Area Forecast Discussion
Issued by NWS Buffalo, NY
Issued by NWS Buffalo, NY
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382 FXUS61 KBUF 040533 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 133 AM EDT Thu Jul 4 2024 .SYNOPSIS... A weak cold front will drop to near the New York and Pennsylvania State line today, with showers fading east of Lake Ontario this morning, and an afternoon spot shower forming near the state line. Otherwise today and tonight will feature dry, but still very warm and humid conditions. Another system will bring more showers and thunderstorms Friday night and Saturday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Regional radars this morning display clusters of showers, primarily east and southeast of Lake Ontario as a weak cold front drops southward across our region. 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 THIS 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 WEDNESDAY/... 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 /06Z THURSDAY THROUGH MONDAY/... For the 06Z TAFS mainly VFR flight conditions are found. There are a few showers near KART, remaining here for the next few hours. Ceilings may lower to MVFR for KART. Across Lake Erie satellite imagery displays a deck of low stratus, that mesoscale modeling expands northeastward within a light southwest wind and moisture rich lower boundary layer. This would bring a scattered to broken deck of low ceilings to KBUF, in a 10Z to 13Z window. Otherwise, within this humid airmass some patches of fog or low ceilings may develop...especially across the Southern Tier (KJHW). A weak cold front will drop across the region this morning from north to south, stalling near the State line this afternoon and overnight...before fading. Any showers this afternoon and overnight along the front will likely stay just south of KJHW - KELZ, with VFR flight conditions across the TAF sites through tonight. Winds will be weak tonight with high pressure extending across the region. 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...Thomas NEAR TERM...Hitchcock/PP/Thomas SHORT TERM...Fries LONG TERM...TMA AVIATION...Thomas MARINE...Hitchcock/PP