Three packets of energy are forecast to make a bundle when they rendezvous on the east coast on Tuesday. All the packets are over the North American continent as of this morning and the accuracy of the computer weather models will increase with this morning’s run and the following runs.
If they come together here, if it’s snow, plan to take Tuesday and perhaps Wednesday as ‘watch the snow’ days.
If you want to see the colliding packets of energy in action, a neat video is at the National Centers for Environmental Prediction. Here’s the link, below. If the direct link doesn’t work, it takes lots of clicks, clicking on North America, the nam model and the sim radar. The simulated radar shows the precipitation with the three packets of energy, from the midwest, the southern atlantic coast and the gulf of Mexico smashing together, making one area of snow and rain over the northeast megalopolis.
Tuesday morning’s radar simulated by the nam model. The color are increasing intensity of precipitation, not rain or snow.
The game plan is for heavy snow from I-95 inland from DC to Maine. But this game plan is wobbly, and the rain/snow line is like the scrimmage line or the rugby scrum with the competing forces of upper air energy, moisture and warmth from both the Gulf and Atlantic. Stir with high winds and we have a blizzard watch.
But as they say, you still have to play the game.
Click on the Weather Briefing for NYC to get the story and keep up with changes.
I didn’t stay up to see the main event, but I caught the pre-show!
The occultation of the bright star Aldebaran in the head of Taurus the Bull was going to be too low in the sky at my house, so I went out earlier when I could set up my camera in front of our house, shielded from the 20 mph wind in the 17 degree temperatures.
Earlier that evening, other, fainter stars in the Hyades cluster were occulted by the moon. Here’s two photos just before and just after star theta-1 disappeared behind the dark limb of the moon. (The one next to it is theta-2.) Depending on your browser, you may need to click on the photos to see the two stars near the lower left faintly lit part of the moon, then one star remains. The third photo is an expanded view of the same photo after the first star disappeared. Note the dim lighting on the eastern half of the moon, that’s light reflected from the earth – earthshine.
Here’s a wider view of the scene, with the V-shaped Hyades cluster on the left with the over-exposed moon and the little-dipper-shaped Pleiades cluster on the right. The blue blob near the Pleiades is a reflection in the lens. The red star on the upper left of the V cluster is Aldebran, which was run over by the moon around 11:10 in Westchester County, NY. I would have had to set up out in the wind and cold somewhere else to see that, so I caught the pre-show.
NWS models put Westchester County on the edge of the snowstorm. That would normally mean little or no snow for our County, but the NWS has indications bands of snow could drop an inch an hour of snow just east of us, just after noontime. The forecast of 2-4 inches includes if we get a brief band. So watch out for travel late morning or early afternoon for a sudden increase in snow rate for a while, especially if you are traveling east or south of here.
From the NWS forecast discussion….
Max snowfall rates may approach 1 inch per hour at the New York City
terminals, with higher rates likely at times at Islip, Bridgeport
and Groton. Lesser rates are expected at Newburgh. Timing of highest
rates would mostly likely be in the afternoon.
Expected snow totals:
1 or less inches...KSWF
Another storm, now threatening North Carolina with heavy snow, will pass off shore on Saturday, giving us the another chance of a light snow – 1 to 3 inches, with the amounts dropping off quickly further west of us and eastern Long Island and eastern Connecticut getting a strong winter storm. A small change in the track of the storm could give us only ‘conversational snow’ or three inches during the day on Saturday.
Here’s the National Weather Service’s words. . .
Forecast models continue to show a developing coastal low moving
off the Southeast coast and tracking northeast, passing well south
and east of Long Island.
Latest forecast guidance continues to point towards a significant
snowfall event across eastern LI and southeast Connecticut with a
advisory level snow across central Long Island and South Central
CT. Most of the forecast guidance also indicating a sharp cut off
in the precipitation. The main question, is where does this sharp
cut-off occur. Most guidance is showing that cut off somewhere
around the NYC or Nassau county line northward. If subsequent
models runs trend towards the west, higher snowfall amounts may
occur further west.
Snow should develop during the morning hours of Saturday and then
end across eastern sections in the evening. As for QPF amounts,
less than a quarter of an inch for NYC metro and a little over
half inch across eastern LI/Southeast Connecticut.
With respect to headlines and totals, A Winter Storm Warning is
in effect for Eastern Suffolk and New London Counties for 4 to 8
inches of snow. A Winter Weather Advisory has been issued for
Western Suffolk County, Middlesex, and coastal New Haven counties
for 3 to 6 inches. Further North and West including NYC should see
1-3 inches. Orange and Passaic may see little to no snow.
With a forecast of clearer skies* for the evening of Sunday, January 1st, 2017 (Happy New Year!), there is still time to see Neptune still near Mars – 1 degree (two crescent-moon-lenghts apart) to the lower right of Mars. You’ll need strong binoculars or a telescope to see much fainter Neptune.
Look early (6 to 6:30pmEST) and see Mars plus Venus and a very thin Moon further down to Mars’ right. (No optical aid needed, although the Moon will look nicer with some magnification.)
There is even a comet glowing faintly at magnitude plus 7.2 even lower down (use binoculars or a telescope- fuzzy objects are even fainter than advertised near the horizon)!
See attached charts from Mobile Observatory zoomed in on Neptune and Mars and showing the wider scene.
[*Forecasts from http://www.cleardarksky.com/c/DrprPrkNYkey.html?1
and National Weather Service http://forecast.weather.gov/MapClick.php…
– check for updates after noontime.]
The National Weather Service’s forecast discussion has the story:
Snow should change to rain at the coast around 8 am and by 10 am
across the interior. Along the coast, there could be an hour or
two of freezing rain due to the cold ground temperatures, while
the interior could see up to a tenth of an inch of ice, possibly
as much as quarter inch, before changeover to all light rain/drizzle
late morning/early afternoon. Snow accumulations will range from
1-2 inches at the coast, to as much as 4 to 6 inches across
northern portions of the Lower Hudson Valley and SW interior CT.
Thus, winter weather advisories remain in place.
Mid levels dry out tomorrow afternoon with light rain and drizzle
through Saturday night.
. . .
Looking for about a 1/2"
of [rain on Sunday] QPF. Temps Sunday running nearly +15 F despite the rain,
but fall short of records (perhaps KISP - but that has a short POR).
PCPN ends before temps support any frozen. Windy on Sunday as well with
gusts up to 30 mph - especially in the afternoon just after the
Hold on tight! Here comes the cold air! A series of cold fronts will bring strong wind and cold air. At NWS Forecast Discussion, you can read about their thoughts about this and some snow due Saturday morning.
Here’s some highlights:
Temperatures drop to the mid-20s tonight, hold steady on Thursday, and fall further Thursday night as winds gust to perhaps 55 miles per hour.
Temperatures will moderate on Saturday, after we get some snow….
Thermal profiles will be plenty cold
enough for a light and powdery accumulating snow Friday Night into
early Sat morning areawide. A change over to a wintry mix then rain
is likely Saturday morning as temperatures aloft rise rather
quickly. Before the change over to rain, 1 to 2 inches of snow is
forecast for SE LI/SE CT...2 to 3 inches for
NYC/NJ metro...increasing to 4 to 6 inches for the NW interior.
Of concern...with primary surface low pressure tracking well to the
W of the region Sat and sub-freezing ground temps...low level cold
air will likely be hard to scour out across the interior. This will
bring potential for a lingering freezing rain threat well into the
day Saturday across the interior...with even a transitional threat
along the coast in the morning. Eventually all wintry precip should
changeover to plain rain across the interior with continued waa
later in the day.
Just when you’ve had enough, plain rain for Sunday. Temperatures rise to the mid-40s on Sunday morning and slide down to below freezing and staying there though Tuesday.
Computer forecast map for Thursday night showing low pressure over the Gulf of St. Lawrence dragging cold air into the eastern United States. The red and blue dashed lines are a calculated temperture from the surface to 18,000 feet. Farther into the area of the blue dashed lines, the colder the air is.