691 FXUS61 KBUF 051803 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 203 PM EDT Fri Jun 5 2026 .WHAT HAS CHANGED... Increased winds and gusts Saturday, especially northeast of Lake Erie. && .KEY MESSAGES... 1) Showers and thunderstorms return Saturday with localized heavy downpours and an isolated severe weather risk. 2) Mainly dry weather returns Sunday through early next week with warm temperatures. && .DISCUSSION... KEY MESSAGE 1...Showers and thunderstorms return Saturday with localized heavy downpours and an isolated severe weather risk. A mid level trough will dig into the Great Lakes and New England Saturday through Saturday night as the pattern amplifies across the northern tier of the US. A weak cold front will move south across the eastern Great Lakes late Saturday through Saturday night, although most of the showers and thunderstorms will focus on a pre- frontal trough and local lake breeze boundaries rather than the cold front itself. The first round of potential showers will cross the area from west to east late tonight through early Saturday morning as a weakening southern stream shortwave crosses the eastern Great Lakes. The most organized area of rain with this feature will likely be north of Lake Erie and Lake Ontario on the Canadian side of the border, although a few showers are likely across Western NY and the eastern Lake Ontario region as well. Instability will be very limited, although a few rumbles of thunder cannot be ruled out. Most areas will see a return to dry weather following the early morning batch of showers. Additional showers and thunderstorms will then develop as DPVA and height falls ahead of the sharpening mid level trough encounter increasing diurnal instability. A moderate southwest flow regime will be in place Saturday, supporting extensive stable lake shadows over and northeast of Lake Erie and Lake Ontario. Its possible the synoptic scale forcing may overcome the lake shadows to some extent, but the best coverage of thunderstorms will likely be inland from the lake shadows from the Southern Tier to the Finger Lakes and southern Tug Hill region. Coverage of rain will be very uneven, with plenty of dry time through the day Saturday. Forecast soundings show favorable shear profiles for organized convection Saturday afternoon and evening, with 30-40 knots of deep layer shear and even some favorable hodograph curvature across the Southern Tier where greater low level shear will be found. The degree of destabilization is more uncertain, with morning clouds and showers possibly holding down surface temperatures in some areas. The greater severe weather risk will likely be across the Southern Tier and Finger Lakes where greater instability is expected away from the stable lake shadows. The main risk will be localized damaging wind gusts, with a lower but non-zero risk of large hail and an isolated tornado. The main severe weather risk will be roughly 2PM to 7PM when instability and forcing maximize. Thunderstorms will also produce brief heavy downpours, but fast storm motion and much drier antecedent conditions compared to a few weeks ago should keep the flooding risk very low. KEY MESSAGE 2...Mainly dry weather returns Sunday through early next week with warm temperatures. The mid level trough will move east across New England Sunday, taking the majority of the showers with it. A few showers may linger east of Lake Ontario in moist, cyclonic northerly flow behind the departing trough, with dry weather prevailing farther west. Morning clouds in northerly upslope flow will give way to some clearing in the afternoon across Western NY. An Omega Block will develop by Sunday night over the Great Lakes, then drift slowly east to the east coast and flatten with time through the middle of next week. This will support dry weather and above average temperatures Sunday night through at least Tuesday. A mid level trough and plume of deeper moisture over the Ohio Valley may move far enough east to bring a chance of showers and thunderstorms again by Wednesday. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... High pressure will maintain VFR conditions through the rest of the day, with some VFR diurnal cu developing this afternoon inland of any lake breeze circulations. A decent lake breeze will develop once again this afternoon northeast of Lake Erie with SW to W gusts of 20- 25 knots through early this evening from KBUF/KIAG over to KROC. Ridge axis slides east of the area tonight, making way for an initial shortwave trough riding northeast along the back side of the ridge to cross the area bringing the possibility for a round of showers and an isolated thunderstorm or two second half of tonight into the first part of Saturday morning. CIGS will thicken and lower through the night, but are expected to remain mainly VFR, with low VFR CIGS possible by late tonight. Any VSBY restrictions will be limited to localized heavier showers/isolated storms. It will be breezy as well with widespread SW to WSW winds gusting 20-25 knots, with 30-35 knots possible northeast of Lake Erie from midday on. Flight conditions will further deteriorate ahead of an approaching cold front with widespread MVFR CIGS developing Saturday, and some IFR CIGS possible across the western Southern Tier and North Country. Another round of showers and thunderstorms are expected to develop Saturday afternoon ahead of the cold front as it crosses the area. Some storms may produce strong gusty winds. However, a stout lake breeze will develop northeast of the lakes with a lake shadow setting up from midday on. This will limit convection for our KBUF/KIAG/KROC/KART sites through much of afternoon, however there is the chance for a secondary line of showers and storms to cross the area late in the day. If the lake shadow weakens enough, a few of these may be able to make it into these aforementioned terminals. Expect localized IFR conditons within any heavier showers and thunderstorms. Outlook... Sunday...Mainly MVFR/VFR. Localized IFR in any showers and thunderstorms east of Lake Ontario. Monday and Tuesday...VFR. Wednesday...Mainly VFR with a chance of showers and thunderstorms. Localized lower flight CATs within any heavier showers or storms. && .MARINE... Southwest winds will increase tonight and especially Saturday ahead of an approaching cold front. Winds will initially be strongest on Lake Erie, where Small Craft Advisory conditions are likely Saturday. Winds will increase on Lake Ontario from west to east through the day Saturday, with low end Small Craft Advisory conditions possible. Scattered thunderstorms are expected Saturday afternoon and early evening, with a few storms producing locally stronger winds and higher waves. The cold front will move south across the lower Great Lakes Saturday night, with post-frontal northwest winds still producing choppy conditions on Lake Ontario Sunday. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ DISCUSSION...Hitchcock AVIATION...JM MARINE...Hitchcock