


Area Forecast Discussion
Issued by NWS Buffalo, NY
Issued by NWS Buffalo, NY
702 FXUS61 KBUF 052339 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 739 PM EDT Sat Jul 5 2025 .SYNOPSIS... Heat and humidity will grace the region Sunday, along with a chance of a few inland showers or an isolated thunderstorm. A cold front arrives Monday with a better chance of showers and thunderstorms, some of which could produce heavy rainfall. && .NEAR TERM /THROUGH SUNDAY/... A marginally unstable air mass combined with remaining lake breeze boundaries may produce a few showers or an isolated thunderstorm through this evening. Otherwise...dry weather will continue to prevail across much of the region. After sunset any remaining convection will fall apart with dry weather expected overnight. A mild night is expected with mercury reading only falling back into the 60s to low 70s. The axis of the flattening mid-level ridge will then slide east across the Northeast Sunday, while multiple partially phasing shortwave troughs ripple across the provinces of Ontario and Quebec. Associated surface high pressure with the aforementioned ridge will support dry weather to mainly prevail. Additionally, 850 mb temperatures will warm to around +20C Sunday, resulting in surface high temperatures well into the upper 80s to low 90s, with a few mid 90s possible across the warmer spots of the Genesee Valleys. Cooler temperatures will lie along the shorelines of both lakes and a few miles inland due to the lake breeze. With humidity levels creeping up, head indices across the Lake Plains, Genesee Valley and into the Finger Lakes will climb up above Heat Advisory criteria, thus a Heat Advisory is in effect Sunday from late morning (11AM) into the evening (8PM). && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... Sunday night through Monday night broad upper troughing over eastern Canada will gradually amplify as shortwave energy ripples through it, which will in turn encourage an approaching frontal boundary to gradually push southeast as a cold front. This may result in some isolated to widely scattered convection developing across the northwestern half of the area Sunday night, with better chances for showers/storms then following areawide on Monday as the front pushes through our region, before diminishing from NW-SE in the wake of the front Monday night. While wind profiles are not all that strong and thus are not particularly favorable for strong to severe storms, the combination of the mostly unidirectional flow and PWATs of 1.5 to 2 inches could pose a risk for locally heavy rainfall and localized flooding should any areas of training cells materialize. Otherwise humidity levels (dewpoints of around 70F) will peak on Monday, lending a very sticky feel to the air in spite of temps that should be some 5-7 degrees cooler than Sunday. Cooler and less humid air will then gradually filter in behind the cold front Monday night. A weak sfc high will move into the region for late Monday night through the rest of the period. This will result in mainly dry conditions for the bulk of the forecast area for the rest of the period from late Monday night onward. However, mid level zonal flow combined with a weak passing shortwave trough and afternoon heating on Tuesday will bring the potential for showers and thunderstorms to portions of the Southern Tier and Finger Lakes. Temperatures for Tuesday along with humidity levels will lower some from Monday`s values, with highs in the mid 70s to low 80s for most areas and Td values in the lower to mid 60s. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... This period will be dominated by persistent broad upper-level troughing across the Great Lakes and Northeast. Currently Wednesday appears to be on the drier side for the most part, with just some limited afternoon convection possible across the Southern Tier/interior Finger Lakes, with this due to the combination of diurnal heating/a developing lake breeze boundary Wednesday. Somewhat better and more general chances for convection may then return for Thursday into the first half of Friday in tandem with a couple shortwave passages. Another approaching frontal boundary from the west will start to increase the potential for showers/storms for Saturday as well, though the guidance unsurprisingly continues to struggle with the details for most of the long term period at this distant vantage point. With that in mind, the chance PoPs advertised by blended guidance look fine for now. Otherwise, temps during this period will average out near to slightly above normal for this time of year. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... There is a low chance of a shower or isolated thunderstorms impacting terminals across the S. Tier this evening, to include KJHW and KELZ. Otherwise...VFR will continue across area terminals through tonight. Mainly VFR conditions will then last throughout Sunday as the aforementioned high pressure exits east. Daytime mixing combined with a low level jet overhead will support southwest winds to mix down, especially across the Niagara Frontier and the Saint Lawrence Valley, thus impacting KBUF, KIAG, and KART Outlook... Sunday night and Monday...A chance of showers and thunderstorms with MVFR restrictions possible. Tuesday and Wednesday...Mainly VFR. Thursday...A chance of showers and thunderstorms with MVFR restrictions possible. && .MARINE... Light winds and wave action will continue through tonight. A southwest winds will pick up Sunday as the pressure gradient tightens between the offshore high and an upstream cold front moving into the central Great Lakes. Wave action will become choppy though likely remain below SCA criteria. Winds look to be marginally high enough that headlines may eventually be needed across some of the nearshore waters, particularly on Lake Erie, Niagara River, and western end of Lake Ontario. While the cold front won`t cross the region until closer to Monday evening, winds will subside by Sunday evening and remain below SCA criteria through much of next week. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...Heat Advisory from 11 AM to 8 PM EDT Sunday for NYZ001>006-011- 013-014. MARINE...None. && $$ SYNOPSIS...AR/EAJ NEAR TERM...AR/EAJ SHORT TERM...JJR/SW LONG TERM...JJR/SW AVIATION...AR/EAJ MARINE...AR/EAJ/PP