textproduct: Burlington

WHAT HAS CHANGED

As of 240 AM EDT Friday...

The severe threat for Saturday has increased.

KEY MESSAGES

As of 240 AM EDT Friday...

1. Thunderstorms and heavy rain expected Saturday afternoon and evening.

2. Seasonable weather and intervals of wildfire smoke expected over the next few days.

3. Frontal passages bring chances for showers on both Tuesday and Wednesday before high pressure dominates our weather on Thursday and Friday.

DISCUSSION

As of 240 AM EDT Friday...

KEY MESSAGE 1: An anomalously strong low for the time of year (sub 1000 mb) looks to take a general track up the St. Lawrence Valley or close to that Saturday into Saturday night. Showers will be more widespread close to the international border on Saturday as the warm front and center of the low would be closer. A powerful cold front will come through in the afternoon and evening, bringing a round of showers and storms. The airmass ahead of the system will be relatively cool and not conducive to high instability. Mean HREF SBCAPE values are around 500 J during this time frame. However, due to the strength of the low, there will be strong shear and dynamics. 0-6 KM shear is forecast to be in the 40-50 KT range. One thing lacking will be a significant surface wind shift/convergence with the front, with southwesterly synoptic flow expected behind the front until the center of the surface low pushes east. Height falls will be quite significant though. Based on this information, the SPC upgraded the region to a split between a slight and marginal risk. These storms will contain heavy rain but with strong background flow, the storms will move quickly and minimize the flooding threat. There also does not look to be a stalled axis of rain along the warm front on the front side that often occurs in these setups. However, the threat for flooding cannot be completely ruled out if areas see multiple rounds of heavy rain, with the greatest threat of that being along the international border.

KEY MESSAGE 2: Highs look to be in the 70s to mid 80s over the next few days, with slightly cooler conditions on Sunday. Lows will generally be in the 50s and dew points will be relatively low. The wildfire smoke makes a return for Saturday as flow becomes westerly to southwesterly, bringing the smoke that is currently over the Midwest and Great Lakes into the region. Thankfully, behind the cold front on Saturday, winds eventually become northwesterly and push the smoke back to the south. The source of the smoke is fires in western Ontario.

KEY MESSAGE 3: Showers wills spread into the region on Tuesday as a warm front lifts across our area associated with a low pressure system which is north of the Great Lakes. Chance for precipitation will continue into Wednesday as cold front crosses our area associated with the same low pressure system. Will need to monitor as we get closer for potential for strong or severe storms and also for heavy rainfall. Drier weather is then expected for both Thursday and Friday as high pressure ridge builds over our area.

AVIATION /06Z FRIDAY THROUGH TUESDAY/

Through 06Z Saturday...Through 06Z Saturday...Currently LIFR conditions at RUT in fog. Seems fog will remain until it lifts around 12z, but should be limited to just RUT as other sites have had drier air move into the area. Otherwise, light winds and VFR conditions at all sites.

Outlook...

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

BTV WATCHES/WARNINGS/ADVISORIES

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