Area Forecast Discussion
Issued by NWS Buffalo, NY
Issued by NWS Buffalo, NY
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382 FXUS61 KBUF 300749 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 349 AM EDT Mon Sep 30 2024 .SYNOPSIS... Low pressure will drift slowly east through the Mid Atlantic States through Tuesday as high pressure builds in from the north. A cold front will cross the eastern Great Lakes Tuesday night and early Wednesday with a period of showers. Temperatures will continue to be above average through Tuesday before a brief, one day cool down on Wednesday behind the cold front. && .NEAR TERM /THROUGH TONIGHT/... Latest nighttime microphysics satellite imagery showing areas of fog and stratus early this morning. Not a large coverage at this point of the morning, but will likely expand through daybreak as a moist northeast flow and cooling continues. The fog/stratus will gradually lift through midday leaving mainly a coverage of mid and high clouds across the region for this afternoon, with more of this cloud cover over southern portions of the area. Despite the cloud cover, the day will be dry as high pressure resides across New England. Temperatures will continue to run solidly above normal with highs reaching the mid 70s for lower elevations and around 70 for higher terrain. High pressure will continue just to our northeast tonight maintaining dry weather. There will continue to be a coverage of mid and high clouds with overnight lows mainly in the 50s. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... The eastern Great Lakes will start the period sandwiched between several upper level features of note. A strong ridge of high pressure will initially reside from New England and across the Canadian Maritimes, as low pressure (and the remnants of Helene) lingers over the Mid-Atlantic states. Meanwhile, a broad longwave trough will be found over the Upper Midwest and western Great Lakes. Through the day Tuesday and Tuesday night, this trough will shift eastward, flattening with time and pushing the other two upper level features along with it. This will result in a cold frontal passage across the eastern Great Lakes late Tuesday night into Wednesday morning, with an areawide round of showers and brief cooldown. While the aforementioned area of high pressure will keep the forecast area mainly dry Tuesday, can`t rule out a few stray showers in the Southern Tier through the early afternoon as moisture circulating around the low over the Mid-Atlantic is advected northward. This moisture advection will briefly deepen across WNY ahead of the approaching cold front later Tuesday afternoon which could touch off some light showers further north, though much more widespread shower activity will come Tuesday night closer to the front itself. This is expected to arrive on the fringes of WNY after midnight, then slowly progress eastward through the pre-dawn hours, being along or just east of the Genesee Valley by daybreak Wednesday. While these showers could be a bit more impressive as they approach the region from Ontario and a lingering thunderstorm or two could possibly reach WNY, increasingly unfavorable upper level jet dynamics as the parent trough flattens should cause precip coverage and intensity to decrease through the night. Forecast basin averaged rainfall totals through Wednesday morning range from just a few hundredths of an inch in most areas to near 0.15" across far western NY. The main area of showers will trudge east across the Finger Lakes and North Country through the day Wednesday. While much of WNY will remain dry as surface high pressure quickly builds in the wake of the front, this will extend east to the rest of the forecast area by the late afternoon/early evening and persist through Wednesday night. As alluded to earlier...While Tuesday will be yet another warm day featuring temps in the low/mid 70s across the Lake Plains and upper 60s elsewhere, the cold frontal passage will bring us closer to normal for early October for Wednesday, with more of a range of 60s across the area. Lows Tuesday night will be in the 50s, then dip into the 40s across the region behind the front Wednesday night. && .LONG TERM /THURSDAY THROUGH SUNDAY/... Moving later into the week, model consensus is initially in good agreement on a large area of high pressure providing dry weather on Thursday as it builds over our area from the west in the wake of the cold frontal passage. A fairly fast zonal flow aloft will develop across the CONUS which will drive systems from west to east fairly quickly through next weekend, before the pattern potentially becomes more amplified toward the tail end of the period. Back down at the surface, this will take the high over our area Thursday and shove it rapidly east to the New England coast by Friday morning. However, this surface high will remain ridged back westward across New York State through the end of the work week, which should provide mainly dry weather through at least much of the day on Friday. High pressure will then continue to press further east off the New England coast, which will allow the next upper level trough and associated surface cold front to approach our region from the upper Great Lakes. As has been the case, the `Big Three` continue to struggle with the exact timing and overall strength of this system. Thus, the forecast package will remain similar to the previous with SChc to low Chc PoPs to account for the cold frontal passage owed to the continued uncertainty. At this point, shower activity associated with the cold frontal passage should occur sometime between Friday evening and Saturday morning depending on the timing of the system. Another area of high pressure will then quickly build in from the west bringing drier and cooler weather through much of the weekend, before the next potential trough arrives late Sunday with renewed chances for showers. Otherwise, temperatures some 5-10 degrees above average Thursday and Friday, will trend closer to average for next weekend with the arrival and passage of the cold front. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... A mid level closed low will move slowly from the Ohio Valley towards the central Appalachians today as surface high pressure builds in from the north. A moist low level northeast flow this morning will promote areas of low stratus and fog with ceiling and visibility restrictions of IFR/LIFR. The lowest conditions are expected at KART and KROC where skies cleared overnight. These conditions could also reach KIAG and KBUF, but confidence at these sites is a bit lower. The low conditions will improve by midday with mainly VFR conditions expected by afternoon, with a coverage of mid and high level cloudiness. Outlook... Tuesday...VFR. Tuesday night...MVFR with showers likely. Wednesday...Showers ending from west to east with a return to VFR weather. Thursday and Friday...VFR. && .MARINE... Northeast winds will continue to produce light to moderate chop on Lake Erie southwest of Sturgeon Point, and on the western portions of Lake Ontario today. Winds and waves will remain below Small Craft Advisory criteria. Winds will become southeasterly Tuesday, directing the greater wave action into offshore and Canadian waters. A cold front will then cross the lower Great Lakes Tuesday night and early Wednesday. This will bring a brief period of elevated winds to the lakes, first out of the south ahead of the front, and then northwest behind it. Winds and waves may briefly approach Small Craft Advisory criteria. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...Hitchcock/TMA NEAR TERM...TMA SHORT TERM...PP LONG TERM...JM/PP AVIATION...Hitchcock/TMA MARINE...Hitchcock/TMA