textproduct: Burlington

SYNOPSIS

Brisk conditions will continue this morning with cold apparent temperatures below zero degrees for most locations. A few snow showers will continue mainly for upslope areas over the next few days with a weak system moving through this weekend bringing some light snow accumulations. Unseasonably cool temperatures are expected to trend back towards seasonal averages by the middle of next week.

NEAR TERM /THROUGH SATURDAY NIGHT/

As of 201 PM EST Friday...Cold temperatures remain the primary weather concern with highs and lows running below seasonal averages. With some light breezes anticipated overnight minimum apparent temperatures will be quite cold outside the Champlain and Connecticut River valleys, feeling like minus 10F and lower tonight. Otherwise, cyclonic flow will promote and a subtle trough will provide enough forcing for some sparse showers overnight into early tomorrow. A more pronounced trough is highly favored to move through Saturday night leading to some scattered snow showers, but moisture will be sharply limited resulting in totals generally less and 1 inch and relegated to higher terrain and St Lawrence County where some Lake Ontario moisture becomes entrained into flow. Otherwise, this will be a fairly inconsequential trough.

SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/

As of 201 PM EST Friday...Isolated showers are favored to linger over the northern Greens into Sunday before dry air scours out low level moisture. This will set the stage for another strong radiational cooling event Sunday night that will drop low temperatures sharply for the region. Portions of the Adirondacks, Green Mountains, and northern New York could see some wind chill values -20 or lower while other locations could range -10 to -15. It will depend on whether or not we maintain some winds; even a light drainage wind of 5 mph or so would be problematic with ambient temperatures below -10F. The Champlain Valley and southern Vermont will be less susceptible to these temperatures, but expected conditions bear continued scrutiny.

LONG TERM /MONDAY THROUGH FRIDAY/

As of 201 PM EST Friday...

* Compared to the previous forecast, precipitation timing is a bit faster: more likely Tuesday night and less likely Wednesday, especially afternoon.

* A wintry mix of precipitation types remains on the table midweek. Further warming is expected late in the week, with potentially an impactful rain event for next Friday.

One last well below normal temperature day for awhile is still on track for Monday. The latest run of the ECMWF Extreme Forecast Index, while slightly less impressive than the previous one, shows unusually low maximum temperatures in our region. An exception would be the western Adirondacks into southern St. Lawrence Valley, where the air mass should moderate sooner as winds turn southerly; low level (925 millibar) temperatures by evening will approach climatological normals (30-40th percentile) in these areas, contrasting with Vermont at largely near the 20th percentile. Increasing clouds will also help limit warming following a frigid start to the day. Most likely high temperatures will be in the upper single digits to mid teens for most locations.

A minor snow event still looks on track for Monday night, but details remain unclear given the weak forcing and latitudinal differences in the shortwave responsible for the precipitation. With the uncertainty in timing/location, light snow still is in the chance category rather than likely for any given location. A more robust low pressure area, though still not particularly strong, will follow for later Tuesday into Wednesday. Again, model spread is fairly large and actually the consensus has shifted a touch colder/farther south with the system. There is still hope for mainly snow rather than rain as probabilities are roughly equal for much of the region. That being said, a primary low pressure system tracking to our northwest still is most likely, which would lead to a wintry mix of precipitation types. Obviously the track of this system will ultimately determine the precipitation details, but amounts should be light to moderate, associated with a system of Pacific origin that does not tap into additional moisture from the Gulf or Atlantic. 90th percentile NBM QMD data shows reasonable higher end totals only about 0.3-0.5", but since even light snow and ice could be meaningful for the Wednesday morning commute timeframe, this will be a period to watch.

Then to end the week, large scale signals for hydrological impacts, in a combination of snow melt and rainfall, are present but not particularly impressive - we aren't looking at a high end event at this time. The timeframe begins next Friday but should continue into the weekend as flow finally amplifies, with a large ridge developing over the eastern US. Generally, precipitation chances for Friday are lower than for the midweek system, but among the ensemble members/model output that show rainfall, heavier precipitation is favored for at least portions of the region. A more meridional flow pattern will support a moist environment; per latest NAEFS mean climatological percentiles, unseasonably high values of PWAT, southwesterly oriented integrated vapor transport (IVT), and specific humidity up to the 500 millibar level, can be expected. The aforementioned 90th percentile data shows a maximum 24 hour period with precipitation amounts mainly in the 0.5-1" range, with wettest guidance in the 1.5"-2" range (about twice that of the midweek event). As an example of the possible river responses, the latest run of the GEFS for Center Rutland shows a large range, but the median forecast depicts a sharp rise beginning Friday morning. The statistics suggest a categorical low chance of reaching action stage on Friday, but continued rises over the weekend lead to a 50% chance of reaching action stage during the period, along with less than 5% chance of reaching minor flood stage.

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/

Through 00Z Sunday...VFR conditions are in place with light west winds and weak high pressure. While high pressure will largely continue, a subtle, moisture-starved front will continue to sink southward through the evening. It should cause winds to become more consistently northerly/northwesterly through overnight and the remainder of the period, but mixing will tend to be limited such that winds remain light. There likely will be enough moisture available for a period of light snow, especially at SLK and EFK and less likely at sites like BTV, PBG, and MPV. Greatest chances of MVFR conditions would be between 03Z and 07Z associated with the clouds and light snow. The increased winds aloft associated with the front, while not enough to be concerned with LLWS, should also prevent any fog formation.

Outlook...

Saturday Night: Mainly VFR, with local MVFR possible. Slight chance SHSN. Sunday: Mainly VFR, with local MVFR possible. NO SIG WX. Sunday Night: VFR. NO SIG WX. Monday: VFR. Slight chance SN. Monday Night: Mainly VFR, with local MVFR possible. Chance SN. Tuesday: Mainly MVFR, with areas VFR possible. Slight chance SN. Tuesday Night: Mainly MVFR, with local IFR possible. Chance SN, Chance RA. Wednesday: Mainly MVFR, with local IFR possible. Chance RA, Chance SN.

EQUIPMENT

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. Use extra caution when navigating the broad waters of Lake Champlain. Please contact us if you observe winds significantly deviating from the recreational forecast.

BTV WATCHES/WARNINGS/ADVISORIES

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