Area Forecast Discussion
Issued by NWS Buffalo, NY
Issued by NWS Buffalo, NY
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524 FXUS61 KBUF 261905 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 305 PM EDT Sun May 26 2024 .SYNOPSIS... Weak high pressure begins to depart off towards New England this evening. A low pressure system tracking through the Great Lakes region will bringing increasing chances for showers and thunderstorms tonight into Memorial Day as a pair of fronts push through our region. Some of the stronger storms will have the potential to produce torrential downpours and also gusty winds. Showers and some thunderstorms will continue to be possible through midweek but drier weather then return for the tail end of the week. && .NEAR TERM /THROUGH MONDAY NIGHT/... Enjoy this nice weather engulfing what looks like will be the nicest day of the Memorial Day Holiday weekend. Other than some fair weather cumulus...dry weather with plenty of sunshine today will send temperatures into the 70s to near 80F. Deteriorating conditions expected tonight...this will take place as a potent shortwave nears the Great Lakes. A warm front tied to this system is advertised to lift northeast into our area between 9pm and 11pm. Otherwise...there is a bit of uncertainty to how strong the convection will be when it arrives late this evening. The HRRR and other various hi-res guidance show a well organized line of storms marching across OH/PA late this afternoon into the evening. It then begins to weakens as it moves northeast into our CWA. However...depending on how this convection holds together given that PWAT values will be around 1.5"...there still will be the potential for locally heavy downpours. Will need to keep an eye on this convection moving across Illinois and into Ohio as of 15Z. Memorial Day...a deepening low pressure system over Michigan looks like it will bring a couple of rounds of widespread showers or even a steady rain Monday morning, and then also some storms with the cold front Monday afternoon. That said...the main challenge will be the amount of destabilization realized in the afternoon which will `likely` allow for the some strong to severe storms. If we see a fair amount....given the environment with PWATS still in the 1.5 range and short MBE vectors..there will be an elevated risk for torrential downpours and localized flooding concerns. While mid lapse rates are NOT forecast to be very impressive (mainly ~7 deg c/km)...GREATLY minimizing the threat of large hail...30-35 kts of bulk shear could support locally strong downburst winds within the stronger convection. Again...the larger concern will be the risk for slow moving torrential downpours. Monday night...broad area of low pressure to our northwest will slowly track NNE into and across Quebec overnight. As the low departs...showers and storms coverage will decrease with the passage of the cold front. Although...we still can`t rule out a few linger showers overnight. Overall...much of the region will see drier weather as the dry slot works through the Lower Lakes. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... The upper level pattern will feature a trough over the Great Lakes region Tuesday through Wednesday night. There will be a series of shortwave troughs that will rotate cyclonically and keep unsettled and cooler conditions across western and north central NY. The first shortwave trough and associated surface reflection will move north of the forecast area Tuesday. A southwest flow will increase through the day with breezy conditions northeast of Lake Erie and east of Lake Ontario by afternoon. At 850mb, winds will be near 40kts with temperatures around +5C. Cool air aloft during daytime heating will create instability across the region. Showers will increase in coverage through the daytime hours with a convergence zone possibly forming from the Niagara Frontier to the Syracuse region. An isolated thunderstorm can`t be ruled out. Showers will quickly diminish in coverage Tuesday evening. The next shortwave trough will sharpen as it approaches the region from the north Tuesday night. A cold front will move into the Saint Lawrence Valley by Wednesday morning. The chance for showers will increase from north to south across the region Wednesday. Showers will increase in coverage across the region Wednesday afternoon with a low chance of thunderstorms. Ridging builds into the region Wednesday night and mostly dry weather is expected overnight. Notably cooler conditions will begin on Wednesday with daytime highs in the mid 60s, upper 50s across the higher terrain. && .LONG TERM /THURSDAY THROUGH SUNDAY/... A relatively quiet stretch of weather expected as we close out the month of May and move into June this period, with mainly dry weather and a gentle day to day warming trend. To open the period Thursday, the region will be situated under a broad, positively tilted upper level trough centered over the Canadian Maritimes. To the west, a strong, progressive ridge of high pressure will be building eastward over the Great Lakes region. The surface high from this feature will "undercut" the initial upper level troughing to a degree, supporting fair albeit cooler than normal weather for Thursday. Long range guidance is indicating an uptick in moisture aloft as the trough axis pivots southward across the eastern Great Lakes later Thursday or Thursday evening, with some even producing some spotty light QPF as it moves through. Have bumped up cloud cover by a small amount, but otherwise at this juncture have stayed close to NBM output which places just sChc PoPs across portions of the North Country Thursday afternoon. The ridge of high pressure will begin to shrink as it quickly moves across the Great Lakes and towards the East Coast Friday through Saturday. On its heels will be a large troughing system over south- central Canada and the Northern Plains. A robust shortwave rotating through the base of this trough will move into the Midwest and into the western Great Lakes in the back half of the weekend, which will cause increased chances for showers and possibly thunderstorms across our area late Saturday night through Sunday. In regards to temperatures...Still under the influence of the upper trough, temps Thursday and Thursday night will likely run some 5-10 degrees below normal with highs in the low to mid 60s and lows ranging in the 40s. By the weekend however, temps should warm to near or slight above normal with highs ranging in the 70s and lows in the 50s. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... VFR flight conditions will be maintain across all terminals into this evening. Tonight...a warm front will approach the eastern Great Lakes bringing showers with some embedded rumbles of thunder to our far western terminals. Expect lowering Cigs overnight with low end VFR to MVFR conditions area terminals. While the potential is low (low confidence)...low level wind shear will be possible over the western counties after 06z. Outlook... Monday...Restrictions likely with showers and thunderstorms. Tuesday and Wednesday...Restrictions possible with showers. Thursday and Friday...VFR. && .MARINE... Light wind and wave action will persist into this evening on area lakes. A warm front nears the Lower Lakes tonight with increasing chances for showers and storms overnight. While winds are still expected to remain light...gusty winds and higher wave action will be possible with any of the showers and storms. Wind flow picks up on Monday and remains elevated through Tuesday. Winds could nudge into the 15 to 25 knots range with possible small craft headlines needed during this time period. Scattered gusty thunderstorms will also be possible Monday. Boaters should continue to monitor the forecast, especially given the holiday weekend which will likely increase boating activity. This will especially be the case on Monday as conditions on the lower Great Lakes will likely deteriorate. Lighter winds and wave action return Wednesday through the rest of the week. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...AR NEAR TERM...AR/RSH SHORT TERM...SW LONG TERM...SW AVIATION...AR MARINE...AR