textproduct: Burlington

WHAT HAS CHANGED

As of 226 AM EDT Tuesday...

A Frost Advisory is in effect for the Champlain Valley tonight.

KEY MESSAGES

As of 226 AM EDT Tuesday...

1. A cold day is expected today with a Frost Advisory for the Champlain Valley tonight. Gradual warming with some chances for light rain by Wednesday afternoon.

2. Dry and seasonable weekend before shower chances return for the beginning of next week.

DISCUSSION

As of 226 AM EDT Tuesday...

KEY MESSAGE 1: Today will be a cool day in the upper 40s to mid 50s across the region. West to northwest winds will continue, but not so strong as yesterday. Max wind gusts this afternoon should top out around 20-25 mph, and higher summits will likely gust around 35-50 mph much of the day. It will be dry, and despite the cool conditions, we should see relative humidity values fall down towards 35 percent this afternoon. This isn't quite enough to push us towards fire weather concerns, but it is a bit close and a sign of the changing seasons. The dry conditions in place will mean that once winds drop off this evening, temperatures will quickly fall as radiational cooling initiates. It will fall into the mid 20s to mid 30s across the region. The Champlain Valley remains in the Frost/Freeze program with the median first freeze around October 11th. Grand Isle is less likely to observe frost, but just in case, threw the whole of the Champlain Valley in to a Frost Advisory for tonight. After about 5-6am, increasing south winds and cloud cover will end the frost potential.

During the day on Wednesday, we'll be at the southeastern periphery of a deep, mature low pressure that will set up near James Bay. Its warm front will cross east midday. Forecast soundings depict wide moisture spread. Given today's expected dryness, I'm inclined to think it will not rain Wednesday morning (precipitation falling as virga). In deference to some wetter solutions, there are some 10-30 PoPs over the northern tier as the warm front crosses. Moderation behind the warm front will bring temperatures into the 60s, with perhaps a few holdouts in the upper 50s across the Northeast Kingdom. A prefrontal trough will approach the St. Lawrence River during the evening, and this could produce a few afternoon showers along the Route 11 corridor in far northern New York.

The actual cold front will arrive midday Thursday. It will bring rain showers in a fashion similar to today. A dynamic set up with modest 150-300 J/kg of instability will allow some convective elements. Although the upper level temperatures aren't quite as cool, there could be some pea sized hail as occurred yesterday, and a rumble of thunder cannot be ruled out either. Cool air will be reinforced behind the system, pushing nighttime lows back into the 30s to lower 40s with a spot shower or two lingering while we remain under large scale cyclonic flow.

KEY MESSAGE 2: Troughing builds in for Friday with strong cold air advection continuing. While most of the moisture and dynamics from the upper low will remain to the north over Quebec, a brief shower/sprinkle is possible on Friday, mostly in the higher elevations. Snow levels are expected to fall below summit levels during this time, so a brief flurry or snow shower is possible in the highest peaks of the Adirondacks and Greens, but the lack of moisture would prevent anything more. Surface high pressure builds in for the weekend, leading to a classic fall stretch. Highs will be in the 50s and 60s with mostly sunny skies. As the high builds offshore to start next week, temperatures could get close to 70 in the valleys. A few showers will be possible early next week as another cold front makes a run at the region.

AVIATION /06Z TUESDAY THROUGH SATURDAY/

Through 06Z Wednesday...VFR conditions are expected to persist for the next 24 hours. Winds will stay elevated through the morning, with westerly gusts in the 10-20 KT range for most places. A couple terminals, notably RUT and SLK, will lose gusts at times and only have sustained winds around 10 KT. Winds will decrease during the afternoon and by tonight, they should be mostly light/variable/terrain driven. Winds become southerly in the later part of tonight and tomorrow morning.

Outlook...

Wednesday: VFR. Slight chance SHRA. Wednesday Night: VFR. Chance SHRA. Thursday: VFR. Chance SHRA, Slight chance TSRA. Thursday Night: VFR. Slight chance SHRA. Friday: Mainly VFR, with local MVFR possible. Slight chance SHRA. Friday Night: Mainly VFR, with areas MVFR possible. Chance SHRA. Saturday: Mainly VFR, with areas MVFR possible. NO SIG WX.

BTV WATCHES/WARNINGS/ADVISORIES

VT...Frost Advisory from midnight tonight to 7 AM EDT Wednesday for VTZ001-002-005-009. NY...Frost Advisory from midnight tonight to 7 AM EDT Wednesday for NYZ028-035.