321 FXUS61 KBUF 161422 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 1022 AM EDT Sun Oct 16 2022 .SYNOPSIS... High pressure ridged from the Ohio Valley to New England will provide our region with fair weather and seasonable temperatures today. A deep trough of low pressure will then dig across the Great Lakes and Northeast tonight and Monday...then will linger across our region right through Thursday. This will result in a prolonged period of much colder temperatures and unsettled weather that will feature scattered to numerous rain showers...and areas of lake effect rain downwind of the lakes. Across the higher terrain... the rain showers may also mix with some wet snow at times each night beginning with Monday night. && .NEAR TERM /THROUGH TONIGHT/... A narrow wedge of high pressure ridged from the Ohio Valley to New England will provide our region with fair and uneventful weather today. Visible satellite imagery late this morning showing a deck of mid level clouds across much of southern Ontario and the Niagara Frontier to near Rochester. This will bring overcast skies through midday to early afternoon from Buffalo to Rochester, and also the North Country from late morning through early afternoon. Upstream satellite trends suggest this area of clouds will move northeast and retreat from our area this afternoon, with increasing amounts of sunshine for later this afternoon. Otherwise...winds today will be much lighter than Saturday though still on the breezy side northeast of Lake Erie...while 850 mb temps of +1C to +4C should translate into highs ranging from the mid to upper 50s across the higher terrain to the lower 60s across the lower elevations. All of this should make for a great opportunity to view the rather vibrant fall foliage that has developed of late...especially when given the weather that is on the way for much of the upcoming week. If you have the opportunity to do so...be sure to take advantage. As we move into tonight...our weather will start to go downhill as a potent shortwave dives through the western flank of the larger-scale upper trough over the Great Lakes...and encourages the development of a closed upper level low over Michigan by Monday morning. At the surface...an associated broad surface low will deepen over Lake Huron...with this increasingly energetic feature helping to slowly push a cold front across our area through the course of the night. While the frontal passage itself should merely produce some scattered rain showers as it crosses the area...increasing cold advection and rapidly deepening moisture immediately in its wake will trigger a strengthening lake response off Lake Erie during the second half of the night...with a rapidly organizing band of lake effect rain showers setting up on a 220-230 degree flow. This will result in a band of moderately heavy rain showers becoming oriented across areas between KBUF and KIAG by later on in the night...with this only expected to strengthen further during the day Monday (for more details on that...see the Short Term section below). Otherwise...we can expect nighttime lows to range from the upper 30s to mid 40s. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... The pattern across North America will become highly amplified through the first half of next week with a large Omega Block across the western US and a deep longwave trough downstream across the east. This will set the stage for an extended period of below normal temperatures and unsettled weather. While it will be chilly, the airmass will only be marginally cold enough to support a chance of some wet snow mix across higher terrain through Tuesday night, with mainly rain for lower elevations. Lake effect rain may be heavy at times, especially Monday and Monday night off Lake Erie from the Buffalo northtowns to Niagara County. Looking at the details, Monday cold air will pour into the eastern Great Lakes as a mid level circulation dives into the longwave trough. Most of the synoptic scale rain showers along the advancing cold front will focus over the eastern Lake Ontario region Monday morning. 850MB temps will drop to around -3C on Monday over Lake Erie. Deep, strong instability over the lake will support the development of organized lake effect rain over and northeast of Lake Erie, with flow averaging 230 degrees in the boundary layer before shifting to the SSW Monday evening. This will direct lake effect rain showers, into the Buffalo Northtowns, Grand Island, and Niagara County. Lake effect rain showers will be heavy at times, with some embedded thunderstorms possible. Rainfall amounts of an inch or more are possible. Precipitation type will stay all rain Monday through Monday evening. Later Monday night some wet snow may start to mix in across the higher terrain of the western Southern Tier and Tug Hill region. The southwest flow will keep the organized lake effect away from higher terrain areas, with some light (an inch or less) accumulations possible across higher terrain late Monday night. Tuesday and Tuesday night the axis of the longwave trough will advance slowly east across the Great Lakes, bringing increased synoptic scale forcing and deep moisture with time from west to east. 850MB temps will remain close to -3C through the period, cold enough for a strong lake response but generally not cold enough for much in the way of snow except for some mix across the high terrain. A bit more uncertainty in band placement here because more subtle shortwaves will pivot around the closed upper low which will impact wind direction. In general a SSW to SW flow will be maintained in the boundary layer, but as shortwaves cross winds aloft may become more westerly at times, allowing lake effect showers to spread a bit further inland. Precipitation type will stay rain at lower elevations Tuesday and Tuesday night, with some wet snow mix possible across the high terrain Tuesday night. Meanwhile over Lake Ontario, even more southerly component will direct most, if not all of the lake effect rain Monday and Tuesday into Canada to the west of Jefferson County, with just a few light upslope showers across the higher terrain east of Lake Ontario. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... Deep closed low will remain along the Quebec/Ontario border on Wednesday, before moving slowly northward to James Bay on Thursday. A moist, cyclonic flow will keep a persistent threat for showers over the entire area Wednesday and Wednesday night. However steadiest showers will be east/northeast of the lakes due to lake enhancement. West winds on Wednesday will shift to the southwest Wednesday night, with corresponding lake effect bands moving north. Meanwhile, temperatures aloft will be marginally cold enough (-3C to -6C) to support some wet snow. This will mainly be the case at higher elevations and during the colder nighttime and early morning periods. Some minor accumulations are certainly possible across higher terrain, with perhaps a few snowflakes but no accumulation expected across lower elevations. High pressure will build across the mid-Atlantic states Thursday, as the deep trough across the Northeastern states begins to lift off to the north. A few lingering showers are possible Thursday and Thursday night, with Friday and Saturday expected to be mainly dry and a bit warmer. High temperatures Wednesday and Thursday will only be in the 40s at most locations with nighttime lows in the 30s. By Saturday, highs will range from the upper 50s to mid 60s. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... High pressure draped from the Ohio Valley to New England will provide our region with fair dry weather through early this evening. There will be a period of mid level clouds between this morning and early this afternoon north of the Southern Tier...with some lake effect clouds also around early this morning in the vicinity of KIAG and east of Lake Ontario. This said...flight conditions will still be VFR. Much lighter winds will also be in place compared to Saturday...though some gusts between 20 and 25 knots can still be expected at KBUF/KIAG from late this morning through mid to late this afternoon. Tonight a cold front will slowly cross the area along with some scattered rain showers and a period of MVFR/lower VFR ceilings. Behind the front...a developing band of lake effect rain showers and attendant MVFR conditions will set up off Lake Erie overnight...with this focused on areas from KBUF to KIAG. Outlook... Monday through Tuesday...Scattered to numerous rain showers along with areas of lake effect rain/MVFR from KIAG-KBUF and mainly northwest of KART. The rain will mix with wet snow across the higher terrain both Monday and Tuesday nights. Wednesday and Thursday...Scattered to numerous rain showers along with areas of lake effect rain/MVFR east and northeast of the lakes. The rain will again mix with wet snow across the higher terrain Wednesday night. && .MARINE... Moderate southerlies will will freshen a bit on Lake Erie today... while also briefly veering to the southwest. While the flow should have enough of a southerly component to keep true advisory-worthy conditions confined to Canadian waters...conditions will still become fairly choppy for a time...particularly well offshore. A cold front will then cross the Lower Lakes region tonight... with winds veering to the southwest on both lakes...and also freshening again across Lake Erie. It's likely that this will eventually necessitate Small Craft Advisories for Lake Erie by Monday morning. A nearly stationary storm system centered over southern Ontario on Monday will then generate fresh to strong southwesterlies... particularly on Lake Erie. High end SCA's will be needed at that time for Lake Erie...while the roughest conditions on Lake Ontario may be confined to the Canadian side of the border. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...JJR NEAR TERM...Hitchcock/JJR SHORT TERM...Apffel/Hitchcock LONG TERM...Apffel/Thomas AVIATION...JJR MARINE...JJR/RSH