textproduct: Burlington

WHAT HAS CHANGED

As of 235 PM EDT Friday...

Snowfall has been increased across the high peaks of the Adirondack and Green Mountain ranges. Widespread frost is now expected Saturday night/Sunday morning and will likely result in frost headlines for portions of the Champlain Valley.

KEY MESSAGES

As of 235 PM EDT Friday...

1. Scattered rain showers with mountain snow showers expected tonight through Saturday morning.

2. Widespread frost expected Saturday night and Sunday morning with additional frost possible Sunday night.

3. Rainy and unsettled weather is expected much of next week.

DISCUSSION

As of 235 PM EDT Friday...

KEY MESSAGE 1: A shortwave disturbance tracking across the southern periphery of the upper level low is expected to bring scattered to numerous showers to the North Country and northern New York tonight. Surface temperatures are expected to be largely above freezing for the wider valleys but could see a few places in the NEK and northern Adirondacks to drop near or just below freezing tonight. While rainfall is expected below 1500 ft, we do expect some light snow to fall; especially across the high peaks of the Adirondack and Green Mountains. The latest high-res guidance has come in to show some decent liquid associated with the showers, especially across the Adirondacks, so we now expect 2-4 inches across the high peaks of the Adirondacks and 1-3 inches across the spine of the Green Mountains. It'll be a wet snow with model sounding showing a deep isothermal layer extending through the DGZ but shouldn't be overly that impactful with most snow falling above where most people live. High pressure is expected to nose in from the west Saturday afternoon which will bring an end to the precipitation with increasing sunshine as we move throughout the day.

KEY MESSAGE 2: We are looking at mostly clear skies and light winds Saturday night through Sunday. Strong raditional cooling is expected with overnight lows dropping into the mid 20s to mid 30s Saturday night which will be favorable for frost formation. Based on climatology, the growing season starts today (May 1st) for the Champlain Valley in NY and VT. Given the forecast of widespread frost Saturday night, we will likely need to issue our first frost advisory of the season but will hold off until tomorrow to issue if needed. Sunday will be on the drier side once again with afternoon RH values dipping into the mid 30s to mid 40s with winds generally in the 5-12 mph range. Recent rainfall has helped wet the fine fuels but we could see an increase in fire danger as we head into late this weekend but no critical fire weather conditions are expected. Cloud cover will begin to build back across the region Sunday night but we could see some frost across eastern Vermont during the first half of the overnight period prior to the clouds moving overhead.

KEY MESSAGE 3: After brief ridging on Monday, a large-scale trough gradually builds into the region during the rest of the week. It will be slow enough that a few different shortwaves will pass through and surface lows will develop along those. The first one passes well to the northwest on Tuesday. A weakening cold front will move into the region late Tuesday and bring a round of rain, particularly to northern New York. A brief rumble of thunder is possible in the afternoon. The next low passes through Wednesday with the center looking to track over the region. The final low looks to track through Thursday into Friday, with the center passing to the east of the region. There will be enough cold air on the backside of it that it could end as a few snow showers in the mountains. Through Friday, GEFS/EPS/CMCE combined ensemble probabilities of receiving 1 or more inches of rain are 80-100 percent, 2 or more inches are 30-50 percent, and 3 or more are 0-20 percent. Most of the precipitation should be stratiform and limit flooding concerns, but the effects of potentially three storm systems in a row will still be watched.

AVIATION /18Z FRIDAY THROUGH WEDNESDAY/

Through 18Z Saturday...VFR conditions to prevail through much of the TAF period with SCT to occasionally BKN ceilings AOA 3500 ft. Clouds thicken and lower after 04z Sat as showers move into the region. Expect all terminals to be MVFR by 08z. There are some indications that KSLK/KRUT/KMPV could drop to IFR, but confidence is not high enough to include in the TAFs at this time. W/NW winds 5 to 10 kt through the daylight hours today with occasional gusts to around 15 kt, becoming light to near calm after 02z Sat.

Outlook...

Saturday Night: VFR. Chance SHRA. Sunday: VFR. Chance SHRA. Sunday Night: Mainly VFR, with local MVFR possible. Patchy frost. Monday: Mainly VFR, with local MVFR possible. Chance SHRA. Monday Night: VFR. Chance SHRA. Tuesday: Mainly VFR, with local MVFR possible. Chance SHRA, Slight chance TSRA. Tuesday Night: Mainly VFR, with local MVFR possible. Chance SHRA. Wednesday: MVFR/IFR conditions possible. Likely SHRA.

BTV WATCHES/WARNINGS/ADVISORIES

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