textproduct: Burlington

WHAT HAS CHANGED

As of 222 AM EDT Wednesday...

Have extended the time frame of drizzle to last for much of the day today and tonight. The late week system has sped up slightly, arriving late Thursday night. Have increased the winds Friday night and Saturday, particularly on the mountains and lake, to better reflect the strong gusts anticipated with this frontal system.

KEY MESSAGES

As of 222 AM EDT Wednesday...

1. As drizzle and light rain showers come to an end today and tonight, periods of breezy winds are expected tonight and early Thursday, resulting in apparent temperatures as low as the mid 20s and 30s.

2. Another frontal system Friday into Saturday will bring initial rainfall, sharply colder temperatures into the weekend, continued gusty winds, and scattered terrain snow showers. Anyone with outdoor plans for the upcoming weekend should monitor the forecast closely.

3. Dry weather with a warming trend expected for the first half of next week.

DISCUSSION

As of 222 AM EDT Wednesday...

KEY MESSAGE 1: Low pressure will cross the forecast area from west to east early this morning, heading off into Maine and the Canadian Maritimes by the end of the day today. Total rainfall amounts are expected to come to around 0.55-2.25 inches this morning, with highest amounts in the Adirondacks and northern Champlain Valley. This will be followed by drizzle and lighter, more scattered rain showers focused on terrain today and tonight. Because of extended long term dry weather, much of the rain is being absorbed by the soil. However, enough runoff is expected to lead to some small rises in area rivers and streams, and poor drainage ponding on roadways has already occurred. As drier and colder air flows into the region tonight, temperatures are expected to drop dramatically into the upper 20s to lower 40s by early Thursday morning. This, paired with north-northwesterly breezes gusting 15-30 mph due to a low level jet on the back end of our rain system, will make for apparent temperatures in the mid 20s to mid 30s when it's time to head to school or work. This will be some of the chilliest air we've had in a while. Thursday during the day, high pressure should decrease winds, but temperatures will still be slightly below average for this time of year with widespread highs in the 50s.

KEY MESSAGE 2: Another frontal system is headed for our forecast area Thursday night through Friday night. Model agreement is exceptional for a large swath of rain to overspread the region late Thursday night and early Friday morning out ahead of a strengthening low pressure system. A vigorous shortwave will dig over the western Great Lakes, merging with a frontal system over the Midwest to help intensify low pressure to our west. This storm will rapidly move northeastward, passing near or right over our region (most likely along the St. Lawrence Valley) Friday afternoon and crossing into northern Maine Friday evening. Precipitation may be impacted by some our topography. A strong southwesterly low level jet will produce downsloping in the northern Champlain Valley, while our western slopes have a little bit of a boost in rainfall amounts. The near surface winds will also likely be strong out of the south on Friday, though rain could limit mixing. Any breaks in precipitation should support 20-30 MPH localized gusts, higher on summits closer to a strong low level jet. Lake Champlain should also see higher gusts in southerly channeling.

A cold front will sweep through the area Friday night, sharply lowering temperatures 10 to 15 degrees from Friday evening to Saturday morning. Temperatures will likely dip below freezing for most if not all locations across the area with only those near Lake Champlain and immediately near the St. Lawrence River staying just above freezing. As temperatures fall, snow levels will also drop, falling to 500-1000ft agl by Saturday. It will be a race against dry air for the temperatures fall at the same time the atmosphere dries out. If there is some overlap in saturated air and cold air Friday night or Saturday morning, we're more likely to see some snowflakes or rain/snow mix in the Champlain Valley. Snow looks highly likely in the higher terrain with temperatures in the 20s. Snowfall impacts will be minimal with road and ground temperatures well above freezing, and with only marginal surface temperatures outside of the highest elevations, snow will likely be of a wet character, with minor accumulation only on the highest elevations and mainly on vegetation only. In addition to the precipitation Friday night into Saturday, winds will turn to the northwest with better confidence in stronger winds Saturday due to a lack of precipitation limitations that existed during the day Friday. With an influx of cold northwest air, lapse rates will quickly steepen with strong mixing late Friday night and early Saturday morning. Highest wind gusts will be widespread 30-40 mph with gusts above 40-45 mph on summits, potentially as high as 45-60 mph. While we don't anticipate needing a Wind Advisory (for gusts greater than 46 mph), trends will need to be watched closely going forward.

KEY MESSAGE 3: Ridging will start to build over the region for the latter half of the weekend, keeping us under northwest flow. Can't rule out a few stray showers over the higher terrain early Sunday, but overall expect a dry though chilly second half of the weekend. The dry weather will persist through mid week as high pressure keeps hold over the Northeast CONUS. Temperatures will warm through the period, with highs to be in the upper 50s/low 60s by Tuesday.

AVIATION /06Z WEDNESDAY THROUGH SUNDAY/

Through 06Z Thursday...Challenging next 6 to 12 hour terminal forecast for many of our TAF sites due to very changeable CIGS/VIS. Currently a mix of IFR at MPV/MSS/PBG, MVFR at EFK, and VFR at SLK/BTV and RUT as several rounds of showers with embedded thunderstorms move from southwest to northeast across our taf sites. These showers/storms will be capable of brief IFR VIS and MVFR CIGS, but as winds shift to the northwest as surface low pres shifts to our east, expect IFR cigs to develop at BTV by 06z and toward sunrise at RUT. Intervals of IFR/LIFR cigs/vis are likely at SLK/MPV and MSS with conditions trending toward IFR at EFK by midnight. As northwest winds prevail, expect conditions to improve to MVFR and eventually VFR at PBG by early Weds. IFR or lower conditions will linger thru 18z at most sites, given moisture profiles, before slowly improving after 18z. Some areas of fog are possible, along with drizzle, especially mountain taf sites.

Outlook...

Thursday: VFR. NO SIG WX. Thursday Night: VFR. Definite SHRA. Friday: Mainly MVFR, with areas IFR possible. Definite SHRA. Friday Night: Mainly MVFR, with local IFR possible. Windy with gusts to 30 kt. Chance SHRA, Chance SHSN. Saturday: Mainly VFR, with local MVFR possible. Windy with gusts to 30 kt. Chance SHSN, Slight chance SHRA. Saturday Night: Mainly VFR, with areas MVFR possible. NO SIG WX. Sunday: Mainly VFR, with local MVFR possible. NO SIG WX.

MARINE

Periods of rough lake conditions are anticipated this week into the weekend. Periods of concern will be Wednesday night and again Friday into Saturday as a couple of fronts move through the region. Overall, it will not be a pleasant week to venture out on Lake Champlain, especially in smaller watercraft.

CLIMATE

On Saturday, daily low maximum temperatures are likely. Current records are indicated below at some climate sites in our region:

Record Low Maximum Temperatures:

October 17: KBTV: 42/1970 KPBG: 44/2015 KSLK: 36/1970

BTV WATCHES/WARNINGS/ADVISORIES

VT...None. NY...None.