Area Forecast Discussion
Issued by NWS Buffalo, NY
Issued by NWS Buffalo, NY
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558 FXUS61 KBUF 111741 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 141 PM EDT Sat May 11 2024 .SYNOPSIS... A weak area of low pressure will slowly cross our region tonight... and this will result in widespread showers and possibly a few evening thunderstorms. The precipitation will gradually taper off during the day Sunday...as weak high pressure will nose into the area. While warmer weather will move in for Monday...it will also once again become unsettled with increasingly widespread showers and thunderstorms that will persist into Tuesday. && .NEAR TERM /THROUGH SUNDAY NIGHT/... Conditions will deteriorate during the remainder of the afternoon across the western counties...as a robust shortwave and attendant sfc low will dive southeast across the Upper Great Lakes. A swath of deep moisture ahead of this system will push across the western counties before moving across the Eastern Lake Ontario region tonight. The resulting lift supplied by moderate hgt falls... low level convergence and being in the proximity of the left front quad of a nominal 90kt H25 jet with this scenario will prompt a renewal in shower activity. The weak low pressure will then slowly push across the forecast area tonight. While the bulk of the associated showers and isolated thunderstorms will be found along and immediately ahead of an attendant occlusion in the area of strongest low level convergence... the pcpn will tend to broaden out during the course of the night. By the time we work past midnight...the showers will tend to give way to areas of light rain and drizzle...mainly under the stacked low itself. Rainfall amounts will generally range from a tenth to a quarter inch...although localized amounts of a half inch will be possible in the vcnty of any evening thunderstorm. The stacked low will further weaken on Sunday with its mid level support briefly `opening up` enough to allow the system to exit across New England. Meanwhile...a low amplitude shortwave ridge will build across Lower Michigan to southern Ontario in its wake. Drying in the mid levels will accompany the associated subsidence so that the pcpn will completely end from west to east with enough clearing to allow for some afternoon sunshine and a decent ending to the weekend. A warm front will work its way northeastward across our forecast area Sunday night. While this should only result in an increase in cloud cover...there will be the chance for some showers over the IAG Frontier and possibly the Thousand Islands region by daybreak. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... Very active weather during this time frame with periods of showers and also chances of thunderstorms. The mid-level low spinning near James Bay will direct a cold front towards the eastern Great Lakes Monday morning with increasing chances for showers. There will also be some thunderstorms with this boundary, especially as diurnal instability increases in the afternoon. That said...another mid-level low over eastern Kansas will begin to advance east towards the Mississippi river valley by late Monday afternoon. As it does so...it is advertised to interact with the front over our region. There is some indication that it will nudge the front back north as a warm front. This would place us again back in the warm sector with a brief period of decreasing showers and storms by Monday night. However...it does not appear to last very long as the eastward advancing low draws the front back south by Tuesday with accompanying deeper moisture. We should see our fair share of showers Tuesday but there is some level of uncertainty as the southern stream low begins to tracks into the mid-Atlantic region. Tuesday night...the speed and track of the low will determine weather we continue to see wet weather areawide or a slow but gradual drying trend. Overall...near to a tad bit above normal max temps with highs in the upper 60s to low 70s. Lows will generally be found in the 50s. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... A weakening mid-level low centered over the northern Quebec Wednesday morning will continue to pull northeast into the Canadian Maritimes by Thursday morning. Meanwhile, ridging to the west across the Upper Midwest and western Great Lakes Wednesday will build across the remainder of the Great Lakes into Thursday night before the next trough dives southeast across the Central Plains Thursday night into the start of the weekend. With weakened low and associated mid-level trough overhead overhead of the area Wednesday, rain showers associated with the cold front the crossed the area Tuesday, will gradually end from northwest to southeast Wednesday. As the aforementioned mid-level ridging pushes east across the Great Lakes, associated surface high pressure will also move into the eastern Great Lakes. This will result in a period of dry weather Wednesday night thorugh much of Thursday. The next chance for showers will return Friday and last into the start of the weekend as warm front pushes across the area. Model guidance this far out remains differed with the placement and track of the upper level features and low level features. Therefore, kept rain shower chances on the lower end due to the lack in confidence. Expect a gradual warming trend throughout much of next week, with subtle warming each day. By the end of the week the temperatures will have rebounded to slightly above normal. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... VFR conditions early this afternoon will give way to deteriorating weather...as a stacked area of low pressure will approach from Lower Michigan. A swath of showers and possible thunderstorms ahead of this system will work across the far western counties during the remainder of the afternoon and evening before the main area of pcpn will move across the Eastern Lake Ontario region later tonight. The pcpn will be accompanied by cigs that will lower to MVFR levels...mainly after nightfall when IFR cigs will become common for most areas south of KBUF and KROC. MVFR cigs over the region Sunday morning will then slowly improve to VFR levels during the course of the midday. Outlook... Monday and Tuesday...VFR/MVFR with the likelihood for showers and thunderstorms. Wednesday...Improving conditions with precipitation exiting. Thursday...VFR weather. && .MARINE... Mainly light, variable winds (less than 10 knots) will be the rule through the most of the weekend, before a more pronounced southwesterly flow (10-15 knots) develops ahead of a warm front approaching from the west toward the tail end of the weekend. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...RSH NEAR TERM...RSH SHORT TERM...AR LONG TERM...EAJ AVIATION...RSH MARINE...JM/TMA