textproduct: Burlington

WHAT HAS CHANGED

As of 216 AM EST Thursday...

No significant changes.

KEY MESSAGES

As of 216 AM EST Thursday...

1. Showers will be widespread through early afternoon, and then more scattered towards evening when a rumble of thunder is possible.

2. Some additional showers are expected over the weekend as temperatures gradually return closer to normal.

3. Somewhat unsettled weather is expected for much of next week.

DISCUSSION

As of 216 AM EST Thursday...

KEY MESSAGE 1: Anomalous moisture, with PWAT more than 200% of normal, and likely near record for the date per Albany, NY sounding climatology, will be present today as a slug of showers slides northeastward across the region this morning. Despite this impressive moisture and very warm air in place, rainfall looks meager as forcing for ascent is weak given a lagging shortwave trough and lack of frontogenesis. That said, low to mid-level lapse rates look to be sufficient for some instability and brief downpours in some of the showers, especially towards midday which helps southern and eastern portions of Vermont have better odds of these heavier showers. Think these will be brief such that total rainfall amounts in a given hour will at most be about 0.25" and mainly up to 0.1".

After this swath of showers and deep moisture exits to our east, partial clearing will support some warm season type of heating and skinny CAPE profiles that bring us a non-zero chance of thunderstorms towards evening. HRRR/RRFS guidance has been consistent in showing a broken line of showers forming in northern New York and gradually translating eastward with increasing MUCAPE, progged to reach about 200-300 J/kg. Chances of thunder in the calibrated REFS data is surprisingly high in far northern Vermont (around 30-40%) based on this CAPE. Greatest chances of a rumble of thunder appears to be during the mid- afternoon near Route 11 in northern New York and then during the evening in eastern Franklin County in Vermont. Most of the remainder of the night, aside from this possible cluster of showers exiting to the east, will be dry and mild. Much of Friday continues to look dry and unseasonably warm despite being a bit cooler than today.

KEY MESSAGE 2: We continue to expect an unsettled weather pattern for the weekend, as a closed upper level low ambles eastward from the eastern Great Lakes Friday night into the Gulf of Maine by Sunday afternoon. Its slow movement will provide a prolonged period of shower chances across the region, but it remains hard to pinpoint where/when rain showers will pivot across a particular location. Generally Saturday afternoon through Saturday night looks like the timeframe where showers should be most abundant over northern New York and Vermont given the proximity of this system, and the track will favor southern portions of our region with regards to rainfall amounts.

While a big soaking rain is not expected, a wetting rainfall of 0.25" through the weekend has increased a bit to a 50-65% chance, while rainfall in excess of 1" is now about 10-15%, except 20-25% in portions of western Vermont in the Winooski and Mad River Valleys and the western Adirondack region. With the expected low pressure track, we also should see some increasing northerly flow towards late Saturday but there isn't much cold air to advect in. Most guidance shows 850 millibar temperatures too warm for snow, but at this point have indicated marginally cold conditions for some snow to mix in with the rain at our higher elevations in New York before precipitation ends given uncertainty in the upper level low track/strength.

KEY MESSAGE 3: Although there remains differences in model solutions, overall we look to remain under cyclonic flow for much of next week. The GFS does try to build ridging in briefly for Mon/Mon night, but this is not supported by either the ECMWF or CMC deterministic solutions, which have multiple shortwaves rotating around upper low pressure centered to our north. Timing of these differ as well, so while there will likely be some dry days, have stayed with WPC/NBM PoPs which give chances for showers through much of the week, especially over the higher terrain. Highs in the 40s/50s mean showers should be rain during the day, but overnight lows near or below freezing could allow rain to mix with/change over to snow overnight, especially in the mountains.

AVIATION /12Z THURSDAY THROUGH MONDAY/

Through 12Z Friday...VFR conditions early in the period will give way to MVFR as rain showers spread from west to east. The bulk of the precipitation will occur through roughly 18z Thu, with scattered showers to persist through 00z Fri. Visibility generally 5-6SM in any rain, with ceilings lowering to 1500-2500 ft during the daylight hours. There could be some improvement after 00z, but generally anticipate MVFR conditions to prevail much of the night. South winds will remain gusty at KBTV through much of the period. Elsewhere, S/SE winds will remain less than 8 kt through early this morning, then becoming gusty to 18 kt after 14z. Gusts will abate after sunset with winds trending more toward S/SW. A 30+ kt LLJ will bring periods of LLWS through 18z, particularly at KRUT/KSLK/KMPV.

Outlook...

Friday: VFR. Slight chance SHRA. Friday Night: Mainly VFR, with local IFR possible. Slight chance SHRA. Saturday: Mainly MVFR, with local IFR possible. Chance SHRA. Saturday Night: Mainly MVFR, with local IFR possible. Chance SHRA. Sunday: Mainly MVFR, with local IFR possible. Chance SHRA. Sunday Night: Mainly VFR, with local MVFR possible. Chance SHRA, Chance SHSN. Monday: Mainly VFR, with areas MVFR possible. Slight chance SHRA.

MARINE

A Lake Wind Advisory is in effect for today on the broad lake. South winds currently are likely 20 to 30 knots, expected to peak early this morning prior to rain arriving. After a lull during the rain, winds will likely pick up again for a few hours, likely after 2 PM and before 7 PM, when winds could occasionally be near 25 knots. Waves will tend to be 2 to 4 feet during the period.

CLIMATE

As of 216 AM EST Thursday...

Following records set on Wednesday, a high minimum temperature is possible at BTV today.

Forecast: 58 Record: 60 in 2022

BTV WATCHES/WARNINGS/ADVISORIES

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