732
FXUS61 KBTV 170554
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
154 AM EDT Sat Aug 17 2024

.SYNOPSIS...
Hazy conditions will persist through this evening as we continue to
remain under the influence of wildfire smoke. Rain chances will
increase late tonight across the St Lawrence Valley, spreading
eastward into the daylight hours Saturday as an upper level trough
slowly crosses the Great Lakes. Unsettled weather is expected
through early next week as the trough moves eastward, peaking on
Monday. Temperatures will be seasonable through the weekend, though
conditions will be a bit on the muggy side.

&&

.NEAR TERM /THROUGH SUNDAY/...
As of 154 AM EDT Saturday...Main change was to update sky
cover. The terrain driven stratus being observed in eastern
Vermont is very well modeled right now by the NAM 3km, so have
heavily relied on its output to bring mostly/cloudy sky cover
across much of this region. Otherwise, showers falling out of a
mid- level cloud deck are quickly pushing into western St.
Lawrence County. Very light rainfall is being observed upstream
(such as 0.01" in Watertown, New York), so keeping PoPs in the
chance category reflecting mainly trace amounts of rain looks
reasonable through the overnight hours.


Previous Discussion...
For Saturday...a slow-moving upper trough will trundle eastward
across the Great Lakes, spreading showers/isolated
thunderstorms into northern NY during the morning hours. Brief
heavy downpours will be possible given increasing PWATs to
around 1.75 inch and deep warm cloud depths, but with convection
limited by poor lapse rates aloft, flooding is not anticipated.
Forcing will be lacking as one heads eastward into the
Champlain Valley and eastern VT, so showers will wane as they
exit northern NY, though can`t totally rule out a stray shower
making into VT. Increasing clouds will keep temperatures a
littler cooler than today, especially in northern NY where highs
will struggle to hit 80F. Further east, low to mid 80s should
be more common. South/southwest winds will become a little gusty
during the afternoon, with gusts of 25-30 mph possible. Showers
look to become a little more widespread, or at least make it
further east, Saturday night as weak shortwaves rotate around
the eastward-advancing upper trough. A few thunderstorms will be
possible as well, but as mentioned above, instability will be
lacking with warm air aloft. Still, can`t rule out a few heavy
rainers, but with showers to remain scattered in nature, no
flooding is anticipated. Saturday night lows will be similar to
tonight, in the 60s in most spots.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
As of 335 PM EDT Friday...A slow-moving trough moves into the region
for Sunday and Monday, producing widespread showers. The bulk of the
rain on Sunday looks to fall over northern New York before spreading
into the rest of the region for Monday. The steadiest rain will fall
on Monday when a linear feature attempts to develop on a passing
cold-front. Before the frontal passage, the rain will be more
showery, but the ingredients will be in place for heavy rain. PWATs
should be above 1.5 inches, and they will be approaching 2 inches in
some places. There will also be deep warm-cloud depths and the
potential for training storms. The large-scale trough will have very
little forward west to east motion so any north-south oriented
prefrontal trough to focus the shower development will be very slow-
moving. Even though the showers look to move with relatively fast
south to north motion, with a slow moving pre-frontal trough, there
is the potential for areas to see multiple heavy showers or training
showers. Combined with the atmospheric conditions favoring heavy
rainfall, isolated flash flooding is possible. Weak instability
should limit the heavy rain threat a bit though. The cold front that
passes through on Monday will end any threat for heavy rainfall. The
front will also be quite strong, sending temperatures into the upper
40s and 50s Monday night. Before the frontal passage, it will be
warm and humid with temperatures in the 60s-70s and dew points in
the 60s. Winds will be relatively strong on Sunday, particularly in
the Champlain Valley due to channeled flow. Gusts between 20-25 KTs
are possible though some areas could see them locally higher. There
will be a low-level jet between 30-35 Kts down to 2,000 FT and the
scattered nature of the showers should allow dry periods and decent
mixing.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 335 PM EDT Friday...High pressure will build into the region
for mid and late week, leading to mostly dry conditions and a
warming trend. However, temperatures will start off below
climatological normals and will only rise to around seasonable
averages, so it will almost have an early fall-like feel! Some model
guidance, including the operational Euro, try to form a cut-off low
just off the New England Coast on Tuesday-Thursday, and this could
bring showers into eastern areas. However, this is only supported by
a small number of ensembles so this time period still looks to be
mostly dry. Overall, the pattern mid-late week will favor extensive
ridging over the Great Plains in an almost Omega Block type pattern.
This will keep any of the heat and humidity away to our west and
south.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
Through 06Z Sunday...VFR conditions in much of the area will
continue. The exception is in eastern Vermont where a shallow
stratus deck has formed, impacting both EFK and MPV with MVFR
ceilings. With steady southeast flow expected to continue,
steady ceilings are anticipated through at least 12Z, then solar
radiation will help scour out the low clouds in the subsequent
hours. Meanwhile, showers along a warm front will affect KMSS
and potentially KSLK from 12-18Z, with more limited coverage
eastward. These showers could reduce vsby to 4-5SM.

Winds will begin to increase from the SSE, especially at KBTV
where gusts up to 18kts are possible before sunrise. Thereafter,
SSE winds of 4-8kts will prevail through the day with gusts up
to 20kts likely at KBTV, and up to 16kts elsewhere.

Outlook...

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

&&

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

&&

$$
SYNOPSIS...Hastings
NEAR TERM...Hastings/Kutikoff
SHORT TERM...Myskowski
LONG TERM...Myskowski
AVIATION...Kutikoff/Lahiff