Delanson, New York Weather Forecast Discussion

298
FXUS61 KALY 161758
AFDALY
AREA FORECAST DISCUSSION
National Weather Service Albany NY
158 PM EDT Tue Sep 16 2025
.SYNOPSIS...
Aside from a few light showers tonight through tomorrow night
for areas south of I-90, mainly dry weather is expected to
continue for the next 7 days. Temperatures will start out above
normal today through Thursday, then drop to more seasonable
levels behind a cold frontal passage on Friday.
&&
.DISCUSSION...
As of 1:55 PM EDT...A 1025 mb sfc high remains centered to the
east of our region beneath confluent upper flow, which is
helping to keep our area dry this afternoon. Aloft, we are in a
Rex Block pattern with a cutoff upper low to our south and upper
ridging overhead. An area of low pressure of the NC/VA coast
that is associated with the upper cutoff is spreading some high
cirrus clouds into the region, which has kept temperatures a
touch below the NBM for areas south of I-90 where the clouds are
more widespread. Daytime highs should be in the mid to upper
70s for most of the region, with some low 80s possible in the
upper Hudson Valley where there is more sun this afternoon.
Tranquil weather continues into the evening, as we remain under
the influence of the sfc high that continues to sit near Nova
Scotia. High clouds continue to increase overnight as the
coastal low slowly drifts northwards. Any areas that see more
breaks of clearing overnight (best chance in the ADKs) could see
temperatures drop a few degrees below the current forecast, but
overall with partly to mostly cloudy skies the NBM lows in the
upper 40s to mid 50s look quite reasonable. As we head towards
daybreak, a few showers may spread into our southern few
counties near the I-84 corridor, but any showers should be
light. Some patchy fog will also be possible again tonight,
although with low-level dry advection from the northeast fog
may not be as widespread or locally dense as last night.
Wednesday through Thursday...The coastal low continues to drift
to the N/NE, up the east coast, but it will be weakening as the
upper cutoff low evolves into an open wave aloft. This will lead
to more clouds across our region tomorrow through tomorrow
night, with more clearing Thursday as the low moves off to our
east. With more clouds around tomorrow, highs will be cooler
than today, with most places in the 60s to 70s. The warmest
temperatures will again be in the upper Hudson Valley and
western Mohawk Valley where there will be a few more breaks of
sun. Thursday will be warmer with highs in the mid 70s to low
80s with more sun and a warming airmass aloft. Isolated to
scattered showers are expected for areas along and south of I-90
tomorrow and tomorrow night thanks to the approaching coastal
low. However, rainfall amounts generally look quite light, at a
couple hundredths possibly up to a tenth of an inch for a few
towns in the Mid Hudson Valley or southwestern New England.
Any lingering showers end Thursday morning, with a mostly dry
day then expected across the region.
Thursday night and Friday...A closed upper low tracking near
Hudson Bay will help to drive a cold front south through our
region late Thursday night or Friday morning. Sfc high pressure
builds into southern Canada behind this front, but it will be
breezy on Friday ahead of this high. Lows Thursday night will
be mainly in the 50s with some 40s in the high terrain. Friday,
highs will range from mid 60s in the ADKs to upper 70s in the
Hudson Valley, with temperatures falling by mid to late
afternoon behind the cold front. Given deeper mixing potential
and low-level cold/dry advection, we lowered dew points by 3-5
degrees from the NBM in collaboration with neighboring WFOs.
Please see fire weather section below for more details.
Unfortunately, moisture ahead of this front looks quite limited,
so we are not expecting much if any rain with the cold frontal
passage.
Friday night through early next week...As the sfc high builds
overhead to begin the weekend, upper ridging also amplifies
aloft. Lows Friday night behind the front will get into the 30s
to 40s, and will similarly be on the cold side Saturday night
with the sfc high overhead. We collaborated with surrounding
WFOs to drop Saturday night lows from the NBM, as some patchy
frost may be possible in the ADKs Friday and/or Saturday night.
Saturday looks like the coolest of the next 7 days with highs in
the mid 60s (terrain) to low 70s (valleys). Sunday will be a
few degrees warmer, and temperatures moderate back to slightly
above normal levels for the start of next week as the sfc high
moves off to the east. The ridge aloft and sfc high will lead to
large-scale subsidence that will keep our region dry through at
least the weekend and likely through Monday. This will make for
a very nice early fall weekend, but also means that we will
continue to add to the existing rainfall deficits.
&&
.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
Through 18Z/Wed, VFR conditions are expected through at least
02Z/Wed. Thereafter, patchy ground fog will likely lead to at least
intermittent IFR/LIFR conditions at KGFL overnight. Elsewhere,
prospects for fog formation appear less than the last couple of
nights due to greater coverage of high clouds, and perhaps a light
breeze developing. Will keep out any mention of fog at this time,
however there is a very low chance (~10-20%) that some fog could
develop at KPSF should breaks in the higher cloud cover/less wind
occur. Any patchy fog/low clouds should lift by 14Z/Wed, with VFR
conditions then prevailing. Light/variable winds are expected
through tonight, although may become southeast at 4-8 KT at KALB
around or after sunset. Winds will become east to southeast at 4-8
KT by late Wednesday morning.
Outlook...
Wednesday Night: Low Operational Impact. NO SIG WX.
Thursday: No Operational Impact. NO SIG WX.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: Low Operational Impact. Breezy. NO SIG WX.
Friday Night: No Operational Impact. NO SIG WX.
Saturday: No Operational Impact. NO SIG WX.
Saturday Night: No Operational Impact. NO SIG WX.
Sunday: No Operational Impact. NO SIG WX.
&&
.FIRE WEATHER...
Friday looks to be the next day with potential fire weather
concerns. Behind a cold frontal passage, north/northwest winds
could gust in excess of 20 mph, with RH values dropping into
the 35-45% range during the afternoon. The greatest overlap of
winds and low RH looks to be in the upper Hudson Valley and
southern Adirondacks. Saturday afternoon may feature RH values
in the 25-35% range, but winds look much lighter on Saturday.
Additionally, little to no appreciable rainfall is expected
through the next 7 days. Therefore, dry conditions are expected
to continue through at least early next week with increasing
rainfall deficits.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...Main
DISCUSSION...Main
AVIATION...KL
FIRE WEATHER...Main

NWS ALY Office Area Forecast Discussion