566 FXUS61 KBTV 120714 AFDBTV AREA FORECAST DISCUSSION National Weather Service Burlington VT 314 AM EDT Sun May 12 2019 .SYNOPSIS... Surface high pressure over Quebec will slide eastward today but lots of clouds are expected with low pressure over western Pennsylvania and a front south of New England. On Monday rain will develop from west to east as low pressure over western New York redevelops off the New England coast. Rain will persist into Tuesday night with some accumulating snow on the mountain summits. Somewhat drier weather is expected on Wednesday before shower chances increase again for the end of the week. && .NEAR TERM /THROUGH MONDAY/... As of 308 AM EDT Sunday...Little change to previous forecast thinking. Low pressure in western PA will be slowly approaching as an upper level trof digs through the Great Lakes. Middle to high clouds are already covering the region and are expected to persist today and tonight but most of the precip should hold off until Monday. That said, there could be a sprinkle in south central VT today closer to the low and frontal system off the the south. Expecting high temps in the 50s to around 60 with the warmest temperatures in the north where clouds are higher and potentially thinner. Lows tonight in the lower to mid 40s for most of us. By Monday morning as the height falls reach the coast and decent QG forcing moves into the northeast, the primary low will move slowly to near BUF. A secondary low will develop in the Delmarva region then move very slowly to near the 40/70 benchmark by Monday evening as the upper level trof closes off. An anomalous easterly low-level flow will bring plenty of cool Atlantic moisture with PW reaching about 0.75". So expecting a nice cool, mainly light rain to develop during Monday first in NY Monday morning, then in VT during the afternoon. This leads to a tricky temperature forecast depending on the start time of the rain with wet bulb cooling which may lead to cooler temps especially in northern NY where the rain starts sooner. Continuing to go with a blend then wet bulb cooling which gives highs in the 50s to around 60 warmest furthest north and east in VT. It's quite cool at 850 with temps only zero deg C +/- today through Monday. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/... As of 258 PM EDT Saturday...Little change from previous forecast with showers across northern New York during the day but mainly dry, albeit cloudy, conditions for Vermont. As surface low pressure transfers energy to coastal New England, chances for precipitation increase across southern zones with only chance for showers for northern NY & VT. The anomalously cold air aloft will provide unseasonably cool temperatures, especially on Tuesday. High temperatures on Monday will be in the upper 50s to near 60s for northern areas, but low to mid 50s across northern NY & southern VT. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... As of 258 PM EDT Saturday...Things still look on track for closed upper level low to slowly traverse the region ushering in a period of unsettled and wet weather for the work week. With anomalously cold upper level low, 850mb temperatures on Tuesday are around -2 to -4 C which is supportive of high elevation snowfall...current thinking around 4-6 inches for highest peaks with a wet 1-2 inches down to 2500 ft Tuesday through Wednesday. Back edge of upper low moves out overnight Wednesday but another piece of vorticity advecting in to low is quick on heels keeping showery and below normal conditions through remainder of work week. && .AVIATION /07Z SUNDAY THROUGH THURSDAY/... VFR. Middle to high clouds with cigs AOB 10K ft through tonight as low pressure moves into western PA, then begins to redevelop off the Delmarva. There is an outside chance of a brief sprinkle vcty and slightly lower cigs 5-10K ft at KRUT but left out mention of precip for now as the probability of measurable precip is very low. Winds will be generally driven by local terrain effects. In the Champlain Valley at BTV and PBG north to northeast winds of 5 to 10 kts are expected. In northern NY St. Lawrence valley channeling may bring a bit stronger winds of 10 kts with gusts to 18 kt at KMSS and even SLK. At RUT and MPV winds will be generally light northeast to southeast. Outlook... Monday: VFR becoming MVFR with developing -RA. Monday Night: Mainly MVFR with -RA. Tuesday: Mainly MVFR with -RA. Tuesday Night: Mainly VFR, with local MVFR possible. Chance SHRA. Wednesday: Mainly VFR, with areas MVFR possible. Slight chance SHRA. Wednesday Night: VFR. Slight chance SHRA. Thursday: Mainly VFR,with areas MVFR possible. Chance SHRA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Sisson NEAR TERM...Sisson SHORT TERM...LaRocca LONG TERM...LaRocca AVIATION...Sisson