875
FXUS61 KBTV 200643
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
243 AM EDT Fri Mar 20 2026
.WHAT HAS CHANGED...
As of 242 AM EDT Friday...
Snowfall amounts have been lowered slightly across the region with
widespread 1-4 inches of snowfall now expected this afternoon.
&&
.KEY MESSAGES...
As of 242 AM EDT Friday...
1. Period of moderate to heavy rain and snow expected this
afternoon into early this evening.
2. Another clipper to bring a mix of rain and snow to the
region Sunday and Monday.
3. Unsettled weather continues next week with a series of
systems expected to move quickly through the region bringing periods
of lower elevation rain, higher elevation snow, and potentially
some mixed precipitation.
&&
.DISCUSSION...
As of 242 AM EDT Friday...
KEY MESSAGE 1: A compact clipper system is expected to move across the
region this afternoon through early this evening. Deterministic
guidance continues to be very aggressive in showing both high QPF and
high snowfall across much of the North Country and northern New
York. For example, the raw NAM believes 3-7 inches of snowfall is
likely across our entire CWA. However, with the increasing March sun
angle and boundary layer temperatures at or above freezing in all
locations, snowfall will likely struggle to initially accumulate. We
used a tool that uses the wet-bulb temperature to help determine
precipitation type as temperatures are expected to cool once we
start seeing the heavier precipitation this afternoon. There will
likely be a window of 2-4 hours of moderate to heavy precipitation
rates where snowfall rates in some locations could reach or exceed
1"/hour. These rates are most likely across northern Vermont where
temperatures will likely be below freezing the whole event.
The NBM wants to use snow ratios of 13:1 to 17:1 across our region
this afternoon which seems excessively high during March daylight
hours and marginal boundary layer temperatures so we made
significant reductions down to 8:1 to 12:1 (below climo normals).
This led to decreased snowfall amounts, generally in the 1-4" range,
but the higher elevations above 2000 ft across central and northern
Vermont and northern New York should still see 4-8" of snow. While
our forecast snow values seem on the lower end compared to some of
the high-res deterministic guidance, we are right around the 50th
percentile when comparing our values to the derived positive snow
depth change.
No changes will be made to the headlines even though forecast snow
values are generally below advisory criteria as the heaviest snow
could impact the afternoon school release and afternoon/evening
commute.
KEY MESSAGE 2: Another clipper will move across the region Sunday into
Monday although a significant amount of uncertainty remains in timing
and potential snowfall amounts. As mentioned last night, model runs
continue to flip flop with some showing a colder and all snow
solution while other have shifted south where we could potentially
miss out on any potential rain/snow. The ensemble consensus still
shows widespread precipitation this weekend and early next week with
precipitation type a huge question mark. Much like the storm system
we are expecting on Friday, snowfall amounts are expected to be
highly elevation dependent given marginal boundary layer
temperatures. Once again, the NBM was giving us snow ratios of 14:1
to 18:1 for this event so we lowered them back to the 10:1 to 12:1
range which gave us a more reasonable snowfall forecast. In general,
the valleys may see a dusting to 2 inches of snow with summits
possibly seeing 6-10" of snow. These amounts will likely change with
new model runs as models continue to struggle depicting the
evolution of this system. Should the low track south, we can cut
those amounts in half. Should the low track further north, we can
add a few inches to the forecast. We will continue to fine-tune this
forecast as it enters the temporal resolution of high-res guidance.
KEY MESSAGE 3: Mid range models continue to portray the region in the
base of a broad long wave trough with downstream flow remaining
unblocked. This pattern will favor rapid moving systems to move
through periodically. Tuesday will likely feature brief ridging
with the previous system ejecting northeastward before the next
trough approaches and moves through mid-week. Blended guidance seems
to be placing moderate chances of snow showers for overnight periods
while daytime chances become more elevation dependent rain/snow.
Individual models point to a weaker wave passing through suggesting
blended guidance may be too aggressive with chances of precipitation.
It seems probable that precipitation chances will be more terrain
focused rather than a swath moving through. Towards the end of the
week, another system is favored to move into the region bringing
similar challenges of trajectory and elevation dependent rain/snow
chances. As for temperatures, model signals point toward near
average conditions favoring above freezing daytime temperatures and
below freezing lows.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
Through 06Z Saturday...Currently VFR CIGS and VIS at all sites
except MVFR CIGS at SLK with 9SM in light snow. Radar imagery
and surface observations indicate light snow with VIS generally
between 4-6SM along a weakening surface cold front. Used some
PROB30 and TEMPO groups for a few hours to indicate the
potential for MVFR conditions with frontal passage with winds
shifting to northwest and becoming light after midnight. A band
of moderate snow with IFR/LIFR conditions is expected to impact
our TAF sites between 16Z and 22Z on Friday. Quickly lowering
visibilities and ceilings are expected with this snow, with some
mix with rain in the valley sites. As precip exits IFR CIGS will
linger thru 00z Saturday with northwest upslope winds of 4 to 8
knots.
Outlook...
Saturday: Mainly VFR, with local MVFR possible. Slight chance
SHSN.
Saturday Night: Mainly VFR, with local MVFR and IFR possible.
Likely SN.
Sunday: Mainly MVFR, with local IFR possible. Definite RA, Likely
SN.
Sunday Night: Mainly VFR, with areas MVFR and IFR possible.
Likely SN.
Monday: Mainly VFR, with areas MVFR possible. Chance SN.
Monday Night: Mainly VFR, with areas MVFR possible. Slight chance
SN.
Tuesday: VFR. Slight chance SN.
&&
.EQUIPMENT...
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...Winter Weather Advisory from 8 AM this morning to 11 PM EDT
this evening for VTZ003-004-006>008-016>018.
NY...Winter Weather Advisory from 8 AM this morning to 11 PM EDT
this evening for NYZ026-027-029>031-034-087.
&&
$$
WHAT HAS CHANGED...Clay
DISCUSSION...Boyd/Clay
AVIATION...Boyd
EQUIPMENT...NWS BTV
|
