textproduct: Burlington

WHAT HAS CHANGED

As of 303 PM EDT Tuesday...

No significant changes were made to the forecast with this package.

KEY MESSAGES

As of 303 PM EDT Tuesday...

1. Showers wind down this evening, with drier weather on Wednesday.

2. Another round of showers and thunderstorms on Thursday, with some storms possibly strong to locally severe.

3. A tranquil period over the weekend will be followed by more shower and thunderstorm chances early next week.

DISCUSSION

As of 303 PM EDT Tuesday...

KEY MESSAGE 1: Scattered showers will continue to drift across the region this afternoon as the upper trough swings overhead. Activity will wane toward sunset with the loss of daytime heating. High pressure starts to nose into the area tonight and crosses on Wednesday, bringing a period of fair weather. After initial clearing this evening, clouds will likely increase overnight, particularly over the higher terrain, as moisture gets trapped under the inversion. Lows tonight will mainly be in the 50s, except in the usual sheltered valleys of the Adirondacks and Northeast Kingdom which could dip into the 40s.

Wednesday will be a pleasant day under partly to mostly sunny skies. Winds will be light as we'll be under the influence of the ridge. Temperatures will top out in the mid 70s to low 80s.

KEY MESSAGE 2: Precipitation chances will increase again Thursday into Friday as another upper trough pushes eastward across the Great Lakes and into the Northeast. Meanwhile, a weak surface low will slide across Ontario into Quebec, dragging a frontal boundary across the region in its wake. While moisture doesn't look particularly impressive, increasing instability ahead of the front and forcing from the approaching trough will allow for the development of showers Thursday afternoon. Shear of 30-35 kt will lend toward organization of storm cells, with some storms potentially becoming strong to locally severe. While areas just to our south seem the most favorable, SPC's Day 3 Marginal Risk of severe thunderstorms definitely seems reasonable, with strong winds and hail the main threats.

Additional showers are expected on Friday as another shortwave rotates around the base of the upper trough, swinging another frontal boundary across our region. Limited instability will keep the threat of severe weather low, but still anticipate some rumbles of thunder, especially in central/southern VT where the front should come through during the mid-late afternoon.

Both Thursday and Friday will feature highs in the mid 70s to mid 80s, though much of northern NY will be cooler on Friday with the cold frontal passage earlier in the day there. Nights will remain comfortable with lows in the 50s to around 60F.

KEY MESSAGE 3: Another dry weekend with seasonable temperatures and low humidity is on track. Following the expected fair weather, a thermal ridge will translate eastward towards or into our region on Monday and will quickly be replaced by a trough. While a warming trend is the consensus for early next week, the ECMWF ensemble slightly favors a scenario where the ridge remains well to our west and temperatures are near to slightly below normal. In contrast, the latest AIGFS shows 850 mb anomalies reaching into the 90-97th percentile Monday afternoon with the ensemble mean in the 80-85th percentile, leading to well above normal temperatures. Statistical guidance generally supports temperatures just a bit above normal, with highs reaching the mid to upper 70s.

In association with seasonable warmth and increasing humidity, the most noteworthy part of the longer term pattern would be a risk of thunderstorms early next week. Some signals in the machine learning guidance and global ensemble clusters of CAPE/Shear suggest Vermont, and especially southern/western areas, may have favorable ingredients in place, but overall the risk currently looks more favorable south of our region. This thunderstorm potential is highly conditional on how Monday plays out; with the passage of a cold front earlier in the day on Tuesday, there would be little or no activity that day. A later passage would support stronger variety storms on Tuesday, while Monday generally looks a bit more likely to see showers and thunderstorms generally. Large uncertainty keeps thunder probabilities rather low (mainly under 15%, lower Tuesday than Monday) but bears watching. At the least, this period looks unsettled with rain at some point rather likely. Rainfall probabilities of exceeding 1" are generally in the 15-30% range over the course of the two days, and 20-50% of exceeding 0.5".

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/

Through 00Z Thursday...A mixed bag of aviation conditions are expected tonight, with low stratus and fog anticipated over portions of the area. The overall signals are still mixed, and thus confidence in stratus vs fog at any given TAF site is on the lower side. At this point, have leaned towards mostly stratus development, given some degree of flow maintained off the surface. However, any areas that see clearing overnight have to potential to develop mist and fog, especially areas that measured rain in the last 24 hours, along with climatologically favored valley locations. High pressure building in will lead to gradual improvement/scattering of any remaining low ceilings after 12Z.

Outlook...

Wednesday Night: VFR. NO SIG WX. Thursday: VFR. Likely SHRA, Chance TSRA. Thursday Night: Mainly VFR, with local IFR possible. Chance SHRA, Slight chance TSRA. Friday: Mainly VFR, with local IFR possible. Chance SHRA, Slight chance TSRA. Friday Night: VFR. NO SIG WX. Saturday: VFR. NO SIG WX. Saturday Night: VFR. NO SIG WX. Sunday: VFR. NO SIG WX.

BTV WATCHES/WARNINGS/ADVISORIES

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