Canaan, Connecticut Weather Forecast Discussion

863
FXUS61 KALY 210605
AFDALY
AREA FORECAST DISCUSSION
National Weather Service Albany NY
205 AM EDT Sun Sep 21 2025
.SYNOPSIS...
High pressure over northern New England this morning will shift
eastward off the coast today. A developing southerly flow will
result in warming temperatures this afternoon and especially
into early next week. Showers and some thunderstorms will become
likely by Tuesday, as a frontal system approaches from the
west.
&&
.SHORT TERM /THROUGH TUESDAY/...
After a chilly/frosty start to the day with temperatures in the
30s and 40s, temperatures will rebound this afternoon as a
warmer southerly flow develops around high pressure departing
off the New England coast. Increasing high level clouds will
filter the sunshine, but not impede warming too much. Highs
should reach the lower/mid 70s in most valley areas. It will
remain dry tonight with surface ridging extending westward into
eastern NY. With modifying air mass low temperatures will not be
as cool as recent nights ranging from upper 30s to upper 40s.
There will be a SW flow aloft in place on Mon, with southerly
winds at the surface. Moisture will start to increase, but any
forcing should remain west of the area except for a few showers
possible in the W. Adirondacks late in the day. High
temperatures will warm back to above normal levels, with lower
elevations expected to reach the upper 70s. With the approach of
a short wave aloft and surface warm front, chances for showers
will gradually increase Mon night mainly for areas north/west of
Albany. Lows will be much milder in the 50s to around 60F with
increasing clouds and a southerly breeze.
Unsettled weather is anticipated on Tue, with the best chances
for measurable many areas have seen in two weeks. A short wave
aloft approaching from the west coinciding with peak heating in
a warm sector Tue afternoon should result in scattered to
numerous showers and T-storms developing. Moisture anomalies
forecast to increase to +1 to +2 STDEV, while SBCAPE of
500-1000 J/kg could develop especially from around I-90 south.
So convective downpours may occur in some areas, along with a
more broad area of showers, which is good news regarding current
drought status. Highs will be quite warm with upper 70s to
lower 80s south of I-90. It will also feel humid as dewpoints
rise into the 60s.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A weak wave of low pressure may develop along the system`s cool
front, which will slow the front`s southward progress. So will
linger chance PoPs through Tue night, although chances for
thunder will lower with increasing stability. The front could
stall near the southern part of our area on Wed, so will
maintain chance PoPs for showers. Depending on the position of
the front, additional instability may develop Wed afternoon so
will mention possible thunder. PoPs gradually decrease Wed night
as the front slowly shifts south towards the mid Atlantic
region. NBM 48-hour probabilities for > 0.25" rain are 60-80%
and 40-60% for > 0.50" rain through Wed, so some beneficial
rainfall is expected.
Forecast confidence lowers Thu to Sat, as a lot will depend on
where/when a closed upper low meanders eastward from the central
CONUS. Latest trends in the guidance are for more surface
ridging developing across the Northeast, which would result in
drier conditions. However, the old front south of our region may
start to return northward as a warm front at some point with
moisture returning north/east of the upper low as it tracks
east. Will go with NBM PoPs of 20-30% during this time until
guidance comes into better agreement. Temperatures will be
relatively cooler, but still slightly above normal.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
Through 06z Monday...Flying conditions are VFR at all terminals
as of 12:40 AM EDT. Still expecting patchy fog/mist with IFR or
lower vsbys and possibly cigs at GFL/PSF to develop. FOg likely
develops first at GFL, while it may take until close to
daybreak for fog/mist to develop at PSF. Can`t rule out some
brief patchy fog near ALB for an hour or two around/shortly
after sunrise, but confidence is too low to mention any vsby/cig
restrictions in the TAFs at this time. Not expecting any fog at
POU. Any fog/mist diminishes by 12z with VFR conditions then
expected to prevail through the remainder of the TAF period with
SCT to BKN high clouds. Winds will be light through the rest of
the night, then increase to 5-8 kt from the S/SE this morning.
Winds become light and variable after sunset at GFL/POU/PSF this
evening, but remain at 5-8 kt from the S/SE at ALB through 06z
Monday.
Outlook...
Monday Night: Low Operational Impact. Slight Chance of SHRA.
Tuesday: Moderate Operational Impact. Likely SHRA...TSRA.
Tuesday Night: Moderate Operational Impact. Chance of SHRA.
Wednesday: Moderate Operational Impact. Chance of SHRA...TSRA.
Wednesday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Thursday: Low Operational Impact. Slight Chance of SHRA.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Frost Advisory until 8 AM EDT this morning for NYZ032-041>043-
     083-084.
     Freeze Warning until 8 AM EDT this morning for NYZ033.
MA...None.
VT...Frost Advisory until 8 AM EDT this morning for VTZ013>015.
&&
$$
SYNOPSIS...JPV
SHORT TERM...JPV
LONG TERM...JPV
AVIATION...Main

NWS ALY Office Area Forecast Discussion