Area Forecast Discussion
Issued by NWS Buffalo, NY
Issued by NWS Buffalo, NY
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131 FXUS61 KBUF 081925 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 325 PM EDT Wed May 8 2024 .SYNOPSIS... Dry and windy weather will prevail most of this afternoon, although a few more showers and thunderstorms are possible later in the afternoon and early evening, especially east of Lake Ontario. Dry weather returns later tonight, then it`ll be an unsettled weather pattern Thursday through the weekend with a series of low pressure systems crossing the region. && .NEAR TERM /THROUGH THURSDAY NIGHT/... 12Z Buffalo sounding has a 45 knot westerly flow at 800mb which will partially mix to the surface this afternoon, resulting in wind gusts of 35 to 45 mph through late afternoon. A secondary shortwave trough will move across northern NY this afternoon, producing another round of showers and thunderstorms which will mainly be east of Lake Ontario, but a few may also along a convergence zone south of Lake Ontario. Strong wind fields aloft, but very limited instability so there`s only a marginal risk of a few strong storms east of Lake Ontario this afternoon and early evening. The shortwave trough will move east of the region tonight with lingering showers and storms ending by midnight. Associated cold front will move across the area resulting in mostly cloudy skies however rain-free conditions will prevail for the rest of the night. 12Z model guidance is slower and further south with a convectively augmented wave of low pressure on Thursday. It now appears it will remain rain-free Thursday morning, with increasing chances for showers across Western New York late Thursday afternoon. Some showers will likely move across the area Thursday night, but these will be weaker producing nominal rainfall amounts. This also will leave our area firmly in a stable northeast surface flow, with little to no risk for thunderstorms. Following this, Thursday will be a much cooler day with highs ranging from the mid 50s to lower 60s. && .SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/... High confidence for BELOW normal temperatures during this period... particularly by day when the mercury is only forecast to reach into the upper 50s to near 60. That will be a solid 5 to 8 degrees below mid May normals. Meanwhile...it will generally be unsettled with perturbations in the mean longwave trough supporting some showers and thunderstorms. As for the details... A shortwave will drive across the Lower Great Lakes on Friday...as a wavy sfc frontal boundary will stretch across the Tennessee valley to the Mid Atlantic region. The resulting DPVA and minimal height falls will couple with a deep cyclonic flow and wealth of moisture to warrant chc to likely pops over the far western counties and cat pops over the Finger Lakes region and portions of the Srn Tier where a change will be made in the wording from showers to rain. There could be several hours of widespread/steady rain for that area. Finally...H5 temps of -20c will enhance the instability aloft...the mid levels will be stable enough to preclude the risk for thunder. A weak shortwave ridge will scoot across the forecast area Friday night. While spotty showers may persist east of Lake Ontario...this scenario will bring an end to the pcpn over the western counties. Saturday...another robust shortwave will drop through the longwave trough and pass just to the west and south of our forecast area... along with a loosely organized sfc reflection. Unlike the previous shortwave passage the day before (Friday)...this will focus the associated forcing over the western counties. Will raise pops for the Srn Tier to categorical...but being largely convective (H5 ~ -24c)...will maintain the wording of showers. The mid levels will be more unstable as well...so will add slgt/chc wording for tstorms for the western counties. Given the mean trough axis will cross the region Saturday night...will maintain at least chc pops for showers. A nominal 70kt H5 jetlet will dig into the base of the aforementioned longwave trough over the region on Sunday and encourage it to close off across New England. The slow exit of the trough will keep at least scattered showers in place...particularly over the Finger Lakes and Eastern Lake Ontario regions. Low single digit H85 temps will keep the cool weather in place with the mercury struggling to make it out of the 50s. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... A closed low and associated deep longwave trough centered in the vcnty of Hudson Bay at the start of this period will rotate out across Quebec during the course of the week. This will result in height rises across the Lower Great Lakes that will lead to temperatures finally returning to ABOVE normal levels. While this general pattern will favor fair weather for the majority of the period...another shortwave will push a cold front through the region later Monday and Monday night. This will result in scattered showers and a minimal risk for thunderstorms. Dry weather should prevail with a passing shortwave ridge Tuesday and Tuesday night...then energy in the southern stream will help to support a storm system that should pass to our south on Wednesday. Being on the northern fringe of this system...there will be the potential for showers. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... VFR flight conditions for western NY, with lingering MVFR cigs east of Lake Ontario this afternoon. Winds gusting to 35 knots this afternoon at KIAG, KBUF, and KROC. Another round of showers and a few thunderstorms are possible east- southeast of Lake Ontario this afternoon into the evening. Increasing clouds and lowering cigs following the passage of a cold front tonight. No precipitation, but this will lower cigs to mainly MVFR with areas of IFR across higher terrain tonight. Low clouds will gradually dissipate during Thursday, but mid and high clouds will expand across the area from the south. Also a chance of showers late in the day. Outlook... Thursday and Friday...Mainly MVFR. Showers likely and MVFR stratus. Saturday through Monday...VFR/MVFR. A chance of showers. && .MARINE... Moderate WSW winds this afternoon, particularly across Lake Erie...where winds and wave action will be sufficient to support Small Craft Advisories as outlined below. Elsewhere choppy...but sub- advisory conditions can be expected. Winds will shift to the northeast and diminish tonight, with a general northeast flow through Thursday night. This will result in choppy conditions along the south shores of the lakes, with conditions approaching advisory criteria on Lake Erie. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...Small Craft Advisory until 8 PM EDT this evening for LEZ020. Small Craft Advisory until 11 PM EDT this evening for LEZ040-041. && $$ SYNOPSIS...Apffel/HSK NEAR TERM...Apffel/HSK SHORT TERM...RSH LONG TERM...RSH AVIATION...Apffel MARINE...Apffel