Area Forecast Discussion
Issued by NWS Buffalo, NY

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000 FXUS61 KBUF 270841 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 341 AM EST Mon Feb 27 2017 .SYNOPSIS... Weak high pressure will bring mainly dry weather through tonight. A warm front will then produce a few scattered showers Tuesday before more widespread rain later Tuesday night and Wednesday as low pressure moves through the Great Lakes. Temperatures will be well above normal through Wednesday before colder air arrives late in the week. && .NEAR TERM /THROUGH TONIGHT/... IR satellite imagery showing mainly clear skies early this morning with just a few patches of mid level clouds supported by a weak warm advection regime. High pressure will drift east off the Mid Atlantic coast today with a weak ridge extending into the Lower Great Lakes and supporting continued dry weather. Meanwhile a weak mid level trough will move east across Quebec, with an associated weak surface trough glancing the North Country. This surface trough, combined with some contribution of lake moisture, will bring some cloud cover to the eastern Lake Ontario region from mid to late morning through mid afternoon. Mid level clouds will also increase later today across the Southern Tier as warm advection increases ahead of a weak Ohio Valley wave. Otherwise the rest of the area will see a good amount of sunshine with just a few passing patches of mid level clouds. Ongoing low level warm advection will support highs in the mid to upper 40s for most areas, with a few low 50s readings in the normally warmer spots of the Genesee Valley and Finger Lakes. Tonight the weak mid level wave in the Ohio Valley will ripple off the Mid Atlantic coast, with a wing of weak mid level warm advection spreading north through PA to Central NY. The warm advection and associated isentropic upglide will bring an increase in cloud cover from south to north tonight. The ascent may be just enough to squeeze out a few flurries or sprinkles from the interior Southern Tier to the Finger Lakes and Central NY later tonight. The increase in clouds will limit radiational cooling, with lows in the mid 30s in most areas and upper 20s North Country. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... On Tuesday, broad troughing carved out across the western CONUS will bring steadily rising heights with broad ridging to the east coast. A wave of low pressure will track from the central Great Plains toward the upper Great Lakes on Tuesday. This will help to push a warm frontal boundary north across the region, bringing a return much above temperatures for mid-week, as well as a batch of precipitation on the nose of the best moisture advection ahead of the low. Instability along the warm front will be marginal, but marginally steep mid-level lapse rates would favor some isolated elevated thunderstorms. Temperatures will top out in the 50s for most locations. Tuesday night into Wednesday, as secondary, stronger, wave of low pressure will track along the baroclinic zone draped from the central Plains to the lower Great Lakes. This will bring added warm air advection, along with much stronger moisture advection and synoptic lift. This will result in more widespread showers Tuesday night in Wednesday, that will likely come in a few rounds: 1/ on the nose of the best moisture advection Tuesday night, then perhaps a pre-frontal trough Wednesday morning and again with the strong cold frontal passage Wednesday afternoon. Thunderstorms will also be possible, and while overall instability will be marginal, the strongly forced and high shear environment could result in a few strong storms capable of producing bowing segments with damaging wind gusts. In fact, SPC has included the area in a marginal risk for severe weather on Wednesday, in the latest day 3 outlook. Will continue to mention this in the HWO. Expect temperatures to remain near steady then rise overnight Tuesday night, while topping out in the upper 50s to mid 60s across the region Wednesday. Rapid cold air advection in the wake of the surface front passage late Wednesday may allow for a brief change over to some snow showers before precipitation tapers off Wednesday evening. Otherwise, strong synoptic wind gusts are also possible late Wednesday the increasing cold air advection and subsidence in the wake of the passing deepening low will help to get some stronger gusts to surface. There remains some uncertainty with how strong these winds would be, as the surface low may not really start to strengthen until is pulling well away from the region, and this would limit the strength of the winds aloft to mix to the surface. However, it is possible a wind advisory may be needed for the typical wind prone lake plains, and thus will continue to mention in the HWO. Temperatures will sharply fall back into the upper 20s to low 30s through Wednesday night returning our weather back to more wintry pattern. && .LONG TERM /THURSDAY THROUGH SUNDAY/... Winter conditions will return for the end of week into the weekend as a deep progressive trough brings a surge of colder air across the northeast CONUS. Weak shortwaves may affect the region in the developing northwest mid/upper level flow. Confidence is getting higher that enough cold air will slide into the area for increasing northwest/west-northwest flow lake effect snows from late Thursday into Friday night as 850 mb temperatures drop to around -18C by Friday night. A stronger Pacific shortwave and surface low moving into the upper Great lakes will bring increasing warm air advection later Saturday and Sunday with precipitation chances diminishing along with moderating temperatures into the 40s by Sunday. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... VFR conditions will prevail today into this evening. Some clouds will develop from mid morning through mid afternoon east of Lake Ontario as a weak surface trough glances the North Country, with CIGS staying in the lower end of the VFR category. Mid level clouds will also increase across the Southern Tier later today. A weak mid level wave will pass by to the south of the area tonight, with warm advection bringing a south to north increase in mid level clouds. Conditions will remain VFR in most areas, but model soundings suggest enough low level moisture across the Southern Tier to allow a low stratus deck to develop across the higher terrain with MVFR CIGS. There may be just enough lift to produce a few sprinkles or flurries overnight from the interior Southern Tier into the Finger Lakes and Central NY, with VSBY remaining VFR. Outlook... Tuesday...VFR/MVFR with a chance of showers. Wednesday...MVFR/IFR with periods of rain. Thursday and Friday...Areas of MVFR with a chance of snow showers. && .MARINE... Southwest winds will gradually diminish today as the pressure gradient relaxes across the Lower Great Lakes. This will allow wind and wave conditions to drop below Small Craft Advisory criteria from west to east today. Winds will then remain light tonight through most of Tuesday. Stronger winds will return Tuesday night and Wednesday as a stronger area of low pressure moves into the Great Lakes region. The moderate to strong winds will then continue Wednesday night through Thursday as this low pressure deepens further over eastern Quebec. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...Small Craft Advisory until 1 PM EST this afternoon for LEZ040- 041. Small Craft Advisory until 10 AM EST this morning for LEZ020. Small Craft Advisory until 4 PM EST this afternoon for LOZ043>045. Small Craft Advisory until 1 PM EST this afternoon for LOZ042. && $$ SYNOPSIS...HITCHCOCK NEAR TERM...HITCHCOCK SHORT TERM...CHURCH LONG TERM...CHURCH AVIATION...HITCHCOCK MARINE...HITCHCOCK

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