[Cambium]

Interesting read. Some technical, some concerning.

Radar shows snow showers moving towards us but air is too dry. So the cold front comes through dry this evening.

Taste of winter Friday morning.

Significant event for weekend.

Siberian airmass coming. Get off the roads Sunday night!

Area Forecast Discussion
National Weather Service New York NY
948 AM EST Wed Jan 16 2019

Increased the cloud cover with this update along with hourly
temperatures and dewpoints. The rest of the forecast appears to
be on track.

Winds will strengthen through the day ahead of an approaching
cold front. With 20-25 kt low level winds, gusts of around
25-30 mph will be possible. High temperatures will be close to
climatological normals in subtle warm advection.


.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
A cold front will move through the area by evening, though given
the dry antecedent air mass, no precipitation is expected with
its passage. Although winds may initially gust in its wake, with
arctic high pressure building in behind, winds will quickly
diminish overnight. Cold/dry advection will then prevail, with
temperatures overnight close to climatological normals.

Continued cold advection into Thursday as high pressure passes
to the north will lead to below normal high temperatures,
generally in the upper 20s to lower 30s. Cloud cover will
steadily increase through the day ahead of an approaching
frontal system.


.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Fast moving system via the southern branch of the jet stream will
provide a taste of winter to begin the period. In general good model
agreement with precip timing, with the NAM still dragging its heels
a bit with precip onset. Ptype looks to be mainly snow through
Thursday night with a change over for to plain rain for far eastern
sections perhaps just before 12z Fri. The timing works out that the
Friday morning commute will be impacted to some degree with cold
ground temperatures to start so snow should stick on most surfaces.
For now thinking a general 1 to 2 inch snowfall, with less than an
inch far east, and perhaps in the 2 to 3 inch range in far
northwestern sections. The lift is not impressive with this system
as the southern branch energy is not consolidated well as there is
little backing in the mid levels to support liquid precipitation
amounts over a quarter inch. Therefore it makes sense that the
modeling by and large has lowered its QPF output over the past
couple of runs. The precipitation will change to plain rain as
warmer air noses in from the southeast in the lower levels during
Friday morning before it moves out shortly thereafter. Most places
should completely dry out by the late morning and towards lunch time
on Friday, with high pressure to follow briefly for Friday night into
early Saturday.

A more significant precipitation event is taking shape for the
weekend as elongated low pressure moves into the lower Tennessee
Valley by Saturday afternoon. Due to the strung out nature of the
upper level energy in the southern branch and its positive tilt, low
pressure will not consolidate initially. The models agree that an
inverted trough is progged to run SSW to NNE. Along and to the
east of this boundary is where most of the liquid precipitation
will set up for late Saturday through early Sunday. Northwest of
this is where a heavy stripe of frozen precipitation will fall.
We will have to keep an eye out for far NW part of the CWA at
least for this potential. Precip types will be tricky with the
front almost taking on a anafront type nature with the nose of
warm air from the initial warm surge during Saturday night
getting into the mid levels just above the boundary layer. As
the colder air rushes in as the surface reflection begins to get
better organized over the region look for a period of freezing
rain in a stripe across inland zones to the northwest. During
Sunday into Sunday evening as the wave amplifies and gets
further northeast the leading edge of arctic air dives in and
any precipitation should transition quickly to all snow.
Difficult at this time to tell if there will still be any
precipitation along the coast by the time the colder air moves
in. Regardless if there is a period of wintry precipitation at
coast into Sunday evening, there will likely be a hard freeze of
any standing water that is left from the rain that fell
earlier. Places that are mainly all rain will get about 2 inches
of rain, before the colder air plows in. Therefore a quick
freeze of all surfaces could make for hazardous travel during
Sunday night.

An airmass of Siberian origin is crossing the pole right now and
will deliver the region the coldest air of the season thus far. With
wind chills likely to be below zero, at least for inland and
northern zones into Monday morning. Temperatures will be hard
pressed to reach the lower 20s at the coast during the day on Monday
with the new ECMWF run forecasting below 500 dm thickness to
the coast by 18z Monday. Therefore windchills would be hovering
in the near zero to the single digits for most places during the
day on Monday. As the winds diminish Monday night should be the
coldest night of the season with respect to the actual air
temperatures even though the wind chills should abate into
Tuesday morning.

[Solstodur]

Originally Posted by Cambium

Interesting read. Some technical, some concerning.

Radar shows snow showers moving towards us but air is too dry. So the cold front comes through dry this evening.

Taste of winter Friday morning.

Significant event for weekend.

Siberian airmass coming. Get off the roads Sunday night!

UKie still going for a big snowstorm. And it's been pretty much equivalent to the Euro in verification

[Cambium]

Gonna be a wicked temp drop Sunday morning to Monday morning. Wow

[Cambium]

Euro12z colder. Is this going to be a Snow/Sleet/ice storm without rain??????????? I need to check the thickness of the warm layer aloft. There definitely is a warm layer at 5000' but how thick?!!


Danbury could see 12" of snow sleet before changing to sleet/ice or rain. What a mess.


2.14" qpf. Over 2" liquid falling with this one!!

[Solstodur]

FV3 windchills for monday morning. Widespread -20°F for CT, a bit warmer at the coasts.

[Cambium]

I'll try to update you guys. Pretty busy here. Maybe someone can post a forecast? Or a tweet?

I think we're going to wake up Sunday morning with half foot or more on ground.

https://twitter.com/wunderground/sta...26284389093376

[Solstodur]

Friday 1/18 Winter Storm Update

To start off, this isn't the big weekend on. This is the precursor to that, but the significance is that a small amount of snowpack could be enough to keep surface temperatures low enough for the other storm, thus making icing a bigger threat.

NAM 3k QPF - around 0.1", so I would suspect that correlates to coating-2"


NAM 3k kuchera total snowfall - yup right around that number.


NAM 3k temperature loop - more than a day of below freezing temperatures so shouldn't be too difficult to get stickage.


HRDPS low for the day before. Yup, that's a good freeze.


HRRR just included to check if this verifies.

Spoiler

So it appears that this might be our second storm this season with >1" of snowfall. Didn't think I'd be saying that mid-January. Will write something for the bigger weekend storm, but busy at the moment.

[Solstodur]

Freezing rain threat is back with a punch for the weekend. Latest NAM showing 0.5", probably more since it hasn't finished at hr 84. This would be a monster storm, the freezing rain band just pivots directly over SW CT

[Cambium]

And it begins.

NWS Snowfall total forecast maps being updated. (subject to changes).

Includes tonights 1-2" as well.


Up to 24" for southern VT, Albany region and Western MA!


10"+ many other areas.







Sources:

https://www.weather.gov/bgm/winter
https://www.weather.gov/ctp/winter
https://www.weather.gov/gyx/winter
https://www.weather.gov/car/winter
https://www.weather.gov/okx/winter
https://www.weather.gov/box/winter
https://www.weather.gov/aly/winter
https://www.weather.gov/phl/winter

[Cambium]

I always forget to mention the ice part of it. Upton hasn't updated yet.







https://twitter.com/GarySzatkowski/s...50489956999168