...phasing with a SW US low...and
then gradually lifting across the US to East Coast by end of the
The phased streams will have a moist SW flow from the subtropical Pacific
developing all the way into the northeast US by Tuesday night with
several disturbances riding along it through midweek.
The first piece of phased energy will have strong low pressure
tracking from central Ontario into central Quebec Tuesday/Tuesday
night...with its warm front...and an absorbed Central Plains low...
approaching the region during this time. Strong warm air advection as described
above will allow for precipitation to overspread the area late Tuesday afternoon as
snow...but with mentioned subtropical Pacific
connection...expecting temperatures aloft to warm fairly rapidly Tuesday
evening/night with snow changing to mixed precipitation then rain from S to north. A
quick 1 to 2 inches of snow city/coast and 2 to 4 interior are
possible before changeover.
Due to the primary low tracking well to the northwest of the region...deep
snow pack and cold water temperatures...the surface warm front will likely
have trouble lifting north Tuesday night into Wednesday. A brief period of
freezing rain with a trace to few hundredths of an inch of ice
possible along the city/coast Tuesday evening before changeover to
rain...but interior portions of the tri-state may struggle to get
above freezing until after daybreak. 1 to 2 tenths of an inch of ice
possible here. With some of the 1/2 to 1 inch of precipitation falling in
frozen form and temperatures not expected to get much above the middle to
upper 30s through Wednesday morning...not expecting a great amount of
snowmelt...so just expecting some nuisance flooding issues across
the coastal plain.
Best lift moves east Wednesday morning with a weak cold frontal passage.
Just some residual shower activity in wake of front.
Stronger cold front moves across Wednesday evening/night with falling temperatures
Wednesday night. Models are signaling potential for another period of
Post-frontal precipitation Wednesday night into Thursday...with a series of waves
developing along the cold front and ahead of approaching upper
trough axis and the region under favorable entrance region of a
175-200kt upper jet. Potential for much of this to be in the form of
snow...with several inches possible. Have trended forecast in this
direction...but will have to monitor next few models runs for
increased confidence in snow threat.
Another shot of Arctic air infiltrates the area Thursday into Friday.
Strong Canadian high pressure then builds towards the area into the
weekend with dry weather. Temperatures will rebound around 5 degrees below
normal next weekend with warm air advection developing.
Aviation /18z Monday through Saturday/...
high pressure over the Ohio Valley this afternoon will build
east...while rapidly deepening low pressure lifts NE into the
Canadian Maritimes. The high will move across the terminals Tuesday
VFR. A gusty northwest flow will prevail for the remainder of the after
and then gradually subside through this evening. Winds become
light and variable Tuesday morning with the high moving across and
then southeast by after. Middle and high level ceilings will move in toward
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: winds will vary right around 310 magnetic.
Klga fcster comments: winds will vary right around 310 magnetic.
Kewr fcster comments: winds will vary right around 310 magnetic.
Kteb fcster comments: winds will vary right around 310 magnetic.
Khpn fcster comments: winds will vary right around 310 magnetic.
Kisp fcster comments: winds will vary right around 310 magnetic.
Outlook for 18z Tuesday through Saturday...
Tuesday afternoon...chance MVFR or lower in light snow late.
Tuesday night...IFR or lower likely. Mix of snow and sleet
changing over to all rain. Low level wind shear likely after 06z.
Wednesday...MVFR or lower possible in light rain in the morning.
Conditions may improve to VFR in the after. Low level wind shear possible in the
Wednesday night-Thursday...MVFR or lower possible in any
precipitation...with a transition back to snow.
Thursday night-Friday...VFR. Northwest winds g15-20kt possible Thursday
northwest winds will be at Small Craft Advisory levels today as low pressure deepens over the North
Atlantic. Winds and seas will begin to subside tonight as hi pressure quickly
builds over the waters. Conditions blw Small Craft Advisory levels on Tuesday. Small Craft Advisory wind gusts
possible on the ocean Tuesday night ahead of approaching cold
front...with accompanying Small Craft Advisory seas developing. Winds likely drop
below Small Craft Advisory on Wednesday...but seas should remain Small Craft Advisory. Small Craft Advisory conditions could
continue into Thursday behind the passage of two cold fronts...with a
tight pressure gradient. Sub-advisory conds for the end of the week as the
pressure gradient weakens with another building high.
between 1/2 to 1 inch of liquid equivalent precipitation is likely late
Tuesday through Wednesday morning. Some of this will fall as plain
rain...therefore the combination of this and some melting snow
pack could cause nuisance urban flooding issues across the metropolitan
and coastal plain Tuesday night into Wednesday morning.
Between 2 to 4 inches of liquid equivalent exists in the snowpack
across the area. With temperatures rising several degrees above
freezing on Wednesday...some melting of snowpack can be
expected...but only enough for nuisance flooding.
Some minor increases in streamflow are possible across primarily the
northeastern New Jersey river basins due to rain and snowmelt late
Tuesday night into Wednesday evening. The probability of ice
movement and ice jam flooding appears low at this time.
Another 1/2+ inch of liquid equivalent precipitation is possible
Wednesday night into Thursday. This will mainly be frozen.
Marine...Small Craft Advisory until midnight EST tonight for anz330-335-
Small Craft Advisory until 6 am EST Tuesday for anz350-353-355.