textproduct: Burlington

WHAT HAS CHANGED

As of 222 AM EDT Saturday...

No significant changes made.

KEY MESSAGES

As of 222 AM EDT Saturday...

1. Generally cool weather is expected over the next several days. Sunday will be briefly warmer, but a front will cross on Monday bringing gusty winds, showers, and a return to the cooler weather.

2. Cold air mid week will moderate by the late week with a pattern change for the weekend.

DISCUSSION

As of 222 AM EDT Saturday...

KEY MESSAGE 1: A broad 1028mb surface high will be positioned to our west over the Great Lakes region today. This will keep northerly flow across the region. Fortunately, the cool air coming in will be more of a glancing blow with zonal flow aloft. Still, it'll feel plenty cool with highs lingering mainly in the 50s, except for a few 60s across south-central Vermont. Mountain summits will likely be in the upper 30s to mid 40s this afternoon. Abundant dry air will promote clear skies. We should radiate quite efficiently tonight with these conditions, and that will bring overnight lows in the 30- 40 F range.

High pressure will start moving east Sunday, and south to southwest winds return. A more moderate day in the 60s is expected for Sunday, with a warmer night around 40-50 F. These warmer conditions will come with some wind, though as pressure gradients tighten against departing high pressure and the next approaching system. Anticipate 10-15 mph winds, and up to 20 mph in the Champlain Valley. The attendant frontal boundary will arrive pre-dawn through the early afternoon. The moisture is not great, but the dynamics of a strong upper jet and modest frontal support could produce a broken narrow line of rain. Larger synoptic scale motion will yield stronger winds behind this front. Combined with the strength of cold air behind it, the 50s forecast on Monday and 25-35 mph gusts across the region will feel nippy. Advective cold will result in mid 20s to upper 30s. The winds may still preclude frost formation in the Champlain Valley, but plenty cool. Moisture quickly departs behind the frontal boundary, but if there's anything lingering, a few flakes or some riming is feasible for mountain terrain.

KEY MESSAGE 2: Strong northwest flow will continue through Tuesday with temperatures feeling solidly like fall, before our air mass moderates towards the weekend. Highs Tuesday will struggle to reach 50 in the higher terrain with low to mid 50s elsewhere with breezy northwest winds as our flow pattern remains fairly confluent. Skies will remain clear into Tuesday night with one of the coldest nights of the season expected. With a stout dry 700-500mb layer, strong radiational cooling will take place with many places falling into the low to mid 30s. Some patchy frost will be possible in the sheltered locations, but with temperatures falling under clear skies, almost the entire region could experience a freeze, with the Champlain valley remaining on alert at this time. This will likely be a curtain call for gardeners sensitive plants in the broad valleys.

Temperatures will slowly moderate back up towards the weekend with the approach of a broad long wave trough associated with a deepening upper low over the Hudson Bay. Highs will warm to the upper 50s to mid 60s, with overnight lows in the upper 30s to mid 40s. A large scale cyclonic gyre will shift south from the interior of Canada leading to several shortwave passages beginning late next week into the weekend. Daily diurnally enhanced showers will be possible starting Thursday with increasing cloud cover into the weekend. In addition to increasing shower chances, each shortwave passage will bring with it some breezy to gusty winds to northern New York, and likely some channeled flow in the Champlain Valley each day.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

Through 18Z Sunday...Aside from early morning fog at climatologically favored terminals, VFR conditions will continue. High pressure and associated dry air has scoured out moisture today; some scattered shallow clouds present near Vermont terminals earlier have quickly trended towards SKC. The only potential impacts through the period will be related to radiation fog. Periods of dense fog will likely result after about 06Z at SLK, MPV, and EFK. With much drier air in place this afternoon compared to yesterday, it will take more time for fog to form but temperatures are favored to drop well below crossover values. Have noted as the center of high pressure moves to the northeast of the airspace overnight, low level southeasterly flow develops and could disrupt fog at MPV and have ended fog a bit earlier there compared to EFK. Following 12Z, increasing southerly flow will occur, leading to winds at Champlain Valley terminals gusting near or a bit above 20 knots, while EFK and MPV see sustained winds also reach 10-12 knots with somewhat lighter winds at SLK and MSS.

Outlook...

Sunday Night: VFR. Chance SHRA. Monday: Mainly VFR, with local MVFR possible. Slight chance SHRA. 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. Slight chance SHRA. Thursday: VFR. Slight chance SHRA.

BTV WATCHES/WARNINGS/ADVISORIES

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