Area Forecast Discussion
Issued by NWS Buffalo, NY

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000 FXUS61 KBUF 211831 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 231 PM EDT Wed Oct 21 2020 .SYNOPSIS... There will be a round of showers and possibly a thunderstorm this afternoon as a cold from moves through the area. Most of tonight will be dry, then a warm front will lift back northward across the area late tonight and Thursday. This front will bring a few showers on Thursday, followed by warmer weather by Friday. A cold front will cross the area late Friday night, bringing some showers and then much cooler air for the weekend. && .NEAR TERM /THROUGH THURSDAY/... At 2 p.m. a cold front extends across our region roughly from JHW-ROC-ART. This front is producing a fairly solid line of showers which will continue to move eastward with the frontal boundary. There are also a few spotty showers, and possibly a thunderstorm out ahead of this boundary where warmer temperatures in the lower to mid 70s support modest instability. It will also be breezy this afternoon, with S-SW winds gusting to 35 mph near the frontal boundary. Tonight will be mainly dry as a bubble of high pressure briefly builds over the eastern Great Lakes. Abundant low level moisture, wet ground, and light surface winds may allow for at least patchy fog to develop from late evening through the overnight across much of the region. If skies clear there is the potential for more widespread fog. 00Z model guidance suggests a greater chance for showers with a warm frontal segment and associated mid-level warm air advection late tonight and Thursday. Some showers may develop late across the Southern Tier as a warm frontal segment begins to come together ahead of the next system moving through the mid section of the nation. Showers should become a bit more widespread Thursday morning as this boundary lifts northward across the area. Because of the front, there will be a wide range of temperatures across the area on Thursday. Forecast favors high resolution model guidance, with forecast highs ranging from the lower 70s across the Western Southern Tier to the upper 50s from Buffalo to Rochester northward. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... A developing low pressure system over the Mid-West will be the driver of the weather conditions throughout the entirety of this period. To start off, the developing surface low will track east-northeast from Iowa to the western Great Lakes Thursday night. As such, the low`s associated warm front will push northeast, though the front will remain north of the region which will promote warm and dry conditions for a vast majority of the region. Warm dry conditions will prevail Friday as the region will remain underneath the warm sector of the low pressure system. Lack of cloud cover combined with the warm air aloft will promote high temperatures in the mid to upper 70s. The aforementioned surface low will continue to traverse northeast across eastern Canada Friday and Saturday. As such, it will drag its associated cold front across the lower Great Lakes and New England. More specifically for the local scale, the cold front will approach far Western New York Friday evening and cross the remainder of the state Friday night into Saturday morning. There is a slight chance for an isolated thunderstorm across far Western New York as the front nears, but confidence is low. With the eastward progression of the front, shower intensity will gradually diminish heading into Saturday morning as high pressure builds across the Great Lakes and eventually push into the region. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... An area of surface high pressure will pass across the Great Lakes and southeastern Canada Saturday and Sunday, resulting a period of dry conditions Saturday night into Sunday. The remainder of this period continues to be unsettled. A deepening upper level trough over Western CONUS will propagate eastward resulting in the next low pressure system to advance northeast across the Mississippi Valley and Mid-Western portions of the lower 48. Model guidance differs on the exact position and timing, but an overall generalization would be a warm frontal passage early on in the week followed by the passage of a cold front sometime after, while high pressure will follow in the wake of the low pressure system and its associated frontal boundaries passages. Thus, better chances and likelihood for showers occur early on in the week and begin to back off by Wednesday, will have to keep an eye on this system as time advances forward. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... A cold front extending from KJHW-KROC-KART at 18Z will continue to push eastward this afternoon. This front will produce briefly lower cigs/vsby along and just behind it. This will be most noticeable at KJHW, where several hours of IFR are expected. Overnight a bubble of high pressure moves into the eastern Great Lakes. Light winds and leftover low level moisture may allow for fog and/or low stratus to develop overnight with areas of IFR. Forecast confidence in fog is low, since it will depend on subtle differences in cloud cover. The best chance for stratus and fog is the Western Southern Tier where there will be moisture trapped beneath an inversion near the front. Stratus and fog will gradually dissipate during the day Thursday, with conditions improving from IFR/MVFR to mainly VFR by the afternoon. Outlook... Thursday night...Mainly VFR. Friday...VFR. Friday night and Saturday...MVFR with showers likely, improving to VFR Saturday afternoon. Sunday...VFR. Sunday night and Monday...VFR/MVFR. Showers likely. && .MARINE... A cold front is across Lake Ontario this afternoon, with a moderate SSW flow ahead of this boundary. This supports small craft headlines for many of our nearshore waters as outlined below. Winds will diminish behind the front through this evening. Northeast winds will develop again on Thursday, producing choppy conditions on both lakes, but Small Craft Advisory conditions are not expected. Winds will become southerly later Thursday night and Friday ahead of the next cold front. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...Small Craft Advisory until 5 PM EDT this afternoon for LEZ020. Small Craft Advisory until 8 PM EDT this evening for LEZ040-041. Small Craft Advisory until 5 PM EDT this afternoon for LOZ042. Small Craft Advisory until 11 PM EDT this evening for LOZ045. Small Craft Advisory until 5 PM EDT this afternoon for SLZ022. && $$ SYNOPSIS...Apffel NEAR TERM...Apffel/Hitchcock SHORT TERM...EAJ LONG TERM...EAJ AVIATION...Apffel MARINE...Apffel

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