Marine Weather and Tide Forecast for Winooski, VT

KEY MESSAGES
As of 303 AM EDT Saturday...

1. Gusty winds associated with an approaching frontal system are expected today with the strongest gusts across northern New York and near the International Border.

2. A cold front will bring widespread rain showers tonight with much cooler temperatures for Sunday into early next week. Rain will turn to snow over higher elevations, with some mountain accumulations expected.

3. Spotty, light precipitation is possible on Tuesday, then temperatures gradually increase into late next week.

DISCUSSION
As of 303 AM EDT Saturday...

KEY MESSAGE 1: A Wind Advisory is in effect for Franklin and Clinton Counties in northern New York from 5 PM today to midnight tonight for wind gusts between 40 to 50 MPH. The strongest gusts will be located along the US Route 11 corridor from Moira, NY to Ellenburg Depot, New York around 8 PM tonight.
A few power outages and downed tree limbs may result.

Ahead of a strong cold front tonight, lapse rates will steepen as large scale divergence leads to drying atmospheric profiles areawide. Surface dewpoints will dry into the low to mid 40s across Vermont with weak cold air damming behind a departing area of high pressure, with dewpoints slightly higher across the St. Lawrence Valley due to increasing southerly flow throughout the day. Temperatures will also surge into the mid 60s to near 70 across Vermont, with low to mid 70s in northern New York where better mixing and southerly flow will be located. These increasing temperatures, coupled with surface drying and an approaching 850 mb low level jet to 50 to 60 knots, will help mix down gusty winds to the surface. Widespread gusts, beginning to increase this morning into this afternoon, will reach 30 to 40 MPH for most locations by mid to late this afternoon, peaking around sunset. The strongest winds are expected to be across the northern fringes of the Adirondacks where enhancement from downsloping will lead to gusts up to 40 to 50 MPH, particularly along US 11 near Malone, NY. Channeled flow in the northern Champlain Valley and St. Lawrence Valley could lead to some isolated briefly higher gusts to 45 MPH, but confidence is lower than portions of northern New York for reaching Wind Advisory Criteria. Winds will subside after midnight tonight as precipitation begins to overspread the region.

KEY MESSAGE 2: A cold front will slide through the area late this evening into tonight with widespread rain expected. The front is expected to move into the St. Lawrence Valley between 7-9 PM, but as it moves east, it will weaken and become washed out by tomorrow morning as it encounters drier air and blocked flow. However, a secondary arctic cold front will provide additional moisture and energy leading to continued precipitation chances across northern New York and Vermont by late Sunday. As the secondary front enters the region, significantly colder air aloft will mix towards the surface with temperatures plummeting below freezing into the 20s by Sunday Night. The timing of this cold air is tricky as the dynamics between the two cold front is not handled very well. It is expected that temperatures will be non-diurnal Sunday with temperatures falling throughout the day, but when the stronger caa arrives will play a role in a precipitation changeover to snow. Mountain summits will see a changeover to snow first during the day Sunday, but the timing of the precipitation with the strongest cold air varies between models. The HRRR and ECMWF ensembles show a warmer system with more delayed cold air arriving leading to rain in the valleys with tapering off precipitation before the colder air arrives. The NAM3K has been consistent, however, in co-locating the cold air arrival with the backside of the precipitation which could lead to a period of briefly heavy snow across the Champlain Valley. Current expectations, and given the time of year, is for a mix of rain/snow with perhaps some sleet mixed in, with little to no valley snow accumulations, however, should the system amplify more and become oriented north-south, slowing the system, some snow may be favored in the deeper valleys. Winds will turn to the northwest with breezy northwest flow, leading to wind chills in the upper 20s to mid 30s. Regardless with precipitation and colder temperatures, expected a raw, damp, and breezy end to the weekend.

Temperatures will remain cold Monday into Monday Night with strong radiational cooling and brisk northwest flow.
Temperatures will struggle to reach 40 degrees on Monday. Some snow upslope snow showers under northwest flow may be possible in the higher terrain, but accumulations will be minimal if at all. Strong radiative cooling under clear skies Monday night will lead to winter like temperatures as overnight lows fall into the low to mid 20s, with some teens in the colder hollows of the Adirondacks and Northeast Kingdom.

KEY MESSAGE 3: An axis of high pressure ridging will shift from northern New York and Vermont into southern New England on Tuesday, returning southerly to southwesterly flow to the region and helping temperatures climb back towards typical springtime normals. Highs Tuesday will still be below seasonal averages in the 40s and lower 50s, but it will be noticeably warmer than Monday with a little more sunshine and the warming south wind. However, clouds will be on the increase throughout the day ahead of our next shortwave that may bring some spotty, light precipitation Tuesday afternoon through early Wednesday morning. Precipitation type will be highly elevation dependent, with snow showers possible in the mountains and rain showers in the valleys as low temperatures vary across the 30s F.
Any snow accumulations would likely be restricted to the high terrain and very minor. Wednesday through Thursday, high pressure over Hudson Bay will remain in control, allowing daytime temperatures to moderate into the upper 40s and 50s but remain below seasonal normals as upper level troughing gyrates over the Canadian maritimes, keeping flow northwesterly as our area is on the edge of the cyclonic flow. Due to this northwesterly flow as well as nighttime clearing under high pressure, lows look to remain near or below normal in the upper 20s and 30s. Towards the end of the week, models project a wave to ride along cyclonic flow into our area, indicating the potential for precipitation. However, deterministic guidance does not agree on timing/strength of this feature, placement of surface features, nor source of moisture for precip, so it is yet to be determined how exactly this plays out. Most likely will be showery and seasonable to start the weekend, but no major impacts anticipated.

AVIATION /07Z SATURDAY THROUGH WEDNESDAY/
Through 06Z Sunday...Patchy dense fog is expected at times this morning, though predictability is low. A frontal system will bring breezy conditions today, followed by widespread rain showers. Rain will turn to snow over higher elevations, with some accumulation expected. Winds are currently strong on mountaintops 30-35 knots, but in areas with where this is not mixing to the surface and where lingering moisture left from yesterday's rain, we're seeing intermittent low clouds and fog.
One such place is KPBG, where we suspect a low-lying lake cloud is helping to produce vis 1-2 miles. Another spot is KEFK, which is beginning to report mist 2-4 miles. It's hard to say how widespread this epidemic of fog is going to become this morning as high clouds start to cover northern New York and proceed towards Vermont. According to climatology, KPBG and KEFK both have about 30% chance of IFR conditions through the morning hours. Widespread VFR conditions are expected to prevail for the majority of the daylight hours today. High pressure will shift east this morning, resulting in increasing southerly return flow throughout the day. Light and variable winds are expected through around 10Z-12Z Saturday when winds increase out of the southeast, around 10-25 knots with gusts 25-35 knots likely around 12Z-18Z onwards through the end of the 24 hour TAF period. Some marginal LLWS is expected at MSS before surface winds increase out of the south-southeast to better match the jet aloft. Widespread rain showers are expected to arrive across northern New York and portions of northern Vermont around 00Z-06Z Sunday, spreading southeastward to other sites afterwards, bringing with them lowering ceilings to MVFR levels as well as the return of LLWS at the majority of the TAF sites.

Outlook...

Sunday: Mainly VFR, with local IFR possible. Chance SHRA.
Sunday Night: VFR. Slight chance SHRA, Slight chance SHSN.
Monday: VFR. NO SIG WX.
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. Slight chance SHRA.
Tuesday Night: Mainly VFR, with areas MVFR possible. Chance SHRA, Slight chance SHSN.
Wednesday: Mainly MVFR, with areas IFR possible. Slight chance SHRA.

BTV WATCHES/WARNINGS/ADVISORIES
VT...None.
NY...Wind Advisory from 5 PM this afternoon to midnight EDT tonight for NYZ027-028-030-031.