137
FXUS61 KBTV 111906
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
306 PM EDT Mon May 11 2026
.WHAT HAS CHANGED...
As of 305 PM EDT Monday...
A Freeze Warning has been issued for the St. Lawrence Valley in
northern New York and in Vermont for areas outside the
Champlain Valley and Northeast Kingdom from midnight tonight to
9 AM tomorrow morning. A Frost Advisory has been issued from 2
AM to 9 AM tonight for the Champlain Valley of northern New York
and Vermont, except Grand Isle County in Vermont.
&&
.KEY MESSAGES...
As of 305 PM EDT Monday...
1. Seasonably cool and mainly dry with frost and sub freezing
conditions tonight.
2. Widespread rainfall expected Wednesday with unsettled
weather continuing through the late week.
3. Cool, showery conditions will persist late this week into
the weekend before warming up early next week.
&&
.DISCUSSION...
As of 305 PM EDT Monday...
KEY MESSAGE 1: As isolated to scattered shower and clouds wain after
the loss of diurnal heating this evening, skies are expected to
clear out as an area of high pressure noses in from the west.
Clearing is expected to be more widespread than last night, where
many locations reached frost temperature thresholds, with better
confidence in widespread frost and freeze conditions areawide
tonight. Temperatures are expected to fall at or just below the
freezing mark in the St. Lawrence Valley and areas in Vermont
outside the Champlain Valley and Northeast Kingdom. Locations near
the St. Lawrence and Connecticut Rivers may not quite reach the
freezing mark, but are still expected to be within frost temperature
thresholds, however, most of the aforementioned areas will be at
risk of reaching freeze conditions. As such a Freeze Warning has
been issued for the aforementioned locations from midnight tonight
to 9 AM tomorrow morning. In the Champlain Valley of northern New
York and Vermont, a Frost Advisory is in effect from midnight
tonight to 9 AM tomorrow morning as temperatures are expected to
reach 33 to 36 degrees. Similarly, locations near Lake Champlain,
including the city of Burlington and Plattsburgh, may not
necessarily reach frost advisory thresholds due to the proximity to
the lake which will help moderate temperatures. Moreover, Grand Isle
County in Vermont, due to the moderation of the lake is not expected
to see frost tonight. However, further inland towards the mountains
and cold hollows of the valley, it is expected that frost thresholds
will be met.
Tuesday will be very similar to today, though with more clear skies
as high pressure moves overhead. Relative humidities will once again
lower towards the 30-40% range, perhaps 25-30% in the Upper Valley
of the Connecticut River. However, fire weather concerns will be low
due to a lack of prevailing winds aloft to mix down to the surface,
with light winds expected tomorrow. Temperatures tomorrow will be
into the low to mid 50s. As high pressure drifts east tomorrow
night, additional frost is possible, though it will be tied to
mainly eastern Vermont as cloud cover move sin from the west ahead
of our next storm system mid week. How fast the cloud cover increase
Tuesday night may limit frost development, but this will be more
refined in the next one to two forecast packages.
KEY MESSAGE 2: Into Wednesday and Thursday, there is an increasing
chance for widespread wetting rainfall. Strong ridging across the
western CONUS will trend our flow pattern towards troughiness with
an upper level low still in place across the Hudson Bay. A
developing upper level trough will shift east displacing the early
week ridging ushering in warmer and more moist air. Rainfall is
expected to overspread the region Wednesday from southwest to
northeast as a warm front lifts through. Good upper level diffluence
associated with the trailing edge of a jet streak will help maximize
precipitation rates with seasonable PWATs to 0.75-1 inch. Rainfall
totals, at this time are forecast to be highest across southern
Vermont and the St. Lawrence and Adirondacks in New York where a
quarter to half an inch is possible. Further north into central and
northern Vermont and near the International Border, lower rainfall
amounts to a tenth to quarter is possible. A strengthening low level
jet on the leading edge of the overarching long wave trough may
allow for a faster frontal passage in addition to shredding of
clouds which could limit the maximum possible rainfall from the
system. Moreover, this jet may lead to a downsloping scenario for
the western slopes of the Greens and northwestern slopes of the
Adirondacks from southeasterly winds. Model soundings show a steep
inversion near mountain summit levels with top of the mixed layer
denoting the potential for 30 to 40 mph wind gusts along the western
facing slopes of the Greens and northwestern slopes of the
Adirondacks. The trouble with the mixing will be the ongoing
precipitation and how much can actually mix down.
The precipitation shield associated with the warm front becomes more
scattered into Wednesday evening as an associated cold front will
move across the southern portions of our area. Depending on how much
clearing from parcel stretching can occur, some instability may
develop across St. Lawrence County before daytime heating ceases
with the potential for a rumble of thunder or two. The overall system
looks to evolve into an upper low as it becomes cutoff over eastern
New England into Thursday. A resurgence of wrap around moisture as
the system deepens and pivots about New England will lead to further
rain chances through the day Thursday with an additional quarter to
half an inch across southern and eastern Vermont. Trends in the hi
res models that go out that far have been towards a deformation band
that sets up somewhere across southeastern Vermont Thursday which
could lead to some enhancement in rainfall amounts across the
aforementioned region. No flooding concerns are expected at this
time due to lower stream flows and recent detachment from previous
rains. Unsettled weather looks to continue into the long term
forecast.
KEY MESSAGE 3: Surface low pressure looks to linger on the New England
Coast Thursday night as upper level low pressure rotates across
southern New England. This will keep the potential for showers
across much of Vermont and parts of northern New York overnight (65-
85% PoPs) and also during the day on Friday (50-70% PoPs) as the
upper low drifts slightly east and the surface low lifts north into
Maine. By Friday night, vertically stacked low pressure will finally
make a bigger move into the Canadian maritimes and surface ridging
will attempt to replace it, lowering PoPs to around 10-30%. The
lingering moisture and showers will keep temperatures below seasonal
averages with highs mid 50s to lower 60s and lows in the 40s.
Another shortwave looks to speed into the region over the weekend,
keeping precipitation potential around 20-40% into early next week
with perhaps a brief drier period Sunday night into Monday morning.
Overall any precip this weekend and early next week would be more on-
and-off showery and no one day seems to be a total washout, though
things could change as we get closer. This should allow temperatures
to rise to near or above seasonal normals with highs in the mid 60s
and 70s and lows in the 40s to mid 50s. Depending on how much
warming we can get early next week, temperatures in southern Vermont
could even approach 80 F.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
Through 18Z Tuesday...Mostly dry today and Tuesday. VFR conditions
are expected to prevail over the next 24 hours with perhaps 20-40%
chance of the odd shower now through 22Z Monday that could lower
visibilities to 4-6 miles and/or lower ceilings to 2500-3000 feet
above ground level. Breezy conditions are being observed this
afternoon with winds out of the west-northwest and gusts 10-20
knots. PBG differs from the other sites with a more light and
variable wind this afternoon, and MSS is seeing more of a valley-
channeled southwesterly flow. Winds this evening will taper off
towards 00Z Tuesday, with several sites expected to go calm and
others maintaining a light (3-6 knots) northwesterly wind, except in
RUT, where a light southeasterly drainage flow will reign. There
remains some potential for SLK to get some fog tonight as winds go
calm and skies clear, but it`s still tricky to say for sure due to
dry air (afternoon dew points observed in the lower 20s). If SLK
gets a rain shower this afternoon/evening, this could increase their
chances of fog tonight. Tuesday during the day, winds are expected
to pick up again out of the northwest with isolated to scattered
gusts 15-20 knots possible. The exception to this would be PBG,
which may develop a northeasterly wind off Lake Champlain instead.
Outlook...
Tuesday Night: VFR. NO SIG WX.
Wednesday: Mainly VFR, with areas MVFR possible. Definite SHRA.
Wednesday Night: Mainly MVFR, with local VFR possible. Definite
SHRA.
Thursday: Mainly MVFR, with local IFR possible. Definite SHRA.
Thursday Night: Mainly MVFR, with areas IFR possible. Chance
SHRA.
Friday: Mainly IFR, with areas MVFR possible. Chance SHRA.
Friday Night: Mainly IFR, with areas MVFR possible. Slight chance
SHRA.
Saturday: Mainly VFR, with local IFR possible. Chance SHRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Freeze Warning from midnight tonight to 9 AM EDT Tuesday for
VTZ006-008-010-011-016>021.
Frost Advisory from midnight tonight to 9 AM EDT Tuesday for
VTZ002-005-009.
NY...Freeze Warning from midnight tonight to 9 AM EDT Tuesday for
NYZ026-027-087.
Frost Advisory from midnight tonight to 9 AM EDT Tuesday for
NYZ028-035.
&&
$$
WHAT HAS CHANGED...Danzig
DISCUSSION...Danzig/Storm
AVIATION...Storm
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