056 FXUS61 KBUF 192335 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 735 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/... IR satellite imagery showing clear skies this evening. Patches of thin/high cirrus upstream across the Central Great Lakes will drift east into our area overnight. 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...lows tonight will range from the upper 40s across interior portions of the Southern Tier/North Country to the lower to mid 50s elsewhere. Continued warming of our airmass will then support 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...mainly clear conditions are expected until increasing mid and high clouds develop out ahead of the next approaching system during Wednesday. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... A surface ridge will track east of the region Wednesday night. A southwest flow will increase in response to pressure falls centered across the central Great Lakes. An area of low pressure will track to the northwest while a cold front approaches the region Thursday. Drier air and lack of synoptic forcing ahead of the front will result in a mostly dry morning. Shower chances increase across far western NY and the northern Tug Hill region late Thursday morning before showers move into the rest of the region by Thursday afternoon. A potent shortwave trough behind this system will result in strong forcing. Showers, heavy at times are likely ahead of the front into Thursday evening. There is a slight chance of thunderstorms Thursday afternoon across interior portions of the region where daytime heating may result in some instability ahead of the front. The front will move to the east and cool air will filter back into the region. Temperatures at 850mb will fall to below zero by Friday morning. Some lake enhanced rain showers are possible into Friday morning. The cool airmass will persist over the region Friday and Friday night. Dry air and weak subsidence will move in aloft while daytime heating and lake induced instability promote the chances for scattered showers and strato-cumulus through Friday. Best chance will be southeast of Lake Ontario. Temperatures will start off in the mid to upper 60s Thursday and fall to the mid to upper 40s Thursday night. They only rebound to the low to mid 50s Friday before falling to the upper 30s to mid 40s Friday night. && .LONG TERM /SATURDAY THROUGH TUESDAY/... An upper level trough will push across the region Saturday and Saturday night, while a reinforcing cold front swings across the region. 850 mb temperatures are expected to cool to near -3C by Sunday morning, behind the front, which will be sufficient for a lake response off both lakes in general west-northwest flow regime. Should be greater moisture and there is potential for shortwave to work 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. Another cold front works through Sunday night with even colder air aloft arriving as low level winds turning more northwesterly. Showers will continue off both lakes and also over the higher terrain locations due to upslope flow. Precipitation type will be mainly rain this weekend, but with 850 mb temperatures as cold as -5C, could see some wet snowflakes across the higher terrain east of Lake Ontario both Saturday and Sunday nights and possibly even over western New York Sunday night. Trough axis will begin shifting east by Monday with the next system quickly bringing increasing chances for rain. && .AVIATION /00Z WEDNESDAY 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. Skies will be mainly clear through tonight with just a few patches of high/thin cirrus overnight. There will be an increase in mid clouds Wednesday out ahead of the next approaching system, but any showers will remain well northwest of our area through Wednesday evening. Otherwise...breezy conditions early this evening will subside. Some low level wind shear will persist tonight southeast of Lake Ontario including KROC. A west to southwest breeze will increase again Wednesday, with gusts of 20-25 knots expected from late morning through the afternoon, especially northeast of Lakes Erie and Ontario. 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 to southwesterly 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 8 PM EDT Wednesday for LEZ020-040- 041. Small Craft Advisory until 2 PM EDT Wednesday for LOZ043. Small Craft Advisory until 11 AM EDT Wednesday for LOZ042. Small Craft Advisory until 11 PM EDT Wednesday for LOZ045. Small Craft Advisory until 5 PM EDT Wednesday for LOZ044. && $$ SYNOPSIS...JJR NEAR TERM...Hitchcock/JJR SHORT TERM...HSK LONG TERM...TMA AVIATION...Hitchcock/JJR MARINE...Hitchcock/JJR