textproduct: Burlington

WHAT HAS CHANGED

As of 227 PM EDT Friday...

A frost advisory has been issued for portions of Vermont and northern New York tonight and Saturday morning. Rainfall amounts have increased slightly on Sunday.

KEY MESSAGES

As of 227 PM EDT Friday...

1. Frost expected tonight across the Adirondacks and Northeast Kingdom tonight. Gusty winds expected across Lake Champlain through early Saturday morning.

2. Dry conditions continue on Saturday with widespread rainfall expected on Sunday. Drier and cool weather to follow.

3. High pressure will dominate the region through much of next week, with dry and below normal temperatures, with frost potential in the climo favored areas

DISCUSSION

As of 227 PM EDT Friday...

KEY MESSAGE 1: Gusty winds will continue across Lake Champlain through 2-4 AM on Saturday. Sustained winds may approach 25 knots at times between 9 PM and midnight but winds will generally range from 20-23 knots. A few gusts closer to 30 knots will be possible, especially following sunset, as a subsidence inversion helps to push the stronger winds aloft closer to the surface. High pressure on Saturday will help the pressure gradient relax and let winds diminish to about 10 to 12 knots. Waves could be in the 2-4 ft range through the remainder of the day with a persistent north wind in the 20+ knot range winds waves subsiding closer to 1-3 ft Saturday morning.

Widespread frost across the Adirondacks and Northeast Kingdom is looking increasingly likely as high pressure settles into the region tonight. Winds initially will range in the 5-12 mph range this evening but should go light by midnight. At the same time, dewpoints will continue to fall as dry air advects into the region. With clear skies and light winds, we should radiate out nicely with temperatures plummeting as winds begin to relax. This will allow for much of northern New York and the Northeast Kingdom to drop into the lower to mid 30s which should facilitate frost formation. Outside of these locations, it'll still be noticeably chilly with lows in the upper 30s to lower 40s.

KEY MESSAGE 2: A 1025 mb high pressure system will be anchored overhead on Saturday with plenty of sunshine, light winds, and seasonably cool temperatures expected across the region. However, Sunday is looking like a much gloomier day with widespread rainfall expected from mid-morning through the evening. Models have come into better agreement with showing rainfall overspreading all over Vermont and northern New York on Sunday while the exact rainfall amounts are a bit more uncertain. Both the GFS and ECMWF keep the plume of deeper moisture further south across the Mid-Atlantic while the NAM tries to inject some of the nearly 2 inch PWAT values into Vermont. Given the NAM boundary layer moisture bias, it's feasible it's much too high on PWATs and the forecast is much closer to the GFS/ECMWF solutions. This will bring widespread rain in the range of a third of an inch to two-thitsdays of an inch with localized amounts upward of an inch. Should the NAM forecast pan out, we could see double those amounts. Even with the worst case scenario, rainfall rates and amounts should be low enough that no flooding concerns are expected; especially given the extended period of drier weather we have seen over the past 30-45 days.

High pressure will build back in to begin the week with some gusty north winds possible on Monday as the pressure gradient remains tight. Winds will weaken throughout the day on Monday as high pressure becomes further entrenched which could set the stage for some fog Monday night.

KEY MESSAGE 3: A Rex block pattern will develop early to mid next week as high pressure over the northern Great Lakes shifts east into central Quebec, with troughing developing over the Mid-Atlantic. Ridging associated with the high over Canada will nudge into northern New England keeping us dry through mid next week with good ensemble agreement in cold air damming across eastern Vermont. Clear skies and subsidence under the ridge will draw seasonably cool air south with highs in the 60s, and overnight lows in the low 30s to the low 40s. Under the coolest nights if good radiational cooling becomes more apparent, frost will be possible each night Tues-Thu in the climo favored areas of the Adirondacks and central/northeastern Vermont.

Towards the end of the work week next week, a coastal low off the Mid-Atlantic will possibly open as it slowly tracks north towards southern New England. Under the Rex Block, moisture from this system may nudge slightly north, opening the door for light shower potentials late week in our south and eastern zones Thursday and Friday.

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/

Through 00Z Sunday...VFR expected through the forecast period with only some scattered, passing high clouds expected as high pressure builds into the region. Only exception will be the possibility of some brief 3-5sm vsby restrictions in mist at KSLK/KMPV/KEFK from 09-12Z. Winds generally light northerly less than 10 kts through the period.

Outlook...

Saturday Night: VFR. Chance RA. Sunday: Mainly VFR, with local IFR possible. Definite RA. Sunday Night: MVFR/IFR conditions possible. NO SIG WX. Monday: Mainly VFR, with local MVFR possible. 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.

BTV WATCHES/WARNINGS/ADVISORIES

VT...Frost Advisory from 2 AM to 9 AM EDT Saturday for VTZ004. NY...Frost Advisory from 2 AM to 9 AM EDT Saturday for NYZ029>031- 034.