Marine Weather and Tide Forecast for Wanakah, NY

NEAR TERM /THROUGH TONIGHT/
Main story today will be a band of moderate to at times heavy lake effect snow that will develop east of Lake Ontario, mainly across Oswego County, but possibly reaching into far southwestern Lewis County at times. Otherwise, the remainder of the area will get a well deserved brief break in the active weather. Lake effect snow details follow just below...

Off Lake Erie...

Westerly flow will begin to back to southwesterly later today with little activity off the lake through the daylight hours. However, as southwesterly flow aligns down the long axis of the lake very late today, may see a few light snow showers develop northeast of the lake for the evening hours with only very minor accumulations expected. Later tonight, winds back even further to south-southwest ahead of an approaching strong cold front. Deeper moisture pushing into the area combined with increasing surface convergence ahead of the front will lead to a band of lake effect snow developing north- northeast of the lake, initially across western Niagara County, possibly sagging as far south as northern Erie County very late tonight with a couple inches of accumulation possible across these areas by daybreak Saturday.

Off Lake Ontario...

Very light lake effect snow showers and flurries southeast of the Lake Ontario across far northeastern Wayne, northern Cayuga and southern Oswego counties will continue into this morning, while slowly working their way further north into Oswego County. Later this morning, winds will realign out of the west down the long axis of the lake, allowing a band of lake effect snow to redevelop and strengthen east of the lake into Oswego County, possibly stretching into southwestern Lewis County at times. An upstream connection to Georgian Bay looks to develop as well, further boosting confidence for a well-organized band to regenerate. Flow will then back to southwest later this evening before shifting to south-southwest and eventually south by daybreak Saturday. This will not only cause the band to shift northward from late this evening through the second half of the night, but weaken it at the same time as the band sweeps from south to north through Jefferson County. As for accumulations, expecting 6-10 inches in the most persistent snows across central and northern Oswego County through this evening where a Lake Effect Snow Warning remains in effect. This warning will remain in effect through Sunday afternoon to encompass a second event that is expected to begin Saturday afternoon. See the Short Term section of this discussion for more details. Otherwise, increasing shear and decreasing fetch off the lake will rapidly weaken the band as it lifts north through Jefferson County tonight with 2-3 inches possible across southern Jefferson County as the band makes its initial move north, then an inch or less through the northern half of the county as what's left of the band moves all the way into the Saint Lawrence Valley by very late tonight.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/
A mid level closed low will advance from near the north shore of Lake Superior Saturday morning to the eastern Great Lakes by Sunday, sharpening and opening up into a trough axis with time. This system will deliver a fresh batch of cold air to the eastern Great Lakes, supporting the next round of heavy lake effect snow east of the lakes.

Outside of lake effect areas, a baroclinic wave will move from the Ohio Valley to southern New England on the southern flank of the digging trough. This feature may produce some widespread (non-lake effect) light snow late Saturday afternoon through Saturday night, especially across the Southern Tier and Finger Lakes with minor accumulations.

The lake effect snow potential will increase again as cold air deepens. Latest 00Z guidance continues to suggest the best setup will be off Lake Ontario, especially Saturday night through Sunday morning. Lake induced equilibrium levels will rise to near 15K feet, peaking Sunday morning as the pool of coldest air aloft and best synoptic scale moisture and forcing move over the eastern Great Lakes.

Off Lake Erie...

A band of lake enhanced snow along the arctic cold front will be northeast of the lake near the Buffalo Metro area and Niagara Frontier early in the morning. This band of snow will move quickly south into the Southern Tier by midday as boundary layer flow veers more westerly. The lake effect setup becomes more complicated for Saturday night as the weak baroclinic wave passes by to the south of Lake Erie, which will likely introduce shear into the boundary layer and disrupt banding structures. Flow will then become northwest on Sunday with lake enhanced upslope snow across the higher terrain, and there will likely be an upstream connection to Lake Huron that will locally enhance snowfall. The northwest flow lake snow continues through Sunday evening before drier air, shear, and anticyclonic flow weakens lake effect overnight.

As far as accumulations go, the setup is not as favorable as Lake Ontario will be, but nonetheless, snow totals will add up over the 36-48 hour period and likely approach low end watch/warning criteria across the higher terrain of the western Southern Tier and Boston Hills. With this in mind, we have issued a Winter Storm Watch for lake effect snow for southern Erie, Chautauqua, and Cattaraugus counties from Saturday through Sunday night. The initial phase of this event may bring advisory worthy snow amounts to portions of the Niagara Frontier and Buffalo Metro area Saturday morning before quickly moving south.

Off Lake Ontario...

A band of lake enhanced snow along the arctic front will intensify northeast of the lake over Canada Saturday morning, then swing southeast across Jefferson County Saturday afternoon before focusing on the Tug Hill region by Saturday evening. The band of snow will then intensify Saturday night near the Oswego/Jefferson county border and western Tug Hill Plateau. A strong convergence signature and ideal cloud microphysics should allow this band to become quite strong, with 2-3+" per hour snowfall rates likely. This intense band will then move south across Oswego County Sunday morning, and settle into northern Cayuga and far northeast Wayne County for a time Sunday. The band will still be quite intense, with 2-3+" per hour snowfall rates continuing through the first half of Sunday. A sharp wind shift associated with a secondary arctic front will then move south across the lake Sunday afternoon, shoving the band onshore and breaking lake effect apart into a spray of much weaker multibands and snow showers along the entire south shore and extending south into the Finger Lakes by late afternoon. This weaker spray of multibands will continue south of the lake Sunday night and gradually weaken.

As far as accumulations go, it will depend on how long the band can stay in one location as it crosses the Tug Hill region and Oswego County Saturday night through Sunday morning. The residence time is relatively brief with a steady southward shift, but even so, intense snowfall rates may still support accumulations of a foot or more across portions of Oswego County, southern Jefferson County, and the western slopes of the Tug Hill Plateau. Accumulations may also get close to low end Watch/Warning criteria in northern Cayuga and eastern Wayne counties as the band moves south on Sunday.

For headlines, the Winter Storm Watch has been upgraded to a Lake Effect Snow Warning for Oswego, Jefferson, and Lewis counties. In Oswego County, it is a long duration warning to cover the the lake snow today, and then the second event late Saturday through Sunday, with a break between. For Jefferson and Lewis counties, the warning is just focused on the second event later Saturday through Sunday. A Winter Storm Watch has also been issued for northern Cayuga and Wayne counties for Sunday through Sunday night.

LONG TERM /MONDAY THROUGH THURSDAY/
Monday, one last mid level trough will cross the eastern Great Lakes. This feature will produce some general light snow, and also support lake enhanced snow east of Lake Erie and Lake Ontario. The favorable lake effect setup is brief, but may support one more round of moderate accumulations east of Lake Erie and Lake Ontario.
Boundary layer flow will back to the WSW, so some of the lake enhancement may impact Buffalo and Watertown.

Monday will be the last wintry day for awhile as the pattern becomes much more zonal across the US by the middle of next week, forcing cold air to retreat back into Canada and allowing warmer air to move northward into the Ohio Valley and Great Lakes. Temperatures will rise above the 40 degree mark for lower elevations by Wednesday, and may get close to 50 by Thursday.

AVIATION /12Z FRIDAY THROUGH TUESDAY/
Very light lake effect snow showers and flurries southeast of the Lake Ontario across far northeastern Wayne, northern Cayuga and southern Oswego counties will continue into this morning, while slowly working their way further north into Oswego County. A band of moderate to at times heavy lake effect snow will then develop east of Lake Ontario today, mainly across Oswego County, but possibly reaching into far southwestern Lewis County at times. Otherwise, the remainder of the area will get a well deserved brief break in the active weather.

Today...westerly flow will keep areas east of the lakes (including KJHW) in mainly MVFR/low VFR CIGS, while mainly VFR conditions are expected across the remainder of our TAF sites. Outside of localized LIFR/IFR VSBY in lake effect snow east of Lake Ontario (south of KART), VFR VSBYs are expected elsewhere through the day.

Tonight...flow will become southwesterly which will cause the lake band off Lake Ontario to weaken and start to shift north through the evening with intermittent MVFR/IFR possible at KART for a few hours later this evening. Also expecting an uptick in lake effect activity north-northeast of Lake Erie ahead of an approaching cold front with MVFR/IFR possible at KBUF/KIAG later this evening as well. MVFR/low VFR will continue across the higher terrain with mainly VFR elsewhere. Later tonight, winds back even further to south-southwest ahead of an approaching strong cold front. Deeper moisture pushing into the area combined with increasing surface convergence ahead of the front will lead to a band of lake effect snow developing north- northeast of Lake Erie, initially across western Niagara County, possibly sagging as far south as northern Erie County very late tonight. This will produce MVFR/IFR at KIAG through the second half of tonight, possibly getting into KBUF toward the tail end of the TAF period. Snow showers will also start to develop northeast of Lake Ontario late tonight ahead of the cold front, with restrictions possible at KART toward the tail end of the TAF period as well.

Outlook...

Saturday...VFR/MVFR with scattered snow showers. Local IFR in lake effect snow northeast then east of the lakes.

Sunday...VFR/MVFR with scattered snow showers. Local IFR/LIFR in lake effect snow east of the lakes at the start of the day shifting to areas southeast and south of the lakes.

Monday...VFR/MVFR with scattered snow showers. Local IFR in lake effect snow east and southeast of the lakes.

Tuesday...VFR/MVFR with a chance of snow showers east of Lake Ontario.

MARINE
Elevated westerly flow will keep long-duration Small Craft Advisories in effect into the overnight hours for much of Lake Ontario, however SCA headlines will remain in effect for far eastern Lake Ontario right through the weekend.

Otherwise, winds will remain below headline criteria on Lake Erie through today as high pressure builds in from the Ohio Valley and central Great Lakes. The break in stronger winds will be brief with another round of long-duration high end Small Craft Advisory to marginal gales expected over the weekend, possibly starting as early as tonight for Lake Erie.

BUF WATCHES/WARNINGS/ADVISORIES
NY...Winter Storm Watch from late Saturday night through Monday morning for NYZ004-005.
Lake Effect Snow Warning until 4 PM EST Sunday for NYZ006.
Lake Effect Snow Warning from 1 PM Saturday to 1 PM EST Sunday for NYZ007-008.
Winter Storm Watch from Saturday morning through late Sunday night for NYZ019-020-085.
MARINE...Small Craft Advisory until 1 AM EST Saturday for LOZ042-043.
Small Craft Advisory until 5 AM EST Saturday for LOZ044.
Small Craft Advisory until 4 AM EST Monday for LOZ045.