-- Discussion containing changed information from previous version are highlighted. --
273
FXUS61 KBTV 222346
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
746 PM EDT Sun Sep 22 2024

.SYNOPSIS...
Stationary high pressure across New England will remain in
place through Tuesday. An approaching frontal system from the
Great Lakes region will spread mid and upper level clouds across
the North Country tonight into Monday. While there is a chance
for light rain showers on Monday across the St. Lawrence Valley,
the frontal system will generally weaken as it encounters the
area of high pressure across our region. A stronger upper level
low will finally bring a wetting rain to the region Wednesday
into Thursday. Temperatures will slowly trend downward over the
next several days, but generally remain above average for late
September.

&&

.NEAR TERM /THROUGH MONDAY NIGHT/...
-- Changed Discussion --
As of 745 PM EDT Sunday...Only change needed to the forecast
this evening was to incerase cloud cover as mid-clouds have
developed in earnest across the Champlain Valley and
Adirondacks. High clouds have thinned out across the region, but
will increase again after midnight from west to east per
upstream satellite trends. Should be overcast across the entire
region come sunrise which could impact the previous low temp
forecast, and we`ll look to make some adjustments there with the
next update if warranted.

Previous Discussion...Stagnant sfc ridging remains in place
this afternoon, with the ridge axis extending from the Gulf of
St. Lawrence swwd across Maine and New Hampshire. Over the past
24-36 hours, maritime moisture from the Gulf of Maine has become
entrained into the clockwise low-level circulation around the
system, yielding stratus and mostly cloudy skies across
central/ern VT throughout much of this afternoon. Skies are
mainly clear across nrn NY unaffected by this maritime air mass.
Aloft, winds are very light in the 850mb to 500mb layer, and
this has resulted in little overall movement of broken cloud
layer, with just modest changes with daytime heating/mixing.

As we head through tonight, will see p-gradient tighten up a bit
west of the ridge axis across our forecast area. Winds in the 950-
900mb layer reach 25kts at times per NAM3/HRRR soundings, and this
combined with some upper level cloudiness spreading in from the
Great Lakes should limit fog potential overnight. Only included
patchy fog mention for 06-12Z tonight across the deeper CT River
valley. Should see stratus clouds begin to scour out across VT
after 00Z as 950-900 mb winds increase. Overnight lows
generally 45-50F, except low-mid 50s in the Champlain and St.
Lawrence Valleys. Should see winds mixing down to the surface
near lake Champlain, with gusts locally 20-25kts across Grand
Isle county overnight into Monday morning and generally near the
lake shore.

On Monday, the shortwave trough across the nrn Great Lakes generally
shears out as it encounters the persistent ridge over New England.
Will see increasing mid-upper level clouds, and did include a 30
percent chance of a rain shower during the day on Monday across St.
Lawrence county (especially far western areas). Precipitation should
diminish/dry up further east, so have limited shower mention to far
wrn CWA. Temperatures trend downward a few degrees on Monday, with
highs generally in the upper 60s to lower 70s areawide.
-- End Changed Discussion --

&&

.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
As of 315 PM EDT Sunday...Dry weather can be expected for most of the
day Tuesday as the region remains under the influence of high
pressure. The high pressure will begin to shift eastward, which will
allow for increasing cloud cover and a few possible showers reaching
northern New York Tuesday night. Temperatures during the day on
Tuesday will be similar to Monday, with highs in the upper 60s and
low 70s. Overnight lows will also be seasonable with temperatures in
the 40s and lower 50s.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
As of 315 PM EDT Sunday...After a stretch of drier weather, unsettled
conditions are expected for the later half of the week as an upper
level trough over the Great Lakes lifts eastwards towards Quebec.
The greatest chances for precipitation will be Wednesday into
Thursday with a frontal boundary moving through. There is still a
little uncertainty regarding the evolution of the synoptic pattern,
between the upper trough to out west, another system to the south
over the southern Plains, and a potential tropical system off the
Gulf Coast, although deterministic guidance has been in agreement
the last few runs which keeps the systems separate and keeps any
tropical moisture well to our south. Ridging looks to build in
towards the weekend, which would bring another stretch of dry
weather to the region, but it`s still a few days out so stay tuned.
Temperatures will continue to be rather seasonable, with daytime
highs in the 60s to low 70s and overnight lows in the 40s to mid
50s.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
Through 00Z Tuesday...VFR conditions will prevail through the
period with a mix of BKN-OVC mid/high clouds this evening
through midnight trending to OVC mid clouds by sunrise and
through the remainder of Monday. Mixed boundary layer winds
should preclude the development of fog tonight as well, mainly
4-8kts from the SSE, which should also stay persistent through
the daylight hours on Monday as well.

Outlook...

Monday Night: VFR. NO SIG WX.
Tuesday: VFR. NO SIG WX.
Tuesday Night: VFR. Slight chance SHRA.
Wednesday: Mainly VFR, with areas MVFR possible. Chance SHRA.
Wednesday Night: Mainly MVFR, with areas VFR possible. Likely
SHRA.
Thursday: Mainly MVFR, with areas IFR possible. Chance SHRA.
Thursday Night: Mainly MVFR, with areas VFR possible. Chance
SHRA.
Friday: Mainly MVFR, with local IFR possible. NO SIG WX.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
As of 315 PM EDT Sunday...A Lake Wind Advisory is in effect for
late tonight into early Monday morning. Lake Champlain water
temperatures near 70 degrees and a developing S-SE low-level jet
tonight will result in efficient mixing of 15-25kt winds down
to the lake surface, especially after 03Z tonight as pressure
gradient tightens across the region. Wave heights over the broad
lake will increase to 2-4ft after midnight. Winds should begin
to subside mid-late morning hours on Monday.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...Banacos
NEAR TERM...Banacos/Lahiff
SHORT TERM...Kremer
LONG TERM...Kremer
AVIATION...Lahiff
MARINE...Banacos