016 FXUS61 KBUF 040938 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 438 AM EST Thu Jan 4 2024 .SYNOPSIS... The coldest airmass of the season so far will pour across the region today in the wake of a cold front that moved through overnight. Temperatures today will be at their highest this morning...generally ranging from mid 20s to lower 30s. The cold airmass will encourage some lake snows over the Finger Lakes today...then a large area of high pressure will move from the Great Lakes to the Mid Atlantic region through Friday to support mainly fair dry weather. && .NEAR TERM /THROUGH FRIDAY/... As a cold front exits to our southeast this morning...one of the coldest airmasses of the season so far will overspread our region. H85 temps will drop to arnd -14c by midday...so our near sfc temps will trend lower through about lunchtime before they stabilize for the afternoon. The cold air will combine with gusty northerly winds to allow for some nuisance lake snow showers south of Lake Ontario (mainly Rochester to Montezuma wildlife refuge). Since the cap will be quite low (blo 5kft)...the multiple bands of snow are not expected to yield more than an inch of accumulation. Tonight and Friday will feature fair weather for the vast majority of the region...as a large sfc high will drift east from the Upper Ohio valley to the Mid Atlantic coast. This will prompt the initiation of a warm advection pattern around the 'top' of the aforementioned sfc high...thus bringing an end to nuisance lake snows east of Lake Ontario. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... Lingering light snow showers/flurries east of Lake Ontario will gradually drift southward and fall apart Friday night as our airmass continues to slowly warm...and as the low level flow across our area becomes increasingly light and disorganized. Otherwise dry weather is anticipated...with lows ranging from the upper teens across interior portions of the Southern Tier/North Country to the lower to mid 20s elsewhere. Saturday and Saturday night a rather broad mid-level trough over the nation's midsection will make its way to the Upper Mississippi Valley and Upper Great Lakes. Shortwave energy rotating through the base and front flank of the trough and associated DCVA will encourage an initial broad/weak surface low over the southeastern states to track northeastward and develop into a strengthening coastal system off the mid-Atlantic coastline by later Saturday night. At the same time...a broad inverted surface trough will develop and extend back westward from this system to a second and much weaker surface low pushing into the Upper Great Lakes. As a result of the above developments...largely dry weather across our region Saturday morning will give way to the opportunity for a general light snowfall later Saturday afternoon and especially Saturday night as the developing coastal low spreads moisture and a period of weak to modest lift across our region. At this juncture it appears that a general 1-3 inches of snow will be possible out of this...with the greater amounts most likely along an axis extending from the interior Southern Tier northeastward across central New York...all of which will lie closer to the developing coastal low. Sunday and Sunday night the coastal low will continue to deepen as it rapidly heads eastward and out into the open Atlantic. Back across our region...the broad inverted trough will remain in place through much of Sunday while gradually weakening...before finally sliding off to our northeast Sunday night as the coastal system pulls further away and surface high pressure builds into our region from the Ohio Valley and Upper Great Lakes. Lingering broad cyclonic flow and moisture attendant to the inverted trough should combine with some weak lake/orographic enhancement to generate some additional light snow/snow showers and associated accumulations of an inch or two during the day Sunday...with the greatest amounts found east and southeast of the lakes. As the trough departs and the surface ridge/drier air builds in Sunday night...leftover snow showers will weaken and become more scattered east and southeast of the lakes...with some minor additional accumulations of another inch or two possible out of these. At this still rather-early juncture...with the snowfall later Saturday afternoon through Sunday night looking to be light in nature and accumulating only 1-2"/1-3" every 12 hours or so...feel that this will probably not be worth any headlines...even though some spots could see snowfall totals of 4-7" or so over the above 36- 42 hour window. As for temperatures...these will average out a little above normal through this period...with daytime highs mostly ranging through the 30s...and nightly lows mainly in the 20s. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... Monday looks to be a quiet day as the axis of the above mentioned surface ridge slowly traverses our region. Associated drier air and subsidence will help to finally squelch any remaining nuisance snow showers and flurries southeast of the lakes...with mainly dry weather otherwise expected. The dry weather will then continue through Monday night as the high slowly drifts off to our east. Highs Monday will again range through the 30s...with lows in the upper teens (North Country) to upper 20s (far WNY) then following for Monday night. After that...the medium range guidance continues to suggest that a much more vigorous southern stream trough and strengthening/ increasingly expansive surface low will track northeastward from the lower Mississippi Valley to the lower Ohio Valley Tuesday...then either directly over or to the west of our region Tuesday night and Wednesday. Unsurprisingly...the various guidance packages continue to show considerable differences in the exact track and strength of this system this far out in advance...factors that are likely to remain unresolved for at least a few more days. Regardless of its exact track...the warm advective wing of this system will overspread our region Tuesday and Tuesday night and likely bring widespread precipitation to our area. The ptype(s) we'll see could range from snow to rain and will be heavily dependent upon the track of the low...with a more westerly track tending to favor a stronger warmup and more in the way of rain than a more easterly one...which would be colder and more wintry. Fairly widespread pcpn should then continue on the backside of this system on Wednesday even once it has lifted north of our latitude. This system could also bring the threat of some strong downslope winds as it approaches Tuesday night...and possibly even some strong to high winds in its wake Wednesday should its center pass by to our west...as is currently rather ominously suggested by the ECMWF. Stay tuned... && .AVIATION /10Z THURSDAY THROUGH MONDAY/... MVFR cigs will be found across the majority of the region into the midday hours. These cigs will be accompanied by scattered snow showers that could briefly lower VSBYs to 3-5SM. As we push through the afternoon...the cigs will thin our from north to south so that widespread VFR weather will be in place through tonight. The exception to this will be across parts of the Southern Tier... and for a short time before sunrise...in the Rochester area. The former will experience IFR cigs at times while IFR VSBYs will be possible in lake enhanced snow at KROC. Outlook... Friday...Mainly VFR with a chance of rain or snow showers east of the lakes. Saturday...Mainly VFR. Saturday night and Sunday...IFR/MVFR restrictions likely with snow developing. Monday...Mainly VFR. && .MARINE... In the wake of a cold front...moderate to fresh northwesterlies will be found across both lakes today. This will support small craft advisories for all of the NY nearshore waters of Lake Ontario as well as for the Lower Niagara River. As a large sfc high drifts east across the Great Lakes tonight...the weakening gradient will allow winds to back off. This in turn will allow the current small craft advisories to drop off. The larger sfc high will move across the Mid Atlantic region on Friday. This will allow a greater pressure to once again develop over the Lower Great Lakes...with fresh to occasionally strong southwesterlies likely buy the afternoon. A second round of small craft advisories would be likely. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...Small Craft Advisory until 1 PM EST this afternoon for LEZ040- 041. Small Craft Advisory until 1 PM EST this afternoon for LOZ030-045. Small Craft Advisory until 5 PM EST this afternoon for LOZ042>044. && $$ SYNOPSIS...RSH NEAR TERM...RSH SHORT TERM...JJR LONG TERM...JJR AVIATION...RSH MARINE...RSH