897 
FXUS61 KBTV 151726
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
1226 PM EST Wed Nov 15 2023

.SYNOPSIS...
High pressure just to our south and east will bring warmer
temperatures and breezy south winds today. Temperatures will
continue to warm each day through Friday before a front brings
widespread rainfall Friday afternoon into Friday night/Saturday
morning. Cooler temperatures will follow the frontal passage 
along with some scattered post-frontal snow showers lasting 
through Sunday night.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 1219 PM EST Wednesday...The forecast is largely on track
this afternoon with minimal changes. Previous discussion below.

High pressure will crest to our south early this morning, then 
shift south and east later in the day. Developing return 
southerly flow will set up over our area with increasing south 
winds in response to tightening pressure gradient. Expect breezy
south/southwest surface winds to ramp up shortly after sunrise 
this morning, peaking this afternoon into this evening with 
gusts in the 10 to 20 mph range for most areas. Expect locally 
higher winds over higher summits today with gusts 25 to 40 mph, 
along with stronger channeled southerly winds up the Champlain 
Valley with gusts 20 to 30 mph forecast. Strongest winds over 
the Champlain Valley today will be over Lake Champlain. A Lake 
Wind Advisory may be needed later in the day, but at this time 
forecast has winds just below criteria. 

In terms of cloud cover, stubborn low clouds that have remained 
steadfast over our area for the past few days are finally eroding 
early this morning, which is good news for those looking to finally 
see the sun again.  We'll see some high clouds spreading over the 
area in the wake, but this will allow for at least some filtered sun 
to reach the surface.  The return southerly flow will allow for 
warmer temperatures today than yesterday, with high temps today 
forecast in the mid to upper 40s most areas, locally in the low 40s 
in sheltered areas east of the Greens. 

A relatively weak front will sink south through our area tonight, 
but no precipitation is expected.  Some brief mid and low level 
clouds are forecast tonight in the wake of the front, especially 
over higher terrain in the northern Adirondacks and northern Greens, 
but no other sensible weather impacts expected. Overnight lows will 
be around freezing for most of the area tonight. The front will lift 
northward again through our area Thursday morning as a weak warm 
front.  Ridging will build in the wake of the front, and Thursday 
looks like a beautiful day overall with sun and highs in the mid 40s 
to low 50s.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 327 AM EST Wednesday...Warm air advection strengthens overnight
Thursday with 925mb temperatures rising to +7 to +12C. Temperatures
will likely be non- diurnal west of the Greens. Given that we are now
48 hours out, have started incorporating more local terrain effects
for the temperature forecast. The warmest spots would be towards the
St Lawrence Valley, which are likely to see overnight 
temperatures hold steady or even rise a few degrees towards 
daybreak. On the other hand, the coldest spot overnight Thursday
will likely be across the Northeast Kingdom and east of the 
Greens, where the low- level cold air will be tougher to scour 
out. It will also become increasingly breezy, with 925mb 
southwest winds increasing to 25-35 kt, especially west of the 
Champlain Valley.

By late Friday morning, a 40-50 kt 850mb jet overspreads the entire
region. Forecast soundings indicate less than ideal mixing, but 25
to 30 mph southwest and southerly winds should still be common. High
temperatures should also reach well into the 50s for many locations
given the warm start despite abundant cloud cover, with global
guidance depicting 850mb and 925mb temperatures in the +7 to +10C
and +9 to +12C range respectively. The higher res NAM does indicate
the potential for stubborn low-level cold air to hold its ground
longer across the Northeast Kingdom, but eventually warmer air
should overspread the entire region. Sharp cold front advances from
the west with an intensifying coastal low pressure system to our
east. At this time, all available global ensemble guidance shows the
coastal low tracking south and east of 70W/40N, which means that our
region is too far removed from any Nor'easter impacts. So our
primary concern will be the cold front that crosses the region late
Friday into the overnight hours. The strong pressure rise/fall
couplet will induce vigorous uplift out ahead of the front producing
an area of precipitation. For our area, this looks to be a mostly if
not all rain event Friday afternoon into the overnight hours with
the 540 Dm isotherm line lagging well behind the moisture. Also, no
concerns with flash freeze with enough time for road surfaces to dry
out before temperatures fall below freezing. Total precipitation is
forecast to be around 0.25 to 0.75 inches with locally up to an
inch, so no hydrologic concerns with the rainfall.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 327 AM EST Wednesday...Heading into Saturday, reinforcing
northern stream shortwave energy will likely result in scattered
terrain-focused snow showers as snow levels fall to below 1500 ft.
The cold air advection will also steepen the low-level lapse rates,
allowing for breezy 15-20 mph northwest winds. With temperatures in
the 30s to low 40s, it will feel more like the teens and 20s. A wild
card to consider is the evolution of the upper level pattern with
regards to the coastal low that undergoes explosive cyclogenesis as
it tracks close to the 70W/40N benchmark and into downeast Maine/New
Brunswick on Saturday. The 00z GFS indicates a faster transition
into a negatively tilted trough as downstream ridging builds over
Newfoundland by Saturday afternoon. In contrast, the 00z ECMWF is
more amplified with the H5 trough, resulting in the transition from
neutral to negative tilt not occurring until Saturday night. If the
GFS solution materializes, then the colder air will catch up with
the exiting precipitation shield, resulting in the formation of an
anafrontal wave east of the Champlain Valley and rain changing over
to accumulating snow. Whereas if the ECMWF is right, then only
scattered snow showers are expected. There is still time for model
guidance to come into better consensus so be sure to monitor the
latest forecast. Either way, it does look like the most significant
wintry impacts with this strong Nor'easter will remain east of our
region.

Canadian high pressure builds in during the latter half of the
weekend into early next week, allowing a continental polar air mass
to be entrenched across our region. So expect the coldest air of the
season so far to bring below a period of normal temperatures.
Typical highs for this time of the year are in the low to mid 40s.
At this time, it looks like Monday is the coldest day with 850mb
temperatures falling to -8 to -12C per global ensemble guidance. For
reference, these values are in the 10th percentile of 850mb
temperatures per the SPC sounding climatology for Albany, NY. If the
model trends hold, then sub-freezing highs likely outside of the St
Lawrence and Champlain valleys on Monday. Temperatures trend warmer
and become more seasonable on Tuesday with low to mid 40s returning
as a brief H5 ridge builds into the region. While a little outside
the forecast period, the weather turns unsettled mid week as we head
into the Thanksgiving holiday period. Stay tuned.

&&

.AVIATION /17Z WEDNESDAY THROUGH MONDAY/...
Through 18Z Thursday...VFR conditions are anticipated for the
next 24 hours. High clouds at or above 20000 ft agl are present
across much of the region, with south to southwest surface winds
at terminals ranging between 8 and 14 knots, locally faster up 
to 18 knots and gusting to 28 knots at KBTV and locally slower 
and southeast at 5 knots or less at KRUT. Beyond 22z, winds will
trend towards 5 knots, and may become variable in KEFK, KMPV, 
and KPBG as a weak front shifts through overnight. A cloud layer
between about 5000-7000 ft agl will accompany it, with little 
or no precipitation expected. LLWS will be possible at KSLK and 
KMSS between 00z and 06z as the front shifts east with southwest
winds at 2000 ft agl increasing to 40 knots, but decays as wind
max shifts into Vermont into Vermont. Conditions will remain
fairly steady beyond 06z Thursday.

Outlook...

Thursday Night: VFR. NO SIG WX.
Friday: Mainly VFR, with local MVFR possible. Windy with gusts to
30 kt. Chance SHRA.
Friday Night: Mainly MVFR, with local IFR possible. Definite
SHRA.
Saturday: Mainly VFR, with areas MVFR possible. Chance SHRA.
Saturday Night: Mainly VFR, with local MVFR possible. Slight
chance SHSN.
Sunday: Mainly VFR, with areas MVFR possible. Chance SHSN, Chance
SHRA.
Sunday Night: Mainly VFR, with areas MVFR possible. Chance SHSN.
Monday: VFR. NO SIG WX.

&&

.MARINE...
A LAKE WIND ADVISORY IS IN EFFECT...

South winds will increase to 15-25 knots later this morning into
the afternoon. Winds diminish to 5-15 knots this evening.

&&

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

&&

$$
SYNOPSIS...Duell
NEAR TERM...Duell/Haynes
SHORT TERM...Chai
LONG TERM...Chai
AVIATION...Haynes
MARINE...