West Dummerston, Vermont Weather Forecast Discussion

755
FXUS61 KALY 150554
AFDALY
AREA FORECAST DISCUSSION
National Weather Service Albany NY
154 AM EDT Mon Sep 15 2025
.SYNOPSIS...
Our stretch of dry weather continues through much of this week
with temperatures ranging 5 to 10 degrees above normal. A
weakening coastal low approaches Wednesday but the probability
of rain showers continues to trend downwards. Then, a more
potent cold front arrives Friday resulting in breezier winds
and more fall-like temperatures for the weekend.
&&
.DISCUSSION...
Those seeking relief from the continued dry weather
unfortunately will not find relief this week. An upper level
Rex Block pattern from the Great Lakes builds eastward through
tomorrow with the associated 590dam anti-cyclone aloft
maintaining mid and upper level subsidence over the Northeast.
Meanwhile, a 1025hPa sfc high from Ontario, Canada builds into
eastern New England with 850hPa isotherms rising to +10 to
+13C, supporting above normal temperatures. The Rex Block will
usher in quite the dry air mass with PWATs not only falling
under 1" but even approaching 0.5" tomorrow. Such a dry air mass
will also promote boundary layer mixing but forecast soundings
shows the subsidence inversion in the 850-700hPa range with very
weak easterly winds. While these factors will likely limit
temperatures from overperforming, we still expect temperatures
to reach 5-10 degrees above normal today and tomorrow. In fact,
probabilistic guidance shows 60-90% chance for highs to rise at
or above 80 degrees in valley areas but nearly 0% chance for
temperatures to reach the mid-80s. The dry air mass and mainly
clear skies at night will also promote a large diurnal range.
Overnight lows both tonight and tomorrow night look to fall into
the 40s to mid 50s with radiational cooling supporting patchy
fog development, especially in valley areas. Otherwise,
generally expecting morning sun to mix with diurnally driven
afternoon clouds today with mainly sunny skies tomorrow fading
behind a cirrus canopy late afternoon as a weakening coastal low
from the Carolinas gradually presses northward.
The weakening coastal low looks to track off the mid-Atlantic
coast Wednesday into Wednesday night and remain south of New
England through Thursday. While it will be nearest to eastern
NY and western New England on Wednesday, probabilistic and
ensemble guidance continues to trend rainfall potential
downwards given weakening forcing and lackluster moisture. POPs
have therefore been lowered to under 20% and limited to areas
well south of I-90 on Wednesday with only low end chance POPs
grazing southern Litchfield. Cloud coverage increases Wednesday,
especially in the mid-Hudson Valley and western New England, as
mid and upper level moisture spreads overhead, which when
combined with the easterly wind fetch, will keep temperatures
lower in comparison to Monday/Tuesday. Still expecting highs in
the low to mid 70s with slightly warmer temperatures in the
Upper Hudson Valley in the upper 70s further away from the
thicker cloud coverage.
Thursday will feature the warmest day of the week as the
coastal low departs to our east and weak high pressure builds
overhead supporting plenty of sunshine ahead of a potent cold
front marching south and eastward out of the Canada. With deep
boundary layer mixing at play and slightly warmer 850hPa
isotherms aloft, probabilistic guidance shows greater than 75%
chance for temperatures to exceed 80 (outside of the higher
terrain) with even 20-40% chance for temperatures to reach the
mid-80s in valley areas. Our potent cold front then arrives
on Friday (still some discrepancies on exacting timing) with
breezy northwest winds in its wake ushering in a much cooler and
more fall-like air mass. Lackluster moisture along the boundary
keeps POPs again under 20% Thursday night and limited to just
the southern Adirondacks. It will feel like fall for the
weekend as 850hPa isotherms fall 1 to 2 standard deviations
below normal per the NAEFS. In fact, probabilistic guidance
shows 50 to 75% chance for daytime highs Saturday to remain
below 70 degrees in valley areas. With favorable radiational
cooling expected Friday night and especially Saturday night, we
will monitor potential frost conditions in the western/southern
Adirondacks.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
Through 06z/Tue...High pressure over the region will being VFR
conditions for much of the upcoming TAF period with a few fair
weather cumulus and cirrus clouds at times. The exception would be
for fog at KGFL/KPSF until 12z/Mon with vsbys lowering to LIFR/IFR
at times. Calm wind through the rest of the overnight will become
variable at 5 kt on Monday. Wind will trend calm again Monday night.
Outlook...
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: No Operational Impact. NO SIG WX.
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: No Operational Impact. NO SIG WX.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: No Operational Impact. NO SIG WX.
Friday Night: No Operational Impact. NO SIG WX.
Saturday: No Operational Impact. NO SIG WX.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...Speciale
DISCUSSION...Speciale
AVIATION...Rathbun

NWS ALY Office Area Forecast Discussion