464
FXUS61 KALY 170002
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
802 PM EDT Fri May 16 2025

.SYNOPSIS...
Scattered showers and and isolated thunderstorms this
evening diminish overnight, but additional showers and
thunderstorms, some strong to severe, are expected again tomorrow
ahead of a cold front. We may still have some lingering showers
around Sunday, but should dry out Monday through the middle of the
week with much cooler weather behind the front. Rain chances
increase towards the middle of next week, with continued below
normal temperatures.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
As of 730pm, overall storm and shower activity late this
afternoon into the early evening hours has been isolated with
just a few storms developing in southern VT and the Upper
Hudson Valley with a few more weak storms heading into the far
western Mohawk Valley. Given radar and satellite trends and
latest CAM guidance (especially the HRRR which seems to be
handling things the best) we have trended POPs downward to just
slight chance and low end chance through tonight. Storm coverage
should remain isolated to widely scattered as overall forcing
is nebulous in the form of very weak sfc boundaries/convergence.
While dew points remain high enough to maintain the humid air
mass, the probability for storms to become severe is diminishing
and turning more unlikely as we head further into the evening
hours/past peak heating.

Previous discussion...Tonight, diffluent flow aloft and low-
level warm advection will lead to plenty of clouds around
tonight and a few lingering showers. A couple non-severe
thunderstorms will also be possible overnight with some pockets
of elevated instability. Lows will be quite mild, mainly in the
50s to 60s. Some patchy fog and low stratus are expected across
the Mid Hudson Valley and southwestern New England due to light
low-level S/SE flow, with some additional patchy fog for areas
that receive rain this evening.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
Key Message:

 - There is a slight risk for severe thunderstorms Saturday from
   late morning through mid to late afternoon for much of
   eastern NY and western New England.

 - The slight risk for severe weather has been shifted further
   north and east from the previous forecast.

Discussion:

Tomorrow, the upper low and occluded low track eastwards across
the Great Lakes region. A weak warm frontal boundary lifts
northwards late tonight/very early tomorrow morning, and there
could be some lingering isolated showers/storms across northern
areas tomorrow morning. However, additional showers and
thunderstorms are expected to develop by mid to late morning as
a pre-frontal trough tracks through the region. Some of these
storms could become strong to severe (more below). There may be
a brief lull in convective activity for a few hours in the mid
to late afternoon, before another line of storms tracks from
west to east across the region ahead of the system`s actual cold
front. Despite strong forcing for ascent, instability should
diminish behind the first wave of convection, so the probability
for severe weather with this second round of convection looks
lower at this time. This is a change from the previous
forecast, which messaged a greater severe potential with the
second round of convection later in the day.

Regarding the severe threat, timing appears to be from roughly
10 AM to 4PM tomorrow. There is some uncertainty in how much
instability develops, but the HREF suggests that 1000-1500+ J/kg
of SBCAPE is possible, with the greatest instability in the
Hudson Valley from the Capital District northwards. This
instability will overlap with 35-40+ kt of deep-layer wind
shear. Damaging wind seems to be the primary threat with DCAPE
values of 700-1000 J/kg, but large hail will also be possible
with WBZ heights near 9.5 - 10.5 kft and mid-level lapse rates
of 6.5-7C/km. There is also a chance for an isolated tornado or
two tomorrow with some low-level curvature to the hodographs and
low LCLs, although the fact that most of the wind shear is
above the lowest 1 km makes this a lower-end threat. The threat
appears greatest from roughly the Capital District north and
east tomorrow, and given this we have collaborated with SPC and
WFO BTV to have the slight risk moved into this area and trimmed
back across the southern part of our area where forcing looks
weaker. Instability should diminish behind this first round of
convection, reducing the severe threat later in the evening.
However, wind shear still looks impressive tomorrow afternoon
and evening, so we can`t totally rule out a stronger storm or
two with the second round of convection if there is more
instability than forecast.

There is also a threat for heavy rain with any thunderstorms
tomorrow, as PWAT values remain elevated at between 1.2-1.4" per
the latest HREF. However, storm motions will be faster with
strengthening flow aloft, and areas north of the I-90 that are
expected to see the greatest convective coverage have received
very little rain over the past 5 days. This should limit the
threat for hydro issues, although any storms moving over
urban/poor drainage areas could still result in some ponding of
water. WPC has placed areas north of I-90 in a marginal risk ERO
tomorrow. Highs will be mainly in the 70s to around 80, and it
will be muggy again with dew points in the 50s to mid 60s.

Saturday night through Sunday night...The cold front tracks
through the region Saturday evening and early overnight.
Convection comes to an end within a couple hours of sunset, and
a much cooler airmass will infiltrate the region behind the
front. There will be some scattered showers lingering,
especially during the day on Sunday, with the upper low and
associated cold pool aloft tracking across upstate NY. It will
be much cooler with overnight lows in the 40s to 50s Saturday
night and 30s to 40s Sunday night. Daytime highs Sunday will be
mainly in the 50s to 60s with lower humidity. West winds also
become breezy with the surface low tracking to our northeast and
broad high pressure building out of Canada towards the Great
Lakes.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Monday through Tuesday night...The upper low moves off to our
northeast, but we remain in persistent NW flow aloft. High
pressure remains northwest of our region, which will keep
breezy conditions around through this timeframe. Temperatures
remain below normal for this timeframe, with 50s to 60s during
the day and 30s to 40s each night for lows. There could be a few
lingering showers across the ADKs or southern Greens, but by
and large most areas will remain dry.

Wednesday through Friday...Chances for rain increase for the
middle of the week, as guidance is in relatively good agreement
on an upper shortwave tracking across the TN valley interacting
with retrograding northern stream energy, eventually forming a
closed upper low. At the surface, an area of low pressure will
likely develop and track near the east coast, so we have
included likely PoPs for Wednesday and Thursday. The details and
timing will still need to be ironed out, including how quickly
the upper low and lingering precip depart to our east Thursday
night and Friday. Nevertheless, with a storm track to our south
and east, we will likely see continued below normal temperatures
each day. CPC is expecting below normal temperatures and above
normal precip to continue for days 8-14.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions early this evening outside of possible
showers/thunderstorms which may impact KALB between 01Z-03Z/Sat.
MVFR/IFR Cigs are then expected to develop between 03Z-06Z/Sat
and persist until 12Z-15Z/Sat. Several bands of
showers/thunderstorms are expected to pass across the TAF sites
from west to east during Saturday, with the most likely times
between 15Z-19Z, then another period between 21Z-24Z/Sat. Brief
MVFR/IFR conditions (mainly Vsbys) will occur within any
passing showers/storms.

South to southeast winds 4-8 KT tonight will increase to 8-12 KT
Saturday morning with a few gusts of 20-25 KT possible. Winds
will shift into the southwest to west Saturday afternoon at
similar speeds. Winds will be stronger, and variable in
direction in and near any thunderstorms.

Outlook...

Saturday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Sunday: High Operational Impact. Windy With Gusts To 30 kts. Likely SHRA.
Sunday Night: Low Operational Impact. Breezy. Slight Chance of SHRA.
Monday: Low Operational Impact. Breezy. NO SIG WX.
Monday Night: Low Operational Impact. Breezy. NO SIG WX.
Tuesday: No Operational Impact. NO SIG WX.
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: Moderate Operational Impact. Chance of SHRA.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.

&&

$$

SYNOPSIS...Main
NEAR TERM...Speciale
SHORT TERM...Main
LONG TERM...Main
AVIATION...KL