Marine Weather and Tide Forecast for Wanakah, NY

KEY MESSAGES
1) Dangerously cold continues across the region this morning.

2) On Tuesday, a winter storm tracking across the forecast area will cause light snow and the potential for a wintry mix south of Lake Ontario and light to moderate snow for the North Country.

3) Upslope and lake enhanced/effect snow will continue across much of the area from Tuesday night through at least Thursday night.

DISCUSSION
KEY MESSAGE 1...Dangerously cold continues across the region this morning.

Surface high pressure is located over the eastern Great Lakes region this morning. Mostly clear skies and calm winds over a fresh snowpack will continue to support very cold temperatures this morning. Wind chill values range from 15 to 20 below zero in cloud free spots across western NY, and between 20 and 25 below zero across Jefferson, Lewis, and far northeast Oswego counties. A Cold Weather Advisory will continue until 10 AM this morning.
Lake clouds will keep areas near Lake Ontario and the Finger Lakes warmer.

The cold airmass retreats to the east today. Temperatures are expected to rise into the 20s across western NY, and the teens across the Eastern Lake Ontario region.

KEY MESSAGE 2...On Tuesday, a winter storm tracking across the forecast area will cause light snow and the potential for a wintry mix south of Lake Ontario and light to moderate snow for the North Country.

A clipper system tracking along the northern shores of the Great Lakes and then to the St. Lawrence Valley Tuesday into Tuesday night will cause a variety of winter weather across the region. A series of strong shortwaves within the larger trough will help to develop new sfc low(s) and transfer the energy as the entire complex tracks southeast to the Gulf of Maine by Wednesday morning. WAA ahead of the system associated with a warm front crossing the area will develop a shield of precipitation across WNY on Tuesday morning, which will then shift east to the North Country by late Tuesday morning or the early afternoon (still some uncertainty with that timing).

With strong WAA for areas south of Lake Ontario, precipitation that will initially start out as snow will change over to a brief mixture of sleet, freezing, snow and rain, before changing over to all rain for a few hours for most areas. There is still plenty of uncertainty among the guidance as to the amount of QPF for areas south of Lake Ontario. This is due to the weaker forcing of the warm front in this area and the timing of a passing shortwave trough. Areas east of Lake Ontario will have better forcing for the increased precipitation, which looks like it will all be in the form of snow for these areas with colder temperatures more locked in. Precipitation for areas south of Lake Ontario that does change to rain will also have the prolonged potential to freeze due to how cold the ground will be pushing into the day.
That will also add to the additional potential for ice, but again, there is still uncertainty in precip amounts for these areas.

The cold front from the system will track across the area from the mid afternoon through the evening from west to east. Precipitation that is falling as a mix or as rain will change to snow with temperature profiles cooling.

For areas east of Lake Ontario where it is expected to remain all snow, the potential for 2 to 5 inches of snow with some higher amounts are possible, especially for the Tug Hill where upsloping will be favorable.

On a side note, for Tuesday, many areas south of Lake Ontario will warm to above freezing for the first time in 2.5 weeks.

KEY MESSAGE 3...Upslope and lake enhanced/effect snow will continue across much of the area from Tuesday night through at least Thursday night.

Cold air advection behind the passing sfc low and its associated cold front will cause lake enhanced and then lake effect snow to develop as the system tracks east. Upsloping will also help aid in snowfall at times as well. The best timing of the lake effect snow will be from late Wednesday night through at least Thursday night.

While conditions are favorable for lake effect snow during this time, temperatures aloft don't get nearly as cold as we have seen the past few weeks, with plenty of uncertainty among guidance in these values. Most of the guidance cools temperatures aloft to around -10C to the low teens C below zero, but with the cold lake waters now in place, the delta Ts are generally rights around or just a bit more than that favorable 12C value. This will limit the lake induced equilibrium levels for this event. However with a good fetch over Lake Ontario and upstream connection with the upper lakes over WNY, snowfall amounts of at least a few inches in any 6 hour period will be possible. Snowfall looks the best southeast of Lake Ontario with the more ice free waters and larger fetch of the lake.

AVIATION /12Z MONDAY THROUGH FRIDAY/
Surface high pressure is located across the eastern Great Lakes region this morning. Besides an area of MVFR lake clouds and flurries from Monroe to Wayne county (KSDC) and to the Finger Lakes region, widespread VFR conditions are expected through tonight.

Outlook...

Monday night...Mainly VFR.

Tuesday through Thursday...Restrictions possible in scattered snow showers.

Friday...Mainly VFR.

MARINE
Surface high pressure is centered across the eastern Great Lakes region this morning. Variable winds less than 10 knots are expected today.

Light offshore winds tonight will become southwest Tuesday with speeds approaching 15 knots. A gradual shift to the west- northwest is expected Tuesday night into Wednesday with speeds of 20-25 knots with an eventual need for small craft headlines during this time frame.

Please note...Most, if not all of the Lake Erie nearshore waters are now ice covered. Waves have been omitted from the forecast.

BUF WATCHES/WARNINGS/ADVISORIES
NY...Cold Weather Advisory until 10 AM EST this morning for NYZ001>008-010>014-019>021-085.
MARINE...None.