textproduct: Burlington

WHAT HAS CHANGED

As of 229 PM EDT Tuesday...

Frost Advisory will end this morning for the Champlain Valley. Timing for rain showers next week has been moved up earlier to Sunday evening.

KEY MESSAGES

As of 227 AM EDT Wednesday...

1. Showery conditions developing for the rest of the week.

2. Dry and seasonable weekend before showers return for the beginning of next week.

DISCUSSION

As of 227 AM EDT Wednesday...

KEY MESSAGE 1: A warm front will push east across the area with relatively little fanfare. Mid-level dry air is expected to limit shower activity as it lifts northeast this morning. Moderation behind the front will push temperatures into the 60s for most today, but with a few spot 50s still in the Northeast Kingdom. Today's main story will be the strong south to southwesterly winds that develop. Modest mixing behind the warm front will bring 20-30 mph wind gusts, locally to 35 mph on the northern slopes of the Dacks near Malone, NY and then near the shores of Lake Champlain. A prefrontal trough will begin to track east towards the St. Lawrence Valley later this evening. Then, it'll translate to Vermont overnight. Showers will track east along the feature, with a greater concentration over northern New York where better dynamics and moisture lies that will degrade heading into Vermont. By Thursday morning, temperatures will begin to cool aloft as an upper low digs southeastwards. Surface pressures will lower as the upper vort swings in, and this could continue to generate showers across the area. This will set up Thursday afternoon to be convective. The combination of a strengthening cold front as a 1001-1002mb low tracks just north of Montreal, mid-level cooling, and surface temperatures in the 60s will allow for the dynamic system to take advantage of around 250- 500 J/kg of CAPE across the area. Like Monday, we may have some pea- sized hail and isolated thunder on Thursday afternoon, with the greatest likelihood near the international border.

Temperatures will sink back near to below seasonal norms in the 50s to near 60 for Friday. The post-frontal air mass will still be beneath a broad upper low, and some spot showers remain possible Friday afternoon. The backside of the upper trough will start sliding east by Friday night. This will allow for one night of radiational cooling and frost potential again in the Champlain Valley. A few additional spot showers will be possible as warm advection begins to nose in heading into Saturday, but nothing significant is expected.

KEY MESSAGE 2: Surface high pressure builds in for the weekend, leading to a couple classic fall days. Highs will be in the 50s and 60s with mostly sunny skies. The remnants of what will likely become Isaias looks to move into the region to start next week. The center of the low should track well to the south, but periods of showers and potentially an area of stratiform rain are increasingly likely for Monday and Tuesday. By the time it reaches the region, it will have weakened significantly so any rainfall will remain beneficial and there will be no wind threat. The next cold front passes through mid- week, bringing more potential showers. Overall, temperatures will be relatively seasonable, with slightly above average temperatures to start the week and slightly below average temperatures to end the week.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

Through 12Z Thursday...VFR conditions are expected to mostly persist for the next 24 hours. The only exceptions could be late this afternoon and late tonight when a few showers move through. While most of them will be too light to cause significant visibility reductions, a brief drop to MVFR visibility is possible. This afternoon, that would likely only occur over northern New York but late tonight, that could occur at any terminal. Winds will become southerly to southwesterly and increase quickly this morning. Gusts in the 15-30 KT range are expected during the day, with the strongest gusts at BTV, PBG and MSS. Winds will decrease a bit this evening and by 06Z, the gusts should mostly be below 20 KT. LLWS is expected to develop in places this evening, especially in Vermont outside the Champlain Valley.

Outlook...

Thursday: VFR. Chance SHRA, Slight chance TSRA. Thursday Night: VFR. Chance SHRA. Friday: VFR. Slight chance SHRA. Friday Night: VFR. NO SIG WX. Saturday: VFR. NO SIG WX. Saturday Night: VFR. NO SIG WX. Sunday: VFR. NO SIG WX.

MARINE

A Lake Wind Advisory will be in effect over Lake Champlain beginning later this morning. Winds are expected to increase behind a warm front that will pass through without much precipitation. South winds of 15 to 25 knots will arrive around 10 AM and peak just under 30 knots over the broad waters by mid afternoon before decreasing very slowly. Waves are expected to build up to 2 to 4 feet, with values closer to 3 to 5 feet over the broad waters. Lingering 2 to 4 foot waves are likely during the evening.

BTV WATCHES/WARNINGS/ADVISORIES

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