136 FXUS61 KBTV 240622 AFDBTV AREA FORECAST DISCUSSION National Weather Service Burlington VT 222 AM EDT Fri May 24 2019 .SYNOPSIS... Low pressure will exit eastward into the Gulf of Maine this morning, allowing for gusty north winds and lingering, abundant low cloudiness. The overcast will limit high temperatures to the low to mid 60s in most locations. Also, a few showers or sprinkles will remain possible, mainly across the northern mountains. Clearing skies will develop this evening, along with diminishing winds as high pressure builds in from the eastern Great Lakes region. The tranquil weather will only last through the first half of Saturday. Thereafter, a warm front pushing in from southwest New York will allow widespread showers to develop across the region from west to east late in the afternoon or evening, into Saturday night. Briefly drier conditions are expected Sunday morning, followed by the redevelopment of scattered showers and possibly a few thunderstorms during Sunday afternoon. && .NEAR TERM /THROUGH SATURDAY/... As of 217 AM EDT Friday...Surface low pressure (1000mb) and attendant vigorous mid-level vort centered near Sherbrooke, Que. at 06Z will translate ESEWD across Maine and offshore through the remainder of this morning. This will set up a moderate N-NW low-level gradient flow across the North Country, with winds 10-20 mph with gusts to 25 mph for a time late this morning into the early afternoon hours. May even see a few gusts closer to 30 mph in the CT River Valley around midday. With low-level CAA, 900-850mb layer will help to trap some low cloudiness, which should linger much of the day per 00Z NAM model soundings. Breaks in the overcast will first appear east of the Adirondacks and Greens in downslope areas, followed by a gradual clearing later in the afternoon or toward evening for the remainder of the North Country. Some light rain showers are also possible early this morning, gradually becoming confined to far nrn/nern VT with orographic effects allowing for some continued sprinkles through 16Z or so. Have shown pre-dawn PoPs 30-50 percent near the international border, but trending below 15 percent by noon or so. The stratus and north winds will result in daytime highs holding in the low-mid 60s in most locations. Skies should clear quite rapidly this evening setting up quiet conditions tonight as high pressure moves in from the ern Great Lakes. With winds becoming light and variable, temperatures will fall into the mid-upper 40s for overnight lows, except closer to 40F for lows at KSLK and across Vermont's Northeast Kingdom. Sheltered locations may reach crossover temps, and added in some patchy fog for the climo favored spots tonight. PoPs NIL. Saturday begins dry, but surging 850-700mb warm frontal zone brings increasing afternoon cloud cover and developing rain showers. Showers should develop first across nrn NY (17-20Z) and then across VT (20-23Z), with PoPs reaching 60-80% by 22Z from the Champlain Valley wwd. Also, appears some weak elevated instability makes it into nrn NY on WSWLY 50-55kt 850mb jet. Thus, added a slight chance of a thunderstorm across Franklin NY and St. Lawrence counties late in the afternoon where a few embedded convective elements are possible. Rainfall through 00Z Sunday should range from <0.10" east of the Green Mtns, to 0.10-0.20" across the Champlain Valley and Adirondacks, and slightly higher across St. Lawrence County where rainfall arrives soonest. Highs Saturday mainly lower 70s across Vermont, but upper 60s to lower 70s across NY with earlier arrival of clouds/precipitation. && .SHORT TERM /SATURDAY NIGHT/... As of 240 PM EDT Thursday...H5 ridge crests across the area during the first half of Saturday, followed quickly by a burst of warm advection driven showers and the approach of a dampening shortwave trough Saturday night. Our prior idea of an increasing threat for showers by later in the afternoon and overnight still looks reasonable at this point and have maintained higher pops from 70-90% in this period accordingly. Best mid-level instability gets shunted south over time so left thunder chances minimal for now. Highs on Saturday to occur by early afternoon given increasing clouds - lower to mid 70s, then seasonably mild Saturday night under broad southerly flow - 50s. && .LONG TERM /SUNDAY THROUGH THURSDAY/... As of 240 PM EDT Thursday...Shortwave trough swings through the area during Sunday as H5 heights fall and a fairly decent late spring cold front crosses the area by afternoon. Have maintained solid chance to low likely pops from late morning into the afternoon hours (40-60%) and with some modest surface instability have kept the idea of non-zero thunder chances in the 20-40% range. Highs remain seasonably warm in the 70s. Front then clears south Sunday evening with modest cooling and dry weather returning for Monday. Thereafter the forecast becomes more uncertain as a mean southeastern US ridge evolves over time with the the forecast area lying on the northern periphery of this feature. This will allow the potential for dampening shortwave trough passages and occasional convective-type debris activity rolling east-southeast into our area from time to time. Always difficult to time such features this far out and as such have held blended 12-hr pops in the chance category in the Tuesday- Thursday time frame accordingly. Temperatures should range near to slightly above normal through much of these latter periods with daily highs mainly in the 70s and overnight lows ranging from the upper 40s through the 50s. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... Through 12Z Saturday...Surface low pressure near Sherbrooke, Quebec will be exiting into the Gulf of Maine later this morning. As this occurs, will see winds shift from west to N-NW across the North Country TAF sites, generally 10-15kt with a few gusts approaching 20kt during the mid-morning through early afternoon hours when gradient flow will be strongest. The low-level northerly flow will be relatively moist, and most TAF locations will see MVFR ceilings throughout the morning hours with HIR TRRN OBSCD. A few showers are also possible through 14Z, mainly in the northern mountains. Ceilings will gradually improve back to VFR with BINOVC this afternoon, followed by more significant clearing skies toward/just after sunset and through the overnight period. Likewise, winds will become light and variable after 00Z Saturday with high pressure building into NY/New England from the Great Lakes region tonight. Outlook... Saturday: VFR. Chance SHRA. Saturday Night: Mainly MVFR, with local IFR possible. Definite SHRA. Sunday: Mainly VFR, with local IFR possible. Chance SHRA, Chance TSRA. Sunday Night: Mainly VFR, with local MVFR possible. Slight chance SHRA. Memorial Day: VFR. NO SIG WX. Monday Night: VFR. NO SIG WX. Tuesday: VFR. Chance SHRA. && .MARINE... Winds will shift into the north before dawn, reaching 15 to 25 knots across Lake Champlain through most of the daylight hours before diminishing rapidly this evening. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Banacos NEAR TERM...Banacos SHORT TERM...JMG LONG TERM...JMG AVIATION...Banacos MARINE...WFO BTV