textproduct: Burlington

WHAT HAS CHANGED

As of 234 PM EDT Friday...

*Frost Advisory for southern Franklin County in New York, and for Essex County in Vermont have been issued from midnight tonight until 7 AM tomorrow morning.

*A cold water special weather statement has been issued for the entire region as water temperatures will be below 50 degrees during the upcoming holiday weekend.

KEY MESSAGES

As of 234 PM EDT Friday...

1. The cool and dry trend will continue into tomorrow with some isolated patchy frost in portions of the Adirondacks and Northeast Kingdom.

2. Light to moderate rain, with cool and breezy conditions are expected late Saturday night into Sunday. Additional showers are possible on Memorial Day.

3. Somewhat unsettled mid to late week but no big storm systems

DISCUSSION

As of 234 PM EDT Friday...

KEY MESSAGE 1: The cool and dry trend will continue into tomorrow with a 1029 mb area of high pressure sliding east across southern New England this afternoon into tonight. The retreating high will allow a large plume of high altitude clouds associated with shower activity over the Ohio Valley with winds turning more east southeast into tonight. The latest HREF trends show these clouds a bit delayed when arriving into the region, which may keep portions of the Northeast Kingdom on the clearer side for most of the night. Furthermore, the mid to low clouds look to arrive after sunrise tomorrow. As such, some patchy frost is possible across mainly Essex county Vermont. Conversely, in the colder hollows of the Adirondacks near the vicinity of Saranac Lake, temperatures may still be able to cool towards freezing if clouds are not as opaque as the NBM denotes. Given raw guidance depicting lows just above freezing, and clear skies for at least the first half of the night, have also issued a Frost Advisory for southern Franklin County as well. Temperatures will likely level off towards the later part of the night areawide as clouds increase in thickness. While the rest of the area will remain above frost advisory, temperatures will still be unseasonably chilly in the low to mid 40s.

Tomorrow will be the pick of the weekend featuring dry, and mostly cloudy to overcast skies in some locations. The precipitation shield will remain to our southeast as a stark area of drier air holds the moisture at bay for most of the day. Temperatures tomorrow will be in the low to upper 60s to near 70 degrees. We want to remind our readers that while temperatures this weekend will be in the 60s to 70s, water temperatures on both Lake Champlain and smaller lakes and ponds across the area are in the upper 40s to low 50s. The risk of hypothermia increases when water temperatures are below 50 degrees. Use caution if boating this weekend and take the necessary safe cold water boating practices. Winds by the late afternoon to evening tomorrow will begin to pick up from the southeast ahead of our next round of rain Saturday night into Sunday.

KEY MESSAGE 2: Increasing trends point towards widespread light to potentially moderate rain Saturday night into Sunday. Precipitation on the leading edge of a triple point with strong isentropic lift will move from southwest to northeast late Saturday night into early Sunday morning. The breakdown of the retreating ridge has become better timed amongst the hi res guidance with the HRRR denoting an arrival into northern New York by midnight, and into the Champlain Valley by 4 to 6 AM. The initial band will likely encounter dry air with less accumulations, but will saturate the air column. Better rain rates are expected after sunrise Sunday. A low level jet will accompany the precipitation shield with 40 to 50 knot south winds at 2500 to 3000 feet, promoting some downslope winds across the western Greens and northwestern facing slopes of the Adirondacks. Mixing of these stronger winds will be dependent on the rain rates and any breaks in the shower activity. Though near summit levels, winds may gust 30 to 40 MPH. Closer to the valley floors, mean mixed layer winds on the HRRR and NAM are around 25 to 30 MPH, though rain may lead to a slight reduction in gust speeds. Currently have 20 to 25 MPH gusts for most of the area with higher gusts in the higher terrain of the northern Greens and northwestern facing slopes of the northern Adirondacks. Better chances for mixed down winds will be Sunday afternoon as precipitation turns from stratiform to more showery. Trends for winds will need to be monitored for any outdoor activities during the day Sunday.

The winds should lead to higher rainfall amounts across southern Vermont and the Adirondacks where rainfall totals have increased to around half an inch, with locally higher amounts possible. Further north and east into northern Vermont and northeastern Vermont, lower amounts to near a quarter will be possible as this region will be closer to the ridge axis decreasing the amount of lift and moisture available. Increased clouds and rain cooled air will lead to a chilly day, especially in the southern and eastern areas due to easterly flow. Temperatures will largely be 10 to 15 degrees below normal in the upper 40s to low 50s.

Shower activity will taper off to more mist and isolated light showers Sunday night with some drying. An additional shortwave will provide enough energy in association with wrap around moisture from a deepening coastal low for some more showery rain on Memorial Day. However, unlike Sunday, warmer temperatures ushered in by westerly flow will increase into the upper 60s to low 70s. Shower chances on Memorial Day look highest in the morning with some clearing and drying trends for the western and northern portions of the region by Monday afternoon.

KEY MESSAGE 3: Confidence is increasing that a deep upper trough and associated cut off surface low will drop down into the region heading into the middle and end of next week. This will lead to a few different shower chances and cooler temperatures. More organized showers are possible on Tuesday into Tuesday night as a cold front pushes into the region. Behind that, the showers look more disorganized and diurnally driven. While enough synoptic scale forcing will be involved to continue the chances overnight, diurnal heating and the cold air aloft will likely be the main contributors later in the week. While there will be these showers around, most of the time it should still be dry. A few snow showers will also be possible in the highest peaks. The NBM probability of snow levels below 5,000 feet range between 25 to 50 percent late in the week.

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/

Through 00Z Sunday...High pressure continues to provide our taf sites with VFR conditions the next 12 to 24 hours. Winds will become light and terrain driven after sunset this evening, before shifting to the south/southeast at 4 to 8 knots on Saturday, except northeast at MSS. Mid/upper level clouds will continue to slowly spread across our region tonight into Saturday.

Outlook...

Saturday Night: VFR. Likely RA. Sunday: Mainly MVFR, with areas VFR possible. Likely RA. Sunday Night: Mainly MVFR, with local IFR possible. Chance SHRA. Memorial Day: Mainly MVFR, with local IFR possible. Chance SHRA. Monday Night: Mainly VFR, with local MVFR possible. NO SIG WX. Tuesday: VFR. NO SIG WX. Tuesday Night: VFR. Chance SHRA, Slight chance TSRA. Wednesday: Mainly VFR, with local MVFR possible. Chance SHRA, Slight chance TSRA.

BTV WATCHES/WARNINGS/ADVISORIES

VT...Frost Advisory from midnight tonight to 7 AM EDT Saturday for VTZ004. NY...Frost Advisory from midnight tonight to 7 AM EDT Saturday for NYZ030.