946
FXUS61 KBTV 270752
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
352 AM EDT Thu Jun 27 2024

.SYNOPSIS...
A cold front will continue to produce scattered showers this
morning across the region, before drier weather with increasing
amounts of sunshine returns by this afternoon. Temperatures
will only warm into the mid 60s to lower 70s with northwest
winds 5 to 15 mph. A cool and clear night with some patchy
valley fog is anticipated tonight, before a beautiful Friday is
expected with plenty of sunshine and comfortable temperatures.
Unsettled weather returns on Saturday afternoon into Sunday,
along with breezy south winds.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 320 AM EDT Thursday...Surface analysis places cold frnt
along the International Border this morning with scattered
showers along this boundary. As this front drops south this
morning, expect areas of scattered showers to prevail from
northern NY into central/northern VT, with greatest
concentration and highest qpf acrs the dacks into the northern
VT mtns. A relatively strong area of high pres for late June wl
continue to build southeast this aftn into Friday with much
cooler and drier air developing on brisk north/northwest winds
this aftn. As mixing develops this wl cause sfc dwpts to drop
back into the 40s with increasing amounts of sunshine this aftn.
As 1028mb high pres settles directly overhead by 12z Friday,
expect mostly clear skies tonight with light north winds under 5
knots. Given these conditions and recent rainfall, anticipate
some localized patchy fog, especially where cross over values
are reaches, such as the northern Dack valleys and parts of the
CT River Valley. Some uncertainty in fog/br coverage over
central/northern VT, due to gradient. Also, a cool night is
anticipated with lows mid 30s SLK to upper 40s/lower 50s CPV.
Would not be surprised to see some patchy frost near SLK. Friday
wl feature plenty of sunshine with just some fair wx cumulus
acrs the trrn with temps warming into the upper 60s to mid 70s
with very low humidity values.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 352 AM EDT Thursday...Changeable weather will continue.
The dry air mass will allow temperatures to cool quickly after
sunset Friday but lows will end up much milder than the previous
night as temperatures steady overnight. The air will be
modulated by warm air advection as high pressure moves to our
east. An unseasonably strong pressure gradient will develop as
said high pressure sits to our east and low pressure moves
northeastward near the central Great Lakes. This pattern will
promote increasingly strong southerly winds, especially in the
northern Champlain Valley due to channeling. Expect rough
conditions on Lake Champlain due to good mixing as air
temperatures aloft will be cooler than the lake water; several
hours of sustained 30 knot winds are likely on the broad lake.
Mean hourly wind gusts will tend to increase during the day and
peak in the late afternoon hours, with maximum values most
likely in the 40 to 45 MPH range in the northern slopes of the
Adirondacks, much of the Champlain Valley, and favored. There is
some uncertainty in the strength of the 850 millibar
southwesterly flow, however. The latest model blend shows 50 to
55 knots looks reasonable, higher than what global ensemble data
suggested. But there is also some more alarmingly strong winds
shown in the 00Z NAM12, which increases the jet to 65 knots and
shows the inversion height just above. At the very least, if you
are on the higher mountain summits, strong winds near 60 MPH
will be possible Saturday evening. The extent of gusty winds
will be dependent on how quickly rain showers overspread the
area. Generally chances of rain will be focused earlier in the
day in western areas, gradually expanding eastward across
Vermont by the evening hours, which will reduce the chances of
mixing down the stronger winds aloft.

The focus Saturday evening into the overnight will then turn to
heavy rainfall potential. At this time, excessive rainfall looks
unlikely but there are some things going for it such that a
marginal risk is reasonable. While lapse rates will tend to be
moist adiabatic such that thunderstorms are unlikely, the
atmosphere looks supportive of efficient, heavy rain processes.
Most parameters, save wind shear, are favorable for torrential
rain in any convection. However, elevated instability looks
limited such that thunderstorms are very unlikely through this
period. Any heavier elements also are unlikely to be training
over a single location as bulk shear vectors look west-
southwesterly, not parallel to the pre-frontal trough that will
be the focus for these showers. This trough will gradually slide
eastward, followed by another area of showers approaching ahead
of perhaps another pre-frontal trough. Given the messy pattern
and continued forcing for precipitation, have maintained chances
of showers areawide through the period. Under the continuous
southerly low level flow, temperatures will be steady and mild
Saturday night in the 60s. Rainfall amounts look to average 0.5"
to 0.75", although that will need to be refined moving forward.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 352 AM EDT Thursday...A moderately strong cold front will
pass through the region Sunday from the west. A blend of model
guidance suggests CAPE of 500 J/kg could develop ahead of this
boundary if it passes through late enough in the day; a morning
passage would put a damper on the instability. At this time,
have maintained a slight chance of thunder for all of northern
New York and Vermont for the afternoon. Following this system,
another period of refreshing air will arrive. Save an isolated
shower Monday morning associated with an upper trough swinging
through, the first half of next week looks stellar for outdoor
activities as anticyclonic flow dominates our weather. Wednesday
we will see more seasonable humidity return as southerly flow
develops, but chances for showers are low, especially east of
the Adirondacks.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
Through 06z Friday...Crntly VFR conditions at all sites except
MVFR cigs at SLK with periods of light rain showers. These
showers will slowly exit our terminal sites by 12z Thursday, but
as winds shift to the northwest expect some lowering cigs toward
MVFR at many sites. A period of blocked flow near sunrise could
produce localized IFR conditions at BTV for an hour or two, but
probability and confidence is too low attm to mention in TAF at
BTV. Otherwise, higher confidence of IFR CIGS associated with
upslope flow is expected at SLK, so have utilized tempo`s to
indicate this potential. Otherwise, CIGS become VFR with
clearing skies by 16z today with northwest winds 5 to 15 knots.
Tonight winds become light north/northwest under 5 knots with
some patchy fog possible toward 06z at SLK.

Outlook...

Friday: VFR. NO SIG WX.
Friday Night: VFR. NO SIG WX.
Saturday: Mainly VFR, with local MVFR possible. Likely SHRA,
Slight chance TSRA.
Saturday Night: Mainly MVFR, with local IFR possible. Definite
SHRA, Slight chance TSRA.
Sunday: MVFR/IFR conditions possible. Chance SHRA, Chance TSRA.
Sunday Night: VFR/MVFR conditions possible. Slight chance SHRA,
Slight chance TSRA.
Monday: VFR. Slight chance SHRA.

&&

.MARINE...
Unseasonably strong winds are expected on Saturday when a Lake
Wind Advisory will be needed for Lake Champlain. South winds
may exceed 25 knots by daybreak and will likely be above 30
knots on the broad lake at times during the day. Rough waves
will develop quickly. Wave heights on the broad lake and inland
sea may build into the 3 to 5 feet range Saturday morning.

&&

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

&&

$$
SYNOPSIS...Taber
NEAR TERM...Taber
SHORT TERM...Kutikoff
LONG TERM...Kutikoff
AVIATION...Taber
MARINE...Kutikoff