textproduct: Burlington

WHAT HAS CHANGED

As of 254 AM EDT Sunday...

Winds this afternoon were increased marginally across Lake Champlain.

KEY MESSAGES

As of 254 AM EDT Sunday...

1. Unseasonably warm temperatures continue this weekend while lake and river water temperatures remain dangerously cold. Breezes on Lake Champlain may result in some rough lake conditions through mid week.

2. Temperatures continue to trend well above seasonal averages Monday through Wednesday with humidity building and highs in the mid 70s to 80s each afternoon.

3. Thunderstorm chances return late Tuesday through Wednesday as a front moves through the region.

4. Seasonably cool and dry conditions are expected for the later half of next week.

DISCUSSION

As of 254 AM EDT Sunday...

KEY MESSAGE 1: The combination of warm temperatures above 70 degrees and cold water temperatures present a hazard to those recreating on area lakes and rivers. Water temperatures in the 40s will promote concerns for hypothermia and cold water shock despite the pleasant air temperatures. This is a deceptive hazard and has resulted in deaths from those enticed to take a dip to cool off.

Winds will present another recreation hazard this week with flow channeling down the champlain valley as a series of impulses increase 925-850mb flow with strong mixing from warmer than usual temperatures. Today, there could be a brief period this afternoon where northwesterly gusts increase across the lake supporting increasing wave heights especially towards the southern end of the lake and towards Shelburne Bay. Flow increases aloft Monday through Wednesday and turns more southerly. It's looking more probable that there will be periods of conditions that will exceed lake wind advisory thresholds.

KEY MESSAGE 2: Unusually warm conditions persist and the anomaly increases Monday through Wednesday as 925mb temperatures are favored to warm into the 20-26C range due to increased south to southwesterly flow aloft. The hottest day will be Tuesday with highs in the 80s. Warmest locations may be east of terrain as flow aloft turns more southwesterly resulting in some compressional warming downslope off of terrain. Heat will continue with cloud cover increasing as a front moves through the region Tuesday night and early Wednesday. The front will provide relief, but timing of its passage will be instrumental with southern locations and portions of the Champlain Valley likely warming into the upper 70s to low 80s. Fortunately, overnight temperatures will cool into the 50s and 60s providing some relief. Thunderstorms and rain showers Tuesday afternoon may also blunt highs for locations that receive showers.

KEY MESSAGE 3: With building heat and humidity, thunderstorm chances will increase Tuesday afternoon and evening. Model CAPE shows the sharpest gradient across southern Vermont extending northward up the Champlain Valley. It's feasible to see 500-1000J/kg of CAPE for Tuesday afternoon as dewpoints climb well into the 50s to low 60s. Temperatures in the 80s, dewpoints in the upper 50s to low 60s, and some projected wind shear ranging 30-40kts are highlights that suggest some potential for a few strong storms. We'll be watching how the movement of the ridge axis evolves over the next couple of days to assess storm potential further.

Chances continue Tuesday night into Wednesday as a front drops out of Canada. There are some questions on timing of the front will be critical in determining concerns for strong thunderstorms. Should the front be delayed, the potential for stronger storms would increase during the day on Wednesday. As it stands now, the projections are for a partial passage through portions of northern New York and northern Vermont overnight with southern Vermont remaining in the warm sector during the day on Wednesday. For now, this is a "keep an eye on the forecast" scenario and not a foregone conclusion that strong storms will occur. However, heating will support potential for at least garden variety thunderstorms for much of Vermont.

KEY MESSAGE 4: Surface high pressure looks to build into the region for the later half of the week, bringing mostly dry and seasonably cool temperatures. High temperatures look to climb into the 60s most afternoons, with overnight lows generally in the 40s. Temperature trends will need to be monitored as we get closer, especially for any frost concerns as the growing season goes into effect for the entire region. Overall, it looks like a fairly pleasant stretch of weather to round out the week ahead.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

Through 12Z Monday...VFR conditions are expected to prevail at most terminals over the next 24 hours as skies remain mostly clear. The only exception will be a period of MVFR conditions at KSLK and possibly KMSS for the next few hours as due to mist, with visibilities generally between 3 to 6 SM. All terminals should trend VFR by 15Z or so and remain that way throughout the remainder of the forecast period. West winds will continue to trend more northwesterly over the next several hours, with gusts of 20 knots or so expected through the afternoon before abating this evening.

Outlook...

Monday: VFR. NO SIG WX. Monday Night: VFR. Slight chance SHRA. Tuesday: VFR. Chance SHRA, Chance TSRA. Tuesday Night: Mainly VFR, with local MVFR possible. Chance SHRA, Slight chance TSRA. Wednesday: Mainly VFR, with local MVFR possible. Likely SHRA, Slight chance TSRA. Wednesday Night: VFR. Slight chance SHRA. Thursday: VFR. NO SIG WX.

BTV WATCHES/WARNINGS/ADVISORIES

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