198 FXUS61 KBUF 061742 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 142 PM EDT Mon Sep 6 2021 .SYNOPSIS... While an isolated shower is possible this afternoon, most areas will remain dry as cold front moves east across the region. Dry and warmer weather is expected on Tuesday. The next chance for showers and thunderstorms will arrive Tuesday night and Wednesday as a pair of fronts move across the region. Cooler weather along with a chance for lake effect rain showers will follow for Thursday. && .NEAR TERM /THROUGH TUESDAY/... An upper level trough with an associated cold pool is moving east over northern NY as a cold front moves SE across WNY. Behind this, an upper level shortwave ridge is approaching the region. This should be overhead by Tuesday morning while associated surface high pressure moves into the central Appalachians. This patterns supports subsidence and valley fog formation, but otherwise quiet weather. For Tuesday, dry and warmer weather is expected under warm air advection as the upper shortwave ridge moves east and lower level southwest flow briefly moves in. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... A sharp mid level trough and closed low will advance from near Lake Superior Tuesday evening to near James Bay Wednesday evening, with a vertically stacked surface low taking a similar track. A surface cold front will surge east across the eastern Great Lakes late Tuesday night and Wednesday. Strong convergence along the front coupled with increasing large scale ascent ahead of the trough will produce a band of showers and possibly a few gusty thunderstorms, entering Western NY late Tuesday night and then advancing east across the rest of the area through the first half of Wednesday. A few storms may contain brief downpours and gusty winds, but the unfavorable diurnal timing will greatly limit the severe weather potential. A dry slot behind the cold front will bring a return to mainly dry weather from west to east later Wednesday. It will become quite breezy Tuesday night and Wednesday as the cold front crosses the area, with gusts of 25-30 knots expected northeast of Lakes Erie and Ontario. Wednesday night through Thursday night the base of the mid level trough will advance slowly east across the eastern Great Lakes. Several embedded shortwaves will move through the trough and cross our region, bringing with them periods of clouds and a few scattered showers. The airmass will also grow cold enough aloft to support the potential for lake effect rain showers. Wednesday night through Thursday morning the greatest chance of a few lake effect rain showers will be east of Lake Erie and Lake Ontario in a westerly flow regime. A passing shortwave will then disrupt the lake response during the day Thursday and result in general scattered showers. Thursday night boundary layer flow becomes northwest, directing lake effect rain showers southeast of Lake Erie and Lake Ontario. && .LONG TERM /FRIDAY THROUGH SUNDAY/... A still fairly-amplified upper level flow across North America at the start of this period will trend flatter and much more zonal over the weekend and early next week. This will result in lingering below average temperatures on Friday (highs ranging from the mid 60s to lower 70s) to climb back to average or a bit above for next week Sunday and Monday. The warmest overall day should be Sunday...when highs should range from the low-mid 70s across the higher terrain to near 80 across the lake plains. With respect to precipitation chances...expect some widely scattered lake effect rain showers southeast of the lakes at the start of Friday to transition to diurnally-driven activity of a similar coverage under lingering upper-level troughing...with this then ending altogether Friday evening as surface-based ridging and drier air build across the region. The aforementioned ridge should then provide us with dry weather for Saturday and much of Saturday night...before the next mid-level trough and its attendant surface front bring renewed lower-end chances for showers on Sunday. Depending upon exactly how quickly these latter features pass through our region...some showers could linger into Monday to at least some extent. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... VFR conditions are expected for the afternoon and early evening as a cold front moves SE across the region. VFR will continue overnight, although some valley fog is expected late. Any morning fog will dissipate early with VFR conditions areawide for Tuesday. Outlook... Tuesday night and Wednesday...Areas of MVFR in showers. Thursday and Friday...Mainly VFR with a chance of showers. Saturday...VFR. && .MARINE... Small craft advisory conditions will diminish late this afternoon and evening, as surface high pressure moves in together with the loss of daytime heating. This should occur first over Lake Erie, and then later over Lake Ontario. Quiet weather is expected for Tuesday as surface high pressure moves through the central Appalachians. The next pair of fronts arrive Tuesday night and Wednesday with a renewed chance for showers and thunderstorms as well as the potential for waterspouts. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...Beach Hazards Statement through late tonight for NYZ003-006- 007. Beach Hazards Statement through late tonight for NYZ004-005. Beach Hazards Statement until 8 PM EDT this evening for NYZ001- 002. MARINE...Small Craft Advisory until 5 PM EDT this afternoon for LEZ040- 041. Small Craft Advisory until 5 AM EDT Tuesday for LOZ043-044. Small Craft Advisory until 2 AM EDT Tuesday for LOZ042-045. && $$ SYNOPSIS...Zaff NEAR TERM...Zaff SHORT TERM...Hitchcock LONG TERM...JJR AVIATION...Zaff MARINE...Zaff