Mount St. Louis Moonstone Snow Report

871 FXUS61 KBUF 010620 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 220 AM EDT Tue Sep 1 2026 .WHAT HAS CHANGED... Minor changes to the forecast with this update. && .KEY MESSAGES... 1) Active weather pattern through midweek with multiple rounds of showers and thunderstorms, including severe thunderstorm potential mainly late Wednesday through Wednesday night. 2) Warm and very humid today through Wednesday with a heat index in the lower 90s Wednesday across portions of Western and Central NY. && .DISCUSSION... KEY MESSAGE 1...Active weather pattern through midweek with multiple rounds of showers and thunderstorms, including severe thunderstorm potential mainly late Wednesday through Wednesday night. A northwest to southeast oriented complex frontal zone will remain in place across the Great Lakes through midweek, with an active pattern continuing. The greatest timeframe of concern will be late Wednesday afternoon through the first half of Wednesday night, when the severe weather and flash flooding potential peak. Today, a mid level shortwave will continue to move southeast across northern and eastern NY through early to mid morning. Large scale ascent from the shortwave will combine with frontogenesis and moisture convergence along the frontal zone to support periods of rain across Central NY and the North Country, but this will taper off later this morning. Farther west, weaker forcing will only support a few scattered showers across Western NY and the Genesee Valley through early to mid morning. There may be a few embedded rumbles of thunder, but coverage of any thunderstorms will remain sparse through this morning. This afternoon, subsidence and a bubble of drier mid level air behind the departing shortwave will keep much of the area dry. The combination of diurnal heating, warm advection, and the arrival of another shortwave late in the day may support a few more scattered showers and thunderstorms across Central NY and the North Country, especially across higher terrain. Farther west, a few isolated showers and thunderstorms may develop along the lake breeze convergence zone from the Niagara Frontier east across the Genesee Valley and western Finger Lakes, but otherwise expect dry weather to prevail in most areas. Tonight, any spotty showers and thunderstorms will end in the evening with the loss of daytime heating. Dry weather will then prevail most of the night. A few showers and isolated thunderstorms may move into Western NY very late tonight or early Wednesday morning as the weakening remnants of upstream convection move into the area. Wednesday through Wednesday night, a strong mid level trough will advance east across Ontario and Quebec, with height falls and DPVA spreading into the Great Lakes in the afternoon and evening. An EML will be captured and advected to near Lake Erie, with EML induced capping allowing a reservoir of strong instability to develop across the southern Great Lakes. Convective initiation will focus along the northern edge of the EML where rising parcels can more easily breach the EML induced cap, with this occuring upstream during the afternoon with the arrival of large scale ascent. Clusters of convection will move ESE across the eastern Great Lakes from late afternoon through the first half of Wednesday night. Severe Weather Potential: Today through tonight, the severe weather potential will remain low but non-zero across the area. A notable lack of forcing for ascent from synoptic scale or meso-alpha scale features combined with warm/dry mid levels will likely keep any coverage of deep moist convection sparse this afternoon and evening. Effective shear is also quite modest today, with 20-30 knots of flow through the mid levels. Strong surface based instability will develop this afternoon, so if any isolated convection does form there will be a risk of isolated strong wind gusts and hail, but this will be the exception rather than the rule. Late Wednesday through Wednesday night continues to look much more interesting, with strong instability, strong shear, and sufficient forcing all potentially aligning in time and space. Strong instability and strong effective shear will potentially support all convective modes, including bowing segments and supercell structures. The strong shear is producing elongated hodographs in forecast soundings, although low level hodograph curvature is relatively modest in largely unidirectional flow. The primary hazard will be damaging wind gusts, with a lower secondary risk of isolated large hail. PWAT values approaching 2 inches will also support some flash flood potential if training occurs. An isolated tornado cannot be ruled out given the forecast shear profiles. Ultimately, the degree of severe potential will hinge in timing and placement of mesoscale features which cannot be reliably resolved in model guidance at this time range. Stay tuned. KEY MESSAGE 2...Warm and very humid today through Wednesday with a heat index in the lower 90s Wednesday across portions of Western and Central NY. Humidity will build today and continue through Wednesday, with surface dewpoints rising into the upper 60s to lower 70s areawide. Dewpoints may approach the mid 70s at times along lake breeze boundaries where low level moisture convergence maximizes. Clouds will help to hold temperatures down somewhat today, with highs in the lower 80s across Western and Central NY with a peak heat index in the upper 80s this afternoon. Temperatures will likely be warmer Wednesday with less cloud cover through the heat of the day. Expect highs in the mid 80s across Western and Central NY, with some of the warmer inland valleys in the upper 80s. Peak heat index values will reach the lower 90s. The frontal zone will gradually drift south Thursday, then move well south and west of the area by Friday. A cooler and much less humid airmass will arrive by Friday, and remain in place through the upcoming holiday weekend. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... A mid level shortwave crossing northern NY will combine with a stalled frontal zone over the eastern Great Lakes to support areas of showers through early to mid morning, with the greatest coverage of showers across Central NY and the North Country. Farther west, any showers will be more scattered in nature across Western NY. Some limited elevated instability may support isolated embedded thunder, but coverage of any thunderstorms will remain sparse through this morning. Areas of MVFR and patchy IFR CIGS will continue through the morning hours with abundant low level moisture in place. This afternoon, areas of MVFR CIGS will continue across portions of Central NY and the North Country, with mainly VFR across Western NY, the Genesee Valley, and western Finger Lakes. A few isolated to widely scattered showers and thunderstorms may develop this afternoon and evening, but most of the time will be rain free. The best chance of a few spotty showers and storms will be across the higher terrain of Central NY and the North Country. A lake breeze driven convergence zone may also support a few isolated thunderstorms from the Niagara Frontier east across the Genesee Valley and western Finger Lakes from mid afternoon through early evening. Tonight, any isolated showers and storms will dissipate this evening with the loss of daytime heating. Mainly dry weather will then prevail most of the night. A few showers and scattered thunderstorms may arrive very late tonight or early Wednesday morning across Western NY from the weakening leftovers of upstream convection. Low level moisture will likely support the development of fog/BR and some low stratus overnight, with areas of MVFR/IFR CIGS/VSBY developing. Outlook... Wednesday through Wednesday night...Occasional showers and thunderstorms, especially late Wednesday through Wednesday night. Some storms may be strong with locally gusty winds, hail, and torrential downpours. VFR/MVFR, with local IFR in storms. Thursday...VFR/MVFR with a chance of showers and thunderstorms, mainly across the Southern Tier and Finger Lakes. Friday and Saturday...Mainly VFR. River valley fog with local IFR each late night and early morning across the Southern Tier. && .MARINE... A frontal zone will remain draped across the Great Lakes through Thursday. Southwest winds will increase into the 10-15 knot range on Lake Erie today and again Wednesday, producing a light to moderate chop. Winds will be lighter and more variable on our other Great Lake. The front will move south of the region by late Thursday through Friday, with west to northwest winds and a light chop in its wake. Winds and waves will remain below Small Craft Advisory criteria through the upcoming holiday weekend. There will be a chance of thunderstorms at times through midweek. Thunderstorm chances will peak late Wednesday afternoon through the first half of Wednesday night. Some of these storms may contain strong winds, hail, and locally higher waves. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ DISCUSSION...Hitchcock AVIATION...Hitchcock MARINE...Hitchcock