545 FXUS61 KBTV 111255 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 855 AM EDT Thu Oct 11 2018 .SYNOPSIS... A cold front will cross the region today with widespread showers and periods of rainfall, especially from the Adirondacks eastward. Behind this front much cooler weather arrives for Friday into the upcoming weekend. && .NEAR TERM /THROUGH FRIDAY/... As of 855 AM EDT Thursday...Based on radar trends precipitation still continues across much of the area and have increased precipitation chances back across the Saint Lawrence Valley of New York. Otherwise rest of forecast in real good shape with additional precipitation expected from another push of rain over central Pennsylvania and southern New York moving northeast as the day wears on. Rest of forecast remains unchanged. Prior discussion... Backdoor front has settled south into the northern St Lawrence and Champlain Valleys, while backing west into eastern portions of VT as of 300 am. As expected, temperatures are showing wide variability across this boundary (50s to lower 70s). Increasing coverage of showers and periods of light to moderate rain remain on track for today as deep subtropical moisture rides northeast ahead of a stronger frontal boundary advancing east from southern Ontario and eastern Great Lakes. Good moisture convergence and synoptic forcing aloft argue for maintenance of high PoPs for all but the SLV which will generally lie just west of the deeper moisture plume. As the front clears east later this afternoon a broad decrease in pcpn is expected from west to east. 12-16 hr basin average QPF should average from 0.25 to 0.5 inches across the SLV, 0.5 to 1.0 inches across the Dacks into central/northern VT, and from 1 to 1.5 inches in southern VT in close agreement with most recent NBM output. Given the rainfall will occur over a longer time frame, hydrological concerns remain minimal at this time. High temperatures will be quite tricky once again given placement of the current backdoor boundary and the degree to which it lifts out in advance of the stronger secondary front. Feel eastern VT counties will struggle the most as low static stability holds tough, so only upper 50s to lower 60s expected in these areas. Further west mainly mid 60s to around 70 looks reasonable at this point as southerly flow becomes re- established here. Any lingering showers then clear south and east with the departing frontal zone this evening, though variable clouds will linger. Highest probabilities of partial clearing to occur in the SLV and the northern Champlain Valley as low level flow trends light west to northwesterly. Low temperatures a blend of available guidance, which appears reasonable at this point - mainly mid 40s to lower 50s. By Friday cool high pressure builds east from the central states while a rather large longwave trough slowly edges east from the Upper Midwest into the Great Lakes and southern Ontario. Some lingering variable cloud cover may still exist in the morning hours, but most spots should trend partly sunny by afternoon. Mean 925 mb temperatures at 18Z range from 4-8C, supporting afternoon maxima from the upper 40s to mid 50s under moderate northwesterly breezes. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... As of 357 AM EDT Thursday...Expect much cooler, fall-like temperatures on Friday night into Saturday behind a cold front. Using a combination of the 1000-500mb thicknesses and 925mb temps I feel that we'll see our first day with a high temp below 50 degrees since April 20th of this year. Anticipate highs across the North Country to be in the mid to upper 40s under partly to mostly cloudy skies with some orographic rain showers possible in the morning as an upper level trough swings through. Saturday evening should be fairly chilly as we'll likely see a reinforcing shot of cold air. Expect we'll see another good frost/freeze night with lows in the low to mid 30s and a few locations in the upper 20s. Winds should be fairly light which would allow for some frost and we're currently already running about a week behind our normal first frost for the Champlain Valley. Sunday should be a fairly pleasant day across the North Country as southerly winds start to bring in some slightly warmer air and temps warm into the mid 50s. We should be fairly quiet under the typical fall pattern of mostly cloudy to overcast skies. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... As of 357 AM EDT Thursday...The work week looks to be fairly seasonably cool with daily highs in the upper 40s to low 50s and lows overnight in the 30s. We'll be under a fairly progressive pattern with chances for showers both Monday and Wednesday as a pair of troughs push through the region. Neither really has much in the way of PWAT so I wouldn't expect much in the way of significant precip but its possible we could see some drizzle and/or flurries in the higher terrain. && .AVIATION /13Z THURSDAY THROUGH MONDAY/... Through 12Z Friday...Frontal system crossing the area today will bring periods of light rain and MVFR/IFR cigs at most terminals. Visibilities quite variable, though ocnl 2-5sm br appears reasonable from time to time in steadier/heavier bursts of rainfall. Wind to generally trend south to southwesterly from 5-10 kts in advance of the front today (though locally northeasterly to around 10 kts at KMSS through 18Z). Front then clears east in the 21-02Z time frame with pcpn tapering off and cigs gradually improving to VFR/MVFR by 03Z. Winds to slowly veer to southwesterly, then west to northwesterly in the 4-8 kt range over time after 00Z. Outlook... Friday: VFR. NO SIG WX. Friday Night: VFR. Slight chance SHRA. Saturday: Mainly VFR, with local MVFR possible. Slight chance SHRA. Saturday Night: VFR. NO SIG WX. Sunday: VFR. Slight chance SHRA. Sunday Night: Mainly VFR, with local MVFR possible. Chance SHRA. Monday: MVFR. Chance SHRA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...JMG NEAR TERM...Evenson/JMG SHORT TERM...Deal LONG TERM...Deal AVIATION...JMG