Morning Sat Jan 7 waiting for snow bands

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:
6-10 inches...KISP/KBDR/KGON
3-5 inches...KLGA/KJFK
2-4 inches...KHPN/KTEB/KEWR
1 or less inches...KSWF

1/7/2017 Another storm

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.

Celebrate New Year with the Moon and Planets in the Southwest Sky

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.]

Dollop of snow, chill of ice, wash down with rain….

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
FROPA.

Cold. Really cold. Really windy. Did I mention cold?

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.

nam_namer_036_1000_500_thick

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.

It’s all about the warm front

Warmer and moister air from the south will push over a warm front tonight. The rising air will cool and produce snow. This snow is already happening above us now. The air just above the ground is dry, so the snow is sublimating before it gets to the ground.

How much snow anyone gets will depend on how quickly the warmer air moving at the surface. Warm fronts are less well defined and the warm air has to push out the denser cold, dry air. The National Weather Service is expecting that to happen and change the snow to rain, with some moderately heavy rain, by early morning. A coating of snow for NYC and an inch for Westchester and Rockland and nearby Connecticut is the most likely outcome.

Forecasts with warm front snow have less certainty that cold fronts or coastal storms, so be ready; if the change over is delayed, a period of freezing rain could occur before sunrise.

Here’s the NWS forecast discussion from early afternoon…..

 

However, if temperatures at the surface closer towards the coast,
such as Rockland, Westchester, Eastern Passaic, Western Essex,
Western Union, trend just a few degrees colder for overnight, the
wintry mix would include freezing rain with a possibility of the
winter weather advisory getting expanded. However, recent model
runs, such as the NAM12 continue to show temperatures and even wet
bulb temperatures a few degrees above freezing for the
precipitation overnight into Monday morning. So, confidence of any
ice accumulation is lower because of this but a chance of freezing
rain is in the forecast.

 

Manhattanhenge coming up

Here’s a preview of the line up of the sunrise with the Manhattan street grid, which usually occurs around December 5th.

I took these photos on November 28th, on Fulton Street in lower Manhattan. Less than 30 minutes after sunrise, the sun lined up down the street, reflecting off Freedom Tower on the other end of the street.

The alignment at sunrise should be on Monday the 5th. Some offices in our building were lit by the rising sun and the reflection from Freedom Tower.