Area Forecast Discussion
Issued by NWS Buffalo, NY
Issued by NWS Buffalo, NY
780 FXUS61 KBUF 171048 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 648 AM EDT Thu Sep 17 2026 .WHAT HAS CHANGED... Minor changes to the forecast with this update. && .KEY MESSAGES... 1) A frontal zone stalled just south of the area will bring another period of showers and isolated thunderstorms through the first half of today. 2) A brief period of drier, cooler conditions is expected tonight through Saturday morning. 3) Unsettled pattern this weekend and into the beginning of next week. && .DISCUSSION... KEY MESSAGE 1...A frontal zone stalled just south of the area will bring another period of showers and isolated thunderstorms through the first half of today. This morning a stalled frontal boundary lies near the state line, with convection across OH/PA. Expect this convection to expand northward across WNY this morning, within a moisture rich environment within an inverted surface trough. Thunderstorm development will be limited as MUCAPE values generally lie below 500 J/KG. However, as Pwats become greater than 1.75 inches to around 2.00 inches and near the 90th percentile or even possible record values per Buffalo sounding climatology for this time of year there is still the potential for localized ponding of water in heavier or training activity. Greatest risk is likely across the Southern Tier, lying closer to the frontal boundary and low level convergence. The timing of convection, generally in the morning, combined with weak instability will lend to a low severe threat, though the moisture rich environment could pose a hydrologic issue with heavier storms, potentially passing over the same areas this morning. KEY MESSAGE 2...A brief period of drier, cooler conditions is expected tonight through Saturday morning. The frontal zone will accelerate southeast and away from the region tonight as high pressure builds southeast across Ontario and Quebec. Dendritic river valley fog is likely to form across the Southern Tier and Black River valleys during the overnight hours. It may even become cold enough Friday night, that if winds become calm, that isolated patches of light frost form in the traditionally colder areas of the inland North Country. KEY MESSAGE 3...Unsettled pattern this weekend and into the beginning of next week. An unsettled pattern emerges Saturday as a warm front lifts back northward across our region as surface high pressure exits to the east. Several additional shortwave troughs will ripple across our region through the weekend and into the beginning of next week maintaining chances for showers and perhaps a few thunderstorms. Ensembles data from the GEFS, GEPS and ENS continue to depict Saturday night into Sunday morning with the greatest chances for precipitation, this as a weak surface low expands northeastward from the Ohio Valley along with developing weak instability. Several additional shortwave troughs and the eventual passage of an open wave trough (currently featured as a closed low over NorCal) will maintain chances for showers through the first half of the new work week. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... For the 12Z TAFS a moist lower atmosphere is forming plenty of IFR to MVFR flight conditions, especially across higher terrain (KJHW) and the North Country. Whether fog or low stratus, expect these conditions to persist through the morning hours as a wavy frontal boundary, with a surface low upon the front, lingers across the southern TAF region. This surface low, with added low level convergence will bring showers, at times locally heavy, and an isolated thunderstorm back into our region mainly across southern zones. The main focus for storms upon the front will include the Southern Tier (KJHW) with a lower chance, and covered by a PROB30 for KROC through about 14Z. Any heavier storm across the Southern Tier may bring brief periods of IFR visibility. As a surface cold front pushes southeastward, it will likely maintain dry weather for KART, with the last of the showers exiting the Southern Tier through the afternoon hours. Behind the front a light northwest to northerly flow will usher in a much drier airmass. Localized fog formation within the Southern Tier and Black River valleys is likely, possibly expanding across KJHW and KART. Outlook... Friday...MVFR CIGS early, improving to VFR. Saturday...VFR deteriorating to MVFR/IFR late Saturday through Saturday night with rain becoming likely. Sunday...MVFR/IFR with rain likely. Monday...VFR/MVFR with a chance of showers, mainly across the Southern Tier. && .MARINE... A frontal boundary just to the south of the eastern Great lakes this early morning is beginning to lift back northward as a warm front. Northeast winds this morning will back around to northwest this afternoon and evening as a weak surface low passes across WNY. Behind the surface low, freshening northwesterly winds over the Lower Great Lakes will bring the next chance for near, but likely sub-small craft advisory conditions, starting late tonight and through Friday. This elevated winds and waves will be short-lived as surface high pressure will ridge southward across the Lakes by Friday night, bringing a much lighter wind flow. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ DISCUSSION...Thomas AVIATION...Thomas MARINE...Thomas