textproduct: Burlington

WHAT HAS CHANGED

As of 232 PM EDT Wednesday...

Confidence has increased in some localized, light mixed precipitation Thursday into Friday. Guidance has also increased wind gusts, potentially as high as 35-40 knots Thursday night and Friday.

KEY MESSAGES

As of 232 PM EDT Wednesday...

1. Light wintry precipitation and light icing are likely in the Adirondacks, the Greens, and east of the Greens Thursday into Friday. Slick travel conditions are possible, particularly during Thursday morning and evening commutes.

2. Active weather continues over the weekend as a series of fronts bring rain and gusty winds. While the weather will be active, no significant impacts are expected at this time.

DISCUSSION

As of 232 PM EDT Wednesday...

KEY MESSAGE 1: Shortwave troughing will track across the southern half of our forecast area tonight, bringing precipitation to southern and central Vermont early Thursday morning as winds aloft turn more southerly. As surface temperatures fall into the upper 20s to mid 30s, southern spots that get precipitation could see some very light wintry precipitation and light icing during the morning commute. During the day Thursday, a surface low pressure system will traverse from the Plains to the Great Lakes, allowing for some warm air advection and more widespread precipitation across northern New York and Vermont. Depending on how much surface cold air gets trapped east of the Greens and in cold pockets of the Adirondacks, icing may continue through Thursday night for some. Where temperatures warm into the upper 30s to lower 40s Thursday afternoon, rain will be the primary precipitation type. Then, Thursday night, temperatures are forecast to fall back into the 30s for most. Isolated ice accumulation may be as much as a quarter of an inch for higher elevations of the mountains. General precipitation amounts of around 0.10-0.50 inches are anticipated, so impacts to rivers should be minimal to none, however, winds will also increase Thursday night out of the south and continue into Friday, likely gusting as high as 35-40 knots for some. Widespread temperatures in the upper 50s and 60s on Friday will finally end the threat of wintry precip, though chances of rain showers will linger as a couple frontal boundaries cross the region. With all the warmth, moisture, and frontal forcing being projected for Friday, there could even be some rumbles of thunder out there.

KEY MESSAGE 2: A closed upper low barreling through the central US will drive the development of a deepening surface low Saturday. This low will become the focus for our next period of active weather. The low pressure system will lift through the Great Lakes Region into southeastern Canada Saturday night into Sunday, sending a series of fronts through the northeastern US. The passage of the warm front will occur sometime late Saturday into Saturday night. Some showers are possible as the warm front moves through. Developing southerly flow and warm air advection will allow Saturday's temperatures to climb to the mid 50s to mid 60s, so any initial showers that move through will be in the form of rain.

Within the warm sector of the system, a 50 to 60 knot southerly low level jet will develop. Forecast soundings showing a stout low-level inversion from the warm air advection, so the majority of this momentum will stay aloft. However, some areas will become windy overnight, especially where southerly channeled flow is favored. NBM wind probabilities are highlighting the northern Champlain Valley and higher elevations of the northern Greens and northern slopes of the Adirondacks as areas that will see the strongest overnight gusts (about 70% probability of seeing wind gusts in excess of 30 mph).

The timing of the passage of the cold front with the system will dictate whether or not we see any flooding threat towards the end of the weekend. Warm temperatures preceding the cold front will promote additional snowmelt in the few areas that still have snow. According to latest NOHRSC analysis, this is just the highest elevations of the northern Adirondacks, northern Greens, and the Northeast Kingdom. In addition to marginal snowmelt amounts feeding into waterways, any locally moderate or heavier rainfall would result in additional river rises. At this point, QPF amounts do not look concerning (NBM Mean 24 hour QPF in the quarter to half inch range). This is due to the progressive nature of the system/ relatively quick frontal passage. However, will have to watch thunderstorm potential, which could result in some locally briefly moderate intensity rainfall. It's worth noting the PW values will climb to over an inch (around 300% of normal for this time of year), however at this point instability looks minimal. The timing of the fronts and potential clearing/window for destabilization doesn't look to line up favorably for thunderstorms based on the deterministic ECMWF and GFS at this point. Overall taking all factors together, we are watching several aspects of this system, but at this point we are not seeing anything overly concerning from a hydro perspective. This is supported by NAEFS and GEFS based simulations for river level probabilities, which show rises on Sunday/Monday but show the most likely scenario is that all rivers stay below flood stage.

Once the cold front sweeps through, expect a quick transition to cooler conditions to start the next work week. Highs next week are forecast in the 40s, which is 5-10 degrees below normal for early April highs.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

Through 18Z Thursday...MVFR conditions currently prevail across terminals this afternoon, with gradual improvement towards VFR ceilings expected into this evening. All terminals are expected to have a period of VFR conditions overnight, with mostly dry conditions expected. After 15Z Thursday, increased moisture across the region will likely lead to another period of MVFR ceilings and increased chances for precipitation late in the TAF period and beyond. Winds continue to be north/northwesterly this afternoon, but are expected to trend light and variable overnight.

Outlook...

Thursday Night: Mainly MVFR, with areas VFR possible. Chance SHRA, Likely FZRA. Friday: MVFR/IFR conditions possible. Windy with gusts to 30 kt. Chance SHRA. Friday Night: Mainly VFR, with areas MVFR possible. NO SIG WX. Saturday: Mainly VFR, with local MVFR possible. Chance SHRA. Saturday Night: Mainly MVFR, with areas VFR possible. Likely SHRA. Sunday: MVFR/IFR conditions possible. Likely SHRA. Sunday Night: MVFR. Chance SHRA, Slight chance SHSN. Monday: Mainly VFR, with areas MVFR possible. NO SIG WX.

EQUIPMENT

The Colchester Reef meteorological station is out of service. This site is not serviced by the NWS. An estimated return to service is May 1st. Please contact us if you observe winds significantly deviating from the recreational forecast.

BTV WATCHES/WARNINGS/ADVISORIES

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