Lake Ontario - Open Waters from Mexico Bay to the St Lawrence River Marine Forecast
|Rest Of Tonight...West Winds 10 To 15 Knots Becoming Southwest 15 To 20 Knots. A Chance Of Waterspouts. Showers, Then Showers With A Chance Of Thunderstorms Late. Waves 1 Foot Or Less Building To 3 To 5 Feet.|
|Monday...Southwest Winds 15 To 25 Knots. A Chance Of Waterspouts. Showers Likely Early, Then Showers From Late Morning On. Waves 3 To 6 Feet.|
|Monday Night...Southwest Winds To 30 Knots. A Chance Of Waterspouts. Showers In The Evening, Then Showers Likely With A Chance Of Thunderstorms Overnight. Waves 4 To 7 Feet Building To 8 To 12 Feet. Waves Occasionally Around 15 Feet.|
|Tuesday...Southwest Winds To 30 Knots Becoming West 15 To 25 Knots. A Chance Of Waterspouts. Showers With A Chance Of Thunderstorms. Waves 8 To 11 Feet Subsiding To 4 To 7 Feet. Waves Occasionally Around 14 Feet.|
|Tuesday Night...West Winds 15 To 25 Knots. A Chance Of Waterspouts. Showers With A Chance Of Thunderstorms In The Evening, Then Showers Overnight. Waves 4 To 7 Feet Subsiding To 3 To 6 Feet. Waves Occasionally Around 9 Feet.|
|Wednesday...Northwest Winds 15 To 25 Knots Becoming North And Diminishing To 10 To 15 Knots. A Chance Of Waterspouts During The Day. Showers Likely During The Day, Then A Chance Of Showers Wednesday Night. Waves 3 To 6 Feet Subsiding To 1 To 3 Feet.|
|Thursday...North Winds 5 To 15 Knots Becoming Northeast. Waves 1 To 3 Feet Subsiding To 1 Foot Or Less.|
|Friday...East Winds 5 To 10 Knots Becoming Southeast. Waves 1 Foot Or Less. Winds And Waves Higher In And Near Thunderstorms.|
| Area Forecast Discussion|
National Weather Service Buffalo NY
1052pm EDT Sunday September 25 2022
A very wet pattern will continue through midweek as low pressure lingers for several days across southern Ontario and Quebec. This will bring periods of showers areawide and heavy lake effect rain at times east of Lake Erie and Lake Ontario with localized flooding possible. High pressure will finally build into the Great Lakes Thursday with a return to dry weather for late week.
Near Term - Through Monday
...SIGNIFICANT LAKE EFFECT RAIN WITH LOCALIZED FLOODING POSSIBLE EAST OF LAKE ERIE AND LAKE ONTARIO... A deep longwave trough will become established across the Great Lakes through Monday, with a mid level closed low developing near Georgian Bay. An east-west elongated surface low will consolidate near Georgian Bay tonight, then drift east across southern Ontario on Monday. 850MB temps will gradually drop to +5C by Monday, and a pool of cool 700MB temperatures and deep moisture will combine with warm lake temperatures to produce strong and deep lake induced instability, with lake induced equilibrium levels around 30K feet through the period. The heaviest rain amounts in these strongly unstable early season lake effect rain events tend to be right along the lakeshore as opposed to extending well inland.
From a synoptic standpoint, DPVA and height falls ahead of the digging longwave trough and sharper shortwaves at times trough will support occasional showers at times. The main story will be lake effect potential, as outlined below... Off Lake Erie... Through Monday a series of low amplitude shortwaves will move through the longwave trough. Each of these shortwaves will enhance the Lake Erie lake effect into Monday, but also modulate intensity and location, making the fine details of the forecast difficult. The very strong and deep instability over the lake combined with passing shortwaves may keep the lake effect showers more convective and cellular in nature, but nonetheless capable of producing locally heavy rainfall.
Initial batch of lake effect rain has become organized east of the lake across Chautauqua and southern Erie counties this evening. A shortwave is moving through with a hint of a mesolow in the radar imagery. Expect these showers to carry on eastward into the early overnight hours across the Southern Tier. An approaching shortwave over Michigan will then back the boundary layer flow to the southwest by early Monday morning, with lake effect rain moving back into southwest NYS well after midnight then becoming centered on the Buffalo Metro area toward daybreak Monday and lasting through most of the morning. Late Monday morning through Monday evening expect most of the heavier lake effect showers to hug the Lake Erie shore from Chautauqua County northeast to near Buffalo. Passing shortwaves will continue to modulate flow and convective depth, so expect lake effect rain organization and intensity to wax and wane numerous times through the period.
Rain amounts will reach 1-2" with locally higher amounts near Lake Erie through Monday evening, with additional rainfall after that as outlined in the short term section below. The risk for flooding will increase with each successive wave of rain as the ground saturates.
Off Lake Ontario... The position of the mid level low is not as favorable for a robust lake response through Monday evening. There will be some lake enhancement east and northeast of the lake from later this afternoon through tonight, centering on the Tug Hill initially this evening and then drifting north into Jefferson County overnight.
On Monday a digging shortwave upstream will back the boundary layer flow to SW or even SSW, shortening the effective fetch over the lake and pushing any lake effect rain north to the Saint Lawrence or even into Canada at times. The shortened fetch and less favorable climatological position of the mid level low will reduce the chance of heavy lake effect rain through Monday evening east of Lake Ontario. This will change by Tuesday, more on that in the short term section below.
Short Term - Monday Night Through Wednesday Night
...Significant lake effect rainfall amounts along with possible localized flooding expected east and northeast of Lake Erie and Lake Ontario... Heading into Monday night, broad upper level troughing will be spread across the eastern half of the continental United States, while ridging remains across the west. Within the troughing pattern a stacked low over southeastern Ontario Monday night will head northeast into southern Quebec Tuesday and continue to promote advection of cool moist air into the region. Overall this will continue to result in well defined lake effect/enhanced rains east and northeast of the lakes Erie and Ontario. Within the lake effect bands, expect heavy rain with the potential for some thunder/lightning closer towards the lakeshores, however with the shift of the low pressure system, west-southwest flow Monday night will veer to more of a westerly flow by Tuesday which will shift the heavier rain and thunder/lightning to east of the lakes. Total rainfall amounts Monday night and Tuesday can amount up to 1.5 to 2.5 inches. If rainfall amounts occur of this magnitude, some localized flooding may be possible and will need to be monitored.
A secondary cold front will cross the region early Tuesday night, which will likely push the ongoing lake effect bands south and onshore of both lakes ahead of its passage. Expect a brief lull in activity immediately after the secondary frontal passage before lake effect rain starts back up now as multiple bands south and southeast of both lakes as flow will be north-northwest to north west. However, if and where a Lake Huron/Georgian Bay connections establishes, expect some better focused lake effect rain. Otherwise with northwest flow regime expect some upslope enhancement.
Cool northwest flow will continue Wednesday morning which will result in lake effect rain showers to persist south/southeast of both lakes. Lake effect rain showers will then slowly diminish throughout the rest of the day Wednesday and Wednesday night as moisture is stripped away from the region from the departing low pressure system and incoming high pressure bubble over the Upper Great Lakes.
Long Term - Thursday Through Sunday
Thursday we will still be under cool cyclonic flow as the upper level trough exits out over Atlantic Canada. Meanwhile in the lower levels surface high pressure will be building in from the west. We could still see lake clouds...and an isolated rain shower south of Lake Ontario early Thursday before drier air from the west wins out and skies begin to clear. Clear skies Thursday night will allow for another cool night with overnight lows in the mid 30s...to lower 40s near the lakes. Inland frost is quite the possibility with light winds.
This surface high will bring fair weather Friday...and possibly into the start of next weekend. The forecast for next weekend will heavily depend upon the track and timing of tropical system Ian...which will move into an area of weak riding aloft over the Northeast. Thus still a bit of uncertainty to any direct impacts to our region.
Increasing southwest winds will bring very choppy conditions to Lake Erie this evening. Low pressure will move slowly east across southern Ontario and Quebec through Tuesday, setting the stage for an extended period of Small Craft Advisory conditions on Lake Erie and Lake Ontario through at least Tuesday night with WSW winds in the 15-25 knot range, with higher gusts.
Cool air aloft and favorable conditions for lake effect rain will continue to produce a chance of waterspouts through Wednesday.
NOAA Buffalo NY Office: Watches - Warnings - Advisories
NY...Beach Hazards Statement through late Tuesday night for NYZ010- 019-085. Flood Watch from 4am EDT Monday through late Tuesday night for NYZ010-019-085.
Small Craft Advisory until 8am EDT Wednesday for LEZ040-041. Small Craft Advisory from 6am Monday to 6am EDT Wednesday for LOZ045.