Area Forecast Discussion
Issued by NWS Buffalo, NY
Issued by NWS Buffalo, NY
800 FXUS61 KBUF 180555 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 155 AM EDT Fri Sep 18 2026 .WHAT HAS CHANGED... Minor changes to the forecast with this update. && .KEY MESSAGES... 1) The next system to bring rain showers and isolated thunderstorms arrives Saturday night and Sunday. && .DISCUSSION... KEY MESSAGE 1...The next system to bring rain showers and isolated thunderstorms arrives Saturday night and Sunday. A plume of subtropical moisture over the central Rockies this morning will crest a central Plains ridge of high pressure today and tonight, carried eastward within a persistent west-east flow over the Great Lakes region and reach the Lower Great Lakes by Saturday night. This plume of moisture will increase PWats over our region to around 1.5 inches, or greater than the 90th percentile for Buffalo sounding climatology. Lift ahead of a few shortwave troughs aloft combined with lower level isentropic lift will generate a period of rain showers Saturday night through Sunday. Activity will advance northeastward across the CWA with showers possible across the North Country by daybreak Sunday morning. The axis of deeper instability will remain south of a frontal boundary that will remain draped across the midwest, leaving the thunder threat low. However the deepening warm cloud depth to over 12K feet on Sunday combined with the anomalously high moisture content of the airmass will lend to heavy rain as the primary hazard. These rain showers will shift to the east Sunday afternoon and evening, though a moisture rich lower atmosphere will remain Sunday and into the evening hours with higher terrain low stratus and fog possible. A broad area of surface high pressure over the province of Ontario will advect a cooler and drier airmass southward later Sunday night and into Monday, possibly bringing a brief period of fair weather before another impulse returns the chances for showers and possible thunderstorms for Tuesday and Wednesday. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... For the 06Z TAFs a light northerly flow is yielding plenty of low level stratus and higher elevation fog this morning. Meanwhile lower terrain, including KBUF, KIAG and KROC will likely remain MVFR within the lower stratus. Drier air advected southward will erode this stratus through the morning hours, with some brief clearing before afternoon cumulus field develops. Steepening lapse rates may allow for these cumulus clouds to collect enough for a BKN sky cover, but likely within VFR flight range. With the setting sun skies will begin to clear tonight with primarily VFR flight conditions. River valley fog is likely, but may not expand across the KJHW airfield due to the abundance of dry lower level air. Outlook... Saturday...VFR. Saturday night through Sunday...MVFR/IFR with rain across the Southern Tier and Finger Lakes. VFR/MVFR farther north near the Canadian border with a chance of showers. Monday...Mainly VFR with an isolated shower. Monday night through Tuesday...becoming MVFR/IFR with showers likely, especially towards the south. && .MARINE... High pressure will continue to produce a northerly flow over the eastern Great Lakes, with a light chop on the waters at times. This flow will begin to veer to northeast and even easterly on Saturday as the surface high departs to the east. The easterly flow may bring wave heights up on the waters west of Hilton up to around 2 feet or so on Saturday. Continued northeasterly flow Sunday will increase a tad stronger than Saturday, with wave heights around 2 or even 3 feet along the southern shorelines of the eastern Great Lakes. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ DISCUSSION...Thomas AVIATION...Thomas MARINE...Thomas