Area Forecast Discussion
Issued by NWS Buffalo, NY
Issued by NWS Buffalo, NY
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750 FXUS61 KBUF 261227 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 827 AM EDT Thu Sep 26 2024 .SYNOPSIS... Weak low pressure will drag a frontal system through the region this morning. A few showers may linger across the Southern Tier and east of Rochester through early afternoon, otherwise high pressure will build across the lower Great Lakes to support fair dry weather through at least Friday. Most, if not all of the significant rains from Helene should stay to our south. && .NEAR TERM /THROUGH TONIGHT/... An area of weak low pressure over Quebec will drift northeast dragging a wavy frontal boundary through the region today. Fairly widespread rain showers east of the Genesee River valley and across the Southern Tier this morning ahead of the approaching surface boundary and main mid level wave. Overall slow movement of the main mid level wave and surface boundary will keep showers around for the remainder of this morning. Latest CAMs similar in suggesting a gradual ending of the showers through early afternoon. Elevated CAPE of 200-400 J/Kg will be found within this environment, so will maintain at least a slight chance for thunderstorms. High pressure will build into the region behind the frontal passage. This will keep the area dry through tonight, however the degree of clearing is in question as upper level moisture well in advance of Helene overspreads the region. && .SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/... An upper level ridge will be centered over the eastern Great Lakes region while being sandwiched between low pressure over Quebec and low pressure over the central Mississippi Valley Friday. Remnants of Hurricane Helene will become absorbed into the area of low pressure to the south Friday into Friday night. A plume of tropical moisture will approach the forecast area from the south, however ensemble means keep the axis of anomalously high PWATS south of the forecast area through Friday which should result in dry weather. The upper level ridge will move slowly east and allow the upper low to move east into the start of the weekend. PWATS will increase from south to north across the forecast area. The chance for rain showers will be introduced across the southern half of western NY Friday night with low chances continuing through Sunday night. Confidence remains fairly low in the coverage and amount of rainfall due to the spread in ensemble members. The upper level ridge axis and surface high over north central NY will likely keep conditions mostly dry for the eastern Lake Ontario region through Saturday night. Light east- northeast winds will be felt at the surface. Above normal temperatures are likely with highs in the mid to upper 70s Friday, Saturday, and Sunday and lows in the upper 50s to low 60s Friday night, Saturday night, and Sunday night. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... The longwave pattern will continue to be dynamic through mid-week, with more unsettled weather re-emerging. By Monday, the remnants of Helene will be circulating within the partially open, positively tilted wave over the Ohio Valley and Mid- Atlantic states. This could lead to a few showers across the far Southern Tier Monday, though high pressure ridging to the north should keep conditions mostly dry. A sharp shortwave trough will quickly approach the region from the Upper Great Lakes region Tuesday. Past model runs showed the potential for this trough to phase with the exiting trough to the south, however it looks like models have separated these systems. Therefore, Tuesday looks mostly dry with the potential for a brief period of ridging across the region. A strong cold front will move through the forecast area Tuesday night through Wednesday. While temperatures are expected to continue to average above normal Monday and Tuesday, much cooler air in the wake of the front will finally give us a taste of fall weather by Wednesday. Models are far from lock and step with the depth of the cooler airmass, though ensemble mean 850H temps are around +8C by Wednesday which should translate to highs in the upper 50s to low 60s. This will also be plenty cold enough to potentially spur some additional lake effect rain showers Wednesday, though the airmass may be initially too dry for this to be realized. && .AVIATION /13Z THURSDAY THROUGH MONDAY/... A slow moving cold front will keep showers around this morning, with a mix of VFR/MVFR to IFR cigs, the latter of which will be focused across the Srn Tier. Dry weather will return to the region by this afternoon. Cigs will improve to VFR levels by late morning/midday, then most areas will lose their cigs altogether by the end of the day with mainly upper level cloud cover across the region. Outlook... Tonight...Mainly VFR. Friday...Mainly VFR...but with a chance of showers across the western Southern Tier. Saturday through Monday...VFR. && .MARINE... Winds will gradually become southwest and then west today as a trough crosses the eastern Great Lakes from west to east, with wind speeds decreasing with the passage of the trough. Northeast flow will then pick up Friday, possibly requiring small craft headlines on Lake Erie and western Lake Ontario. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...AR/RSH/TMA NEAR TERM...Apffel/TMA SHORT TERM...HSK LONG TERM...HSK/PP AVIATION...AR/RSH/TMA MARINE...AR/TMA