Grout, Vermont Weather Forecast Discussion

632
FXUS61 KALY 221026
AFDALY
AREA FORECAST DISCUSSION
National Weather Service Albany NY
626 AM EDT Mon Sep 22 2025
.SYNOPSIS...
Today starts off mostly dry, but a few showers will be possible
this afternoon and tonight for the western Mohawk Valley and
southern Adirondacks. There is a better chance for showers
tomorrow for most of the region, with another round of much-need
rain possible Thursday. Temperatures will tend to run a few
degrees above normal through much of the next 7 days.
&&
.DISCUSSION...
Key message:
- There is a 60-70% chance for some much needed rain both on
  Tuesday and Thursday.
Discussion:
.Update...As of 6:25 AM EDT...Minor adjustments made to
temperatures to reflect current trends. Portions of western New
England and the Taconics have seen temperatures fall into the
upper 30s this morning with favorable radiational cooling
conditions. Areas further west have and in some of the valleys
that did not decouple last night have temperatures in the low
to even mid 50s to start the day. Also adjusted sky cover up
considerably for a few hours this morning across the Mid Hudson
Valley and eastern Catskills as GOES 16 Nighttime Microphysics
RGB satellite product shows an expansive area of low stratus
moving into the region. Some of this low stratus has made it up
the Hudson Valley as well. We think this low stratus should mix
out by mid-morning, but this will be something to keep an eye on
over the next several hours, as temperatures could under-perform
today if this low stratus lingers longer than expected.
Otherwise, previous forecast remains on track with more details
below...
.Previous...Today and Tonight...The sfc high weakens as it
drifts further east, which will allow a warm front to track E/NE
across our region today. Behind the front, dew points will rise
into the 50s, with daytime highs in the mid to upper 70s
outside of the high terrain. Our region will remain downstream
of an upper trough and associated sfc cold front, and these
slow- moving features will lead to some isolated to scattered
showers across portions of the western Mohawk Valley and/or
southern ADKs this afternoon and evening, continuing through
tonight. Unfortunately, most of the rest of the region will
remain dry through most of tonight, especially south and east of
the Capital District. Clouds will be on the increase tonight
and winds should remain more elevated compared to previous
nights, so lows will be quite a bit warmer, mainly in the mid to
upper 50s.
Tuesday and Tuesday night...The upper trough axis remains west
of our area, but a shortwave aloft tracking through the mean
flow and the sfc cold front will track across our area. The
increased forcing, combined with increasing moisture (PWATs
increase to 1.5-1.7" which is around +2 sigma for late
September) will lead to scattered to numerous showers on
Tuesday, lasting into Tuesday night. Showers should diminish
from northwest to southeast Tuesday evening/overnight behind the
cold front. HREF guidance suggests up to a few hundred J/kg of
CAPE, so a few rumbles of thunder will be possible as well. This
rainfall will be very beneficial given the recent drought
concerns. However, QPF amounts generally look to only be
between a quarter and half inch, so this will not be enough to
make up the recent rainfall deficit. Temperatures on Tuesday
will be mainly in the mid to upper 70s again, although portions
of the Mid Hudson Valley and southwestern New England may get
into the low 80s ahead of the front. Lows will be similar to
those on Monday night with clouds around once again, and many
areas holding onto a light wind.
Wednesday...The cold front will stall to the south of our
region as high pressure builds into southern Canada. PWATs also
decrease to around 1.25". However, our proximity to the stalled
frontal boundary and lingering weak upper troughing may allow
for a few isolated to scattered showers Wednesday. Coverage of
showers will be much more limited compared to Tuesday, and any
additional rainfall amounts look relatively minor. Temperatures
Wednesday and Wednesday night will be similar to the previous
few days with highs in the mid to upper 70s and lows in the
mid to upper 50s.
Wednesday night through Thursday night...Guidance is beginning
to come into better agreement that the lingering upper trough to
our west will interact with a separate upper disturbance
ejecting eastward from the Rocky Mountains, forming a
closed/cutoff upper low over the Ohio Valley. There is also
decent agreement that as this feature tracks eastwards, a sfc
low will develop and track somewhere near the eastern Great
Lakes Thursday. While the exact evolution and track of these
features does remain somewhat up in the air, current guidance
would suggest that most areas will see some additional rainfall
between in the Wednesday night to Thursday night timeframe.
Should this system take a favorable track, as shown by the
current suite of guidance, then we could see another round of
appreciable rainfall that would help to make up some of the
recent rainfall deficit. NBM probabilities for >0.5" of rain in
48 hrs ending 8 AM Saturday are generally 50-70%, with
probabilities for >1" of 30-50%. Local research has shown that
the current probabilistic version of the NBM has a wet bias
across the ALY CWA, but there is meteorological support for
these rainfall amounts with a strengthening LLJ aiding in better
moisture transport ahead of the upper forcing. Any rainfall we
receive will again be very beneficial, and we are not at all
concerned about any hydro issues. Given that Thursday could end
up on the wetter side, temperatures will be cooler compared to
previous days with upper 60s (terrain) to low 70s (valleys).
Friday through the weekend...Forecast confidence remains low
during this time period due to uncertainty in the upper flow
pattern evolution. Some sources of guidance push the upper
low/trough off to our east, allowing for cooler and drier
weather across our region. However, some deterministic and
ensemble guidance lingers the upper trough near or even west of
our area, which could result in continued chances for much-
needed rain/showers. Given the tendency for guidance to struggle
with upper low placement/track in the medium to long term, it
will likely take a few more days before forecast confidence
increases during this timeframe. Looking ahead to days 8-14, the
CPC is expecting continue above normal temperatures with a
return to below normal precip.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
Through 12Z Tue...Some stratus has developed across eastern NY this
morning.  Cigs will vary from the MVFR to VFR range in the 2.5-4.5
kft AGL range.  A brief period of MVFR/IFR stratus is possible at
KPSF prior to 15Z/Mon.  VFR conditions are expected after the
stratus burns off between 14Z-16Z/Mon. Mid and high clouds will
increase in the afternoon, as a low pressure system and its warm
front will continue to lower the cloud bases to 3.5-5 kft AGL
between 22Z/Mon and 04Z/Tue.  Some scattered showers will impact
KALB-KPSF northward after 06Z/Tue and PROB30 groups were used in the
08Z-12Z/Tue time frame.  Widespread MVFR conditions are expected
towards the end of the TAF cycle.
The winds will increase from the southeast to south in the late
morning into the afternoon to around 10 KT with a few gusts 15-20 KT
for KALB/KGFL. The winds will decrease from the south to 7 KT or
less tonight.
Outlook...
Tuesday Night: High Operational Impact. Likely SHRA.
Wednesday: Moderate Operational Impact. Slight Chance of SHRA.
Wednesday Night: Moderate Operational Impact. Chance of SHRA.
Thursday: Moderate Operational Impact. Chance of SHRA.
Thursday Night: High Operational Impact. Likely SHRA...TSRA.
Friday: Moderate Operational Impact. Chance of SHRA...TSRA.
Friday Night: Moderate Operational Impact. Chance of SHRA.
Saturday: Moderate Operational Impact. Chance of SHRA.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...Main
DISCUSSION...Main
AVIATION...Wasula

NWS aly Office Area Forecast Discussion