textproduct: Burlington

WHAT HAS CHANGED

As of 120 AM EST Monday...

The light snow showers this morning look on track. Concern for some light freezing drizzle for Tuesday morning has increased and could have impacts on the morning commute.

KEY MESSAGES

As of 120 AM EST Monday...

1. Light snow showers possible this morning.

2. Snow, rain, and freezing rain possible late tonight into Tuesday morning.

3. Snow likely to impact parts of northern New York and Vermont around midweek to late week, though uncertainty remains in regards to precipitation type and areal coverage.

4. Seasonable late week and weekend conditions expected with additional chances of precipitation.

DISCUSSION

As of 120 AM EST Monday...

KEY MESSAGE 1: A weak shortwave will interact with limited moisture this morning which should be sufficient to create some scattered light snow showers. Snowfall totals will be limited to a dusting to a few tenths of an inch, at most, but will coincide with the morning commute. This could create for some lower visibilities on area roadways and some slick conditions cannot be ruled out for roads that become snow covered. These showers will dissipate by mid- morning with above freezing temperatures and drier weather expected this afternoon.

KEY MESSAGE 2: It's beginning to look like tonight into Tuesday morning could be quite messy in terms of precipitation type. We expect scattered snow showers to move into the region around midnight. The thermal profiles at this time show a saturated DGZ but the DGZ itself is about 10,000 ft AGL which is going to be a significant factor as we head into Tuesday morning. As the overnight period progresses, we will start to see drier air work into the DGZ while the 10,000 ft below the DGZ will remain largely saturated. The concern is that as we lose the ice nuclei, we could see a transition from snow showers to freezing drizzle between 4 AM and 10 AM across portions of northern New York and Vermont. The period where surface temperatures are below freezing and an unsaturated DGZ coincide for any one location should only be 1-2 hours but could allow for freezing drizzle accumulations of a few hundreths of an inch to occur. If the timing is just right, it could coincide with the morning commute and lead to slick roadways. The good news, however, is that temperatures on Tuesday are expected to warm quickly into the upper 30s to lower 40s which will allow for any freezing rain that does fall to melt and no longer pose a threat to travel.

KEY MESSAGE 3: Wednesday and Thursday, a surface low pressure is expected to slide eastward across the Northeast with a frontal boundary moving through the region as an upper level low stretches across the Great Lakes. We'll also likely have high pressure blocking and dry air developing over eastern Canada, which could put northern New York and Vermont right on the line between dry weather and precipitation. The deterministic GFS continues to be the most aggressive with dry air across our region, keeping the low and its precipitation shunted just to our south. The deterministic ECMWF brings precipitation furthest north across the forecast area, while Canadian and NAM solutions fall in between at the moment. Precipitation type is also highly uncertain, though most models seem to agree that if precip does overcome dry air and reach into our forecast area, we'll be on the northern end of the system and see mostly snow. Occasional freezing rain, sleet, and rain are not out of the question, though as highs Wednesday and Thursday reach into the 30s and lows in the teens to lower 20s. At the moment, forecasting anywhere from 1 to 5 inches of snow with this system, though we urge you to stay tuned to subsequent forecasts in the coming days.

KEY MESSAGE 4: Temperatures will be near normal from late week likely into the weekend but still cold enough to support some winter precipitation. On Thursday, shortwave ridging builds behind midweek system discussed by Key Message 3. Late Friday through late Saturday- Saturday night, a more significant trough digging across the central U.S. and Great Lakes with a surface low moving across Great Lakes and eventually the northeast. Decent mid-upper level dynamics on the backside of the upper ridge with the approaching shortwave should allow for some decent lift and overrunning. The models still have a spread in the details of the evolution of this northern system and a southern stream system. Separate systems mean lighter QPF while merging (as suggested by some of the ensembles) would equal more QPF, especially in southern areas with temperatures profiles around 0 C.

AVIATION /12Z MONDAY THROUGH FRIDAY/

Through 12Z Tuesday...Light snow showers possible this morning. Snow, rain, and freezing rain possible late tonight into Tuesday morning. A weak shortwave will interact with limited moisture this morning which should be sufficient to create some scattered light snow showers. This could create for some lower visibilities on area runways and some slick conditions for runways that become snow covered. Winds this morning will be light and variable with a general southerly component. The snow showers will dissipate by mid- morning with above freezing temperatures and drier weather expected this afternoon with increasing winds (remaining below 10 knots though). Ceilings are also expected to be intermittently 2000-3000 feet above ground level at KSLK, possibly also at KPBG, KMPV, and KRUT, from around 14Z through at least 22Z Monday as moisture at this level appears to linger. Our next round of precipitation is expected to arrive around 03Z-07Z, most likely beginning as light snow showers. We'll also see ceilings return to 2000-3000 feet above ground level or lower around this time associated with the showers. Visibilities should quickly fall to 3-6 miles or lower. Beyond 12Z, drier air is expected to work into the portion of the atmosphere that needs to be saturated to produce snow. We could see a transition from snow showers to freezing drizzle during this period. More on this in future TAF issuances today.

Outlook...

Tuesday: Mainly MVFR, with areas IFR possible. Chance FZDZ, Chance SHSN, Slight chance SHRA. Tuesday Night: Mainly MVFR, with areas VFR possible. NO SIG WX. Wednesday: Mainly VFR, with local MVFR possible. Chance SN. Wednesday Night: VFR. Chance SN. Thursday: VFR. Slight chance SN. Thursday Night: VFR. NO SIG WX. Friday: VFR. Chance SN.

EQUIPMENT

The KMPV AWOS has suffered a communications failure. The issue has been diagnosed, but there is currently no estimated time of return to service. Terminal Aerodrome Forecasts will continue, but amendments to those forecasts will be suspended.

NOAA Weather Radio station WXM-44, transmitting from Mt. Ascutney, Vermont, on frequency 162.475 MHz is non- operational at this time. NWS technicians have diagnosed the problem, but repairs will likely not be able to occur for quite some time due to circumstances beyond our control. Therefore, the time of return to service is currently unknown. The following NOAA Weather Radio transmitters may be able to provide service during this outage: WWG 50 from Burke Mtn, VT at 162.425 MHz and WNG 546 from Hanover, NH at 162.525 MHz.

The Colchester Reef meteorological station is out of service. This site is not serviced by the NWS and there isn't an estimated return to service at present. Please contact us if you observe winds significantly deviating from the recreational forecast.

BTV WATCHES/WARNINGS/ADVISORIES

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