Marine Weather and Tide Forecast for Winooski, VT

KEY MESSAGES
As of 213 AM EDT Monday...

1. Widespread rainfall and a few strong thunderstorms expected today.

2. Drier weather on Tuesday and Wednesday; showers return on Thursday.

3. Seasonably warm and unsettled weather expected for the end of this week into next weekend.

DISCUSSION
As of 213 AM EDT Monday...

KEY MESSAGE 1: The Bermuda Ridge across the western Atlantic continues to strengthen and has shifted northward slightly overnight. This is causing the upper level trough and associated surface reflection to move slowly across the Northeast. Much of the region has been in a lull for precipitation over the past few hours but increasing upper level diffluence and moisture advection will soon point the fire hose across portions of northern New York and Vermont. Given the lack of rainfall thus far, we are basically starting from scratch with soils that can absorb a decent amount of rainfall. An airmass with PWAT values between 1.9-2.1 inches (99th percentile) will move overhead soon and will be supportive of very efficient rain processes with the freezing level between 13kft and 14kft. Rainfall rates could reach an inch per hour in some of the embedded convective elements but rainfall rates overall should remain well under a half inch per hour. Still, with multiple rounds of showers possible through the day, the threat for flash flooding does exist albeit on the very low side based on how things have played out thus far.

This afternoon is a bit of a wild card as we will have the potential for a few strong to locally severe thunderstorms across Vermont.
This potential is very conditional and is dependent on us being able to see a few breaks in the clouds behind the initial round (about to come through now) and the frontal passage this afternoon. Lapse rates will generally be moist adiabatic as a result of the anomalously high PWAT values but any surface heating could allow for more dry adiabatic lapse rates in the low levels that could mix down some 40-50 knot winds down to the surface. These storms are not figured to be widespread although some of the latest high-res guidance does show a distinct line of convection associated with the cold front. Basically, it'll be a messy day with several possible hazards so it'll be a good day to keep an eye on the weather. These showers and thunderstorms will shift eastward after sunset with high pressure quickly building into the region tonight into Tuesday morning.

KEY MESSAGE 2: Surface high pressure will settle into the region on Tuesday while the Bermuda high continues to build north and west.
This will set the stage for deep layer ridging and bring sunny skies and dry weather to the region on Tuesday and Wednesday. A building trough across the central US will displace the Bermuda High a bit to the south on Thursday and will open up the stream of deep Gulf moisture back to the region. With upper level diffluence in place, some decent mid-level forcing will coincide with the moisture to bring scattered to numerous showers to the region Thursday afternoon with the potential for a few strong thunderstorms.

KEY MESSAGE 3: No significant changes have been made to the forecast for the end of the week into the weekend, with warm and unsettled weather expected as the region remains in between a Bermuda high to our east and troughiness across the Plains. Broad southwesterly flow across the region will allow for plentiful moisture to advect into to the region, with occasional shortwaves passing overhead helping to drive shower chances. As usual in this time frame, there is some uncertainty in to the overall extent and timing of precipitation, but several rounds of showers and possible thunderstorms look likely at this point. With fairly weak forcing and limited instability, severe weather looks unlikely however areas of locally heavy rain will be possible with PWAT values near 2 inches, although there should be enough flow to limit any flood threat but trends will need to be monitored as we get closer. Temperatures during this time frame look to be on the warmer side, with highs climbing into the 80s areawide this weekend, with increased humidity making it feel a little uncomfortable at times.

AVIATION /12Z MONDAY THROUGH FRIDAY/
Through 12Z Tuesday...A mix of VFR and MVFR conditions currently prevail across terminals this morning as scattered showers continue to move through the region. Periods of MVFR conditions are expected to persist over the next several hours, primarily due to ceilings. Shower activity may wane a bit towards the afternoon, but a frontal passage may bring an additional round of showers and thunderstorms to the region after 18Z or so, with the best chances for thunderstorms currently across eastern Vermont. Winds will continue to become more northwesterly through the forecast period. It will be a bit breezy throughout the afternoon, with gusts generally 15 to 20 knots, although 30 knot gusts will be possible. Some pockets of LLWS are possible, especially across some of the mountain terminals. High pressure will build in overnight tonight behind the front, bringing clearing skies and light winds.

Outlook...

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

BTV WATCHES/WARNINGS/ADVISORIES
VT...None.
NY...None.