textproduct: Burlington

WHAT HAS CHANGED

As of 241 PM EDT Thursday...

Liquid amounts were increased across the front as it moves through tonight. Amounts will mostly remain below 0.5 inches except for a few locations in southern Vermont where up to 0.75 inches may be possible.

KEY MESSAGES

As of 241 PM EDT Thursday...

1. Widespread light rainfall is expected this evening and tonight. Rain will change over to snow as temperatures fall with very light accumulations possible.

2. Much colder temperatures are expected for Friday through Saturday night with most locations remaining below freezing for the entire time period. Wind chills will be quite cold Friday morning.

3. Following a mainly dry start to the week, a seasonably warm and wetter period is expected midweek.

DISCUSSION

As of 241 PM EDT Thursday...

KEY MESSAGE 1: Precipitation is spreading west to east this afternoon with showers moving into the Champlain Valley by 3 PM. An impulse is moving along a quasi-stationary boundary draped along the Canadian border as a deeper trough approaches. Westerly flow aloft may cause shadowing initially in the Champlain Valley and for areas east of the Greens before flow shifts more northwesterly this evening. Coincidentally, model timing of the stronger impulse associated with the primary trough will be moving through the region. Some more favorable dynamics for precip output are phasing over Vermont this evening which has resulted in an increase in QPF expected. Still, most locations will see less than 0.5" but portions of southern Vermont may range 0.5-0.75". There's about a 25% chance that portions of eastern Vermont range 0.33-0.66" should flow be stronger across the boundary. Lowest amounts are favored in the northern Champlain Valley where shadowing will be most pronounced with totals ranging 0.1-0.33". Elsewhere, 0.25-0.50" is favored. As cold air advection increases tonight, rain will change over to snow with a dusting to 0.2 inches favored for most places in northern Vermont and northern New York while up to 3 inches is possible for the summits of the Adirondacks and northern Greens.

KEY MESSAGE 2: Breezy northerly winds behind the cold front Friday will usher in unseasonably cold temperatures. The daily high for Friday will likely be midnight tonight with cold air advection increasing through day break before winds begin to taper down. Gusts will generally range 20 to 30 mph Friday morning resulting in some cold wind chills in the single digits for portions of northern New York and teens for much of Vermont. As -14 to -18C temperatures settle overhead at 925mb and 850mb respectively, surface temperatures will likely remain below freezing for most locations Friday (southern Vermont likely to range 32-36 degrees Friday) through Saturday night. Lows tonight are favored to dip into the single digits for the Adirondacks and northeastern Vermont with 10-15 degrees for most other locations' projected to dip into the teens for Saturday night.

KEY MESSAGE 3: A weather pattern featuring faster than typical westerly flow aloft will continue into early next week, allowing for weak fronts and light mixed precipitation to be possible with marginally cold air pushing out of southern Canada when low level flow turns northerly. This pattern should be disrupted by Wednesday when the jet stream retreats farther north and entirely Pacific air, rather than mix of Polar and Pacific, overspreads northern New York and Vermont. Currently there are limited signals for significant weather. Only the very wettest model guidance (under 5%) suggesting heavy rainfall, especially for the Adirondacks.

That being said, a quasi-stationary front may set up to our southwest with a long duration of overrunning precipitation possible. The wettest cluster in the 12Z ensemble guidance shows a 24 hour precipitation average beginning Wednesday afternoon of over an inch in western portions of northern New York, indicative of the potential soaking rain during this period. That being said, there is large variation in the position of the front, especially moving into Wednesday night. Therefore, not only precipitation amounts but temperatures become more uncertain, which could trend back to wintry from north to south as shallow cold air is pushed southward. There is a slight lean towards the warmer scenarios based on the latest data, but it remains worth paying attention to as we approach this wetter period.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

Through 18Z Friday...A nearly stationary front just north of the airspace will support periods of rain before it slips south of the area tonight. Steadiest rain appears to be favored in southern portions of the airspace, where both ceilings and visibilities are more likely to be reduced into the MVFR category south of the front, mainly from 22Z to 02Z. The wind shift from south-southwest to northerly flow will occur between 22Z and 04Z from north to south, with gusty winds expecting as the boundary passes with frequent gusts of 20 to 25 knots expected. A brief changeover of rain to snow before precipitation ends is possible, with greatest probabilities at EFK.

In the vicinity of the front, especially just north of it, IFR ceilings with cloud bases near 600 to 900 feet are expected at most terminals. Expected duration of IFR conditions remains short, generally 1 to 5 hours, with predominately MVFR ceilings otherwise. Given the timing of the front, MSS is the site most favored to see IFR conditions before 00Z (about a 50% chance). Expect a marked improvement to VFR as clouds gradually scatter towards daybreak, with a BKN MVFR cloud deck scattering last in central/eastern Vermont and Adirondacks by the end of the TAF period.

Outlook...

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

EQUIPMENT

The Colchester Reef meteorological station is out of service. This site is not serviced by the NWS. An estimated return to service is May 1st. Please contact us if you observe winds significantly deviating from the recreational forecast.

BTV WATCHES/WARNINGS/ADVISORIES

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