textproduct: Burlington

WHAT HAS CHANGED

As of 235 AM EDT Thursday...

Risk for gusty winds on Friday has increased, mainly in the Champlain Valley.

KEY MESSAGES

As of 235 AM EDT Thursday...

1. After a quiet day today, a storm system brings gusty winds, rain, and mountain snow Friday through Saturday.

2. Temperatures trend near to below normal Sunday night through Thursday with mostly dry conditions prevailing.

DISCUSSION

As of 235 AM EDT Thursday...

KEY MESSAGE 1: Other than some patchy drizzle/fog early this morning, expect today will be a dry day with skies becoming partly sunny. Winds will subside as high pressure builds across the region. Highs will be seasonable though on the chilly side as most spots will top out in the 50s.

Things become much more interesting thereafter as an upper trough digs into the Great Lakes tonight into Friday, eventually swinging over our region on Saturday. The associated surface low will lift through the St Lawrence Valley, then move east-northeast through the Crown of Maine and toward the Canadian Maritimes. Moisture will stream northward on deep southwest flow ahead of the trough, resulting in increasing clouds tonight. Given the dry airmass that will be in place, rain will be a little slower to develop, but expect widespread precipitation to develop by daybreak Friday. A potent 55+ kt jet wrapping around the surface low at 850 mb will move overhead on Friday, leading to very windy conditions atop mountain summits; gusts of 55-65 mph are likely. Winds at lower levels are a bit harder to determine, but note that several of the CAMs indicate we could see a some breaks in the rain mid-day Friday with the main swath of rain lifting north of the international border. This means less potential hindrance for mixing, increasing potential of gusts of 30 mph or more at lower elevations. The Champlain Valley would be particularly susceptible to strong gusts due to channeling of the south winds up the Valley. Note that the 15/00z HREF indicates 85-100% probabilities of gusts greater than 40 mph along Lake Champlain and the eastern side of the Champlain Valley, from the international border down toward Hinesburg and Bristol. The northern slopes of the northern Greens have similar chances of strong winds, with 90+% in locations such as Newport, Montgomery, and Glover. Have bumped up gusts with this forecast package, though have kept them below Wind Advisory level (46 mph). However, it looks like some places could get close to needing an Advisory; subsequent shifts will need to monitor trends closely.

The surface low pressure slides by just to our north Friday afternoon, allowing us to nudge into the 50s to close to 60F. However, once the low moves to our east, its attendant cold front will quickly sweep through our area, bringing much colder temperatures later Friday and Friday night. The incoming airmass will also be quite dry, but expect there will be enough moisture around to squeeze out a bit of mountain snow later Friday night into Saturday morning before precipitation ends Saturday afternoon. With temperatures dropping into the mid 20s to mid 30s by Saturday morning, even the lower elevations could see a few flakes, though any accumulation looks to remain limited to 1500 ft and above. Even there, though, expect an inch at most given the decreasing moisture and relatively warm ground.

Saturday will see decreasing clouds and much colder temperatures. Highs will only reach into the mid 30s to low 40s, and expect the summits to remain in the teens and 20s through the day. Winds will still be gusty though not quite as strong as Friday. However, they'll be enough to produce wind chills in the teens and 20s Saturday morning, with the higher summits seeing wind chills in the single digits. Anyone who plans to be recreating in the mountains should prepare for wet, windy, and bitterly cold conditions Friday through Saturday.

KEY MESSAGE 2: High pressure over the mid-Atlantic is expected to strengthen Sunday night and Monday, expanding into New England to start the work week. Global deterministic models differ on the exact placement of this high pressure, which could have some minor impacts for coastal New England, but up in northern New York and Vermont, dry weather seems very likely Sunday night through at least next Thursday despite a couple week frontal boundaries that swing through the region. High temperatures each day should remain around seasonable values in the mid 50s to lower 60s. Nights will remain on the chilly side with lows in the upper 20s to lower 40s due to the clearer nights and decoupled boundary layer winds under high pressure.

AVIATION /12Z THURSDAY THROUGH MONDAY/

Through 12Z Friday...VFR conditions will prevail today through 08Z-10Z Friday with winds out of the north/northwest this morning at 5-15 knots and gusts up to 20 knots. Winds will become light and variable this afternoon, then switch out of the southeast at 03Z-07Z Friday, gusting 15-25 knots early Friday morning. In addition to this switch and increase in surface winds, LLWS is anticipated to begin at most, if not all, sites by the end of the 24 hour TAF period as a strong low level jet moves overhead. Showers are also anticipated to begin 08Z-10Z Friday, likely lowering visibilities to 3-6 miles or lower and dropping ceilings to 3000 feet or lower above ground level.

Outlook...

Friday: Mainly MVFR, with local IFR possible. Definite SHRA. Friday Night: Mainly MVFR, with local VFR possible. Chance SHRA, Chance SHSN. Saturday: Mainly VFR, with local MVFR possible. NO SIG WX. Saturday Night: VFR. NO SIG WX. Sunday: VFR. NO SIG WX. Sunday Night: VFR. NO SIG WX. Monday: VFR. NO SIG WX.

MARINE

North to northwest winds of 15 to 25 kt will continue through early this morning before gradually winding down by mid day. After briefly calmer conditions this afternoon and tonight, south winds will increase again on Friday, sustained 20 to 30 kt with higher gusts expected.

CLIMATE

Daily low maximum temperatures will likely be broken on Saturday. 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.