textproduct: Burlington

WHAT HAS CHANGED

As of 309 PM EDT Thursday...

Increased rainfall amounts in southern Vermont based on some upstream observations, but little changes otherwise.

KEY MESSAGES

As of 309 PM EDT Thursday...

1. A bit or rinse and repeat between today and Sunday with a trend towards cooler conditions.

2. High pressure will provide our region with mostly dry conditions and below normal temperatures, along with the potential for frost in climo favored areas.

DISCUSSION

As of 309 PM EDT Thursday...

KEY MESSAGE 1: A stalled boundary resides across the region. Weak low pressure (barely falling below 1020mb) will try to shift the boundary northwards, but with little success due to a trough digging on the west side of a longwave trough and a strong high pressure building into Ontario Province this evening, which will promote more west-northwest flow. So little, if any, latitudinal gain of the low is expected. Good isentropic ascent and a somewhat favorable jet configuration should at least produce light to moderate rain across southern Vermont. Otherwise, cool on Friday with highs in the 60s. That'll lead into some frost potential. With the strong high nosing in, it looks like Vermont will hold onto some gradient flow, but northern New York will see it collapse Friday night. There will be an upper lobe of vorticity tracking south, and that will likely produce some high clouds. This could put a hold on frost formation, but if it is thin or has breaks, it may still take place. So there is some frost noted in our public products, but keeping it fairly limited for now. Saturday will feature similar conditions with a cool day in the 60s again. Another cool night is expected, but high clouds will again come into play ahead of the next weather system of note and a switch to south winds as high pressure moves offshore.

For Sunday's system, it will bear a strong resemblance to today. Another weak low pressure will amble east, but struggle to gain any latitude as another upper trough paired with a strong Canadian high will keep moisture shunted south. This one looks a little more likely to get farther north with surface pressures around 1012mb for Sunday's low pressure. But with high pressure nosing in and stable conditions, stratiform rain is expected mainly south, and there are no local hydro concerns.

KEY MESSAGE 2: An extended period of North Country mid September Chamber of Commerce type weather is anticipated acrs our fa for days 4 thru 7. Large scale synoptic pattern shows large 1035mb high pres anchored acrs southern Canada with cool-dry north/northeast flow expected. This fast confluent flow aloft wl help suppress any heat/humidity, along with best instability well to our south thru most of next week. Given pw values <0.50" and deep dry layer in place, expect large diurnal range in daily highs/lows, along with large difference btwn valleys/summits. Daily highs mostly in the mid/upper 50s to mid 60s with lows low/mid 30s colder valleys to mid/upper 40s near Lake Champlain. As high pres slowly breaks down toward late next week, a return flow of slightly deeper moisture and warmer air develops, along with better potential for rain showers. There still is a large spread in the timing of high pres breaking down and potential return of moisture by late week or next weekend.

AVIATION /00Z FRIDAY THROUGH TUESDAY/

Through 00Z Saturday...With diurnal heating cut off, clouds will erode quickly this evening. The clear skies and light winds that result will allow the favored locations to develop fog between 06-09z. With CAA and dry air moving in behind today's front, fog will be more patchy with SLK, MPV, and EFK going IFR. RUT is a more borderline situation and for now have left it as TEMPO. Fog will burn off quickly in the morning as the shallow inversion gives way to mixing. Saturday will be pleasant all around with only some high clouds to deal with.

Outlook...

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

BTV WATCHES/WARNINGS/ADVISORIES

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