textproduct: Burlington

WHAT HAS CHANGED

As of 220 PM EDT Wednesday...

Confidence is increasing on the potential for strong radiational cooling on Thursday night into Friday morning, and nighttime lows have been adjusted to reflect the potential for frost in the Adirondacks and central Vermont into the Northeast Kingdom. Additionally, precipitation chances have been decreased for Saturday based on the majority of model scenarios trending slower.

KEY MESSAGES

As of 220 PM EDT Wednesday...

1. Temperatures will trend below seasonal normals, and frost will be possible outside the Champlain Valley, mainly on Thursday night.

2. Dry conditions are expected with a trend to very low relative humidity, but also slackening winds.

3. Shower chances to end the weekend and begin next week.

DISCUSSION

As of 220 PM EDT Wednesday...

KEY MESSAGE 1: Our moisture starved, but strong cold front is shifting southeastwards in piecemeal fashion. After one more day of warmth and humidity with spotty showers now shifting south, we'll experience 50s to near 60 Thursday, and then 60s for the rest of the region during the day. Very cool weather is expected, tonight. North flow will bring a significantly cooler air mass taking temperatures into the 30s across much of northern New York and the Northeast Kingdom, but it will be in the 40s across the Champlain Valley and south-central Vermont. It will be an advective cold with a steady north to northwest wind overnight, and that will likely keep frost limited.

Temperatures on Thursday night appear likely to tank. Very dry mid- level conditions will be present beneath a 1030mb. Widespread frost/freeze is expected in the Adirondacks and central Vermont up into the Northeast Kingdom. The probabilities for the Champlain and St. Lawrence Valley are a little lower, but mid 30s may not even be out of the question, especially for areas removed from the St. Lawrence River and Lake Champlain. Some moderation takes place, and we'll trend relatively close to seasonal norms with decreasing chances for frost the remainder of the week.

KEY MESSAGE 2: The incoming air mass will be quite dry. Dewpoints will likely fall near to below freezing on Thursday. Even with the cool temperatures, the 30-35 degree dewpoint depression will result in afternoon relative humidity values of 30-40%, locally in the upper 20s. Steady northwest winds around 10-15 mph and gusts up to 20 mph will be possible. We'll be somewhat further removed from precipitation across the region, especially southern Vermont, which last saw the greatest rainfall from the 1-2" soaker from a week ago.

For Friday, the warmer temperatures will come with little change in surface dewpoints. The strong 1030mb high will be right overhead, and sunny skies with variable winds are expected. Relative humidity values will likely be in the 20s over most of the region. Saturday will also be dry, but recycled maritime air will add at least some humidity back into the air 32-40% over Vermont, and 35-45% over northern New York. Some precipitation will approach the area from the southwest, but likely not until Saturday night or later as a decaying warm front struggles against the strong surface high.

KEY MESSAGE 3: Surface high pressure centered over Quebec retreats to the northeast on Sunday as a low attempts to gain entry into the region. While the precipitation associated with it will become more disorganized as it moves in, shower chances persist from Sunday through Monday. By the end of Monday, the combined GEFS/EPS/CMCE ensemble probability of receiving over 0.5 inches of rain ranges between 50 to 75 percent, with the highest values farther southwest. The probability of seeing an inch is between 25 to 50 percent. The rain will mostly be showery and stratiform and will not present a flood threat. Uncertainty remains on how far north the precipitation makes it, but under any situation, the days will not feature consistent rainfall. Mostly dry weather should prevail toward mid week, though a few chances of showers will continue.

AVIATION /18Z WEDNESDAY THROUGH SUNDAY/

Through 18Z Thursday...VFR conditions are expected to prevail for the next 24 hours. While a few clouds should drop into the 3,000 - 5,000 foot level in the early afternoon, ceilings should remain VFR. Winds will gradually change from westerly to northwesterly and northerly this afternoon. Winds will generally gust in the 10 to 20 KT range, with brief gusts to 25 KT possible. They drop a bit tonight and tomorrow but should remain in the 5-15 KT range.

Outlook...

Thursday Night: VFR. NO SIG WX. Friday: VFR. NO SIG WX. Friday Night: VFR. NO SIG WX. Saturday: VFR. Chance SHRA. Saturday Night: VFR. Chance SHRA. Sunday: Mainly VFR, with local MVFR possible. Chance SHRA. Sunday Night: MVFR. Chance SHRA. Memorial Day: Mainly MVFR, with local IFR possible. Chance SHRA.

MARINE

As of 220 PM EDT Wednesday...

After a quick burst of gusts from the switch to northwest to north winds on Lake Champlain having taken place, steady 10-20 knot winds are expected for the afternoon. By evening, winds will likely increase over Lake Champlain again, especially around midnight before tapering off again tomorrow morning. Waves overnight could build to 2-4 feet over the broad waters south of Colchester Reef, and mostly 1-2 feet elsewhere.

BTV WATCHES/WARNINGS/ADVISORIES

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