000
FXUS61 KBTV 101425
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
1025 AM EDT Wed Apr 10 2024

.SYNOPSIS...
Scattered to numerous showers and possibly a few rumbles of thunder
are expected this morning through this afternoon. A more potent
storm system moves into the region Thursday night and Friday
bringing periods of moderate, further river rises, and gusty winds.
Showers remain possible heading into the weekend while temperatures
remain at, or slightly above, seasonal averages.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 1022 AM EDT Wednesday...Main tweak was to PoPs. As
expected, some scattered showers are developing along an area of
convergence along Route 11, but we`ve also had a batch of
showers develop across Rutland and Windsor Counties. Otherwise,
everything is on track for scattered showers and a few rumbles
of thunder possible. Also knocked down winds on Lake Champlain,
as with rain showers, conditions should be fairly stable across
the lake and latest guidance and observations suggests more in
the 10 to 20 knot range than the near 30 knots indicated
earlier.

Previous Discussion...A decaying boundary becomes stationary
and continues to be the focal point for rain and 10-20% chance
of a thunderstorm this morning through this afternoon. Shear
developing over the boundary has kept overnight showers and a
few thunderstorms ongoing. As temperatures begin to warm after
sunrise, relative low level instability could aid in
invigorating isolated thunderstorms across the Adirondacks
eastward into the Green Mountains. Mesoscale models have
increased moisture across this boundary for the late
afternoon/evening hours, so precipitation amounts have been
increased; still, less than 0.5" for the day though. Should a
thunderstorm get going this afternoon, there is about a 10%
chance of associated heavy rainfall that could push localized
totals closer to 1". Temperatures will be cooler than yesterday
given the cloud cover and rainfall, but still above seasonal
averages in the 50s to low 60s

Cloudy conditions will prevail overnight while forcing decreases
allowing for a lull in precipitation. Temperatures will remain mild,
staying in the 40s. Rain chances increase once again Thursday as a
warm front for the next system moves through the North Country.
Model trends continue to deflect the maturing low northwest of the
region into a less favorable position to stall the warm front over
the North Country. As such, QPF with the warm front will be limited
to amounts less than 0.25" for most spots and less than 0.5" for the
Adirondacks. Southeast winds will be rising through the day as a
strong pressure gradient moves into the region supporting afternoon
gusts above 20 mph and to around 30 mph for downslope spots on the
northwest flanks of the Adirondacks and west slopes of the Green
Mountains.

Snowmelt continues allowing for continued river rises with higher
flows each subsequent day so far. The added rainfall coincident with
peak melt reaching rivers could cause some spots, like the Barton
River at Coventry, to briefly reach action stage overnight
tonight before subsiding by Thursday morning. Remember, our
rivers are running fast and cold, it`s best to keep your
distance from them.

&&

.SHORT TERM /THURSDAY NIGHT/...
As of 409 AM EDT Wednesday...The active weather continues into
Thursday night with the main concerns being gusty overnight winds
and some scattered moderate to briefly heavy rain showers. During
the overnight hours, our forecast area will be solidly within the
warm sector of the cyclone, when precipitable water values and the
low-level jet will be at their peak of the event. Looking at winds
first...60 to 70 knot southerly low-level jet will move directly
overhead between Thursday evening and Friday morning. Within the
strong warm air advection regime, always difficult to forecast how
much of the low-level jet momentum aloft will mix down to the
surface given the inversion in the low- levels. Based on current
guidance, forecasting overnight gusts in the 25 to 35 mph range for
much of the area, strongest within breaks in precipitation.
However, the orientation of the southerly jet will be more favorable
for stronger downslope wind gusts along the northern slopes of the
Adirondacks and northern Green Mountains, where gusts in the 35 to
45+ mph range area expected.

As far as overnight precipitation goes...expect some waves of
moderately to heavy rain showers. Given the strong southerly jet,
terrain will play a large factor in rainfall amounts, with southern
and southeastern slopes expected to see the highest overnight
amounts (between 0.3 and 0.7 inches). Meanwhile, the northern
Adirondacks into the northern Champlain Valley and portions of the
Northeast Kingdom will be more rain shadowed overnight, and should
expect just a few tenths of overnight rainfall.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 409 AM EDT Wednesday...As the surface low pressure system lifts
northeastward from Ontario in Quebec, the cyclone will push a cold
front through our forecast area during the day on Friday. Expect a
line of rain showers along the front with potentially some embedded
thunderstorms. Progged surface based instability is meager but non-
zero, and will depend on degree of clearing Friday morning. If
there is a break in cloud cover before the front moves through,
expect a slight uptick in destabilization. However, if the front
moves through in the morning hours with ample cloud cover ahead,
thunderstorm threat would be minimal. Good news is by the time the
cold front moves through, the 60+ knot low-level jet will have
cleared to our east, so any gusts within convective showers or
thunderstorms would be capped around 20 to 30 mph.

With regards to the flooding potential for late week, a combination
of snowmelt and rain will result in rivers and streams running high.
Warm temperatures with relatively high dewpoints coupled with windy
conditions will quickly eat away at the snowpack Thursday and
Friday. The good news is that storm total rain amounts look less
impressive than they did a few days ago. Current forecast is for
0.5 to 1.0 inch of rain to fall in most areas between Thursday and
Friday, with some isolated higher amounts possible in favorable
upslope areas. In addition, expect some breaks in between waves of
precipitation, which will lessen the impact of the rain on the area
streams and rivers. Ensemble river forecast guidance depicts the
25th to 75th percentile range for our rivers below minor flood
stage, but we will be watching rivers closely leading up to and
throughout the event as they will be approaching bankfull. In
addition, if any thunderstorms do materialize, some localized
ponding on roads may occur. Any areas that see multiple rounds of
moderate to heavy rainfall throughout the event could see some
localized flash flooding, but chances of this are decreasing as our
QPF amounts lower.

Scattered lighter showers will continue into Saturday behind the
front, mainly along and around northern slopes of higher terrain.
Conditions are drier for Sunday, but additional shower chances
resume early next week as additional northern stream shortwave
energy dives down into the broader cyclonic flow. Temperatures will
run slightly above normal through the long term.

&&

.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
Through 12Z Thursday...Scattered to numerous showers are
exiting Vermont this morning with some clearing evident on
satellite. This clearing will allow for more showers to form as
an area of forcing moves along the stationary boundary draped
across the North Country. Scattered to numerous showers are
expected to reform as early as 14Z depending on morning warming
trends and will track west to east. Heavier shower elements will
be possible and could briefly lower CIGS/VIS to IFR if they
track over terminals. Isolated convection cannot be ruled out,
but chances are around 15-20% for 14-20Z period. VFR CIGs will
otherwise lower this afternoon to MVFR with increasing/lowering
clouds. LLWS should occur at all the terminals this morning,
before stronger winds mix down to the surface as the day
progresses and reduces the shear. Wind gusts up to 20-25 KTS
possible at any terminal during the day Wednesday. After 00Z,
shower chances likely end with continued MVFR CIGs for most
terminals. MSS may clear out after 06Z presenting chances for
morning fog.

Outlook...

Thursday: Mainly VFR, with local IFR possible. Likely RA.
Thursday Night: Mainly MVFR, with local IFR possible. Windy with
gusts to 30 kt. Definite RA.
Friday: Mainly MVFR, with areas VFR possible. Windy with gusts to
30 kt. Definite SHRA, Definite RA, Slight chance TSRA.
Friday Night: Mainly VFR, with areas MVFR possible. Likely SHRA.
Saturday: Mainly MVFR, with local IFR possible. Likely SHRA.
Saturday Night: Mainly MVFR, with local VFR possible. Chance
SHRA.
Sunday: Mainly VFR, with areas MVFR possible. Slight chance SHRA.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.

&&

$$
SYNOPSIS...Boyd
NEAR TERM...Boyd/Haynes
SHORT TERM...Duell
LONG TERM...Duell
AVIATION...Boyd