textproduct: Burlington

WHAT HAS CHANGED

As of 236 AM EDT Monday...

PoPs have been increased for this afternoon with a secondary cold boundary passage.

KEY MESSAGES

As of 236 AM EDT Monday...

1. A strong cold front will continue to move through the area this morning with a secondary boundary by the afternoon. Showers will taper off by the mid afternoon, with gusty winds continuing.

2. Frost potential remains on track Tuesday night, mainly for portions of eastern and southern Vermont. Temperatures moderate back to near normal by midweek.

3. Seasonable conditions for the latter half of the week with periodic showers.

DISCUSSION

As of 236 AM EDT Monday...

KEY MESSAGE 1: A strong cold front continues to push east through the area with a well-defined corridor of showers on radar stretching from Chazy, NY to Wanakena, NY as of 2 AM this morning. This area of light to locally moderate rain is expected to weaken as it approaches Vermont this morning though some isolated to scattered showers remain likely through the morning hours for the Champlain Valley into northern Vermont. A gap in precipitation is expected to follow before additional isolated shower chances return by the early afternoon. CAM solutions have denoted an increasing chance for a secondary shortwave to develop by the late morning with additional shower chances. This feature is already taking shape with showers across Lake Huron. It should be noted that model soundings show a shallow area of 100-200J/kg of CAPE associated with this secondary boundary, albeit still well below the equilibrium level. We did see a few rumbles of thunder associated with the current boundary as it entered our region from eastern Ontario, and the showers across Lake Huron did also have a rumble of thunder or two. With this, the environment would support an isolated rumble of thunder, though the confidence of a rumble or two occurring in any given location is low. However, showers, mainly in central and southern Vermont do have the chance for an isolated rumble of thunder. Any showers today, regardless of thunder, will not be impactful. Stratocumulus will likely blanket the area today with strong caa from the northwest.

Gusty winds will continue with mixing profiles extending potential to 12,000 ft agl. Top of the mixed layer flow around 40 kts with bottom of the mixed layer around 20 knots would be supportive of valley winds between 25-30 MPH, especially in the wider valleys of the area, including on Lake Champlain. A Lake Wind Advisory will continue throughout the entire day today; see Marine section for additional details. Mountain summits, areas along US-11 in northern New York, and locations on the east downwind side of the Adirondacks could see gusts between 30-40 MPH as efficient mixing this afternoon takes place. Minor impacts may be possible with trees still leafed out, though winds are unlikely to produce any impacts warranting a Wind Advisory. Winds will remain gusty into Monday night with temperature falling behind the front this evening.

KEY MESSAGE 2: Conditions will turn cold behind the early week cold front today. Strong northwest flow will advect seasonably cold Canadian air into the area beginning tonight through Wednesday morning. A Canadian high will build into the region Monday night with drying and some clearing conditions, mainly for the wider valleys of northern New York and Vermont. Cyclonic flow will likely keep some mountain wave clouds and stratocumulus lingering across the Northeast Kingdom. Lows will dip into the low to mid 30s for majority of the area, with some pocket upper 20s in the Adirondacks. Gusty westerly winds around 15-20 MPH will continue Monday night as our upper low pulls off to the northeast. These winds should mitigate frost for many locations, though innately chilly cold advection will bring many locations to near freezing, stifling any agricultural interests. The Canadian high will move overhead Tuesday with chilly conditions remaining as highs will only be in the upper 40s to low 50s. Main impacts Tuesday will be the potential for a dewpoint bomb. Strong northwesterly cold advection, coupled with a stout dry layer between 925-700mb and good mixing profiles in the low levels of the atmosphere will create conditions for dewpoints to fall rapidly in the afternoon. Expect dry conditions Tuesday afternoon with the lip balm handy.

Winds will trend calmer Tuesday night, with a better shot at more areawide frost and freezing temperatures. With light winds and clearer skies, radiational cooling should be strong enough to push many into the upper 20s to low 30s, with frost potential for the central and southern Champlain Valley. The broad waters of Lake Champlain and increasing south flow by Wednesday morning should limit any frost potential. As winds turn to the south Wednesday morning, gusty channeled flow will return as our next weather pattern arrives for the later week. Gusts around 25 MPH will be possible in the Champlain Valley with another Lake Wind Advisory for Lake Champlain likely. Temperatures will begin to rebound with highs returning to the 60s Wednesday afternoon, with a generally nice day expected otherwise.

KEY MESSAGE 3: A brief 500mb ridge wedged between two upper lows sets up for the day on Wednesday, as surface high pressure ambles offshore. This will produce nice weather conditions, followed by increasing clouds and some showers over northern New York later in the day. Deep southwest flow will moderate temperatures closer to seasonal norms in the 60s during the day, and then a warm night in the 40s.

A broad, and relatively weak, upper low will set up over James Bay by Wednesday night with a mature cyclone festering across northern Quebec Province. It won't send any significant systems our way, but periodic troughs rounding the southern periphery of this cyclone will bring waves of showers and maintain cool to seasonable conditions until the feature departs the area on Saturday. Once it does, ensemble guidance suggests a broad ridge developing over much of the CONUS and a solid 1030mb surface high over the Mid-Atlantic that should dry us out and start warming up.

AVIATION /06Z MONDAY THROUGH FRIDAY/

Through 06Z Tuesday...A sharp cold front is moving east across the northern New York, producing some visibility reductions, down to 2SM at KMSS at 04z, within convectively enhanced showers. As the feature approaches Vermont, it is expected to slowly decay, and then exit east around 12-13z. A west wind shift will take place behind it, along with a gradually increasing period of winds and some patchy MVFR ceilings. Brisk west-northwest flow will result in 12-17 knots surface winds with gusts 20-27 knots, mainly 15z-23z. Some scattered showers are expected to redevelop during the afternoon behind the feature, and there are PROB30s noted for that potential. Winds decrease overnight, but likely remaining around 5-10 knots out of the west to northwest.

Outlook...

Tuesday: VFR. NO SIG WX. Tuesday Night: VFR. Patchy frost. Wednesday: VFR. NO SIG WX. Wednesday Night: VFR. Slight chance SHRA. Thursday: VFR. Chance SHRA. Thursday Night: VFR. Slight chance SHRA. Friday: Mainly VFR, with local MVFR possible. Chance SHRA.

MARINE

As of 236 AM EDT Monday...

A Lake Wind Advisory remains in effect for the entirety of Lake Champlain. South winds this morning will continue to be around 25 kts sustained with gusts up to 30-35 kts, leading to wave heights between 2 to 4 feet. Winds will somewhat weaken after day break as the wind direction turns to the northwest. Sustained winds will lower to 20 to 25 kts by the afternoon, however, a boundary will slide through the area concurrently, leading to renewed gusts between 25-30 kts and wave heights remaining 2 to 4 feet. With the northwest flow wave funneling may occur with locally higher waves between 4 to 5 feet near the mouth Shelburne Bay and the east side of the Broad Waters towards Burlington Bay. While there will likely be a period between sunrise and the late morning where winds may be below Lake Wind Advisory thresholds, with gusts continuing to be strong by the afternoon, the Advisory will continue through the day today.

BTV WATCHES/WARNINGS/ADVISORIES

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