textproduct: Burlington

WHAT HAS CHANGED

As of 223 AM EDT Monday...

Forecast for broader rains Monday evening into Tuesday continues to trend southwards.

KEY MESSAGES

As of 223 AM EDT Monday...

1. Dry today, and light shower activity possible on Tuesday.

2. A vigorous low will be capable of producing locally heavy rain and thunderstorms on Wednesday into Wednesday night.

3. Trending drier into the weekend with a few chances for lingering showers as an upper low departs to the east.

DISCUSSION

As of 223 AM EDT Monday...

KEY MESSAGE 1: Widespread fog across Vermont and northern New York will give way to supremely comfortable weather today. Patchy mid to high level clouds will continue to stream along sluggish boundary to our southwest. So the Northeast Kingdom should be nice and sunny, while the North Country sees a bit more cloud cover. Temperatures will rise into the 70s during the afternoon with light winds.

For this evening and overnight, the range of high res and global models remain in better consensus of a southward position of elevated convection along the aforementioned quasi-stationary front. The high res guidance the last several days likely had some convective feedback, and now that we're closer, those models have less time to get carried away. There should still be a swath of moderate rain along the borderlines with our neighboring forecast offices across Vermont and northern New York and little to no rain across far northern Vermont. This also lowers the likelihood of thunder. Pulled QPF back even further from the previous forecast. About a third to half inch is likely in southern Rutland/Windsor counties, and approaching the southern Adirondacks and far souther St. Lawrence Counties, and just a couple hundredths at Vermont's international border. During the evening and overnight, a trough will begin to develop while surface pressures rise along Coastal New England. This appears like it will trap moisture along eastern slopes. If forecast soundings weren't too dry near the surface, I would think this would be a drizzle/mist type set up. Flow aloft remains somewhat fast, so perhaps there some forcing that produces very light rain showers that linger into Tuesday night.

KEY MESSAGE 2: The more potent system appears to be the Wednesday system. A trough tracking across the Northern Plains will eject east as it gets caught between a closed upper low north of the Great Lakes and an upper high in the southeastern US. Favorable conditions for height falls will allow the development of a strengthening surface low across the Great Lakes quickly moving east by Wednesday afternoon. Initially, we'll still have high pressure in the Canadian Maritimes holding dry stable air east and west-northwest flow aloft still maintaining the line between this dry air and warm, moist air to our south. As the surface low develops a warm front will shift east late morning into the early afternoon. Light rain should push west to east, but any rain from it will be tempered by the low-level dry air. That warm front will shift just north of the international border, and then the surface low will follow Wednesday night. Increasing instability (mostly aloft) and sharp frontogenetic forcing against stubborn high pressure will produce thunderstorms that will be capable of heavy rainfall. The degree of elevated instability remains in question, and there will almost certainly still be some wobbles in the exact track as we've seen for Tuesday's system depending on convective processes and where exactly low pressure will track along a still present sluggish thermal/moisture gradient.

KEY MESSAGE 3: Our Wed/Thu system will occlude Thursday night off the southeast New England Coast, dragging its parent low southeast with it. Showers look to continue as wrap around moisture lingers across Vermont, with some drying in northern New York. The upper low will drift over northern Maine by Friday keeping cyclonic flow northeasterly flow entrenched. While most of the late week and weekend looks to be on the drier side, isolated to scattered diurnally driven showers during the day will be possible, mainly over eastern Vermont and the Adirondacks. Current precipitation chances are around 35-50%, with the exception of the higher terrain which currently have PoPs to 60-70%. Any daytime shower activity will wane by the evenings. Skies look to remain on the cloudy side Friday into Saturday. Friday looks to be the best chances for rain in the late week and weekend with rain chances decrease each day towards next week. Temperatures will generally be seasonable in the 60s and 70s, but there is a chance for some lower temperatures than current guidance is suggesting across eastern Vermont should more clouds, and precipitation develop. Overnight lows will trend cooler into the weekend towards the mid 40s to low 50s as subtle ridging and some radiational cooling nights are to be expected heading into next week.

AVIATION /12Z MONDAY THROUGH FRIDAY/

Through 12Z Tuesday...Fog has developed at all terminals this morning. Conditions look to improve back towards VFR between 12-13Z for BTV/PBG/RUT, and closer to 13-14Z for EFK/SLK/MPV. MSS will trend towards MVFR by 13Z with low stratus around 1500ft agl, ten VFR by 14Z. Quiet VFR aviation conditions are expected after 14Z through 00Z with mainly clear skies, and light and variable terrain driven winds. Clouds back build in after 00Z tonight with showers possible at all sites except EFK beginning after 00Z through the end of this TAF period.

Outlook...

Tuesday: Mainly VFR, with local MVFR possible. Likely SHRA, Slight chance TSRA. Tuesday Night: Mainly MVFR, with local IFR possible. Chance SHRA. Wednesday: Mainly MVFR, with local IFR possible. Likely SHRA, Slight chance TSRA. Wednesday Night: Mainly MVFR, with local IFR possible. Chance SHRA, Slight chance TSRA. Thursday: Mainly MVFR, with local IFR possible. Chance SHRA. Thursday Night: Mainly MVFR, with local IFR possible. Chance SHRA. Friday: MVFR/IFR conditions possible. Chance SHRA, Slight chance TSRA.

BTV WATCHES/WARNINGS/ADVISORIES

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