129
FXUS61 KBTV 292127
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
527 PM EDT Fri May 29 2026
.WHAT HAS CHANGED...
As of 247 PM EDT Friday...
Wind gusts have been increased for the northern St. Lawrence
Valley with recent guidance denoting stronger gusts near
Massena, NY. Rainfall amounts areawide have also been increased
slightly with recent trends.
&&
.KEY MESSAGES...
As of 247 PM EDT Friday...
1. Rounds of showers and mountain snow are expected through the
rest of today and into the weekend.
2. Gusty Winds are expected through the rest of the day today
into tomorrow, especially in the northern St. Lawrence Valley and
near mountain summits.
3. After some lingering shower potential Tuesday night, drier
conditions return with a warming trend from mid to late next week.
&&
.DISCUSSION...
As of 247 PM EDT Friday...
KEY MESSAGE 1: Widespread precipitation is beginning to overspread the
region this afternoon from the north as a surface low shifts south.
Upper level cyclonic flow associated with a blocked upper trough
over the Canadian Maritimes will to increased moisture with upper
level northwest flow. Surface precipitation today will come in two
waves with the initial wave currently along the International
Border. This initial round will be light with perhaps some virga as
surface relative humidities remain low. However, this round will
help saturate our air columns in time for the next convectively
driven round of showers. The second round will be diurnally driven
under the core of the low, and may contain some isolated rumbles of
thunder as steep lapse rates with strong cooling aloft lead to
modest instability. Some small graupel and perhaps small hail are
possible, but impacts will be minimal if any. This more convective
round will be closer to 6-8 PM this afternoon. Beyond sunset,
temperatures will fall to 10 degrees below normal with overnight
lows in the valleys near 40. More significant cold will be present
across the higher terrain of the Greens and Adirondacks with lows
falling to near freezing. With any shower activity, precipitation
above 4000 ft will see all snow with light accumulations to an inch
or two on the mountain summits. Wet bulbing and dynamic cooling
could bring a few flakes as far as elevations at 2000 to 2500 ft in
the Adirondacks and eastern Greens. Any hikers or recreators should
use extra caution if heading to the mountains as conditions will
rapidly deteriorate with elevation for those unprepared for winter
conditions.
More steady rain will follow behind for tonight as the surface low
becomes occluded and stalls over the region. Along the triple point
of the occlusion a coastal low will develop near Cape Cod with
reinforcing moisture and precipitation, focused in the Northeast
Kingdom and near the Connecticut River Valley. Steady light to
moderate rain will result through early tomorrow morning. The bulk
of the rain will taper off around sunrise to mid morning tomorrow.
Total rainfall amounts have increased with around an inch to an inch
and a quarter in the Northeast Kingdom, and a quarter to half an
inch elsewhere. Lesser amounts may be possible in the southern
Champlain Valley and St. Lawrence Valley due to shadowing and
further distance from the core of the moisture axis, respectively.
As the system departs, lingering moisture and cool air may lead to
patchy frost and some patchy fog primarily Saturday night in the
Northeast Kingdom and areas of the Connecticut River Valley.
Additional shower activity is expected Sunday as cyclonic flow keeps
the region moist with embedded shortwaves. Additional rainfall
amounts will be a few tenths. Temperatures however will begin to
moderate beginning Sunday as wider valleys will see mid to upper
60s, with some lingering low 60s for the higher terrain.
KEY MESSAGE 2: As a surface low begins to pass directly over the
region, a strengthening low level jet to 50 knots at 2000 ft will
shift south towards the St. Lawrence Valley this evening into
tonight. Geostrophic northeasterly winds aloft will be aligned with
the orientation of the St. Lawrence Valley which will enhance the
strength of any associated surface gusts. However, surface winds
will be more north to northwesterly, and not fully unidirectional
with the strongest gusts. This will help limit the full mixing of
the low level jet, though winds will still be gusty. Gusts near
Massena, NY are forecast to be around 40 to 45 MPH, with the
strongest winds occurring between Midnight and 5 AM tonight.
Elsewhere, winds are expected to be between 15 to 25 MPH. Higher
elevations above 2500 ft will also see stronger winds to 30 to 40
MPH which coupled with near freezing temperatures will lead to wind
chills in the Adirondacks and Greens in the teens to low 20s. Hikers
and recreators should plan for winter conditions if planning to be
in the higher terrain tonight or tomorrow. Winds will turn to the
north by tomorrow morning with channeled flow likely in the
Champlain Valley. A Lake Wind Advisory is likely to be needed by
sunrise tomorrow with winds gusting to 25 to 35 MPH on Lake
Champlain and the surrounding areas. As the system shifts out late
tomorrow afternoon, gusts and winds will trend towards calm for
Saturday night.
KEY MESSAGE 3: Model guidance is somewhat split on how much moisture
will wrap northwestward from an offshore low, but consensus favors
some isolated to scattered showers progressing into eastern Vermont
again by Tuesday night. Otherwise, ridging is favored to build
Wednesday through the end of the week promoting highs back around 80
degrees for many places by Thursday and Friday. The big questions
for next week into next weekend will be: how fast will the blocking
high actually move, and if it does, how much will the ridge axis
flatten? Blocking features usually move slower than model
projections, so we could see some showers potentially linger into
Wednesday, especially with warmth otherwise beginning to build.
Current guidance also points to an approaching wave on Friday, but
models tend to break down ridges too quickly while being too
progressive with migratory features at this time scale. It`s
possible that the ridge axis will hold into the beginning of next
weekend at least.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
Through 18Z Saturday...VFR conditions will continue through the
afternoon until the next wave rolls into northern New York and
Vermont 00-06Z. Likely see CIGs dip to MVFR, then IFR for most
terminals after 06Z. LLWS will also be a concern for aviators with a
low level jet moving through this evening, then as more pronounced
backside northwesterly flow increases aloft with the passage of the
upper low and surface cold front. Conditions favored to slowly
improve after 12Z with northerly winds increasing; gusts in excess
of 25kts will be possible 12-18Z on Saturday.
Outlook...
Saturday Night: VFR. NO SIG WX.
Sunday: VFR. Chance SHRA, Slight chance TSRA.
Sunday Night: Mainly VFR, with local MVFR possible. Chance SHRA.
Monday: Mainly VFR, with local MVFR possible. Likely SHRA, Slight
chance TSRA.
Monday Night: VFR. Slight chance SHRA.
Tuesday: VFR. Chance SHRA.
Tuesday Night: VFR. Slight chance SHRA.
Wednesday: VFR. Slight chance SHRA.
&&
.MARINE...
A Lake Wind Advisory is in effect for all Lake Champlain. A band
of showers and storms is approaching, and winds ahead and behind
this convection will likely drive winds upwards to 15 to 25
knots, with gusts 30 knots likely. After activity has moved
south, winds may briefly calm, but then are expected to increase
after midnight as north winds begin channeling down the valley.
Waves 1-2 feet will increase towards 2-4 feet, especially when
more sustained flow is established overnight into Saturday
morning.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
WHAT HAS CHANGED...Danzig
DISCUSSION...Danzig/Boyd
AVIATION...Boyd
MARINE...Haynes
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