500 FXUS61 KBUF 060242 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 1042 PM EDT Fri Apr 5 2019 .SYNOPSIS... High pressure will build across our region tonight, with lingering rain and wet snow showers ending across eastern zones. This area of high pressure will result in dry weather and warmer conditions spreading across the region over the weekend. && .NEAR TERM /THROUGH SATURDAY/... This late evening surface temperatures remain at or above freezing, with falling precipitation of the rain, and higher elevation snow now mainly across the Eastern Lake Ontario region. A shortwave that aided in the precipitation today, is now exiting our eastern zones, with upper level heights rising behind the shortwave within the mean west to east flow. These height rises, combined with the eastward push of deeper moisture will result in precipitation ending across our eastern zones overnight. Dewpoints will remain nearly stationary and above freezing overnight. As winds become more southwesterly overnight these winds over the cooler Lakes may bring some fog in from over the Lakes, especially off Lake Ontario. Also any break in the clouds overnight over the saturated ground may allow for localized areas of fog. Temperatures tonight should remain at or above freezing, especially across WNY where overnight lows will be in the mid to upper 30s. Saturday will likely start cloudy over much of the region, with some areas of fog near Lake Erie. As high pressure builds across the region, and associated drier air, we will see skies clearing some through the day, with a mix of clouds and sunshine Saturday afternoon. Highs tomorrow will be at or above normal. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... High pressure will track from the eastern Great Lakes to the New England coast Saturday night through Sunday. Although dry conditions are expected mid to high level clouds will increase from the northwest. A southerly flow will begin Sunday and temperatures will rise into the low to mid 60's away from the Lakes. Warm air advection and moisture will increase Sunday night as a 40kt low-level jet approaches western NY. Rain will spread across the forecast area from southwest to northeast overnight persisting east of Lake Ontario into Monday morning. Some elevated instability may be present as the low-level jet moves northward during this time and a few thunderstorms are possible. The forecast area will be located in the warm sector Monday morning while a cold front approaches from the west. Overall, the 12z suite of model guidance is increasing the speed of this system so although showers will be diminishing in coverage Monday, a cold front may reach western NY by midday impacting high temperatures across western NY. Temperatures across interior NYS may reach the upper 60's to low 70's. Rainfall amounts will range from a quarter inch across western NY to a half inch east of Lake Ontario through Monday. The cold front will continue to track east-southeast across the forecast area by Monday night. Dry, westerly flow will put an end to showers while cloud cover decreases from west to east. Temperatures will drop to the mid to upper 40's overnight. The combination of rain and melting snow from the higher terrain east of Lake Ontario will bring rises in the Black River basin by early next week. Overall rain amounts do not appear excessive at this point, so the risk of flooding is low, but non-zero. && .LONG TERM /TUESDAY THROUGH FRIDAY/... A progressive pattern will keep active weather in place across the Lower Great Lakes for the majority of this period...as temperatures will gradually trend to below normal levels. While there is above normal confidence in that general forecast...there is plenty of uncertainty as to the timing and extent of the expected pcpn. That being said...a shortwave digging across the Upper Great Lakes Monday night and Tuesday will help to briefly phase a split flow over the northeastern Conus. This will help to consolidate disorganized low pressure in the vcnty of eastern New York/Penns. The result should be scattered rain showers over our forecast area...but confidence in this solution is lower than normal. Several ensemble members (including the operational GFS) depict an unphased solution that would feature a warmer and drier scenario. In either case...the complex surface feature will push off the East Coast Tuesday night...taking its associated mixed pcpn with it. Wednesday should then be the 'nicest' day of this long term period. A shortwave ridge will build across the Upper Mid West while a large surface high will nose south from Hudson Bay. While there may still be a fair amount of cloud cover left in place (esp east of the Genesee Valley)...this scenario will favor dry but chillier weather. An open wave progressing across the Upper plains Wednesday night will support a fairly well organized sfc low that is forecast to track from roughly St Louis to Cleveland by late Thursday. A coupled H25 jet and strong frontogenetic forcing will then support the likelihood for rain across our forecast area for Thursday...possibly starting as a sloppy mix of rain and wet snow late Wednesday night. This part of the forecast period actually has the most consistency between the various ensembles...so confidence in this solution is exhibited by the high likely pops. Unsettled weather should then remain over our region Thursday night as the system will actually move across the Lower Lakes. Slow improvement can then be expected on Friday. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... For the 00Z TAFS MVFR flight conditions are becoming widespread, and these conditions will likely lower to IFR or lower near Lake Erie as winds over the cooler lakes bring some fog inland. This will likely impact the airfields after midnight, and first along the Lake Erie shoreline and the So. Tier. This fog will likely expand northward towards the BUF airfield briefly around sunrise. A little fog is also possible near KART as dewpoints increase through the night. Across KROC visibilities with a slight westerly downslope flow will likely remain MVFR or greater. An area of high pressure will build across the region tomorrow, and this feature will bring a slow clearing to the fog/skies. Expect widespread VFR flight conditions by tomorrow afternoon with light winds. Outlook... Saturday afternoon and Sunday...VFR. Sunday night through Wednesday...MVFR/VFR with scattered showers. && .MARINE... A southerly flow tonight will become southwest to westerly overnight behind a shortwave aloft. An area of high pressure will then build across the Eastern Great Lakes region through the weekend with winds and waves to remain below SCA conditions. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...Thomas NEAR TERM...Thomas SHORT TERM...Hitchcock/HSK LONG TERM...RSH AVIATION...Thomas MARINE...Thomas