011 FXUS61 KBUF 151023 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 623 AM EDT WED JUN 15 2016 .SYNOPSIS... After a mostly sunny start to our day, clouds will begin to increase across Western New York State. Ahead of a warm front a few showers may pass through the Southern Tier today, and then increase in coverage area tonight across Western New York tonight. A few thunderstorms will be possible as well through the night as instability lingers. Surface high pressure, along with fair and dry weather returns for Friday. && .NEAR TERM /THROUGH TONIGHT/... IR satellite imagery this morning displays a few cirrus clouds across the region in addition to a band of mid level clouds now pushing into SW NYS. A few showers are nearing the OH/PA line. Water vapor imagery depicts well a shortwave trough of low pressure spiraling over the Northern Plains this morning...this feature topping a persistent ridge of high pressure over the Plains/Ohio Valley region. For today, aloft the ridge of high pressure remains east of the Plains, with its axis over our region. This will promote a dry start to the day. However moisture will increase today, with this moisture well to the north of a warm front that lies over the Ohio Valley. Moisture along the warm front will pivot northeastward around the upper level shortwave...with deeper moisture reaching the western Southern Tier by early afternoon. This will increase the clouds today, and enough instability coupled with the weak isentropic upglide will provide the lift for showers today. Activity will likely remain scattered at best through the afternoon hours. Not until the upper level shortwave rounds the ridge, and starts to dive southeastward towards our region will showers and possible thunderstorms increase in number. Lift ahead of this shortwave should provide ample lift through the night to leave chance to likely Pops across WNY. Instability of several thunder J/kg will remain north of the warm front through the night, and a nocturnal thunderstorm will remain possible. During and after these showers, moisture will build in the lower levels such that low stratus may develop over the hills of SW NYS. Will place patchy fog for both low clouds, as well as some possible ground fog as dewpoints briefly rise with the warm front within the vicinity of SW NYS. East of Lake Ontario will see some increase in clouds tonight, but this region will lie far enough from both the deeper moisture and substantial lift for any showers. Thus will maintain a dry forecast here through the overnight time period. Highs today will reach into the upper 70s to mid 80s across the region as warming continues in both the low and mid levels. Tonight mostly cloudy skies across WNY will bring more typical mid June lows...with overnight lows in the upper 50s to lower 60s. East of Lake Ontario where clouds will be sparse, overnight lows will drop back into the mid 50s. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... Parts of the region will pick up some badly needed rain as we open this period...but this will only be the case across the western counties where basin average rainfall amounts are not expected to be significant. For most of the forecast area...and certainly the eastern Lake Ontario Region...the abnormally dry conditions will only intensify. A very robust Pacific shortwave...seen in WV imagery over Northern Minnesota this morning...will track from Lower Michigan to eastern Ohio on Thursday. Meanwhile...its loosely organized sfc reflection will pass to our west along a warm frontal boundary. The corresponding baroclinic zone will lie directly over the southwest portion of our forecast area. A fair amount of H925-70 frontogenetic associated with this gradient should be enough to produce some showers and possible thunderstorms...particularly from the Genesee Valley westward. Its not even out of the question that any storm over Chautauqua and Cattaraugus Counties could become rather 'frisky' as MUCAPEs could approach 2000 j/kg with 6km bulk shear averaging 40 knots. A higher risk for severe weather though will be found well to the southwest of our forecast area. Meanwhile...low level ridging and a notably drier airmass should encourage plenty of sunshine across the North Country. This is also where it should be the warmest...as temps should break the 80 degree mark. The shortwave and its attendant sfc low will track southeast to the Mid Atlantic region Thursday night...while ridging and significantly drier air will gradually build south across Lake Ontario. Any residual showers over the Southern Tier during the evening will taper off as the night progresses. Min temps will be in the 50s for the vast majority of the region. On Friday...an impressive +2 std +592dm ridge over the center of the country will extend across the Upper Great Lakes to James Bay. This is the same ridge responsible for the record heat that has been felt across the nations mid section...and where H85 temps have been 3 std abv normal mid June levels. In any case...the ridge will be supportive of an expansive area of high pressure that will be centered over Quebec. This feature with its large scale subsidence and abundant dry air will produce sun drenched skies across our region on Friday...while H85 temps averaging 12c will allow afternoon temps to climb to near 80 degrees across the lake plains and in the valleys. Outstanding weather can then be expected for the weekend. The nose of the strong H5 ridge will fold across all of the Great Lakes region during the first half of the weekend...while its associated sfc high will drift across our forecast area before making its way off the East Coast. This will keep dry weather in place over our region with clear...moonlit skies Friday night being followed by sun filled skies on Saturday. Temperatures will climb into the lower 80s for most areas Saturday afternoon. && .LONG TERM /SUNDAY THROUGH TUESDAY/... A massive 600dm H5 ridge centered over the Southern Rockies will extend eastward across the Ohio Valley Sunday and Monday...and this will guarantee fair dry weather over our forecast area along with a further increase in warmth. An interesting tidbit is that the strength of this ridge corresponds to a once in a generation (>25 yr) return interval for this time of year. Sun filled skies Sunday and Monday will be accompanied by H85 temps in the mid teens...which when combined with the highest sun angle of the year...will easily send temps away from the lakes into at least the mid 80s. The mercury in many areas will most likely climb into the upper 80s Monday ahead of an approaching cool front...with lower 90s fully anticipated for the Genesee Valley and much of the Finger Lakes region. A cool front will then settle south across the region Monday night and early Tuesday. While this could spark a few showers or thunderstorms...coverage and associated rainfall amounts are not expected to be significant. In fact...many areas could get through without measuring any rain. Temperatures in the wake of the cool front will then settle back towards normal for Tuesday afternoon...with most areas experiencing highs of 75 to 80. Medium range ensembles then suggest that a relatively low amplitude will be positioned over the Great lakes region for much of the remainder of the week. This would favor dry weather with temps averaging near...or just above normal. In this scenario...oppressive heat and humidity would be suppressed well to our south and west. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... VFR flight conditions at 12z will persist through most if not all of the upcoming TAF cycle. IR satellite imagery displays a few wisps of cirrus across the region, with lower mid level clouds now nearing SW NYS. A narrow ridge of high pressure this morning will fade eastward, allowing a warm front to slowly edge through the Ohio Valley today and tonight. Clouds spill southeastward ahead of this warm front will increase through the day today and tonight, with these clouds eventually lowering to under 10k feet. A few showers will be possible across SW NYS late this afternoon and evening, but coverage area will be scattered and will leave just a VCSH in the TAF for now through the evening hours. After midnight activity will become a little more definite, and will have -SHRA in the KJHW TAF, and introduce a VCSH in the KIAG/KBUF TAF. There may also be a thunderstorm across the Southern Tier through the evening hours. Later in the TAF period there may be some patches of fog forming, mainly across the hills of SW NYS Wednesday night, that may result in localized IFR ceilings. Outlook... Thursday...VFR/MVFR with showers becoming likely south and west of KROC...where there could also be a few thunderstorms. Friday through Sunday...VFR. && .MARINE... A warm front will lift towards our region today and tonight, producing a few showers and thunderstorms over Lake Erie and the western/central shoreline of Lake Ontario. Winds and waves will remain below small craft advisory with this activity. Thereafter, high pressure will establish itself over the Great Lakes region through the weekend, with below SCA wind and wave conditions. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...THOMAS NEAR TERM...THOMAS SHORT TERM...RSH LONG TERM...RSH AVIATION...THOMAS MARINE...THOMAS