Marine Weather and Tide Forecast for North East, PA

KEY MESSAGES
1) Widespread heavy snow expected Sunday through Sunday night, with wrap around lake enhanced snow through Monday.

2) Cold weather will continue through next week.

3) Lake enhancement will bring a continued threat for accumulating snow Monday, albeit with lesser intensity and coverage compared to Sunday.

4) Following the widespread snow, moderate to heavy lake effect snow is likely east and southeast of Lake Ontario through at least midweek.

DISCUSSION
KEY MESSAGE 1...Widespread heavy snow expected Sunday through Sunday night, with wrap around lake enhanced snow through Monday.

A mid-level trough over the Canadian Rockies this afternoon, will become amplified as it moves across the Plains and phases with a southern stream trough through Sunday night. A developing area of low pressure across the Tennessee Valley will tap into Gulf moisture as it moves just west of the Appalachians through Sunday. A secondary low will develop off the Carolina coast and move northward with another plume of moisture. These systems will continue to deepen and eventually phase off the southern New England coast by Monday.

Strong moisture advection and isentropic lift will lift across the forecast area tonight, and snow will move from south to north across western NY late tonight and continue northward across the eastern Lake Ontario region Sunday morning-afternoon. Impressive dynamics will occur across the region, as a strong upper level jet moves north of the region Sunday. As the favorable right entrance region moves over the forecast area, strong frontogenesis with anomalously high moisture content will move towards the Northeast. Moderate to heavy snow will spread across western and north-central NY, with snowfall rates averaging an inch per hour Sunday afternoon through Sunday night. As the surface low moves off the coast Sunday night, the strong dynamics will retreat to the east, and snowfall intensity will decrease from the western Southern Tier into western NY. Wrap- around moisture and a cold column will maintain light to moderate snow across the forecast area through Sunday night.

Forecast soundings show a well saturated column in the DGZ for most of the area Sunday through Sunday night. Snow ratios are expected to be 20:1 so expect a dry, fluffy snowfall. As you move eastward, warmer air in the mid-level levels may reduce snowfall efficiently, and snowfall ratios may fall to 15:1. Overall, this shouldn't limit accumulation due to the abundant moisture content. The bulk of the steady, heavy snow will be from 1PM Sunday to 1AM Monday. Lake enhancement will result in heavy snow continuing along the southern shore of Lake Ontario into Oswego county Monday through Monday night.

A widespread area of 10-18" of snowfall is expected across western and north-central NY, with the higher end amounts 12-18" from the southern shore of Lake Ontario to the southern Tug Hill region Sunday through Monday night. Snowfall amounts increased slightly on the northwest of the expansive precipitation shield due to increases in the forecast QPF.

Easterly winds 10 to 15 mph are expected through the event and will limit blowing and drifting snow.

KEY MESSAGE 2...Cold weather will continue through next week.

A very cold airmass is situated across the eastern Great Lakes region today. Winds have diminished which is resulting in improving wind chill temperatures, however cold wind chills and temperatures will remain across the region well into next week.

The next period of dangerous wind chills (10 to 20 below zero) is Monday night into Tuesday morning across far western NY. A Cold Weather Advisory may be needed for this time period. Be sure to cover all exposed skin if you must be outside for a long duration.

KEY MESSAGE 3...Lake enhancement will bring a continued threat for accumulating snow Monday, albeit with lesser intensity and coverage compared to Sunday.

By Monday, the massive winter storm will have transferred nearly all of its energy to the strengthening secondary low off the East Coast.
This low will be initially situated off the coast of Cape Cod by daybreak, then slowly drift by the Gulf of Maine before moving east along the Canadian Maritimes through Monday night. The western fringe of its large precipitation shield may still be over the North Country Monday morning, though general wrap around snow showers will likely continue across much of the region through the day Monday.
The airmass over the Great Lakes will remain rather frigid in the wake of the system, with northwest flow and residual synoptic moisture allowing for lake enhanced bands of snow to form downwind of Lake Ontario. Highest confidence in a few additional inches of accumulation will be along the shoreline north and east of Rochester.

Relatively lower confidence in the snow potential east of Lake Erie.
Satellite imagery the past couple of days indicates a rapid expansion and thickening of the ice on the lake, but still a fair amount of thinner ice on the eastern end of the lake between Long Point and the Buffalo Harbor. This ice will dampen the response off the lake to some extent, but not completely mute it. There is also the possibility of a Lake Huron and/or a Georgian Bay band pivoting around and locally enhancing the snowfall south of Buffalo. As of now, snowfall totals are a couple of inches higher from the Chautauqua Ridge to the Boston Hills area.

The more widespread snow shower coverage and number of lake enhanced bands should diminish Monday evening and overnight as the flow veers and EQL heights come down with the passage of an 850mb ridge.

KEY MESSAGE 4...Following the widespread snow, moderate to heavy lake effect snow is likely east and southeast of Lake Ontario through at least midweek.

Despite the passage of the mid-level ridge mentioned in Key Message #3 Monday night, 850mb temps will remain quite cold while residual synoptic moisture remains within the crest of the ridge. This moisture will remain over Lake Ontario and as winds begin to veer, the increasing fetch and convergence will allow a more focused band of snow to develop in the vicinity of Wayne/N. Cayuga/S. Oswego counties Monday evening. This mobile band will then drift northward to the Tug and further intensify overnight, with snowfall rates of 1- 2" per hour likely. Could see snowfall rates briefly exceeding 2" per hour for a time, though current forecast snowfall remains modest as the movement of the band should help limit more significant accumulations in any one area.

The next sharp trough will then pivot through the Great Lakes Tuesday into Tuesday night, forcing a decaying clipper low across southern Ontario and Quebec. The main lake effect area off Lake Ontario should remain across much of Jefferson County Tuesday in a weakened state from the previous night as shear increases from a sfc high cresting over the region. The clipper should then force the band to get shunted back southward across the Tug and into the same general vicinity where it began, though there remains higher uncertainty in regards to band strength as this occurs. Note that this clipper low may also bring more widespread light snow to areas outside of the lake effect Tuesday into Tuesday night.

Wednesday onwards, confidence is much lower as to the nature of the lake effect off Ontario as a more robust upper level trough moves back over the Great Lakes. This said, there is little doubt that it will remain cold with the lake mostly ice-free, which in conjunction with the increased moisture and forcing, moderate to heavy lake enhanced snow will remain a threat east and/or southeast of the lake through at least Thursday, though possibly beyond.

Off Lake Erie...As alluded to in Key Message #3, ice cover on the lake is increasing and thickening which will likely hamper the lake response. With no signs of this cold airmass letting up much over the next 7 days, this trend will continue, though the degree to which it will weaken the lake response remains uncertain. Therefore, chances for snow are generally higher east of the lake through the week, but snowfall intensity remains to be seen.

AVIATION /19Z SATURDAY THROUGH THURSDAY/
A very cold airmass will continue across the eastern Great Lakes region through tonight. A northwest flow has maintained weak lake effect snow showers near the lakeshores against the western Southern Tier and southern shore of Lake Ontario. This will continue to produce MVFR/IFR conditions at KJHW and KROC today. Elsewhere, VFR conditions are expected across the region.

Attention turns to the large area of low pressure that will move to our south Sunday through Monday. A widespread heavy snow will move into the eastern Great Lakes region from south and north late Saturday night through Sunday morning. Flight conditions will lower to MVFR/IFR from south to north across western NY Sunday morning, reaching the eastern Lake Ontario early Sunday afternoon. Conditions will fall to IFR/LIFR as moderate to heavy snow expands across the region Sunday.

Outlook...

Sunday Night...IFR/LIFR with moderate to heavy snow.

Monday...LIFR in widespread moderate to heavy snow, diminishing later in the day.

Tuesday and Wednesday...Localized lake effect snow and IFR southeast of Lake Ontario.

Thursday...Chance of snow, locally heavier near the Lakes. IFR or below is possible.

MARINE
Light wind and little wave action will continue on Lake Erie and Lake Ontario through tonight.

A light easterly flow will begin across the Lakes Sunday in response to a large area of low pressure south of the region. East-northeast flow will continue through Sunday night, before winds increase out of the northwest by late Monday. Small Craft conditions are likely on the western side of Lake Ontario Sunday.

CLIMATE
Buffalo Record low minimum temperature Record low high temperature

January 24 -11 (1976) 1(1963)
January 25 -14 (1884) 5(1884)

Rochester Record low minimum temperature Record low high temperature

January 24 -10 (1963) 2(1963)
January 25 -6 (1945) 7(1884)

Watertown Record low minimum temperature Record low high temperature

January 24 -30 (2014) RECORD BROKEN 0(2004)
January 25 -18 (2007) 3(1992)

BUF WATCHES/WARNINGS/ADVISORIES
NY...Winter Storm Warning from 7 AM Sunday to 7 PM EST Monday for NYZ001-002-010-011.
Winter Storm Warning from 7 AM Sunday to 7 AM EST Tuesday for NYZ003>008.
Winter Storm Warning from 1 AM Sunday to 7 PM EST Monday for NYZ012>014-019>021-085.
MARINE...None.