textproduct: Burlington

WHAT HAS CHANGED

As of 312 PM EDT Sunday...

No significant changes made with this forecast package.

KEY MESSAGES

As of 312 PM EDT Sunday...

1. Developing gusty winds with showers overnight into Monday.

2. Additional chances for showers and thunderstorms are expected on Tuesday and Wednesday with much above normal temperatures.

3. Warm and unsettled weather to continue late next week into the weekend.

DISCUSSION

As of 312 PM EDT Sunday...

KEY MESSAGE 1: Mid/upper lvl analysis shows mid/upper lvl ridge acrs the SE CONUS, with deep sub-tropical moisture advection on backside over the central/southern Plains. GOES-19 mid lvl water imagery shows deeper moisture advecting into northern NY along a strengthening warm frontal boundary. This boundary is expected to become stationary near the International Border as fast westerly flow aloft prevails on northern periphery of ridge. Sfc dwpts in the upper teens to lower 20s has resulted in rh values in the mid 20s to mid 30s this aftn, while initial surge of rain is dissipating or falling as virga. Eventually saturation of all layers of the atmosphere occurs this evening with a period of warm frontal rain showers expected. Maybe a few high elevation wet snow flakes as Whiteface is only 28F attm. Rainfall amounts generally a 0.10 to 0.25" with some locally higher amounts mtns and lighter amounts downslope shadowing areas.

A strengthening 850mb jet of 50 to 65 knots develops acrs northern NY toward 06z, while strongest core passes just northwest of the SLV. The strongest 925mb winds of 45 to 50 knots are expected over the SLV into northern Dacks, while lighter winds are progged over eastern and southern VT tonight into Monday. As always, the challenge wl be amount of mixing given rain and cooler bl temps, but as inversion strengthens and helps to enhance channeled flow, expect localized gusts 35 to 45 mph possible northern CPV and northern slopes of the Dacks. Strongest winds will be along Route 11 corridor from Malone to Altona btwn midnight and noon. Much lighter winds are anticipated in the deeper/protected valleys of central/eastern VT. Temps wl cool initially this evening, but should warm after midnight, especially downslope areas of the northern Dacks. Additional showers are likely on Monday afternoon and evening as s/w energy and moisture crosses our cwa. Localized heavy downpours possible as pw values surge above 1.25".

KEY MESSAGE 2: Forecast challenge on Tues and Weds is position of boundary and impacts on temps/instability acrs our cwa. Latest guidance shows very little agreement or confidence in position of sharp north to south boundary acrs our region, which wl be focus for additional showers and thunderstorms. Given fast westerly flow aloft some convective debris clouds and a messy warm sector is likely, with best instability located over central NY. However, if more sfc heating/instability develops than progged, especially on Tues aftn, wind profiles are favorable for rotating storms with some organization possible. There is a non zero or conditional threat for strong to locally severe storms. The 0 to 6 km deep layer shear is 40 to 60 knots, while 0-1KM SRH is 150-300 m^2/S^2, while 0-3KM SRH is >400, but question is on the amount of instability, especially with lingering boundary and potential for clouds. In addition, timing of embedded s/w energy in the fast flow aloft looks a little unfavorable with first wave moving thru around 12z Tues, with secondary energy after 00z Weds. Each wave of energy is expected to have at least a round of showers with embedded rumbles of thunder. The strong to severe potential wl be driven on how much sfc heating/instability can develop. On Weds, a large difference is noted in progged position of boundary, with NAM having us well into the warm sector with 925mb temps of 21C, while GFS is 12C with north winds. Thinking convective outflow on Tues, could act to push boundary south on Weds, resulting a cooler/more stable solution. However, confidence is low in any particular solution attm. It does seem localized heavy rainfall is possible within any convection, especially with pw values approaching 1.50" or 2 to 3 STD above normal on Tues into Weds. Always have to watch for training convection and the potential for flash flooding with a stationary boundary nearby.

KEY MESSAGE 3: An active weather pattern will continue through the end of this upcoming week into next weekend. Upper level high pressure will remain situated across the southeastern US which will leave us on the periphery of the mid-level ridging. Multiple disturbances are expected to push through the region Thursday and Friday which will help push a series of frontal passages through the North Country. This will lead to period of rain showers, with possibly a few rumbles of thunder, into to the weekend. Temperatures will remain a good bit above seasonal normals with highs climbing into the 70s both Thursday and Friday. The upper level ridge will begin to build northward early in the weekend and allow for even warmer temperatures and moisture to advect northward. A cold front will then pass through the region later in the weekend and a bring a return to a cooler and more seasonal air mass. Deterministic guidance varies on the timing of the actual frontal passage as the building mid-level heights across the eastern US may slow the front down. Rainfall amounts late this week and into the weekend appear to range between 0.5 to 0.75 inches so even with an extended period of wet weather, no significant weather is expected at this time.

AVIATION /00Z MONDAY THROUGH FRIDAY/

Through 00Z Tuesday...Light rain is shifting east across the region while a warm front briefly stalls across the area. Increasing southwesterly flow will cause the boundary to shift northeast of the international border in 3 to 6 hours and take precipitation with it. Rain may briefly reduce visibility to 4-6SM and some 2500-3000 ft agl ceilngs will be possible. Increasing southeast to southwesterly winds are expected behind the front, and winds aloft will also increase such that LLWS is mentioned at all TAFs. Precipitation will scatter within somewhat drier air and fast flow aloft. Skies may partially clear as well. However, by 15z-18z, another batch of rain will shift east. Winds will also begin to make a southwest shift with ceilings lowering towards 2000-4000 ft agl.

Outlook...

Monday Night: Mainly VFR, with areas MVFR possible. Chance SHRA. Tuesday: Mainly VFR, with areas MVFR possible. Windy with gusts to 30 kt. Likely SHRA, Chance TSRA. Tuesday Night: MVFR/IFR conditions possible. Chance SHRA, Chance TSRA. Wednesday: Mainly MVFR, with local IFR possible. Likely SHRA, Slight chance TSRA. Wednesday Night: MVFR. Likely SHRA. Thursday: Mainly MVFR, with local IFR possible. Likely SHRA, Slight chance TSRA. Thursday Night: MVFR/IFR conditions possible. Chance SHRA. Friday: Mainly MVFR, with areas IFR possible. Slight chance SHRA.

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.