582 FXUS61 KBUF 191746 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 146 PM EDT Tue Oct 19 2021 .SYNOPSIS... High pressure extending from the Southeastern states to the Upper Ohio Valley will provide our region with warm and dry weather through Wednesday. A cold front will then cross the area on Thursday with widespread showers...with cooler conditions then returning for Friday and the upcoming weekend. && .NEAR TERM /THROUGH WEDNESDAY/... Broad high pressure extending from the Southeastern states to the Upper Ohio Valley will remain in place through Wednesday...while heights aloft continue to rise in the wake of a departing upper level low over Atlantic Canada. The net result of all this will be fair dry weather...along with notably warmer temperatures. The latter will also be aided by a relatively tight pressure gradient on the northern periphery of the surface high...which will not only result in breezy conditions/good mixing by day...but will also help to prevent significant decoupling at night. Speaking more specifically with respect to temperatures...850 mb temps of +6C to +8C will support highs in the mid to upper 60s across much of western New York this afternoon...with the higher terrain running a category or so cooler. Across the North Country... it will be a bit cooler still...with highs in the upper 50s to lower 60s. Lows tonight will then range from the upper 40s across interior portions of the Southern Tier/North Country to the lower to mid 50s elsewhere...with continued warming of our airmass then supporting fairly widespread highs in the mid 60s to lower 70s on Wednesday... with the warmest readings found across the lower elevations of the Finger Lakes and north of the Niagara Escarpment. In terms of cloud cover...lingering mid level clouds across the North Country and Saint Lawrence Valley will exit to our east this afternoon...with otherwise mainly clear conditions expected until increasing mid and high clouds develop out ahead of the next approaching system during Wednesday. && .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/... Progressive compact shortwave trough tracking across the Great Lakes through the period will bring next chance of rain to the region. Majority of showers well ahead of this feature in leading warm air advection regime will hold off til after midnight on Wed night, first reaching western NY and also arcing up toward North Country. Eventually swath of showers will spread across rest of region on Thursday ahead of cold front. Small chance of thunder with at least some MUCAPE and increasing low-level jet ahead of the front. Low-level jet will also result in breezy conditions Thursday afternoon into Thursday evening. Once the front crosses on Thursday evening, showers later Thursday night may become enhanced off lakes due to cooling west-northwest flow. Actually a brief potential for robust lake enhancement southeast of Lake Ontario with lake ELs rising quickly above 20kft, so could be some thunder in this activity. && .LONG TERM /FRIDAY THROUGH MONDAY/... A cold front exits east of the region Friday morning. Dry advection behind the front should result in minimal lake effect on Friday with best chances southeast of Lake Ontario. Temps drop back into the 50s for all areas. Weaker shortwave works across later Friday night into Saturday morning, so may be some light rain showers especially over Southern Tier to Finger Lakes. Later Saturday into Saturday night, as upper level trough drops across, a reinforcing cold front will swing across the region. H85 temps drop to at least -2c by Sunday morning behind that front which is sufficient for a lake response off both lakes in general west- northwest flow. Should be greater moisture and there is potential for shortwave to be working through at this time as well. Overall that will result in increasing chances for showers first downstream of the lakes, then expanding to more areas later Sunday as the trough axis/colder air aloft works across. Yet another cold front works through Sunday night (H85 temps -4c or even lower), veering winds to more northwesterly. Showers will continue off the lakes and also over the higher terrain locations due to upslope flow/lift. Ptype will be mainly rain next weekend, but with H85 temps flirting with -5c or even -6c at times later in the weekend per some of the colder guidance, could see some wet snowflakes across the higher terrain east of Lake Ontario (Sat night and Sun Night) and possibly even over western NY (Sun night). Trough axis will begin shifting east next Monday but next system could quickly bring another chance of rain. Pops were kept in the slight chance range for now. Temps will be similar or even cooler to what just occurred with daytime highs Saturday through Monday only in the 50s and even staying in the 40s east of Lake Ontario. Nighttime lows for all but the immediate lake plains (around 40) will drop into the 30s. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... Widespread VFR conditions will dominate our weather through Wednesday thanks to high pressure ridged from the Southeastern states to the Upper Ohio Valley. In terms of cloud cover...lingering mid level clouds across the North Country and Saint Lawrence Valley will exit to our east this afternoon...with otherwise mainly clear conditions expected until increasing mid and high clouds develop out ahead of the next approaching system during Wednesday. Otherwise...breezy conditions (gusts to 20-30 mph) this afternoon will give way to lighter surface winds tonight. While winds aloft will remain elevated enough to potentially lead to some LLWS southeast of Lake Ontario...this should remain away from our terminal locations. Outlook... Wednesday night...Mainly VFR with a chance of showers. Thursday...Restrictions likely with periods of showers. Friday through Sunday...VFR/MVFR with a chance of showers. && .MARINE... Broad high pressure extending from the southeastern States to the Upper Ohio Valley will only slowly drift to the east coast through Wednesday. A fairly tight pressure gradient on the northern periphery of this surface high will produce a moderate westerly flow into Wednesday...necessitating Small Craft Advisories for the nearshore waters of both lakes. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...Small Craft Advisory until 5 PM EDT Wednesday for LEZ040-041. Small Craft Advisory until 5 PM EDT Wednesday for LOZ043>045. Small Craft Advisory until 11 AM EDT Wednesday for LOZ042. && $$ SYNOPSIS...JJR NEAR TERM...JJR SHORT TERM...JLA LONG TERM...JLA AVIATION...JJR MARINE...JJR