Area Forecast Discussion
Issued by NWS Buffalo, NY
Issued by NWS Buffalo, NY
424 FXUS61 KBUF 271040 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 640 AM EDT Mon Jul 27 2026 .WHAT HAS CHANGED... Minor changes to the forecast with this forecast update. && .KEY MESSAGES... 1) Greater coverage of showers and thunderstorms is expected from Monday through Tuesday night, some of these storms may produce gusty winds and heavy rainfall. 2) Chances for showers and thunderstorms are expected to linger into Thursday, with drier conditions for the end of the work week. && .DISCUSSION... Key Message 1...Greater coverage of showers and thunderstorms is expected from Monday through Tuesday night, some of these storms may produce gusty winds and heavy rainfall. Overhead today, a broad ridge across much of the western and central portions of the CONUS, with a longwave trough centered over the Northeastern Seaboard. With this pattern, the central and eastern Great Lakes will be under the ridge-trough transition zone, where a shortwave trough will dive southeast across the Great Lakes tonight into Tuesday. Ahead of the trough, diurnal heating along with dewpoint temperatures in the 60s will support showers and thunderstorms to develop inland from the lake breeze boundaries this afternoon. However, unlike this past weekend, there will be better coverage of showers and thunderstorms today due to higher CAPE values. With the passage of the shortwave trough, an associated surface low is expected to move across the central Great Lakes and toward Lake Erie today and through tonight. With this system, there is an area of increasing mid-level winds, steepening mid-level lapse rates, and high PWAT values that will move across the Ohio valley and into portions of western New York tonight. Additionally, mean 0-6km wind shear will increase to between 25 and 30 knots across far western New York, while remain under 20 knots east of the Genesee Valley. This being said, the risk for an isolated strong thunderstorm increasing across western New York tonight, especially if organized convection develops west of the area. Timing for storm development is 05Z to 11Z Tuesday (Midnight to 7AM Tuesday). Primary hazards for any storms are damaging winds and locally heavy rainfall. Upper level troughing will remain overhead the eastern Great Lakes Tuesday, with the surface low becoming vertically stacked and stationary across western and central New York. Diurnal heating within a moist and soggy environment will support numerous showers and thunderstorms. Despite weak winds within the stacked low, a low- level jet will wrap around the low supporting a few strong thunderstorms to develop and result in locally heavy rainfall across portions of western and central New York Tuesday afternoon and into the evening. The surface low will move into southern New England Tuesday night, supporting the warm moist conveyor belt to move into eastern Lake Ontario, supporting the potential for showers and thunderstorms producing heavy rainfall to persist. Northerly flow and wrap-around moisture will move into western NY and chances for showers will remain overnight. All of this being said, there is a Marginal Risk for Severe Weather today and tonight, and a Marginal Risk for Excessive Rainfall Today and Tuesday. Key Message 3...Chances for showers and thunderstorms are expected to linger into Thursday, with drier conditions for the end of the work week. 850mb temperatures will tumble towards +10 to +13 degrees Celsius Wednesday, as the stacked low will persist across the Northeast. Plenty of moisture will persist across the area Wednesday, before drier air builds into the region Wednesday night through Thursday. Diurnal heating will support another day of showers and thunderstorms across the region. Cooler weather is expected Wednesday and Thursday with highs in the 70s. High pressure will move into the eastern Great Lakes region for the end of the week bringing dry and seasonal weather. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... Mainly VFR conditions prevail across the region this morning, however due to some passing showers Sunday evening, lingering moisture this morning some patchy IFR/MVFR fog has developed across the Southern Tier and across the Niagara Frontier impacting both KJHW and KIAG terminals. Patchy fog across will dissipate shortly after sunrise, due to the return of daytime heating and mixing. Continued diurnal destabilization will support some isolated to scattered showers and thunderstorms bringing brief/localized restrictions to develop inland from the lake breeze boundaries this afternoon. Otherwise, VFR conditions will prevail. Showers and thunderstorms will pass east across the region tonight, crossing WNY between 05Z to 11Z and causing initial VFR conditions to lower to MVFR and IFR. Line of storms will then push east across the area into Tuesday morning. With the initial arrival of the storms across far western NY, damaging winds and locally heavy rainfall will be possible. Outlook... Tuesday through Tuesday night...Showers and scattered thunderstorms pushing across the area from west to east, with conditions lowering to MVFR/IFR. Wednesday...Showers and a few leftover thunderstorms with initial MVFR/IFR possibly improving to VFR/MVFR. Thursday...Mainly VFR with a chance of showers and slight chance of thunderstorms inland from the lakes. Friday...Mainly VFR. && .MARINE... Weak surface-based ridging will linger across our region today, with a corresponding weak pressure gradient resulting in light to modest winds and minimal wave action. Additionally, localized lake breezes will develop near the lakeshores this afternoon. Tonight through Tuesday a broad wave of low pressure will settle southeastward across the Great Lakes, with the low then slowly drifting to the mid-Atlantic coastline Tuesday night and Wednesday. Out ahead of the low a light to modest southerly flow will develop tonight. Winds will then transition to northerly to northeasterly for Tuesday night/Wednesday once the low passes off to our southeast, though the finer details of this transition are not yet clear as these will be highly dependent upon the exact timing and track of the low (factors which remain rather uncertain at this time). Once under the northerly/northeasterly flow behind the low a moderately brisk and supportive of choppy conditions along the south shores of the lakes Tuesday night into Wednesday, with lower-end SCA- level conditions possible. Winds will then lighten and turn more westerly Thursday and Friday, allowing for a commensurate decrease in wave action. Out ahead of the approaching low, some widely scattered to scattered showers and thunderstorms will also become possible today into this evening, with more widespread showers and scattered thunderstorms then expected later tonight and Tuesday as the low crosses our region. Any storms could produce locally higher winds and waves, with this potential greatest across Lake Erie later this afternoon and tonight. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ DISCUSSION...EAJ AVIATION...EAJ MARINE...EAJ/JJR