146 FXUS61 KBUF 130022 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 822 PM EDT Sun Sep 12 2021 .SYNOPSIS... A cold front dropping across the region will support showers and scattered thunderstorms. Some of the thunderstorms could produce strong winds and heavy rainfall. Unsettled weather will continue through the middle of next week with possible showers and thunderstorms. && .NEAR TERM /THROUGH MONDAY/... ...Scattered severe thunderstorms possible tonight... An MCV crossing Lower Michigan this evening is generating strong to severe convection. Upstream soundings from 18z were showing a pronounced EML...and now 00z soundings from KBUF and KDTX continue to show the very favorable environment. CAMs have been consistent with timing the convection after 04z for the western counties of New York...although some 'garden variety' storms will be possible in the hours leading up to that. The main severe weather threat will be damaging straight line winds...but there should be intense downpours and frequent lightning under the cores as they move through. Convection will diminish late tonight as the shortwave (MCV in this case) will push east. Some partial clearing could bring some fog especially to areas that receive rain. Frontal boundary does look to sneak south of the area briefly on Monday, but will start to work back north as a warm front Monday afternoon. Shortwave pushing across the area will trigger some scattered convection along the frontal boundary late in the day. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... A stationary front will be oriented northwest to southeast from northern Michigan to northwest Pennsylvania Monday night. Surface high pressure will be inching into the North Country resulting in dry conditions from the Finger Lakes into the North Country. A weak impulse is forecast to ride along the front further west and showers with a slight chance of thunderstorms are possible across far western NY including the western Southern Tier. Overnight lows will range from the low 50s across the North Country to the upper 50s low 60s across western NY. The front will move north as a warm front across western and north central NY Tuesday. Dewpoints and mid-level moisture will increase while surface temperatures climb to the upper 70s to low 80s. Surface based instability will climb with strong winds in the low to mid levels. Showers and thunderstorms will likely form by afternoon ahead of an approaching cold front. Some storms may become strong to severe in the afternoon into the evening. Main threats would be strong winds and large hail. Thunderstorms will track east with a short break before another round of showers and storms enters the region as a cold front approaches from the west. Uncertainty exists Tuesday night as the wind field and surface based instability decreases ahead of the front. Warm, overnight night with lows in the 60s. Model guidance is in agreement that widespread showers or rain with thunderstorms will track across the entire forecast area Wednesday and Wednesday as the cold front tracks east. This increase in low level convergence will initiate thunderstorm development with some strong to severe storms. The strongest storms are expected to be east of the forecast area however if the front slows down that could change. Slightly cooler Wednesday with highs in the mid to upper 70s. && .LONG TERM /THURSDAY THROUGH SUNDAY/... A sfc ridge will provide for mostly quiet weather for the first half of the long term period. Some guidance is suggesting an upper level trough/low over eastern PA and southern New England may cause some showers for the area. Will need to see how the scenario evolves as there is decent model spread still with how much of an impact these upper level features will have. For now have high slight chance to low chance POPs. A frontal boundary passing south across the area on Sunday will bring a few showers and some thunderstorms. The front will then shift back north as a warm front later on Sunday into Monday. Temps during the long term will be 5 to 10 degree above normal for this period. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... Complex of thunderstorms with gusty winds and heavy rain looking likely to roll across western NY after 3/4z. Brief IFR possible during these storms. After the storms later tonight, expect MVFR ceilings with IFR possible across the southern Tier. May see some fog as well if any clearing occurs. Outlook... Monday and Tuesday...Mainly VFR with a chance of showers. Wednesday...Mainly MVFR with widespread showers. Thursday and Friday...Mainly VFR. && .MARINE... A pseudo stationary cold front straddling Lakes Erie and Ontario early this evening will gradually push south overnight. In its wake...gentle to moderate northwesterlies will become established. While winds and waves will average below small craft advisory criteria...there will be the risk for strong thunderstorms between 04 and 08z...particularly over Lake Erie. mariners should be alert for possible special marine warnings. High pressure centered over northern Ontario will start to pass by the north on Monday. This will support light and variable winds on Lake Erie and light northwesterlies on Lake Ontario. As the area of high pressure moves east across Quebec on Tuesday...a cold front will approach from the Upper Great lakes. A tightening sfc gradient between the two will lead to freshening winds on both Lakes Erie and Ontario. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...TMA NEAR TERM...RSH/TMA SHORT TERM...HSK LONG TERM...SW AVIATION...JLA/TMA MARINE...JLA/TMA