227 FXUS61 KBUF 100200 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 1000 PM EDT Tue Oct 9 2018 .SYNOPSIS... Very warm and humid conditions will remain over the area through midweek. A strong cold front will then cross the area Thursday with showers and scattered thunderstorms. Dramatically cooler temperatures will move into the area Friday through early next week. && .NEAR TERM /THROUGH WEDNESDAY/... It's a pleasant evening across Western New York with mostly clear skies and warm temperatures. A deep southerly flow over the area will continue through the nighttime hours as the sandwich between high pressure anchored south of the New England coast and low pressure over the Upper Midwest will deliver consistent gradient flow from the SW over the area. This will translate into a very warm night, with the warmest temperatures across the lake plains where this flow tends to downslope. A slow pattern evolution will allow for another sultry October day on Wednesday, as well. Temperatures at 850 hPa fail to evolve really at all from the readings seen this afternoon, and with a similar mixing profile, high temperatures in the neighborhood of those seen today seem reasonable. As such, widespread low to mid 80s seem probable across the area. However, owing to the fact that most climate sites have higher record values tomorrow as compared to today, new record highs seem less likely tomorrow. && .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/... Conditions will rapidly deteriorate Wednesday night...as a sub 1000mb low in the vicinity of Lake Superior will push its strong cold front across the Upper Mid West to the western end of Lake Erie. Meanwhile...the well established southerly flow in advance of the front will advect deepening moisture across our region. This could include some of the moisture from what will be left of tropical system Michael...although it is looking more likely that most if not all of that should stay well to our southeast. In any case...the increased moisture will initially be lifted by forcing being offered by a diffluent upper level flow within a sheared negatively tilted trough...but moreso by being under the right rear entrance region of a 100kt H25 jet over the Upper Great Lakes. This will later SUPPLEMENT the main source of lift...which will be convergence near and ahead of a pre-frontal surface trough. The rain should arrive around midnight across the far western counties...then quickly spread east and become more widespread through the wee hours of the morning. It could become heavy at times during the late night hours as well...particularly for sites EAST of the Genesee Valley if the tropical moisture can become entrained into the environment. Basin average rainfall amounts should remain under a half inch... with localized amounts up to an inch. The cold front will plow across our region on Thursday...likely clearing the Eastern Lake Ontario by mid afternoon. The steadiest... most widespread rain will be found some 25 miles ahead of this main front where the previously described forcing with the pre frontal trough will be maximized. Nevertheless...the showers will gradually taper off from west to east during the afternoon when some breaks in the cloud cover will advance across the state as well. While cold advection in the wake of the front will likely force our max temps to occur during the midday...the mercury should still make it to within a few degrees of 70. This will especially be the case for sites east of the Genesee valley. Strong cold advection will be then found across the Lower Great Lakes Thursday night with H85 temps plummeting from double digits to near zero c by daybreak Friday. At this time of year when lake temps are in the lower 60s...this will undoubtably support increasingly unstable conditions over the lakes. The deepening cold air will establish lapse rates as steep as 10 deg c/km over Lakes Erie and Ontario by daybreak...although a robust 4 deg c cap based around 6k ft will limit the intensity of the ensuing lake driven rain showers. A well aligned 290-300 flow will aim the Lake Erie showers across the bulk of the Southern Tier while a more organized band of showers will impact sites from the Wayne county shoreline to Oswego county. The latter activity will be enhanced by a multiband connection to Lakes Superior and Huron. Our weather will turn colder with several chances for rain showers Friday and Friday night. A mid-level trough on the heels of Thursday's cold front passage will bring in a shot of modified western Canadian air across the Great Lakes. 12z GFS/EC consensus drops 850mb temps over the eastern Great Lakes to -2C. This is cold enough to support lake effect showers with the 12z GFS BUFKIT profile over Lake Ontario showing lake induced equilibrium levels rising to around 15 kft Friday night. Guidance does suggest synoptic moisture will be sufficient to support lake effect rain showers Friday and Friday night before tapering off Saturday as surface high pressure ridges over the eastern Great Lakes squashing the lake plumes. Have maintained continuity in the forecast with chance POPs for rain showers east/southeast of Lake Erie and Ontario Friday and Friday night under 290-300 flow. There may even be some wet snow mixing in on the higher terrain of the Tug Hill Friday night with a slight chance Saturday night as surface temps dip into the mid/lower 30s. The remnants of Hurricane Michael are forecast to pass well south and east of western New York through Friday. && .LONG TERM /FRIDAY THROUGH TUESDAY/... Surface ridging with the center of high pressure passing to our south will support a lull in shower activity later Saturday into Saturday night. Global model consensus then agrees on an opportunity for more widespread showers, Sunday into next Monday as the remnants of Hurricane Sergio in the eastern Pacific cross the CONUS and potentially reach the eastern Great Lakes by Sunday. A blend of guidance generally led to widespread chance POPs with likely POPs limited to far western NY Sunday and east of Lakes Erie and Ontario Sunday night. Confidence drops off considerably for Tuesday...as medium range ensembles have two main trains of thought. One is that low level ridging over the Lower Great lakes will give way to an advancing warm frontal boundary...while the other suggests a deepening cutter storm going by to our west. Will lean towards the former as per WPC guidance. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... Tonight dry weather and widespread VFR conditions are expected to continue, with the exception of some low MVFR/isolated IFR stratus possibly forming after midnight once again across the higher terrain of the Southern Tier, mainly across Cattaraugus and Allegany Counties. VFR conditions return during Wednesday with gusty SW winds again. Outlook... Wednesday night and Thursday...Areas of MVFR with showers and a chance of thunderstorms. Friday...Areas of MVFR/IFR southeast of the lakes in lake effect rain showers, VFR elsewhere. Saturday...A chance of lake effect rain showers and MVFR early southeast of the lakes, otherwise VFR. Sunday...A chance of MVFR conditions in rain showers. && .MARINE... High pressure will remain anchored to the east with modest winds and no marine headlines tonight and Wednesday. A strong cold front will then cross the eastern Great Lakes Thursday. Southwest winds will become moderate to strong behind the cold front, and gradually veer to the northwest through Friday as much cooler air pours into the eastern Great Lakes. This will produce higher end Small Craft Advisory conditions on Lakes Erie and Ontario during the late week period. && .CLIMATE... A very warm airmass will remain across our region right through Wednesday. Below are the record temperatures this period. New record highs were set for Buffalo and Watertown today, with Rochester falling a couple degrees short. Also, today's record warm minimum temperature is in serious jeopardy for all 3 locations today. Buffalo... Date Record High/Year Record Warm Minimum/Year 10/9 81/1909 65/1913 10/10 85/1949 65/1879 Rochester... Date Record High/Year Record Warm Minimum/Year 10/9 88/1949 64/1914 10/10 89/1949 64/1914 Watertown... Date Record High/Year Record Warm Minimum/Year 10/9 81/1949 58/1950 10/10 82/1949 62/1949 && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...Fries NEAR TERM...Apffel/Fries SHORT TERM...RSH LONG TERM...RSH/Smith AVIATION...Apffel/Fries MARINE...Apffel/Fries CLIMATE...Thomas/JJR/Apffel