textproduct: Burlington

WHAT HAS CHANGED

As of 242 AM EDT Monday...

No significant changes were made with this forecast package.

KEY MESSAGES

As of 242 AM EDT Monday...

1. A couple of rounds of light snow showers are expected for the start of the work week, along with much colder temperatures.

2. High pressure will bring dry weather and a warming trend for mid week.

3. Seasonable warmth and sunshine is likely over the weekend following a weaker variety cold front late Friday or Friday night.

DISCUSSION

As of 242 AM EDT Monday...

KEY MESSAGE 1: Broad cyclonic flow will persist through Tuesday as we remain on the southern periphery of a large scale upper trough. A few weak shortwaves and associated surface boundaries/troughs will rotate across our region as the main system slides by to our north. Although moisture will be somewhat limited, there will be just enough to produce a couple of rounds of light snow showers with each of these shortwaves/boundaries. The first of these is moving through early this morning, and indeed, scattered showers have blossomed across the region. Temperatures have cooled into the low to mid 30s in most spots, but even where it's still several degrees above freezing (ie 38F here at BTV airport), the dry air has allowed wet bulbing to occur; hence, precipitation has been falling mainly as snow, with perhaps some rain and/or sleet mixed in from time to time. A perusal of area webcams shows that little to no accumulation has occurred with these showers so far, but we do anticipate there could be a dusting to perhaps around half an inch through daybreak, perhaps locally around an inch, especially in higher elevations. Roads could be a little slick where snow is able to accumulate, so travelers may want to leave some extra time for their Monday morning commute.

Extent of additional shower activity is a bit more uncertain for the daylight hours today. Some of the hi-res guidance, in particular the HRRR, FV3, and to a lesser extent the NAM3, show isolated to scattered showers develop this afternoon as we remain under cold air advection. Moisture still looks meager, but there could be some enhancement from the Great Lakes. The latest HREF indicates 6-hrly probabilities of 20-50% of measurable snow today, mainly across the Adirondacks and northern Greens (50-80% above 2000 ft). Meanwhile, the NBM is much less generous, keeping precip chances below 20% areawide. The NBM often struggles in this sort of set up, so have gone ahead with slight chance/chance PoPs across the higher terrain this afternoon. Like we've seen so far this morning, any precipitation should fall mainly as snow due to wet-bulbing. With temperatures to top out in the mid 30s to low 40s though, any accumulation will be minimal and likely to melt as soon as the shower passes by.

A reinforcing shot of cold air spreads out of Canada tonight and Tuesday, dropping temperatures well below normal for early April. Any showers will dissipate once the sun sets, so anticipate a dry but chilly night in the teens and 20s. However, another round of snow showers is possible on Tuesday with another shortwave trough crossing overhead. Model solutions differ with this system as well. The NAM in particular shunts the upper shortwave further south, keeping the bulk of any precipitation south of our forecast area. This is an outlier for now, though did note some of the other guidance trended southward (but still remains north of the NAM solutions). Either way, west/southwest flow ahead of the incoming trough and surface front will allow for some lake enhanced moisture off Lake Ontario. Used a blend of deterministic guidance for PoPs on Tuesday, resulting in 20-30% north and 40-55% south. This seems reasonable given the uncertainty. Snow amounts would be light, an inch or two, at most. Tuesday will easily be the coldest day of the week with highs only in the 20s and 30s across much of the region. Tuesday night will be even colder as we see clearing skies and decreasing winds under building high pressure. Lows will be in the teens to around 20F.

KEY MESSAGE 2: High pressure will crest directly overhead Wednesday morning, then slide eastward and off the coast Wednesday night and Thursday. Wednesday will feature ample sunshine, along with light winds generally trending toward the south by late in the day. As a result, temperatures will be a good 10 degrees or more warmer than Tuesday. It'll still be a little below seasonal normal, but with the sunshine and light winds, highs in the 40s to near 50F should make for pretty pleasant day.

A warm front lifts across the region Wednesday night into Thursday, but with limited moisture, don't anticipate much beyond increasing clouds. Warm air advection will continue on breezy south winds; gusts of 20 to 25 mph are expected, locally higher in the Champlain Valley due to channeling. Most areas will warm into the 50s, with a few spots topping out around 60F.

KEY MESSAGE 3: There is strong multi-model consensus on a storm track next week that is farther west/north than this past week, which will support less impactful weather as low pressure tracks through northern portions of Quebec. As such, as it drags a cold front through the region, while clouds and some rain are expected on Friday and perhaps lingering into early Saturday, precipitation may be scattered and will tend to be light. Per the NBM QMD QPF product, there is about a 25% chance of little or no precipitation. The 48 hour mean rainfall looks reasonable for this type of event with rainfall in most places on the order of 0.1"-0.2" of an inch. Again, with this low track even if we yet again have a strong high pressure area to our east/northeast, there will not be nearly the type of wind fields we saw this past week in the warm sector. Per the useful ECMWF EFI, there is only a weak signal for in the eastern side of northern Lake Champlain, corresponding to likely gusty winds in the Thursday night to Friday morning timeframe.

Temperatures following the cold front over the weekend are relatively uncertain compared to Friday with typical differences in the degree of colder air filtering in and the return of milder air aloft as high pressure crosses the region from the west. Consensus right now shows Sunday should be the warmer of the two days, but both days appear to be in the realm of climatological normal. Regardless of subtle differences in the upper level pattern amongst model clusters, there is a trend from near normal 925 millibar temperatures to above normal on Sunday. A more aggressive warming scenario does bring these temperatures to about the 80th percentile by Sunday afternoon, supporting temperatures perhaps a few degrees above the current forecast, which already is on the higher side of the median of the blend.

AVIATION /12Z MONDAY THROUGH FRIDAY/

Through 12Z Tuesday...A mix of MVFR and VFR conditions will be present throughout the TAF period, although snow showers are resulting in instances of IFR visibilities at times. Ceilings will tend to be MVFR at MSS, EFK, and SLK. Following morning snow showers, more widespread snow showers will develop this afternoon with most sites likely to see at least temporary IFR conditions after 18Z and perhaps as late as 02Z before precipitation winds down. Overall the confidence in IFR snow is low for a given hour given the scattered nature of showers, but probability of occurrence has increased. West to northwest winds will be gusty around 20 to 25 knots for much of the period before diminishing between 22 to 00Z.

Outlook...

Tuesday: VFR. Chance SHSN. Tuesday Night: VFR. NO SIG WX. Wednesday: VFR. NO SIG WX. Wednesday Night: VFR. NO SIG WX. Thursday: VFR. NO SIG WX. Thursday Night: VFR. Chance RA. Friday: VFR. Chance RA.

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.