Area Forecast Discussion
Issued by NWS Buffalo, NY
Issued by NWS Buffalo, NY
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176 FXUS61 KBUF 220619 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 219 AM EDT Sun Sep 22 2024 .SYNOPSIS... A narrow ridge of high pressure will bring a dry day for most areas, with a mix of clouds and sunshine through yet another warm day. A cold front will near the region late tonight and Monday, bringing showers and an isolated rumble of thunder to again primarily Western New York. As a warm front lifts across the region Tuesday night and Wednesday more widespread rain showers will fall upon the entire region. && .NEAR TERM /THROUGH TONIGHT/... This early morning clearing skies and light winds are allowing for areas of fog and low stratus to develop, including the traditionally foggier areas of the Southern Tier, but also portions of NW NYS. Fog may be locally dense in the river valleys through around 8-9 am. Morning fog and low stratus will erode, and contract back towards Lake Ontario by mid morning, leaving a mix of sun and clouds for the rest of the day with dry weather prevailing as a narrow ridge builds across the eastern Great Lakes. A southeast flow through the day will meet developing lake breeze boundaries, with perhaps a spot shower for inland areas of Western New York. However most areas should remain dry through the day. Temperatures will remain above normal with most highs in the mid 70s to around 80. Dry through the evening and much of the overnight hours. It will remain warm with a light southerly flow ahead of a cold front that will approach from the west. As moisture increases aloft, and a shortwave trough reaches WNY, clusters of light showers ahead of this cold front will move into far western locations late tonight. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... Monday, a weakening mid-level warm front and the nose of a 90-100kt 250mb jet rounding the base of the southern stream trough will enter the eastern Great Lakes by early morning. This will provide ample large scale lift to support a round of scattered to widespread showers from west to east through the day Monday. As the jet weakens and lifts northward, the attendant surface low will slow to a crawl just west of the forecast area, leaving the washed out frontal boundary stalled over western NY. This should lower overall coverage and intensity of showers/storms as they move towards the central Finger Lakes and North Country. While more frequent breaks in the precip should also be found across far western NY by Monday afternoon, with the low just to the west cannot rule out additional showers through Tuesday morning. Basin averaged rainfall amounts through Monday night are expected to be between 0.1-0.25". The next round of widespread showers and a few embedded thunderstorms will then move through the region from southwest to northeast late Tuesday afternoon through Tuesday night. With greater upper level support from the poleward exit region of the southern jet streak, this batch looks more impressive in regards to rainfall potential than the one on Monday. Where exactly the heaviest rainfall will occur remains uncertain, though additional amounts of 0.5-1" across much of the area seems likely, with locally higher totals plausible. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... A northern stream trough will cross the Great Lakes through Wednesday night as additional robust shortwave energy peels northeastward from the upper level closed low over the southern Plains/lower Mississippi Valley. This will cause the northern stream trough to also slowly close off in the vicinity of New England by Thursday night, then quickly shift off the East Coast and into the western Atlantic by Saturday. Meanwhile, a strong ridge of high pressure across the western CONUS will ride over the southern stream closed low across the Upper Midwest. Much of how this pattern ultimately evolves will hinge upon how the northern/southern stream branches of the jet stream phase earlier in the week, the details of which remain murky at this range. In general, with the northern trough moving across the lakes, expect unsettled weather with periods of rain and possibly a few thunderstorms through at least Wednesday. The aforementioned ridge cresting over the southern stream low should then bring a gradual drying trend from west to east Wednesday night through early Thursday night, though low-end chances (15-25%) for precip linger through Saturday as there could be diurnal, wrap-around, or even possibly some lake enhanced showers during this period. As the details come into better focus however, could see much of this period ultimately being dry. As cooler air pooled within the northern stream low pulls away from New England, areas mainly east of the Genesee Valley will see a gradual, day-to-day warming trend through the end of the week. Temps may be a touch on the cool side in these areas Wednesday/Thursday, though will otherwise average near to a few degrees above normal across the forecast area. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... For the 06Z TAFS the concern will be the formation and location of fog through the first 6-9 hours of the TAF cycle. Expect fog in the traditionally Southern Tier tonight, but also NW NYS, including KIAG where low level moisture with clearing skies should allow for fog and low stratus. This fog or low stratus will near KBUF from the north but struggle to pass over the airfield with slightly drier airmass overhead...due to a lack of recent rainfall. Otherwise for the Genesee Valley and east of Lake Ontario mainly VFR flight conditions today. Light winds today will become more southeasterly this evening and overnight. This, along with increasing clouds aloft will limit fog formation tonight. Ahead of a cold front a few showers may near the three far western TAF sites late tonight. Outlook... Monday through Thursday...VFR/MVFR with chance to likely showers and a chance of thunderstorms at times. && .MARINE... Negligible wind and waves overnight as a weak ridge builds in. Low pressure and a cold front will approach from the west late Sunday night and Monday, with increasing south to southeast winds on both lakes. This wind direction will once again keep the greater wave action well offshore and in Canadian waters. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...Thomas NEAR TERM...Thomas SHORT TERM...PP LONG TERM...PP AVIATION...Thomas MARINE...Apffel/Hitchcock