954
FXUS61 KBTV 051736
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
136 PM EDT Tue May 5 2026
.WHAT HAS CHANGED...
As of 455 AM EDT Tuesday...
Quick update to increase pops this morning, adjust temps, and
winds grids. Radar imagery showing greater areal coverage of
showers/embedded rumbles than original expected over northern
NY.
Issued Wind Advisory for portions of northern NY. Also, added
gusty wind wording associated with thunderstorm potential this
afternoon.
&&
.KEY MESSAGES...
As of 254 AM EDT Tuesday...
1. Gusty southwest winds expected today, especially across
northern NY. A few stronger thunderstorms possible this
afternoon with localized gusty winds as the primary threat,
along with frequent lightning.
2. A widespread 1 to 2 inches of rain expected between today
and Wednesday evening across our region, but threat for flooding
is low.
3. Unsettled weather with cooler temperatures this weekend into
early next week.
&&
.DISCUSSION...
As of 254 AM EDT Tuesday...
KEY MESSAGE 1: A Wind Advisory has been issued from 15Z to 00Z
today for gusty southwest winds 15 to 30 mph with gusts up to 50
mph for portions of northern NY. Latest 00z NAM/HRRR and RAP
sounding data all suggests very favorable mixing profiles up to
750mb today, resulting in localized gusty southwest winds,
especially across portions of northern NY, where progged 925mb
to 700mb winds are the strongest. NAM12KM and NAM3KM soundings
show favorable mixing under warming bl temps, with top of the
mixed layer winds of 45 to 55 knots, while bottom values are in
the 35 to 45 knot range, supporting localized gusts 40 to 50 mph
possible. The core of strongest winds wl be from OGS to MSS,
then angling along the northern downslope areas of the Dacks
from Malone to Altona from roughly noon to 5 PM. Soundings
suggest favorable dry adiabatic mixing profiles with 0-3km lapse
rates in the 8-9 C/km range. Also, the timing of clouds/precip
is important toward the amount of llvl instability/mixing, as
earlier arrival limits sfc heating and depth of mixing and would
support lighter winds per GFS solution. Elsewhere, winds 10 to
25 mph with gusts 25 to 40 mph is expected over the CPV and
parts of central/eastern VT.
Have coordinated with SPC this morning with regards to
maintaining the new Day 1 Marginal Risk (1 out of 5) acrs our
cwa this aftn. Little has changed with regards to our thinking,
as latest GOES-19 mid lvl water vapor imagery shows a rather
messy upstream scenario. Mid/upper lvl trof conts to deepen over
the northern Great Lakes, while modest heights falls are
occurring over the eastern Great Lakes associated with initial
700-500mb embedded vort and pre- frontal sfc trof. Meanwhile,
have noted multiple pockets of convection and plenty of
clouds/moisture in the developing warm sector under deep
southwest flow from the SLV into the northern Ohio Valley. The
challenging aspect with regards to convection this aftn is how
much does the upstream convective debris cloud canopy hinder bl
layer heating/instability from developing. Latest 00z CAMs
suggest ML CAPE values in the 500-1000 J/kg range, but as mixing
improves during the early aftn hours, sfc dwpts could drop back
into the upper 40s. Sounding profiles are very impressive with
steep sfc to 3km lapse rates in the 8-9 C/km range, supporting
higher based convective capable of localized gusty winds within
mini bowing line segments. Also, noted unidirectional wind
profiles through 500mb and more straight lined hodographs today,
which is confirmed with area VAD profiles, suggesting bowing
line segments as primary convective mode. Still concerned
developing deep layer shear near 50 knots and modest CAPE
profiles may shear higher/stronger convective tops apart,
minimizing severe potential. If greater clearing develops and
instability can approach 1500-1800 J/kg, the probability of
stronger/more robust updrafts and severe threat increases acrs
our cwa this aftn. Its pretty much a nowcasting scenario, in
monitoring latest clearing/heating/instability trends and
evolution of upstream convection today.
KEY MESSAGE 2: Numerous showers and embedded thunderstorms this
aftn evolve into a widespread stratiform rain event late
tonight into Weds acrs our cwa. 00z guidance continues to
support a widespread 1 to 2 inches of rainfall by Weds evening
acrs our cwa. This wl be driven off synoptic scale lift, from
tightening low level thermal boundary and developing weak area
of low pres lifting along boundary on Weds. Most of our cwa is
progged to be on the cool/north side of this system, with
limited instability and rainfall rates in the 0.10 to 0.25 inch
per hour range. The strong llvl convergence, combined with a sw
to ne axis of enhanced 850mb to 700mb fgen forcing, should
produce enough synoptic ascent to support this moderate rainfall
event. Current guidance suggests heaviest axis of rainfall wl
be from the central Dacks into central VT, where some localized
values in the mountains could exceed 2.0". Given the anticipated
rates and long duration event, no river or flash flooding is
expected with this event. A cold raw and wet Wednesday is
predicted with highs only in the mid 40s to mid 50s, maybe lower
60s near VSF. Steadier rainfall slowly tapers off by late Weds
night with some areas of fog/low clouds likely into Thurs
morning.
KEY MESSAGE 3: The general unsettled weather pattern will
continue into the long term. This is due to broad
troughing/cyclonic flow that will remain anchored over eastern
Canada. As multiple shortwaves round the base of the trough and
transit over our forecast area, we can expect off and on periods
of rain over the weekend and into early next week. Temperatures
will stay slightly below seasonal norms, but will be warm
enough to support rain as the dominant precipitation type in all
but the highest elevations. Overnight low temperatures may
support some frost development this weekend (depending on
evolution of cloud cover and overnight winds), especially
Saturday morning in the northern Adirondacks and eastern
Vermont. However, the Champlain Valley is the only area within
our forecast area of responsibility that has started the
"growing season" as per our frost-freeze program, and conditions
there will remain warm enough to preclude a frost threat. Thus
at this point headlines are not anticipated, but keep an extra
eye on the late week/weekend forecast if you have sensitive
vegetation.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Through 18Z Wednesday...The greatest aviation concerns are
gusty winds and potential for thunderstorms this afternoon.
Southerly winds continue to gust between 20 and 35 kts,
occasionally 40 kts at MSS. Areas of low level wind shear
continue to be possible this afternoon. Scattered showers and
thunderstorms are expected through about 22z this afternoon.
Localized strong and gusty outflow winds are possible, along
with areas of enhanced turbulence and shear, especially near any
convection. Visibilities could drop into the 2-4SM briefly in
the heavier convection, while ceilings would be in the MVFR
range. Additional rain develops toward 06z with lowering
ceilings to MVFR conditions by sunrise on Wed, along with winds
shifting to the northwest.
Outlook...
Wednesday Night: Mainly VFR, with local MVFR possible. Chance
SHRA.
Thursday: VFR. NO SIG WX.
Thursday Night: VFR. NO SIG WX.
Friday: VFR. Slight chance SHRA.
Friday Night: VFR. Slight chance SHRA.
Saturday: Mainly VFR, with local MVFR possible. Chance SHRA.
Saturday Night: VFR. Chance SHRA.
Sunday: Mainly VFR, with local MVFR possible. Chance SHRA.
&&
.MARINE...
Southerly winds 10 to 15 knots are slowly increasing this
morning and should be 15 to 25 knots by sunrise with a few
higher gusts possible this morning, before subsiding back into
the 10 to 20 knot range by this afternoon. Wave 1 to 2 feet
build 2 to 4 feet this morning, before decreasing by sunset this
evening.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...Wind Advisory until 8 PM EDT this evening for NYZ026>028-030-
031-034-087.
&&
$$
WHAT HAS CHANGED...Taber
DISCUSSION...Duell/Taber
AVIATION...Neiles
MARINE...NWS BTV
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