Area Forecast Discussion
Issued by NWS Buffalo, NY
Issued by NWS Buffalo, NY
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023 FXUS61 KBUF 120539 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 139 AM EDT Sun May 12 2024 .SYNOPSIS... A weakening area of low pressure will slowly cross our region overnight, resulting in areas of showers. The precipitation will gradually taper off during the day Sunday as weak high pressure noses into the area. While noticeably 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 /UNTIL 6 PM THIS EVENING/... A mid level shortwave and attendant weak surface low will slowly cross the region overnight. The center of the low is evident on regional radar with showers rotating counterclockwise across the eastern Great Lakes region. The aforementioned area of weakening low pressure will then slowly push across the forecast area overnight. While the bulk of the associated showers will be found along and immediately ahead of an attendant occlusion in the area of strongest low level convergence, the precipitation will tend to broaden out during the course of the overnight. Working into the second half of the night, the showers will tend to give way to areas of light rain showers with some patchy fog, mainly under the stacked low itself. Rainfall amounts will generally range from a tenth to a quarter inch. Lows tonight will range from the low 40s across the higher terrain to the mid and upper 40s elsewhere. The stacked low will further weaken on Sunday with its mid level support briefly `opening up` enough to allow the mid level system to exit across New England. Unfortunately, it appears even though the surface low completely falls apart over our area, a weak surface convergence boundary will linger, and looks to set up in the vicinity of the Genesee Valley/Finger Lakes region. This will mean as most areas dry out Sunday afternoon, some showers will continue across this aforementioned area into the afternoon, finally tapering by off late in the day. Otherwise, for the remainder of western and north-central NY, 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 precipitation will completely end from west to east with enough clearing to allow for some afternoon sunshine and a decent ending to the weekend. Daytime highs will range from the mid 50s to low 60s. 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 Niagara Frontier and possibly the Thousand Islands region by daybreak. Lows will again range from the low 40s across the higher terrain to the mid and upper 40s elsewhere. && .SHORT TERM /6 PM THIS EVENING 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 /06Z SUNDAY THROUGH THURSDAY/... A weakening area of low pressure is evident on regional radar with showers rotating counterclockwise across the region. Low level moisture and showers will persist resulting in MVFR/IFR conditions across the region overnight. VFR conditions at KROC and KART will become MVFR late tonight. Showers are capable of reducing visibility for a short (1-2 hours) period. Flight conditions will slowly improve Sunday morning as the weak low dissolves across the region. A surface trough will be left behind across the Finger Lakes region and showers will linger south of KROC. VFR conditions with dry conditions are likely Sunday evening. 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 Sunday night, although southwest winds becoming northwest later tonight may approach 15 knots between Dunkirk and Ripley producing some moderate chop in this area. A more pronounced southwesterly flow (10-15 knots) will develop on eastern Lake Erie Sunday afternoon ahead of a warm front approaching from the west that will bring some light to moderate chop, but waves should mainly be less than two feet. Southwesterly winds on Lake Erie/western Lake Ontario and southerly winds across eastern Lake Ontario will freshen on Monday with near Small Craft Advisory conditions possible across these aforementioned areas. Otherwise, winds and waves are expected to remain well below Small Craft conditions with just some light chop at times through at least Tuesday. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...JM/RSH NEAR TERM...HSK/JM/RSH SHORT TERM...AR LONG TERM...EAJ AVIATION...HSK MARINE...JM