textproduct: Burlington

WHAT HAS CHANGED

As of 250 AM EDT Wednesday...

No significant changes.

KEY MESSAGES

As of 250 AM EDT Wednesday...

1. Trending showery and cooler heading into the end of the week.

2. Unsettled with below normal temperatures on Sunday into early next week.

DISCUSSION

As of 250 AM EDT Wednesday...

KEY MESSAGE 1: A cold front comes through today and it will begin a trend of gradually cooling temperatures, with them reaching their nadir on Saturday. The front will come through without fanfare and mostly dry conditions will prevail through Thursday night, though a few isolated showers are expected Thursday. A deep upper-level low moves through Friday night into Saturday, bringing anomalously cold air for the time of year. Its passage will cause widespread showers due to the forcing and instability caused by the cold air aloft. Snow levels will likely drop below summit levels, though any snow showers should remain in the mountains. There is still some model uncertainty on the time of the passage of the core of the low and associated showers. A GEFS/CMC/EPS ensemble mean brings the lowest temperatures aloft late Friday night and early Saturday morning, but some guidance like the GFS brings it through Friday evening. Saturday will likely be showery and cool, though there is the possibility of an earlier passage that keeps Saturday mostly dry, a bit warmer and with some clearing in the afternoon.

KEY MESSAGE 2: The large scale pattern continues to indicate a highly amplified omega block acrs the CONUS, which is relatively stable with minimal change. Always challenging to predict when this omega blocking pattern breaks down and the associated change in wx. For Sunday, additional northern stream s/w energy and pocket of mid lvl moisture wl cross acrs our cwa, with more showers and a few embedded rumbles of thunder possible. GFS sounding data shows 200-400 J/kg with highest values over northern NY, along with steepening low to mid lvl lapse rates from sfc heating and cool pool aloft. This is not a severe setup, just a few shallow convective cells capable of a rumble or two of lightning. Highs on Sunday mostly in the 60s with high 35 to 50% probability of precip.

Mid/upper lvl trof prevails acrs the NE CONUS for early next week with additional threat for showers. Difficult to time individual s/w's and placement of deepest moisture, but given general troughiness, pattern looks unsettled. In addition, the lack of sfc heating and northern flow wl suppress best instability well south of our cwa thru midweek, so probability of any strong or severe weather is very low thru mid week. Progged 925mb temps warm a couple degrees by Monday, supporting highs in the mid 60s to lower 70s. By midweek progged 925mb temps warm btwn 12-15C, supporting highs back into the 70s to near 80F with increasing potential for sunshine as Central Plains ridge slowly builds eastward toward our cwa. Lows generally in the mid 40s to mid 50s through the midweek of next week with comfortable humidity values.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

Through 12Z Thursday...A weak cold front is near the International Border this morning and will continue to drop south. This will switch our winds to the north-northwest at 5 to 15 knots this morning. Multiple layer of mid/upper level clouds will continue to impact our TAF sites through this evening with some lowering toward MVFR conditions possible at SLK/EFK. Otherwise VFR conditions are anticipated for the next 12 to 24 hours.

Outlook...

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

BTV WATCHES/WARNINGS/ADVISORIES

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