textproduct: Burlington

WHAT HAS CHANGED

As of 251 AM EDT Friday...

No significant changes.

KEY MESSAGES

As of 251 AM EDT Friday...

1. Two rounds of showers this weekend and some flakes in the mountains.

2. Gusty winds today and tomorrow.

3. Drier and warmer weather expected mid to late week, as trough is slowly replaced by ridging at all levels.

DISCUSSION

As of 251 AM EDT Friday...

KEY MESSAGE 1: Two shortwaves pass down from the north in the upcoming days, bringing two rounds of showers. The first will be this afternoon into tomorrow morning and the second will be Sunday night into Monday morning. From the first one, rainfall totals will have a sharp northeast to southwest gradient, with the Northeast Kingdom expected to see over an inch while only around a tenth of an inch is expected for the St. lawrence Valley and southern Essex County NY. The notable feature with this one will be the cold temperatures aloft. Mean HREF 850 mb temperatures drop to around -3 Saturday morning, and 925 mb temperatures drop to around 1 celsius. This puts snow levels down to 3,000 feet for most places. Above that level a few tenths of an inch are possible, with 1-2 inches possible on the summits. Lower temperatures aloft will be present farther east, and a few fakes could drop down to 2,000-2500 feet across eastern Vermont, though accumulations are not expected that low. A few flakes will mix in the higher elevations in the Northeast Kingdom, and could also occur in the higher elevations south through Groton and into Orange County. The rain showers will exit early Saturday morning and some clearing should occur by afternoon, so Saturday should overall be a decent day with highs in the 50s to low 60s. The second round of showers arrives Sunday afternoon and continues Sunday night, though the dynamics will be weaker with this one. Temperatures aloft will also be warmer, so snow levels should be mostly above summit levels, though a few flakes cannot be completely ruled out at the summits of the High Peaks. Highest rainfall totals will again be across the Northeast Kingdom, but a widespread couple tenths of an inch is currently expected.

KEY MESSAGE 2: A westerly low level jet passes overhead this afternoon, with the strongest part over northern New York. Ample mixing up to around 4,000 to 5,000 feet will allow much of it to mix to the surface. Winds at the top of the mixed layer look to be between 40- 45 KTs, and soundings indicate that this should be able to mix down to about 30-40 mph. Gusts in the 20 to 30 mph range are expected over Vermont. Overall, impacts from this should be very minor.

KEY MESSAGE 3: A highly amplified blocking type pattern is expected to prevail into Tuesday, before a slow pattern shift evolves. The timing and evolution of this pattern shift is challenging and has low predictability, given large model spread and high amplification. GFS is still most aggressive with closing 700-500mb circulation becoming stationary over southern New England for most of next week, while most other guidance is showing a more progressive mid/upper lvl trof lifting to our northeast by midweek. The latest WPC forecast indicates high chc (40-50%) pops for Tuesday afternoon with a sharp decrease to 10-25% by Tues night and keeping the rest of the week dry. However, buyer beware with potential cyclonic northerly flow lingering thru midweek at least, additional s/w energy and pockets of better mid lvl moisture, combining with low lvl upslope flow could produce additional showers on Weds aftn/evening and again on Thurs. Also, given cool pocket aloft progged to be centered acrs the NE CONUS thru mid week, I cannot rule out aftn instability type showers developing, especially acrs the higher trrn. Eventually mid/upper lvl ridge and sfc high pres that has been anchored over the Central Plains wl shift eastward into our cwa by late week/next weekend. This should provide us with drier conditions and warming temps into the mid 70s to lower 80s. The probability of hazardous or highly impactful weather for the next 4 to 7 days is very low, along with the potential for any strong to severe thunderstorms. The lack of sfc heating and instability is the limited factor.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

Through 12Z Saturday...Multiple changeable flight categories and wind directions expected at our taf sites in the next 12 to 24 hours. VFR conditions will prevail at all sites thru 18z today. As rain showers arrive from north to south between 18z-22z this afternoon expect cigs to lower toward MVFR conditions by sunset with mostly VFR vis, except MVFR in the heavier showers. Winds will be from the south/southwest 5 to 15 knots with localized higher gusts ahead of boundary. Winds shift to the north/northeast behind a cold front this evening and cigs will lower toward IFR by 04-06z at SLK/EFK/BTV and MPV. A 2 to 6 hour window of IFR cigs are possible at these sites with intervals of rain showers persisting, before conditions slowly improve toward 12z Saturday. Localized gusts 15 to 25 knots are possible late tonight into early Saturday morning from the north.

Outlook...

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

BTV WATCHES/WARNINGS/ADVISORIES

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