463 FXUS61 KBUF 251843 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 143 PM EST Thu Jan 25 2024 .SYNOPSIS... Yet another bout of widespread rain can be expected tonight...as low pressure organizing over the Ohio valley will approach overnight then pass over the region Friday morning. While there will be a break in organized precipitation Friday afternoon through Saturday...a storm system passing to our south during the second half of the weekend will likely generate some accumulating snow. && .NEAR TERM /THROUGH FRIDAY NIGHT/... A strong mid level shortwave...seen in WV imagery near the confluence of the Ohio and Mississippi rivers...will track northeast across the Ohio valley this. Unlike the previous shortwave... this one is more vigorous and will induce more significant cyclogenesis. This will result in a broad...but well defined sfc low that will take direct aim on our forecast area for later tonight. The area of low pressure will track along the aforementioned frontal boundary that has been stalled from our general forecast area southwestward to the Ohio valley for the past few days. As the low nears later tonight...an associated 45kt low level jet will help to push the boundary back to the north across our area. Strong low level convergence and a brief period of significant lift supplied by a coupled H25 jet will be found in the vcnty of the advancing boundary...and when coupled with deep moisture to the tune of 1.5" PWAT values...the result will be a period of steady rain that could be heavy at times. This should be able to verify the forecast QPF of roughly a half inch...most of which will fall over a two to three hour period. While the pcpn tonight will fall as rain...we will have to keep our eyes on areas north of Watertown. It may be cold enough in that area...esp in the Thousand Islands region...to allow for another period of freezing rain. A winter weather advisory has been issued for this potential. As the sfc low and supporting shortwave exit to our east during the day Friday...notably drier air in the mid levels will sweep across the forecast area. This...and the removal of the aforementioned forcing...will allow the pcpn to rapidly taper off and end across the western counties. Sites east of Lake Ontario will take much of the afternoon to experience an ending to the rain. Plenty of low level moisture will remain trapped below an inversion parked around 5kft though...so cloudy skies will persist. Generally fair uneventful weather is expected for Friday night... although a weak shortwave could allow for a couple brief rain or wet snow showers...mainly near Lake Ontario. && .SHORT TERM /SATURDAY/... Weak area of low pressure over WNY Friday morning will slowly meander east across the region with the steadier precipitation lifting north of the region. Otherwise...expect some lingering showers early before just cloudy and cooler conditions take over across Western NY. Chances for precipitation may linger east of Lake Ontario and St. Lawrence Valley through Friday afternoon before any measure of improvement occurs Friday evening-night. With lingering low-level moisture we will likely have to deal with some patch fog, there especially areas that still have a snow pack. Weak ridging begins to take over Friday night and then continue to provide largely dry weather Saturday ahead of the next system of interest. A developing sfc low over TX/OK heads northeast towards the Mid- Atlantic states Saturday night into Sunday. Its northward advancing precipitation shield is advertised to extend into the region by early Sunday morning. As has been mentioned, the track of the sfc low continues to be a challenge. However...there is a general theme with the parent sfc low giving way to a rapidly developing and intensifying coastal low. It looks like initially p-type will be an issue, that is until the coastal low takes shape and draws in somewhat colder air. Have continued the previous theme of a rain/snow mix which then transitions over to all snow late Sunday into Sunday night. Given the marginal temperatures and issues with the track of the sfc low will hold off on any mention in the HWO. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... High pressure follows behind the departing system Monday with mainly dry weather through at least Monday night, possibly even longer. That said...there is plenty of uncertainty in regards to the next upstream shortwave which is advertised to make its appearance possibly by Tuesday or even Wednesday. Given the uncertainty have followed close to NBM guidance with a chance for snow showers as the air mass appears cold enough to support it. && .AVIATION /19Z THURSDAY THROUGH TUESDAY/... IFR cigs will be found throughout the region through this evening. While there may be areas of IFR ti LIFR vsbys in fog...the low ceilings will be the main factor. IFR to LIFR cigs will remain in place across western and north central New York tonight...but an approach area of low pressure out of the Ohio valley will spread the next round of steady rain across the region during the second half of the night. The rain could start off as freezing rain from Watertown northwards to the Thousand Islands region. The rain will quickly taper off and end across the western counties Friday morning...while it will take most of the afternoon to end east of Lake Ontario. Meanwhile...IFR to LIFR cigs will persist regionwide. Outlook... Saturday...Dry but with IFR to MVFR cigs. Sunday...IFR conditions in rain and wet snow. Monday...VFR to MVFR cigs. Tuesday...Mainly VFR. && .MARINE... High pressure over Quebec will drift east overnight...while low pressure over the Ohio valley will take aim on the Lower Great Lakes. This will maintain moderate northeasterlies across the region through the night. While choppy conditions are expected on Lake Ontario west of Irondequoit Bay and on Lake Erie southwest of Dunkirk...small craft advisories are not expected. On Friday...the aforementioned storm system will exit across the Adirondacks. This will encourage winds to back to the north and northwest...but without winds forecast to freshen...conditions should remain below small craft advisory levels. A very weak sfc pressure gradient over the Lower Great Lakes Friday night through at lest Saturday night will support weak winds and negligible wave actions for the first half of the weekend. && .HYDROLOGY... Dry conditions will end this evening as the next system brings another soaking rain to the region. Rainfall amounts will likely exceed a half inch and bring rises to area rivers and creeks, especially in areas east/northeast of Lake Erie where deep snowpack and considerably more snow water equivalent is found. The greatest snow water equivalent is in the Buffalo area in the lower reaches of the creeks rather than in the headwaters, which is not ideal for more significant rises in water levels. There are ice affected gauges on area creeks and streams today. An ice jam was reported on Big Sister Creek in the town of Evans however the water has been receding and there are no current issues. There have also been pictures and reports of ice moving under the Stevenson St Bridge on the Cazenovia. Fortunately, the risk for flooding still remains limited to minor and mainly restricted to poor drainage and low lying areas. There is soft and slushy ice in the Buffalo area creeks concentrated in Buffalo and West Seneca. Patchy ice is reported on creeks in the western Southern Tier. Overall the thickness of the ice is thin. The ice will break up with rising flows through tonight, but the lack of ice thickness is not supportive of anything more than a low risk of minor, short lived ice jams. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...Winter Weather Advisory from 10 PM this evening to 6 AM EST Friday for NYZ007. Flood Watch through Saturday morning for NYZ010-019-085. Dense Fog Advisory until 1 AM EST Friday for NYZ019>021. MARINE...None. && $$ SYNOPSIS...RSH NEAR TERM...RSH SHORT TERM...AR LONG TERM...AR AVIATION...RSH MARINE...RSH HYDROLOGY...HSK