Marine Weather and Tide Forecast for Grandyle Village, NY

KEY MESSAGES
1) Below normal temperatures and mainly dry weather will continue through the upcoming week, with a few showers possible across the Southern Tier at times.

DISCUSSION
KEY MESSAGE 1...Below normal temperatures and mainly dry weather will continue through the upcoming week, with a few showers possible across the Southern Tier at times.

An upper level trough and closed low will slowly move east across the Midwest to Ohio Valley through mid-week. High pressure will remain across eastern Canada, bringing continued northeast flow across the eastern Great Lakes region though a majority of the work week.

A shortwave trough will move across the Ohio Valley this evening.
Subsidence and dry air will maintain mostly dry weather across the region, however isentropic lift and deep moisture will approach the NY/PA line. Widely scattered showers are possible across the western Southern Tier through tonight, mainly near the PA state line.
Otherwise, a dense shield of cirrus will continue across the eastern Great Lakes through much of the night, with some partial clearing possible towards daybreak. Low temperatures will fall to the 40s with locations across the North Country possibly seeing the upper 30s. Confidence in temperatures reaching the upper 30s is low, as the position of the high well to the north and uncertainty in cloud cover does not offer the best set-up for radiational cooling. With that being said, there is a non-zero chance of patchy frost in known cold spots across Jefferson and Lewis counties tonight.

Low-level easterly flow will increase to our south ahead of the approaching closed low Tuesday. A few showers along the NY/PA border can't be ruled out. An upper level ridge is expected to move south from eastern Canada for the end of the work week, and widespread dry weather is anticipated across the forecast area. Temperatures will gradually increase each day but stay below normal for late September.

AVIATION /00Z TUESDAY THROUGH SATURDAY/
Strong high pressure will remain in place across Ontario and Quebec tonight through Tuesday, keeping the majority of the deeper moisture, rain chances, and lower CIGS south of the area. A dense shield of cirrus will continue to stream northeast across the eastern Great Lakes tonight, with VFR prevailing. A few sprinkles or light showers may clip areas along the NY/PA line, otherwise dry weather will prevail for the rest of the area. Some lake effect clouds may develop overnight in ENE flow across the Niagara Frontier, with patchy MVFR CIGS possible. The most likely TAF location to experience MVFR CIGS in lake effect clouds is KIAG, with a lower chance at KBUF and KROC given the expected ENE flow direction.

Tuesday, low level moisture over PA will spread a little farther north into the Southern Tier, with areas of MVFR CIGS developing across the higher terrain. Otherwise, VFR will continue to prevail for the rest of the area with cirrus level clouds and scattered diurnal cumulus.

Outlook...

Tuesday night through Saturday...Mainly dry weather with predominantly VFR flight conditions expected through the period. The exception will be river/lake valley fog and local IFR potential on any given night where winds become light, and skies become clear to partly cloudy late night into the hours surrounding daybreak.

MARINE
Expansive surface high pressure over Ontario Province will build across Quebec and strengthen through midweek...while weak surface troughing slides eastward across the Ohio Valley and mid-Atlantic states. The resulting pressure gradient will maintain a moderate to fairly brisk flow across the Lower Great Lakes through midweek that will also gradually veer from northeasterly to easterly over time.

This will allow for SCA-level conditions across the nearshore waters of both lakes with the exception of Mexico Bay to the Saint Lawrence River. SCAs will become more confined to areas from Hamlin Beach to the Niagara River by Wednesday as the flow veers more easterly. Any lingering SCA-level conditions should then subside Wednesday night as the surface ridge builds further southward and results in a weakening of the pressure gradient across our region...along with a commensurate lowering of winds and wave action.

BUF WATCHES/WARNINGS/ADVISORIES
NY...Beach Hazards Statement through Wednesday evening for NYZ001- 002.
Beach Hazards Statement through Wednesday morning for NYZ003- 004.
MARINE...Small Craft Advisory until 11 PM EDT Tuesday for LEZ040-041.
Small Craft Advisory until 8 PM EDT this evening for LOZ030.
Small Craft Advisory until 8 PM EDT Wednesday for LOZ042.
Small Craft Advisory until 8 AM EDT Wednesday for LOZ043- 044.