textproduct: Burlington

WHAT HAS CHANGED

As of 830 AM EDT Wednesday...

The Frost Advisory has been cancelled.

KEY MESSAGES

As of 227 AM EDT Wednesday...

1. Dry weather with seasonable temperatures will continue through Friday, with areas of frost likely again tonight.

2. Uncertainty remains in the track of a coastal system this weekend and what, if any, impacts it will have on our area.

DISCUSSION

As of 227 AM EDT Wednesday...

KEY MESSAGE 1: Broad high pressure remains firmly in place across southern Quebec/Ontario, spreading over the international border and into northern New York/New England. This feature shows no sign of budging over the next few days, and confidence has increased that we now will stay dry through at least Friday. Mostly clear skies will persist through Thursday, along with light winds. Temperatures will remain seasonable, with highs mainly in the 60s and lows in the 30s to near 40F. There will be another round of frost away from Lake Champlain tonight, and expect subsequent shifts will issue another Frost Advisory for tonight.

Clouds start to increase Thursday night and Friday as low pressure off the Mid Atlantic coast attempts to force its way north toward coastal New England. Model guidance has come into better agreement in keeping any precipitation associated with this system shunted to our south through Friday, so no rain is expected in spite of the increasing cloud cover. Thursday will be a little warmer than the previous couple of days, with highs in the mid 60s to around 70F.

KEY MESSAGE 2: Models continue to exhibit differing solutions in how a coastal system will evolve as it meanders off the New England coast this weekend. Just how close to the coast it tracks is still uncertain, as is how far north and west its precipitation spreads inland. Given the strength of the high to our north and the extent of the dry air, it seems likely there will be a tight precipitation gradient on the northern/western side of the system, so small changes in track could result in significant changes in rain chances and amounts. There will also be a tightening pressure gradient over our area between the strengthening low and the high pressure anchored over southern Canada, so at the least expect winds to increase late this week and over the weekend, particularly over the higher terrain and down the Champlain Valley, where gusts of 25 to 35 mph look possible, likely higher at summit level.

One other potential impact from this system will be its effect on temperatures. With the very dry air currently in place, any rain that does hold together long enough to wrap back into our region would likely result in sharply cooler conditions; note that deterministic guidance lowers temperatures into the 50s where rain would be falling.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

Through 18Z Thursday...Aviation challenge is timing and areal coverage of fog and associated IFR or lower conditions. Currently VFR conditions prevail at all taf sites, but did not sfc dewpoints are 3 to 5 degrees lower this aftn, which will delay development of fog as it takes a bit longer to reach cross over values. Given the fog development last night and latest sounding data feel the highest probability of fog (80-90%) will be at EFK/MPV and SLK between 08z-13z. Similar to last night brief IFR is possible at MSS near sunrise on Thurs, and some Winooski River Valley fog could impact the north end of the runaway at BTV near sunrise. Otherwise northwest to northeast winds 4 to 8 knots become light east/southeast tonight, before shifting to the north again on Thursday.

Outlook...

Thursday: VFR. NO SIG WX. Thursday Night: VFR. NO SIG WX. Friday: VFR. NO SIG WX. Friday Night: VFR. Slight chance SHRA. Saturday: VFR. Chance SHRA. Saturday Night: Mainly VFR, with areas MVFR possible. Slight chance SHRA. Sunday: Mainly MVFR, with local VFR possible. Chance SHRA.

BTV WATCHES/WARNINGS/ADVISORIES

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