044 FXUS61 KBUF 250534 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 134 AM EDT Wed Mar 25 2020 .SYNOPSIS... Low pressure will pass by to our south today, spreading plenty of clouds across the region. Most of the area will remain dry, with just a small chance of a few light rain and snow showers near the Pennsylvania state line this morning. A weak cold front will then cross the area Thursday afternoon and Thursday night with a chance of a few light showers. && .NEAR TERM /THROUGH TONIGHT/... IR satellite imagery showing mid/high clouds spreading into the eastern Great Lakes early this morning to the north of a weak system over the Ohio Valley. There are still some areas of low stratus leftover as well, mainly across the Southern Tier and Finger Lakes, and also east of Lake Ontario. A mid level shortwave will track from the Ohio Valley to the Mid Atlantic today, with a weak surface low developing off the Virginia Capes by midday. The shortwave will continue to spread extensive cloud cover across the eastern Great Lakes today. DPVA ahead of the mid level trough and an area of frontogenesis to the north of the weak surface wave will pass through Pennsylvania this morning through early afternoon. The vast majority of associated precipitation will stay south of the area, although a few light rain or wet snow showers cannot be ruled out this morning near the Pennsylvania state line. Highs will reach around 50 on the lake plains of Western NY, and generally mid 40s elsewhere. The mid level trough and surface low will move well offshore by this evening, with a weak ridge surface and aloft building into the Great Lakes. Cloud cover will likely linger through this evening, with a brief period of partial clearing possible through the middle of the night before clouds begin to increase again ahead of a cold front moving into the central Great Lakes. The cloud cover and weak warm advection will keep lows in the upper 30s to around 40 on the lake plains of Western NY, with mid 30s in the cooler Southern Tier valleys and east of Lake Ontario. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... Dry weather will last through early Thursday. After that point, shortwave bringing a round of wet snow to parts of the Upper Great Lakes on Wednesday night will be heading toward the Ottawa River valley. Though associated sfc low pressure system stays mainly north over Ontario and Quebec on Thursday, weak cold front tied to the low drops across the region Thursday afternoon. Expect scattered showers along the front with proximity to strongest forcing from the shortwave favoring the North Country for the most rainfall. Warm advection ahead of the front will result in temps well into the 50s across the region. Front that moves though on Thursday will settle to the Ohio Valley and Mid Atlantic states on Thursday night before stalling out. Looks quiet on Thursday evening before a weak low pressure wave rides along the stalled out front to possibly bring some rain showers to the south of Lake Ontario late Thursday night. Would expect showers to likely focus on southern edge of broad upper jet cresting the Ohio Valley and where moisture transport is maximized on the nose of elevated instability working in from the Southern Plains along the stalled out front. That said, there is a potential that good portion of showers late Thursday night into Friday morning may only push as far north as the Southern Tier. Recent NAM runs into this idea supported by ECMWF. GFS and Canadian farther north though. Key on this will be how far south the front settles on Thursday evening. Whatever occurs from this batch of showers, it will quickly exit the region by late Friday morning leaving mostly cloudy conditions for rest of the day. Weak north to northeast flow will result in cooler day than Thursday with highs mainly in the 40s to maybe near 50F in a few spots. Friday night starts off dry, then as deepening low pressure system over the middle Mississippi River valley takes shape pushing a warm front toward Ohio Valley, expect showers to spread into western NY late evening through the overnight. Showers will be supported by the approaching warm front in addition to right entrance of jet from Ontario to the Mid Atlantic and another jet from the southern Plains to the central Great Lakes along with broad area of warm advection and moisture transport. Rain will be most widespread west of the Genesee valley but looks like North Country likely stays dry though through Friday night as high pressure persisting over southern Quebec keeps low-levels too dry for any precip. && .LONG TERM /SATURDAY THROUGH TUESDAY/... A couple of rounds of rain are expected Saturday and Sunday as a surface low traverses northeast through the Great Lakes. The first round of rain will result from the passage of the surface low's warm front on Saturday. Heading into Sunday, the associated cold front from the aforementioned low pressure system will sweep through the region again causing the next round of rain. While the surface low does appear to be filling in at this point, chances for rain are favorable due to the upper level jet dynamics and bountiful moisture in the region. As we start the work week, the low pressure system will continue to weaken as it positions itself over southern Ontario and Quebec. Throughout Sunday night and Monday, the parent low will slowly give way to a secondary low developing off the coast of New England. This will keep the chances for some showers across the region, especially for far eastern areas in our region due to the developing low off the coast. As the low pushes further east, colder air will wrap around on the backside of the low Monday afternoon. A period of cold air advection combined with any lingering moisture may be conducive for some lake enhancement east of Lake Ontario resulting in rain and eventually snow Monday afternoon through Monday night. As compared to previous model guidance, the period of cold air advection appears to momentarily reach -6C at 850 mb and therefore depreciating the chances for any real snow accumulations in the higher terrain in the areas east of Lake Ontario. We'll have to keep an eye on this as it approaches. High pressure builds in Tuesday allowing for a brief period of dry weather. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... A few areas of low stratus will continue through the rest of the overnight, mainly from the Southern Tier through the Finger Lakes with areas of MVFR and high terrain IFR CIGS. Otherwise VFR will prevail for the rest of the area with thickening and lowering mid level clouds. A weak wave of low pressure will pass to the south of the region today, spreading extensive cloud cover across the eastern Great Lakes. CIGS will continue to lower, but should stay mainly VFR across lower elevations. The higher terrain, especially from the Southern Tier through the Finger Lakes will continue to see areas of MVFR CIGS through the day. A few scattered light rain/snow showers are possible this morning down near the PA state line, otherwise dry conditions will prevail today. Weak high pressure will build into the eastern Great Lakes tonight. This will maintain VFR conditions in most areas, although some patches of MVFR to IFR CIGS may develop across the Southern Tier mainly east of KJHW as low level moisture over PA advects northward. Outlook... Thursday...Mainly VFR but with a chance of rain showers. Friday...VFR. Saturday...Mainly VFR with a chance of showers across the western Southern Tier. Saturday night and Sunday...MVFR/IFR with rain likely. && .MARINE... East winds averaging around 15 knots will continue to produce choppy conditions on the western portion of Lake Ontario through this morning before diminishing this afternoon. A cold front will then cross the area Thursday afternoon and evening. Southwest winds will increase ahead of the cold front. This will produce choppy conditions on both lakes, although winds and waves may stay just a little below Small Craft Advisory criteria. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...Hitchcock NEAR TERM...Hitchcock SHORT TERM...JLA LONG TERM...EAJ AVIATION...Hitchcock MARINE...Hitchcock