124 FXUS61 KBUF 070613 AFDBUFArea Forecast Discussion National Weather Service Buffalo NY 213 AM EDT Sun Sep 7 2025
.SYNOPSIS... A cool airmass over the region will lead to another fall-like day with periodic lake effect rain showers through tonight. Drier weather arrives Monday and lasts through the rest of the week as high pressure builds over the region. A warming trend will emerge through midweek before cooling off again through Friday.
&&
.NEAR TERM /THROUGH TONIGHT/... The axis of a deep longwave trough across the Great Lakes will advance eastward and cross the forecast area today. The 500mb cold core within this trough will slide northeast from near Lake Huron this morning to Quebec by the afternoon, with 850mb temps around +3C to +5C across the eastern Great Lakes. This will lead to another very autumn-like day with sfc high temps only in the 60s.
While most areas will remain dry today, synoptic moisture advecting in and WSW boundary layer flow will support lake effect rain showers off both lakes through at least the morning hours. Instability from the relatively warm lake waters could be sufficient to even support an isolated rumble of thunder closer to the shorelines. Behind a leading shortwave the steering flow will become more WNW oriented with decreasing moisture, which should both direct the lake effect activity more due east of the lakes and lessen the overall intensity. This should first occur off Lake Erie after daybreak, with Lake Ontario following suit by mid-morning. With the cold pool aloft and diurnal heating, a few more widely scattered showers may develop this afternoon.
As the BL flow becomes increasingly NW`erly and another thin plume of synoptic moisture moves overhead this evening, additional periodic lake effect rain showers are expected southwest of the lakes through much of tonight. Low temps may dip into the upper 30s across the interior S. Tier and N. Country overnight, with a range of 40s elsewhere.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/... Lake effect rain showers off Lake Ontario will come to an end prior to daybreak Monday, with just a few clouds left near the southeast corner of the lake Monday morning.
Strong surface high pressure over the eastern Great Lakes and Ohio Valley Monday will drift east across New England Tuesday, then reach the Canadian Maritimes Wednesday while a narrow ridge axis continues to extend back across New England and the eastern Great Lakes. Associated subsidence and dry air will bring a long stretch of dry weather to our region Monday through Wednesday and beyond.
Monday will still be cool, with highs ranging from the upper 60s for lower elevations to the low to mid 60s across higher terrain. Clear skies and light winds will allow for good radiational cooling Monday night, with lows well down into the 40s in most areas. The typical cold spots of the Southern Tier and North Country will likely drop into the mid to upper 30s with some patchy light frost possible. Day to day warming then develops Tuesday through Wednesday, with upper 70s across lower elevations by Wednesday afternoon.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... The extended period of dry weather will continue through the end of the week as high pressure and subsidence dominate much of the Northeast US and eastern Canada. A weak backdoor cold front will move south across the Great Lakes and New England Thursday, but this front will be starved for moisture and large scale support, likely coming through dry. The front will bring temperatures down a little for Friday before another warming trend develops next weekend.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/... A deep area of low pressure aloft with cool air flowing across the eastern Great Lakes will allow for lake effect clouds and showers through at least mid-morning today. Localized MVFR conditions are possible within the main lake effect areas, which will be initially east-northeast of the lakes early this morning (south of KBUF off Erie, north of KART off Ontario) before shifting southward. An isolated thunderstorm will be possible near the lakeshores through about 12z. VFR will prevail elsewhere through the day today.
Mainly VFR conditions will continue through tonight. As the boundary layer flow becomes more northwesterly this evening, additional lake effect showers will be possible southeast of the lakes through much of the night with very localized MVFR possible. This activity is expected to remain north of KROC (centered closer to KFZY) off Lake Ontario though may impact KJHW off Lake Erie. Otherwise, valley fog may develop in the Southern Tier though impacts are not expected at the TAF sites.
Outlook...
Monday through Thursday...VFR.
&&
.MARINE... Westerly winds on both Lakes will start to strengthen again early this morning, especially on central and eastern Lake Ontario where another round of Small Craft Advisories (see below) will be on tap through tonight. As winds briefly back to the southwest this afternoon, winds on Lake Erie may reach 15kts for a few hours with a noticeable increase in chop.
With a cool airmass overhead, lake effect rain showers, thunderstorms, and waterspouts will also be possible at times. The primary timeframe of concern for these will be through the morning hours today.
High pressure building over the lakes will cause winds to subside tonight into Monday, becoming light by Monday evening.
&&
.BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...Small Craft Advisory from 8 AM this morning to 8 PM EDT this evening for LOZ043. Small Craft Advisory from 8 AM this morning to 2 AM EDT Monday for LOZ044-045.
&&
$$
SYNOPSIS...PP NEAR TERM...PP SHORT TERM...Hitchcock LONG TERM...Hitchcock AVIATION...PP MARINE...HSK/JM/PP
NWS BUF Office Area Forecast Discussion