Area Forecast Discussion
Issued by NWS Buffalo, NY
Issued by NWS Buffalo, NY
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750 FXUS61 KBUF 040219 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 1019 PM EDT Wed Jul 3 2024 .SYNOPSIS... A weak cold front will move across the area tonight and generate a few showers and scattered thunderstorms with uneven coverage, especially east of Lake Ontario. Most of the showers will taper off and end late tonight and early Thursday. While most areas will then be rainfree for the Fourth of July, it will remain very warm and humid for the holiday. The next round of widespread showers and a few thunderstorms will then arrive Friday night. && .NEAR TERM /UNTIL 6 PM THURSDAY EVENING/... Radar imagery late this evening showing an area of showers east of Lake Ontario. This area of showers, and possibly a few rumbles of thunder, will continue to move slowly east across the area through the midnight hour, and may develop a little more to the southwest. Farther west across Western NY, very little is occuring as of 1020PM, with just a few showers over Lake Erie and the western Finger Lakes. High-res CAMS guidance continues to suggest showers will tend to fill in over the next few hours across Western NY. A weak prefrontal trough will slowly work its way through the eastern Great Lakes from west to east this evening, acting as a focus for weak/sporadic showers and a few thunderstorms. Weak DPVA and moisture transport/convergence supported by a 40knot low level jet will allow for a few showers and thunderstorms to continue into the night along the advancing trough, and a few more showers may develop overnight as the weak cold front moves southeast across the area. Overall, expect the best coverage of rain to be found across the Southern Tier, Finger Lakes, and east of Lake Ontario, with more spotty coverage from the Niagara Frontier to Rochester. Forecast profiles and SPC objective mesoanalysis shows moderate CAPE and shear available, but very poor mid level lapse rates are proving difficult to overcome as developing updrafts quickly weaken as they encounter the unfavorable thermodynamics of the mid levels. PWAT values are around 2" so any storms that develop will produce brief/local downpours, but the progressive nature of the system and disorganized nature of convection should prevent anything problematic. Otherwise...It will be a rather muggy night with lows in the upper 60s to low 70s and plenty of residual humidity. Shower coverage will taper off late tonight into early Thursday morning as the frontal boundary moves south and stalls across Pennsylvania. Mainly dry weather will then persist through Independence Day as the better moisture and forcing for precipitation remains well to our south, but an isolated shower or thunderstorm can`t be ruled out across the Southern Tier and southern Finer Lakes region. With very little of an airmass change on the `cooler` side of the boundary, expect another warm and humid day, though not quite as oppressive. Highs will range in the low to mid 80s with dewpoints still well into the 60s. Mainly dry weather for Thursday night as weak surface high pressure remains over the region. Light winds at the surface and aloft will make any firework smoke slow to clear. Lows will again be warm, ranging in the mid to upper 60s. && .SHORT TERM /6 PM THURSDAY EVENING THROUGH SATURDAY/... Potent southeasterly flow will encompass the area on Friday. This flow will strengthen through the afternoon and evening hours, eventually turning more southerly. Off the deck, consensus 850 hPa temperatures surge toward +18 to +19C and momentum mixes through the boundary layer below that level. This combined with southeasterly flow, which relegates the lake influence to almost nil across the majority of the area, should all for temperatures to skyrocket on Friday. Highs should jump toward 90F, especially along the Lake Erie shoreline, Buffalo area, and the Genesee Valley. Friday`s warmth will be short-lived as the brisk southerly flow comes in advance of a southwesterly low-level jet nose that nudges into the area by Friday evening. This combined with a right entrance of an upper jet streak and solid DPVA should work on the remaining instability from the hot day on Friday to trigger widespread showers and thunderstorms Friday evening in WNY that spread eastward overnight. Organized ascent slowly translates across the area into Saturday, when the North Country should be the shower focus for the early half of the day at least. The remainder of the area looks to largely move into the mid-level dry slot of the system that will be occluding by that juncture over the northern Lake Huron region. Thus, deep layer dry advection and modest cold advection should at least temporarily cut off rain chances from west to east as the afternoon ensues on Saturday. Likewise, temperatures will be falling back in cold air advection to a bit below normal across at least the western half of the area. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... Surface ridging and drier air moving in behind the cold frontal passage gives fairly high confidence that the area will see dry weather through Monday. Showers and thunderstorms return to the forecast for the Tuesday through Wednesday period as a mid level trough enters the region and a wave of low pressure tracks to our north bringing a cold front through the region. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... A weak cold front will move across the area tonight and generate a few rounds of showers and scattered thunderstorms. The best coverage of rain is expected to be east of Lake Ontario, with lower coverage across Western NY. Thunder has been minimal with this activity so far, but enough instability lingers into tonight to support a few spotty thunderstorms. Mainly VFR will continue through the first half of the night outside of any brief/local restrictions in heavier showers. Overnight, areas of low stratus will develop with MVFR CIGS, especially across higher terrain and over/east of Lake Ontario. The weak cold front will move southeast of the area Thursday morning, with any remaining showers and thunderstorms coming to an end. This will leave mainly dry weather for the rest of the day. Lingering areas of MVFR stratus in the morning will improve to VFR by midday. Outlook... Friday...Mainly VFR with increasing chances for showers and thunderstorms. Friday night...MVFR with showers and thunderstorms likely. Saturday...Mainly VFR with decreasing chances for showers. Sunday and Monday...VFR. && .MARINE... A weak cold front will cross the lower Great Lakes tonight with a few rounds of showers and widely scattered thunderstorms. A southwest breeze will persist ahead of this front, with a moderate chop on the eastern nearshore waters through early tonight. In the wake of the cold front...fair weather will return to the region late tonight with subsiding southwest breezes. Looking ahead to the Fourth of July...gentle to moderate winds will be in place throughout the region. These winds will be from the southwest on Lake Erie and primarily from the west on Lake Ontario, becoming locally onshore in the afternoon. Winds will then shift out of the east Friday, becoming southwesterly again by Saturday when the another round of SCAs appears likely. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...Hitchcock/PP NEAR TERM...Hitchcock/PP SHORT TERM...Fries LONG TERM...TMA AVIATION...Hitchcock MARINE...Hitchcock/PP