Johnson, VT Weather

What Has Changed

As of 248 AM EDT Wednesday...

No significant changes made.

Key Messages

As of 248 AM EDT Wednesday...

1. High pressure continues through Friday with increasing fire weather concerns on Thursday into Friday with slightly stronger winds and low humidity values.

2. Quiet weather continues into early next week with a cooling temperature trend.

Discussion

As of 248 AM EDT Wednesday...

KEY MESSAGE 1: GOES-19 mid level water vapor imagery shows deep dry layer overhead associated with mid/upper lvl ridge, while closed cyclonic circulations lingers off the mid Atlantic Coast. As sfc low pres moves slowly northward the pres gradient btwn low and high pres increases late Thurs into Friday, for a period of elevated winds. In addition, this wl help push a weak cold acrs our cwa on Thurs aftn, with slightly cooler temps on Friday.

Progged 925mb temps range btwn 8-10C this aftn, combined with plenty of sunshine supports highs mid 50s to lower 60s, very similar to Tuesday. Lows tonight wl be highly depend on elevation as a sharp llvl thermal inversion develops with poor rh recoveries possible acrs the mid-upper elevations within this thermal belt. Lows wl range from the mid 20s to mid/upper 30s with a sharp humidity range from excellent recoveries in the valleys to poor acrs the ridges. As the boundary approaches on Thurs, did note a slight increase in 925mb to 850mb moisture, along with a strengthening low level jet of 20 to 35 knots. Strongest winds appear to occur btwn 00z and 12z Friday, when mixing profiles are less favorable, but expect localized gusty winds on ridges and Lake Champlain. Once again with developing winds poor rh recoveries are possible, especially summit lvl on Friday morning with a large spread in temps anticipated. Friday is the coolest day of the week with highs upper 30s to lower 50s acrs our region, did utilize the max temp by elevation tool to highlight sharpening gradient btwn warmer valleys and cooler summits. Fire weather concerns increase Thursday aftn into Friday with slightly stronger surface winds, near critically dry humidities and recent dry spell resulting in receptive fine fuels, especially leaf litter. Winds and humidities look to fall short of red flag conditions, but we wl continue to monitor closely in the upcoming days ahead.

KEY MESSAGE 2: Surface high pressure will remain the dominant feature Sunday into Monday, leading to a continuation of quiet weather. Late Monday into Tuesday, a front will drop south out of Canada, though the frontal passage will once again be largely uneventful. A few isolated light showers or mountain flurries are possible as the front moves through, however lack of deep moisture will be a limiting factor for precipitation potential. Temperatures will trend downward behind the front, dropping to slightly below normal by midweek.

Aviation

Through 06Z Thursday...Clear skies and light winds will dominate over the next 24 hours with high pressure remaining in control. The one question will be which sites (if any) see fog development this morning. Best window will be between 09Z and 12Z, though conditions don't look overall super favorable given the dry air mass in place. The highest chances of fog/mist will be at KMSS, and less so at KSLK, where some tempo group for BR have been included in this TAF package. These sites are already at or below their crossover temperatures, with low dewpoint depressions as of latest observations. However, despite calm winds at the surface, winds increase just of the deck. This will keep the lower levels somewhat mixed, making it difficult for any persistent fog to develop.

Outlook...

Thursday: VFR. NO SIG WX. Thursday Night: VFR. NO SIG WX. Friday: VFR. NO SIG WX. Friday Night: VFR. NO SIG WX. Saturday: VFR. NO SIG WX. Saturday Night: VFR. NO SIG WX. Sunday: VFR. NO SIG WX.