textproduct: Burlington

WHAT HAS CHANGED

Extended the Red Flag Warning until midnight for the Champlain Valley fire weather zones.

KEY MESSAGES

As of 100 PM EDT Tuesday...

1. Critical fire weather conditions continue until midnight for portions of the Champlain Valley.

2. A period of widespread rainfall is expected Wednesday evening into Thursday, along with cooler temperatures, bringing fire weather concerns to an end.

3. Unsettled and cooler conditions are expected to linger through the weekend into early next week.

DISCUSSION

As of 700 PM EDT Tuesday...

KEY MESSAGE 1: Given the wildfire near Middlebury, VT has grown from just a few acres to near 37 acres per local reports and the potential for increasing winds associated with a nocturnal low level jet, I have extended the Red Flag Warning until midnight for the Champlain Valley fire weather zones. Current conditions show humidities in the 23% to 30% as recovery has been slow with good mixing here in the Champlain Valley as temperatures hold near 70F. Sounding data indicates a strengthening low level inversion this evening, but increasing southerly winds at the top of the mixed layer between 25 and 35 knots. The strongest wind gust potential will be between 9 PM and Midnight, where localized gusts 25 to 30 mph will be possible, especially away from the cooler Lake Champlain waters, which includes the Middlebury area. Some localized higher gusts are possible along the western slopes of the Green Mountains in favorable southeast downslope areas too thru this evening. Conditions should improve after midnight as humidities continue to increase and winds slacken. Otherwise, no other changes made to the fcst attm.

KEY MESSAGE 2: Rain moves into the St Lawrence Valley and Adirondacks Wednesday afternoon, and into Vermont Wednesday evening. It will taper off from west to east Thursday afternoon into evening. Can't rule out a few storms especially in southern portions of the area, but threat is very limited. Rain however looks moderate to locally heavy at times, and totals areawide will be in the range of 0.75 to 1.25 inches. No flooding is expected. As the precipitation trails off Thursday into Thursday night, it could change to snow over the higher summits, but accumulations look very light.

KEY MESSAGE 3: An upper level trough will remain over our region from Friday through Monday. This will bring us cooler than normal temperatures and several chances for light rain or snow showers. Snow showers will be possible mainly for elevations above 2000 feet. No significant accumulations, but a fresh coating of an inch or so of snow from time to time can be expected. Highs are favored to be in the mid 40s to mid 50s, and lows in the 30s except 20s at higher elevations. Perhaps a warmup finally toward Tuesday/Wednesday, but confidence is low.

One thing to note is that the climatological start to the growing season in the Champlain Valley begins May 1st (this Friday) when we expect overnight lows to be near Frost Advisory criteria (32-36F) both Friday night and lesser so Saturday night. Cloud cover may limit the overall cooling that takes place, but conditions may be favorable for frost development. We will monitor this in the coming days.

AVIATION /14Z TUESDAY THROUGH SATURDAY/

Through 18Z Wednesday...Gusty south winds through the rest of this afternoon, with winds becoming a bit lighter from 0z onward tonight, but not tapering off entirely. VFR this afternoon into tonight. MSS likely to developing an MVFR cig around 3K AGL around 5z tonight, which should persist into 12-18z Wed. SLK could get an MVFR cig too, but going for just above MVFR cig in TAF starting 9z.

Outlook...

Wednesday Night: Mainly VFR, with local IFR possible. Definite SHRA. Thursday: Mainly MVFR, with local IFR possible. Likely SHRA. Thursday Night: Mainly MVFR, with areas VFR possible. Chance SHRA. Friday: Mainly VFR, with local MVFR possible. Chance SHRA. Friday Night: Mainly VFR, with local MVFR possible. Slight chance SHRA. Saturday: VFR. Chance SHRA. Saturday Night: VFR. Slight chance SHRA. Sunday: Mainly VFR, with areas MVFR possible. Chance SHRA.

BTV WATCHES/WARNINGS/ADVISORIES

VT...Red Flag Warning until midnight EDT tonight for VTZ030. NY...Red Flag Warning until midnight EDT tonight for NYZ205.