696 FXUS61 KBTV 170223 AFDBTV AREA FORECAST DISCUSSION National Weather Service Burlington VT 1023 PM EDT Sat Mar 16 2019 .SYNOPSIS... A weak front will cross the area this evening with a period of numerous, mainly mountain snow showers. Thereafter, high pressure generally dominates sensible weather conditions into the middle of next week with mainly dry weather and seasonably cold temperatures. && .NEAR TERM /THROUGH SUNDAY NIGHT/... As of 1017 PM EDT Saturday...The weak secondary front is crossing the region at this hour, producing an area of snow concentrated across southern Clinton County NY eastward into Chittenden, Lamoille, and Washington Counties in VT. Latest observation indicates snowfall already up to 0.3 inch at BTV, and while the band is moving very slowly southward, it should still produce another half inch to inch as it progresses. Have increased PoPs and snow totals in the aforementioned areas to match the latest radar trends, though this still gives most spots 2 inches or less overnight. Upstream obs indicate temperatures in the teens to around 20, so forecasted overnight lows still look good. No other changes were needed with this update. Previous discussion...Scattered light snow showers and flurries continue across the area this afternoon under broad cyclonic flow aloft and westerly flow at the surface. Variably cloudy skies persist as temperatures have trended steady or slowly fallen over the past 6 hours under steady cold thermal advection. The forecast headed into tonight remains largely on track. Both global and CAM output maintain consistency in showing a secondary surface trough passage later this evening along with a general reblossoming of light snows/snow showers, mainly across the Adirondacks and to a lesser extent the northern Greens. Here, overnight minor accumulations should range in the dusting to 2 inch range with localized totals to 3 inches or so in most persistent activity. Given the low level flow will lie within 30 deg. of westerly the broad valleys and southern VT counties should largely stay clear of the steadier pcpn with just a passing light snow shower or a few flurries expected. Low temperatures to range from 10 to 20 above with local variability as winds abate and veer slightly northwesterly overnight. Mainly quiet and seasonably cold weather is then expected for Sunday into Sunday night. We remain under large-scale upper troughing aloft though broad surface ridging building east from the Great Lakes and Ohio Valley will keep the boundary layer on the dry side. A weak and final trough passage will occur Sunday night with little fanfare other than a brief window of mountain flurries/light snow showers. Coverage should be considerably less than this evening's feature with limited available moisture. As mentioned we'll be on the chilly side by mid-March standards as daily highs range from the mid 20s to lower 30s and overnight lows bottom out in the 8 to 18 above range in general. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... As of 254 PM EDT Saturday...Broad cyclonic flow will continue across the North Country Monday and Tuesday with an upper level trough anchored across the region. Several weak shortwaves are expected to rotate through the trough but given the lack of available moisture, any shower activity looks marginal at best. With the trough anchored overhead, a modified arctic air mass will remain in place which will bring the return of below normal temperatures to the region. Temperatures on Monday and Tuesday will warm into the mid 20s to lower 30s with overnight lows Monday night in the single digits to mid teens. This pocket of colder air will continue to modify through Tuesday before a shortwave ridge begins to displace the trough Tuesday night. This will yield some warmer overnight temperatures Tuesday night as temperatures will only drop into the upper single digits to upper teens. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... As of 254 PM EDT Saturday...Another short-lived pattern change will take place on Wednesday as a low-amplitude ridge works it's way into the region. There will be pretty significant warm air advection in the 925 mb to 850 mb layer as flow aloft switches to the west/southwest. This will allow temperatures to warm back into the 40s across the North Country Wednesday and again on Thursday but cloud cover will accompany the warm up as the southwesterly flow ushers in an increase in moisture. On Thursday, models have been in good agreement with bringing a potent cold front attached to a surface low over Newfoundland through the North Country. As this happens, an upper level trough over Canada will sharpen and quickly drop southward to boost some dynamics associated with the approaching cold front. Nevertheless, PWAT values less than 0.4 inches will really limit much of the rainfall/snowfall accumulation. The main impacts from this new trough will be felt Friday and Saturday as another arctic air mass descends across the region. Looking at 850 mb temperatures (better proxy than 500 mb thickness this time of the year), temperatures on Friday and Saturday will likely struggle to warm into the mid 20 to mid 30s. Overnight lows on Friday night will be unseasonably cold with temperatures dropping into the mid single digits to mid teens under partly to mostly clear skies. However, there is some good news for those ready to experience more spring-like weather. High amplitude ridging will move over the North Country Saturday night into Sunday with temperatures expected to warm 10 degrees or so from those seen Friday night. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... Through 00Z Monday...Mainly VFR at KMSS/KPBG/KBTV/KRUT. Mix of VFR/MVFR/IFR at KSLK/KMPV through 06Z, then MVFR/VFR. Steadier MVFR/IFR snow showers are developing across northern areas at this hour and this trend will continue, especially at KSLK and to a lesser extent KMPV in the 00-06Z time frame with mainly VCSH at other terminals as a weak wind shift pushes through. After 06Z snow showers generally taper off. West winds abating gradually overnight and veering slightly to west- northwest, becoming a bit gusty with daytime mixing Sunday morning. Outlook... Sunday Night: VFR. Slight chance SHSN. Monday: VFR. NO SIG WX. Monday Night: VFR. NO SIG WX. Tuesday: VFR. NO SIG WX. Tuesday Night: VFR. NO SIG WX. Wednesday: VFR. NO SIG WX. Wednesday Night: VFR. Chance SHSN. Thursday: Mainly VFR, with areas MVFR possible. Chance SHRA, Chance SHSN. && .HYDROLOGY... As of 250 PM EDT Saturday...The Flood Watch for ice jams has been cancelled as of mid-afternoon. Most rivers have crested and are steadily falling as of this typing. While we can't rule out some isolated additional ice movement, cooling temperatures and limited additional snowmelt have largely ended the threat flooding. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...JMG NEAR TERM...Hastings/JMG SHORT TERM...Clay LONG TERM...Clay AVIATION...Hastings/JMG HYDROLOGY...WFO BTV