Area Forecast Discussion
Issued by NWS Buffalo, NY

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000 FXUS61 KBUF 140834 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 334 AM EST Fri Dec 14 2018 .SYNOPSIS... High pressure will slide off the New England coast which will bring milder air to our region today and through the weekend. A weak trough may bring a few showers to areas near the Canadian border today. Low pressure over the southeastern states will then move up along the East Coast for the weekend and will bring a chance of some rain, especially to the Southern Tier. && .NEAR TERM /THROUGH TONIGHT/... Skies cleared out across a good portion of Western New York overnight, but IR satellite imagery shows mid and high clouds will spread across the area through daybreak. Some light fog has developed as a result of this clearing, but this should not become more dense due to the expanding cloud cover and 5 to 10 mph winds which will help keep the boundary layer mixed. A mid level shortwave will move from the Upper Great Lakes to western Quebec today, with a trailing weak low level trough glancing our region. Increasing moisture, convergence, and warm advection along and ahead of the trough axis will bring a period of thicker cloud cover. Model consensus suggests the southern fringe of an area of rain will clip the Lake Erie shore and Niagara Frontier from mid morning through early afternoon, and also areas near the Saint Lawrence Valley in the afternoon. Farther south and east it will remain dry. Otherwise, today will be notably warmer, with highs in the mid 40s on the lake plains of Western NY with a little boost from modest SSW downslope winds. Tonight, low pressure will track into the mid-Atlantic states. The far northern fringe of rain associated with this system may reach the NY/PA border tonight, while the rest of the area will remain dry. This system will help maintain a fair amount of cloud cover in our region, especially across southern portions. && .SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/... A closed upper level low will meander from across the Tennessee Valley Saturday to the southern mid Atlantic states on Sunday. Meanwhile at the surface an area of high pressure centered over Quebec and northern New England will suppress the northward extent of the precipitation shield associated with this upper level low...while also supplying dry air across our region. It will not be until Saturday night that the upper level low will drift far enough northward, and falling precipitation is able to over come a dry low level for precipitation to reach the ground across our So. Tier. Light precipitation will spread northward Sunday, though likely remaining along and south of Lake Ontario. The surface high to the north will also bring cool air at the lower levels across our region such that the falling rain may encounter a subfreezing surface. Will continue the mention for chances for freezing rain Saturday night and Sunday...though no headlines at this time due to the still uncertainty to the exact northward extent of the precipitation shield. As the closed low is captured by the mean upper level flow aloft Sunday and Sunday night, it will increase in speed towards the New England coastline. A brief period of dry weather is expected later Sunday between this departed upper level low, and the next system to near us from the west. A shortwave trough now within the northern branch jet will then dip towards our region Sunday night. This trough will bring chances for now primarily snow showers Sunday night across the region. As the upper level trough swings across the region Monday synoptic snow showers will expand across the entire region, with lake effect snow likely along the southern and southeastern Lake Ontario shoreline. Low level moisture and lapse rates are still not optimal for a major lake effect response, though lake induced equilibrium levels climbing to near 10K feet may allow for a moderate lake effect band briefly southeast of Lake Ontario. Coupled with cold air advection a brisk west-northwesterly wind will become gusty with gusts through the day nearing 25 to 35 mph. Behind the upper level trough Monday night a northwest flow will continue lake clouds and light lake snows to the southeast of the Lakes. With the core of the cold pool overhead, overnight lows will dip 10 to 15 degrees colder than the previous night. && .LONG TERM /TUESDAY THROUGH THURSDAY/... An upper level ridge will cross the region this period, continuing a rather quiet period for our region...this at a time when we typically are very active in the snow department. A few lake effect snow showers will linger Tuesday, mainly southeast of Lake Ontario on a northwest flow. As the ridge passes us Wednesday expect a dry day with perhaps a fair amount of sunshine. This ridge will slide eastward Thursday and we could see the impacts of the next weather system...this approaching us from the Midwest with a mix of rain and snow. && .AVIATION /09Z FRIDAY THROUGH TUESDAY/... Spotty MVFR CIGS will continue across higher terrain overnight, but otherwise VFR will prevail for the bulk of the area tonight with varying amounts of cloud cover. There also will be some light fog in areas which clear out, however this is unlikely to become dense due to 5-10 mph winds which will help keep the boundary layer mixed. A weak trough will glance the region today. The bulk of the more organized rain will remain across southern Ontario, although a few showers may clip areas near the Canadian border. CIGS/VSBY will remain VFR in most locations, with some MVFR possible across the Saint Lawrence Valley in the afternoon where the greatest rain chances will be found. Tonight, low level moisture will increase a bit with IFR stratus and possibly some fog developing across higher terrain. This will likely result in IFR conditions at KJHW, with mainly VFR conditions likely at other terminal locations. Outlook... Saturday...Mainly VFR with a chance of rain showers. Sunday...Mainly VFR. Monday and Tuesday...VFR with a chance of snow showers. && .MARINE... Southeast to south winds will remain on the lakes through tonight, but are likely to remain just below small craft thresholds. Another storm system will near the region for the weekend, though north winds associated with this system may remain light enough to continue favorable boating conditions. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...Apffel NEAR TERM...Apffel SHORT TERM...Thomas LONG TERM...Thomas AVIATION...Apffel MARINE...Apffel

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