Assembly Point, New York Weather Forecast Discussion

398
FXUS61 KALY 220614
AFDALY
AREA FORECAST DISCUSSION
National Weather Service Albany NY
214 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:
As of 2:15 AM EDT...1024 mb sf high pressure remains centered
east of our region early this morning, which has allowed for
low-level S/SE flow. For much of the thruway corridor, light
winds have kept temperatures elevated in the low to mid 50s,
while some of the more outlying areas that have decoupled have
seen temperatures drop into the low 40s per latest NYS Mesonet
and ASOS obs. So, expecting a fairly wide range in low
temperatures tonight. These areas that have effectively
radiatively cooled may see some patchy fog between now and
daybreak, but any fog should mix out fairly quickly after
sunrise this morning.
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 /05Z MONDAY THROUGH FRIDAY/...
Through 06Z Tue...Some radiational mist/fog is expected this morning
at KGFL/KPSF with IFR/LIFR conditions.  KGFL has dropped to MVFR
levels at 05Z/Mon already.  TEMPO groups were used between 06Z-
10Z/Mon at KGFL and 07Z-11Z/Mon at KPSF for IFR/LIFR mist/fog and
low stratus.  VFR conditions are expected at KPOU/KALB with some
scattered high clouds in advance of a warm front.  VFR conditions
are expected after localized mist/fog burns off with increasing mid
and high clouds.  A low pressure system and its warm front will
continue to lower the cloud bases to 3.5-5 kft AGL by 23Z/Mon from
KALB north to KGFL with a few showers in the vicinity.  Mid and high
clouds will continue for KPSF to KPOU into tonight. The better
chance of showers will not be until after 06Z/Tue.
The winds will be southeast to south at 7 KT or less at KALB early
this morning with light to calm winds at KGFL/KPOU/KPSF. The winds
will increase from the south in the late morning into the afternoon
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