Lake Ontario - Open Waters from Mexico Bay to the St Lawrence River Marine Forecast
|Tonight...West Winds 15 To 20 Knots Becoming Northwest 10 To 15 Knots. Showers Likely Early, Then A Chance Of Showers Late This Evening. Waves 3 To 6 Feet Subsiding To 2 To 4 Feet.|
|Thursday...Northwest Winds 5 To 15 Knots Becoming West. Waves 1 To 3 Feet.|
|Thursday Night...West Winds 10 Knots Or Less Becoming Southwest. Showers Likely Overnight. Waves 2 Feet Or Less.|
|Friday...West Winds 10 Knots Or Less Becoming Northwest. Showers Likely. Waves 1 Foot Or Less.|
|Friday Night...Northwest Winds 5 To 10 Knots Becoming West. Showers Likely. Waves 1 Foot Or Less.|
|Saturday...West Winds 10 To 15 Knots. A Chance Of Showers During The Day. Waves 1 To 3 Feet.|
|Sunday...West Winds 5 To 15 Knots Becoming Northwest. Waves 1 To 3 Feet.|
|Monday...Northwest Winds 10 To 15 Knots. Waves 1 To 3 Feet Building To 2 To 4 Feet.|
| Area Forecast Discussion|
National Weather Service Buffalo NY
751pm EDT Wednesday May 5 2021
Rain showers are possible this evening before drier air sweeps across the region from west to east tonight. This dry air will bring clearing skies and cool conditions later tonight. Pleasant, but seasonably cool conditions Thursday before another upper level disturbance brings rain showers back into our area Thursday night and Friday. Seasonably cool conditions will continue through the weekend.
Near Term - Through Thursday
Regional radar shows scattered showers moving from west to east across western NY and north central NY this evening. Most of the shower activity will be light and short-lived with an area of greater shower activity entering the Eastern Lake Ontario region this evening.
The leading edge of a cooler airmass will dive across our region this evening. A secondary cold front over southern Ontario, just north of the Lakes will lead to scattered showers this evening. Eventually though the front will clear out the moisture, such that skies will gradually clear from west to east tonight though it may take until well after midnight in some areas. Still looks like there will be a gentle breeze within a modest pressure gradient across the area so although there could be some frost or maybe some fog over Southern Tier, do not expect frost to be widespread enough to justify an advisory at this point for Chautauqua county. Expect lows to drop into the mid to upper 30s.
Lingering clouds early on Thursday will mix out and result in mostly sunny skies through at least mid afternoon before clouds increase again ahead of next system due to bring some rain in here on Thursday night. It will stay cool though with highs warmer than today, but still below normal by 5-10F. Expect readings to reach 56-57 on the lake plains and maybe near 60F in Genesee valley around Dansville, while staying in the upper 40s/around 50F on the higher terrain east of Lake Ontario.
Short Term - Thursday Night Through Saturday Night
The last of the surface high pressure will be shoved east into New England during the first half of Thursday night. Therefore, dry conditions from earlier in the day will continue into the evening.
An upper level closed low over James Bay and its associated broad trough over the eastern half of the contiguous United States will allow a few shortwaves to rotate through its base Thursday night through the weekend. The passage of the shortwaves will support shower chances starting late Thursday night and last through much of Saturday. Conditions will begin to dry out Saturday night.
Otherwise this pattern will support a cooler Canadian airmass overhead, which will keep our temperatures below normal. Expect highs to range in the 50s throughout the period.
Long Term - Sunday Through Wednesday
A broad trough spanning east of the Mississippi River earlier in the week will have begun to transition east at the start of the period, putting another closed low over the Northern Great Lakes and zonal flow over the region. While the trough is still overhead, a couple of more shortwaves will pass through for the later half of the weekend and start of the next work week, continuing the chances for showers. However, the better chances look to remain north and south of the area and therefore mostly dry conditions should prevail.
As the trough pushes east Tuesday, a broad area of surface high pressure will work its way into the region and support a period of dry weather to last through at least the middle of next week.
In regards to temperature, cool conditions will continue as the large trough pattern remains overhead/in the vicinity. Thus, expect below normal temperatures throughout the entirety of the period.
A secondary cold front will slice across the Lakes this evening, and west to northwest winds behind the front will strengthen on Lake Ontario...with small craft conditions continuing through the night along the southern and eastern shoreline. Winds, and eventually waves, will diminish late tonight and Thursday as surface high pressure pushes toward the Lakes.
An upper level disturbance will pass across the eastern Great Lakes late Thursday Night and Friday, but with this system rooted more aloft than at the surface, expect waves to remain under small craft thresholds.
NOAA Buffalo NY Office: Watches - Warnings - Advisories
Small Craft Advisory until 8am EDT Thursday for LOZ043-044. Small Craft Advisory until 5am EDT Thursday for LOZ042- 045.