Area Forecast Discussion
Issued by NWS Buffalo, NY
Issued by NWS Buffalo, NY
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064 FXUS61 KBUF 171821 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 221 PM EDT Wed Jul 17 2024 .SYNOPSIS... There will be showers and a few thunderstorms with a cold frontal passage this afternoon into early this evening. Much drier air will build in behind the front, resulting in more comfortable humidity levels. High pressure will build in behind the front, resulting in fair weather Thursday through at least Saturday. && .NEAR TERM /THROUGH THURSDAY/... A cold front draped across the region early this afternoon will continue to push southeastward through this evening. Cloud cover has limited instability today, but LAPS shows CAPE 500 to 1000 J/Kg across the Southern Tier. With the approaching front and some instability this will generate showers and thunderstorms across the Western Southern Tier. Radar shows these developing, with mesoscale guidance bringing these into the Southern Tier between 2 and 5 p.m. this afternoon. PWAT values still around 1.75 inches ahead of the front, so some heavy downpours and localized flooding cannot be ruled out there. Otherwise, the mid-level trough will move across the region tonight, and this will usher in a cooler and drier air mass. Can`t rule out a stray shower with this trough this evening, before the drier air mass wins out later tonight. The light winds and partial clearing will allow for fairly good radiational cooling, and possibly some river valley fog in the Southern Tier. Lows will mainly be in the mid to upper 50s. On Thursday surface high pressure will be centered near Iowa, with the mid level trough axis still across our region. The air mass should be too dry to support much precipitation, but isolated showers can`t completely be ruled out along with some strato-cumulus cloud cover. It will be notably cooler and more comfortable with highs will be in the lower to mid 70s. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... Any remaining lingering showers will wrap up Thursday evening,then gradual clearing skies will likely take place. This will support good radiational cooling overnight, with the cooler spots found in the upper 40s and a range of 50s elsewhere. A spectacular finish to the work week is on tap for Friday and dry with low humidity levels. Highs on Friday will generally be found in the 70s. As we progress into the weekend a gradual day to day warming trend is advertised to take place. Other than that, high pressure anchored over the Great Lakes and Ohio Valley will likely keep much of the region dry. That said...there is a weakening front approaching from the north late Saturday afternoon and Saturday night. This feature may introduce a shower or isolated thunderstorm across the St. Lawrence Valley and North Country by Saturday night. Have kept very low end chance PoPs for now for the above locales. Otherwise...highs on Saturday will be found in the upper 70s to low/mid 80s. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... Mid-level low pressure centered over Quebec, Canada will amplify Sunday as a shortwave trough rounds its base. At the surface, high pressure spread across the area Saturday will remain mostly in place Sunday, however a backdoor cold front will slide southeast across New York state. This front looks to be moisture starved, and therefore a low chance for a few spotty showers. In the wake of this front, surface high pressure will re-establish itself across the lower Great Lakes for the start of the week, continuing dry weather Monday and Monday night. Uncertainty remains for Tuesday and Wednesday with a broad, weak trough over the Plains moving slowly east into the Mississippi Valley. This will support a diffuse area of moisture and general low pressure drifting northeast across the Ohio Valley. Depending on the northward extent of the moisture Tuesday, chances for showers will be possible, and remain likely south of the forecast area. As the moisture further creeps northward Wednesday, the chances for showers will continue. Otherwise, temperatures will warm this weekend with highs slightly above average for the end of the weekend and the start of next week. Highs will range in the low to mid 80s. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... A cold front across the region early this afternoon will continue to push southeastward through this evening. This will mainly generate showers and a few thunderstorms ahead of the boundary, with only light showers possible behind it. Thunderstorms may impact KJHW this afternoon, but otherwise expect mainly VFR flight conditions at our TAF sites. Mainly rain-free and VFR flight conditions tonight and Thursday. There`s a risk that river valley fog will bring IFR or lower visibility at KJHW, with a non-zero risk for fog elsewhere. There may be patchy MVFR cigs tonight and Thursday. Outlook... Thursday night through Monday...VFR. && .MARINE... A cold front will push south of the lakes through this evening. Northwesterly winds will increase to 10 to 20 knots on Lake Ontario, which will approach small craft advisory criteria along the south shores of Lake Ontario. For now, expected conditions fall just short of criteria. High pressure will then build across the Lakes later tonight through the end of the work week with a light wind flow. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...Apffel/Thomas NEAR TERM...Apffel SHORT TERM...AR LONG TERM...EAJ AVIATION...Apffel MARINE...Apffel