984 FXUS61 KBUF 270606 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 206 AM EDT Sun Jul 27 2025 .SYNOPSIS... A slow-moving area of low pressure and attendant warm front will bring increasing chances for scattered showers and storms across much of the area early this morning. Showers and a few thunderstorms will linger past daybreak this morning, then taper off from northwest to southeast midday through mid afternoon as high pressure builds across the region bringing drier conditions that will persist into the start of the new work week. Increasingly hot and humid weather is set to return for Sunday through Tuesday, peaking on Monday. && .NEAR TERM /THROUGH TONIGHT/... Regional radar shows clusters of thunderstorms extending from Lake Huron to the northern shore of Lake Ontario early this morning. Another, less organized area of storms is along the northern shore of Lake Erie. There is a Marginal and Slight Risk of Excessive rainfall across the forecast area through 8AM. A very humid airmass resides across the region. The Advected Layer Precipitable Water (ALPW) product displays moisture from surface to 300mb. Mesoanalysis shows PWATS greater than 2" across the forecast area. A shortwave trough across the Central Great Lakes region is evident on water vapor imagery early this morning. Showers and thunderstorms have developed along a warm front from Lake Huron to the northern shore of Lake Ontario and south into central NY early this morning. Radar trends and hi-res guidance shows the line of thunderstorms moving further into the Eastern Lake Ontario region through daybreak. Excessive rainfall is likely between 2-8AM and localized flooding is possible if storms train over the same location. Further south, the probability of flooding is lower, however radar trends do indicate the potential for localized flooding through daybreak. A surface trough/wind shift will move through the region today. The moisture axis will move east of the region and the risk for showers and storms will diminish from west to east through late morning. Mostly dry weather is expected this afternoon, with a low chance for a pop-up shower across the Niagara Frontier. Dry weather will continue into tonight. Patchy fog is possible, especially in valley locations across the western Southern Tier. && .SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/... Broad mid-level ridge will anchor across the southern half of the CONUS Monday through Wednesday. Meanwhile, to the north across the far northern reaches of the CONUS and across much of Canada a shortwave trough passing across the eastern Great Lakes Monday night will cause a longwave trough to dive southeast across the Upper Great Lakes and into the Central Great Lakes Tuesday night and Wednesday. Initially ahead of the trough`s arrival, a brief period of mid-level ridging will pass across the eastern Great Lakes region Monday. With the ridging overhead Monday, surface high pressure will work its way across the central and eastern Great Lakes resulting in a period of dry weather for the start of the week. However, a few widely scattered showers and thunderstorms will be possible across the Saint Lawrence due to an approaching frontal boundary. Additionally, with the ridging aloft, 850mb temperatures will warm up towards +19 to +20 degrees Celsius Monday supporting another warm day on tap with highs in the upper 80s across much of the region and some low to mid 90s across the lake plains south of Lake Ontario from Niagara Falls to Rochester and the Genesee Valley. These warm temperatures combined with dewpoints in the upper 60s to low 70s will support heat indices in the low to mid 90s for the Niagara Frontier to the Genesee Valley. A weak shortwave trough will not only encourage the longwave trough to dive southeast across the Great Lakes, but also introduce a weak cold front to pass east across the Lower Great Lakes Monday night and Tuesday resulting in the next chance for showers and thunderstorms. Coverage of these showers and thunderstorms will be rather limited due to the weak nature of the boundary and loss of upper level support with time. Despite any airmass change, the airmass will be weak and brief, and therefore another warm muggy day will be on tap Tuesday. Heat indices again will range in the low to mid 90s for the Niagara Frontier to the Genesee Valley. A significant pattern change will then take place Wednesday as the longwave trough axis enters the central and eastern Great Lakes, introducing a secondary cold front to the area and result better chances for showers and thunderstorms to pass across the area. && .LONG TERM /THURSDAY THROUGH SATURDAY/... After the cold frontal passage mid-week, surface high pressure will lie across the Great Lakes late in the week and into the start of the weekend. Aside from a few lingering showers and thunderstorms a drying trend will persist for the end of the week and start of the weekend. Additionally with the trough overhead, expect a cooler and drier airmass to filter overhead, supporting below normal temperatures for the later half of the week. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... A very humid airmass resides across western and north-central NY tonight. Showers are likely across the entire region, with clusters of thunderstorms producing torrential rainfall and low vsby in localized areas late tonight. VFR conditions will prevail outside of heavy showers and thunderstorms through 9Z, then flight conditions will likely lower towards sunrise. A west to east oriented line of thunderstorms will likely move into north-central NY after 8z, which may impact KART for a few hours. Similarly but not as organized, training convection may occur across western NY through sunrise. A front with drier air will move across the region Sunday. Flight conditions will improve from northwest to southeast through Sunday. VFR conditions should be widespread across the region by mid- afternoon. Dry weather will continue Sunday night. Patchy fog is possible, with higher confidence across valley locations. Outlook... Monday...Mainly VFR. Tuesday through Wednesday...Mainly VFR. Chance of showers/afternoon thunderstorms. Thursday...Mainly VFR. && .MARINE... A wave of low pressure will cross the lower Great Lakes tonight and early Sunday. An organized area of rain and storms may impact the Lakes tonight. Southwesterly to westerly breezes will increase modestly Sunday behind this wave, with some light chop developing on both Lakes. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...HSK NEAR TERM...HSK SHORT TERM...EAJ LONG TERM...EAJ AVIATION...HSK MARINE...HSK