Lake Ontario - Open Waters from the Niagara River to Hamlin Beach Marine Forecast
|Today...South Winds 5 To 10 Knots Becoming Southwest And Increasing To 15 To 20 Knots. Rain This Morning, Then A Chance Of Showers Early This Afternoon. Waves 1 To 3 Feet Building To 2 To 4 Feet.|
|Tonight...Southwest Winds 15 To 25 Knots Becoming South. A Chance Of Showers After Midnight. Waves 3 To 5 Feet.|
|Friday...Southwest Winds 15 To 25 Knots. A Chance Of Waterspouts. A Chance Of Showers. Waves 3 To 6 Feet.|
|Friday Night...Southwest Winds 15 To 20 Knots Becoming South 10 To 15 Knots. Waves 3 To 6 Feet Subsiding To 1 To 3 Feet.|
|Saturday...South Winds 15 To 20 Knots Becoming West. A Chance Of Waterspouts. Showers Likely. Waves 1 To 3 Feet Building To 2 To 4 Feet.|
|Sunday...Southwest Winds 15 To 20 Knots Becoming West. A Chance Of Waterspouts. A Chance Of Showers. Waves 2 To 4 Feet Building To 3 To 6 Feet.|
|Monday...West Winds 5 To 15 Knots. A Chance Of Showers Monday Night. Waves 2 To 4 Feet Subsiding To 1 To 3 Feet.|
| Area Forecast Discussion|
National Weather Service Buffalo NY
650am EDT Thu September 23 2021
A cold front will slowly move from west to east across the area, with the steadiest and heaviest rain across Western NY this morning before moving across the Eastern Lake Ontario region this afternoon and evening. Cooler and drier weather will return for most areas on Friday, except northeast of Lake Erie where some lake effect rain showers will be possible. Another cold front will then bring a chance of more showers on Saturday.
Near Term - Through Tonight
A closed off and occluded low across western Lake Erie this morning will will drift slowly northward across Lake Huron today. Meanwhile, a cold front will very slowly move east across the area today. Strong moisture transport and dynamics ahead of the system will support a swath of moderate to heavy rain along the slowly advancing cold front.
So far rainfall amounts are in line to slightly lower than consensus Quantitative Precipitation Forecast. Storm totals are around an inch and a quarter across far Western New York, but radar shows the back edge of the heavy rain is very close with steady rain ending shortly after daybreak in Buffalo. Marginal instability supports a few thunderstorms through today, but so far lightning strikes have been isolated in nature.
The band of moderate to heavy rain will slowly move from west to east across the forecast area today. 00Z model guidance ends precipitation slightly faster than previous runs. Storm total rainfall amounts of 1-2 inches expected. This will support rises in creeks and rivers, and some ponding on roadways but is unlikely to produce widespread flooding.
Otherwise, pre-frontal temperatures in the lower to mid 70s will drop into the 60s following the frontal passage today. A distinct dry slot will even support some sunshine across Western New York this afternoon.
Steady rain will exit east of Lewis County shortly after midnight tonight which will leave the vast majority of the area rain-free. The exception is the Niagara Frontier where some lake effect rain showers are likely late tonight. Persistent winds will limit radiational cooling, especially across the Niagara Frontier where winds will gust to 30 mph near the lakeshores. Even with limited radiational cooling, the cooler air mass will support low temperatures from the mid 40s to lower 50s.
Short Term - Friday Through Saturday Night
Friday and Friday night a closed upper level low initially over the Central Great Lakes will lift north to Hudson Bay...while opening up and eventually merging with another large-scale upper level trough digging southeastward across the Upper Mississippi Valley/Upper Great Lakes. The lingering cool cyclonic flow and wraparound moisture attendant to the departing closed low will support a short-lived lake response northeast of Lake Erie Friday...and northeast of Lake Ontario later Friday afternoon into Friday evening.
In the case of the Lake Erie activity...an initially sheared south- southwesterly flow will direct a broken band of showers mainly across the Niagara Peninsula to Niagara county through about mid- morning...with this then settling a bit further south to areas between KIAG-KBUF later in the morning with some subtle veering of the low level flow. After that time...strong diurnal influences and drying of the column will result in the activity breaking up into some scattered showers...before eventually falling apart altogether by late in the day. Given the above disruptive influences and the rather sheared flow/inversion heigheights of only 6-7 kft to begin with...have capped Probability of Precipitation in the likely range and kept rainfall amounts from this activity rather modest.
As for the Lake Ontario lake effect...insufficient moisture should preclude any lake response until early to mid afternoon...and even then the general sheared southerly flow/short fetch and diurnal influences should keep this initially confined to some scattered showers across Jefferson county and the uppermost Saint Lawrence River valley. Some veering of the still-rather sheared flow may then allow for a brief uptick in coverage/areal extent late Friday into early Friday evening...but even then any showers should remain largely scattered before diminishing after midnight as the column dries out.
Otherwise...mainly dry and cool weather will be the rule through Friday night. 850 mb temps of +4 to +6C will support highs mainly in the lower to mid 60s on Friday...with lows Friday night then settling into the mid to upper 40s across most of the area...with some lower 50s found closer to the lakeshores.
Saturday and Saturday night the next upper level trough will become increasingly negatively tilted as it slides from the Upper Great Lakes to the Ontario/Quebec border and New York State. As it does so...it will swing its attendant cold front eastward and across our area...though the various guidance packages still exhibit some disagreement on the exact timing of the frontal passage. Given the negative tilt to the supporting trough and the anafrontal nature of the boundary...feel that a somewhat slower solution is more in order and have therefore backed off a bit on the timing of any associated precip...with dry conditions expected until at least early afternoon across far WNY and through most if not all of the day further east. Once the front does arrive...expect a period of scattered to numerous showers to follow its passage...with the greatest potential for/coverage of these found across far western New York. As Saturday night progresses...a fresh shot of cooler air will overspread our region in the wake of the boundary...and this in tandem with sufficient synoptic moisture should result in additional lake effect rain showers developing northeast of both lakes.
As for temperatures...brief warming out ahead of the front will send 850 mb temps back up to +8/+9C on Saturday...or enough to support highs in the upper 60s across the higher terrain and lower to mid 70s on the lake plains...with the warmest readings found across the Finger Lakes Region. Cool advection following the frontal passage will then result in temps falling back to the upper 40s to lower 50s Saturday night.
Long Term - Sunday Through Wednesday
Following Saturday's frontal passage...a cyclonic west-southwesterly to westerly flow of cooler air will continue through Sunday and Sunday night. This should result in some lake effect/lake-enhanced showers northeast and east of both lakes...with upsloping also helping to enhance the showers at points. With this in mind have continued to adjust NBM PoPS for this period to better reflect the expected lake and terrain enhancement. By Monday...the medium range guidance diverges significantly with respect to the placement of surface synoptic features and the low-level thermal structure of the airmass across our region...so for that time frame have reverted to more broadbrush slight chance PoPs.
Looking further out into next week...a general amplifying upper level trough is favored to persist over the Lower Great Lakes and Northeast...though the various guidance packages also unsurprisingly show some disagreement on exactly how amplified the trough will get and the placement of its axis...with the 00z GEM/ECMWF (European Centre for Medium-Range Weather Forecasts) both deeper and further west than the GFS. This said...all three suggest at least some potential for an Alberta Clipper-like system to slide southeastward through the larger-scale trough and potentially bring some showers to our region Monday night and/or Tuesday...with lake effect and/or lake-enhanced showers also appearing possible downwind of the lakes given the seasonably cool cyclonic flow that should be in place. With this in mind...have indicated a general mix of slight chance to low chance Probability of Precipitation to cover this.
Otherwise temperatures will range from near to a little below average throughout this period...with daily highs mostly in the 60s and nightly lows ranging from the mid 40s to lower 50s.
Brisk S-SE flow today will direct the highest waves offshore and across Canadian waters even though winds will run 15 to 20 knots at times. Winds will shift to the SSW behind the cold front and eventually to the SW. Cooler temperatures behind the front will allow for better mixing, so hedge above model guidance for winds behind the front late today and tonight. Winds and waves likely to support SCA (Small Craft Advisory) headlines tonight and Friday for Lake Erie and the Upper Niagara River. Small craft headlines may also be needed for the eastern waters of Lake Ontario. Winds will diminish Friday night when a high pressure ridge nudges closer to the waters.
There's a limited risk for waterspouts Friday and Friday night. Winds will be a bit on the strong side Friday, then once winds diminish and allow better land breeze convergence the moisture will be limited.
NOAA Buffalo NY Office: Watches - Warnings - Advisories