435
FXUS61 KALY 080548
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
148 AM EDT Wed May 8 2024

.SYNOPSIS...
A warm front will increase clouds with showers and some
thunderstorms today.  A couple storms this afternoon could be on the
stronger side. After a seasonable day on Thursday with showers
increasing in the afternoon, temperatures trend cooler for the end
of the week.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
As of 1257 AM EDT...Mid and high clouds are beginning to
increase over w-central NY spilling into eastern NY. Some
showers and a few thunderstorms are getting into western NY
ahead of the warm front near the NY-PA border. Temps have cooled
a little quicker into the low-mid 40s in the southern Dacks and
eastern Catskills due to radiative cooling with the sfc high
nearby. For example, Indian Lake fell to 43F in the NYS Mesonet.
We retrended hourly temps and tweaked the timing of the showers
and elevated thunderstorms which will increase 4-6 am. The best
EML is upstream at the Davenport, IA 00Z sounding. Our 00Z
sounding is very dry with a PWAT of 0.34". Upstream over extreme
western NY, the SPC RAP Mesoanalysis indicates PWATs jump
quickly to an inch beneath the weak elevated instability with
Showalter Stability indices of -2C. We kept isolated to
scattered thunderstorms in the forecast in the mid to late
morning. Lows due to wet bulb cooling will be in the 40s to
lower 50s.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/...
Forecast for tomorrow remains complicated, with a chance for
some stronger storms...The day begins with the surface warm
front continuing to lift northwards through our region. There
will likely be lingering convection around to start the day
associated with this warm front, especially north of I-90. Then,
later in the afternoon, the upper low will open up as it tracks
through upstate NY. The system`s cold front will track through
tomorrow evening, pre-frontal trough will track through the
region tomorrow afternoon.

Behind the warm front, we should get into the warm sector with
temperatures climbing well into the 70s, especially for areas
along and south of I-90. With steep mid-level lapse rates in
excess of 7C/km, this will lead to SBCAPE values approaching
1000 J/kg, with some pockets of locally higher values possible
in the Mid Hudson Valley and western New England. Deep-layer
shear also increased to 60-70 kts. While this parameter space
is fairly impressive for our area, the best upper forcing will
remain to the north and will not overlap with the best
instability/shear. The best chance for any stronger storms
appears to be across the Mid Hudson Valley, western MA, and
western CT with any storms that develop with/ahead of the pre-
frontal trough. Therefore, it looks like a fairly narrow window
from very late morning through mid-afternoon where storms are
possible. With mean flow perpendicular to the low-level forcing,
and weak upper forcing, some discrete storms could develop in
these areas ahead of the pre-frontal trough. The severe threat
is conditional on convection initiating, but if any storms do
develop the primary threats look to be gusty winds with
steepening low-level lapse rates and mid- level drying. Mid-
level dry air and long, straight hodographs also indicate the
possibility of hail with any discrete storms that develop.
Accordingly, SPC has placed our area in a marginal risk for
severe weather tomorrow.

Behind the pre-frontal trough, winds shift to
the west and drier low and mid-level air gets advected into the
region, which will reduce instability and make convective
initiation more difficult. A few additional showers/storms are
possible later in the evening for the Mohawk Valley/western
Adirondacks ahead of the true cold front, but the severe threat
looks more limited at this time with waning instability due to
drier air and loss of daytime heating.

Tomorrow night, lingering showers/thunderstorms come to and end
in the evening/early in the overnight period as heights rise
aloft. The cold front drops southwards across the region, but
may not make it all the way to our southern border with OKX. For
areas behind the front, northwesterly winds advect cooler and
drier air into the region. Lows will generally be in the 40s
(north) to 50s (south). Some patchy fog can`t be ruled out
either, especially ahead of the cold front.

Thursday through Friday...Thursday starts off dry but rain
chances increase through the day. A broad, positively tilted
upper trough will approach the Great Lakes, and there will be
numerous upper shortwaves rotating around this upper trough. At
the surface, an area of low pressure will track from the Ohio
Valley off the Mid-Atlantic coast, bringing increased chances
for showers to the region tomorrow afternoon through Friday. Due
to the amount of small-scale shortwaves, there is quite a bit of
forecast uncertainty, more than would be expected at this lead
time. The best chance for showers will be for areas along and
south of I-90, although some sources of guidance suggest showers
could make it much further north. Chances for showers continue
through Thursday night and into Friday, with a secondary surface
low potentially tracking towards our region Friday. Will attempt
to refine the timing and amount of precipitation over the
coming days with guidance hopefully coming into better
agreement. Daytime highs Thursday and Friday will be much
cooler than the previous few days, with overnight lows in the
40s to around 50 Thursday night. Severe weather is not expected
during the Thursday through Friday timeframe.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Unsettled and cool conditions describes the weather pattern for
the upcoming weekend as a long wave trough remains positioned
over the Eastern CONUS with a series of shortwaves tracking
from the Midwest into the Northeast. After showers Friday night,
some brief ridging and subsidence aloft ensues for at least the
first half of Saturday which should support a dry break.
However, an additional shortwave from the Ohio Valley will
provide enough lift to support showers returning Saturday
afternoon into Saturday night. The shortwave lingers overhead
through Sunday with sufficient mid-level moisture and some weak
warm air advection as winds aloft shift to the south or
southeast. This set-up will maintain chance POPs through the day
with even a slight chance for thunderstorms as some instability
may sneak northward. While temperatures Saturday remain cooler
than normal with highs only in the 50s to low 60s thanks to
west-northwest flow aloft, temperatures should trend a bit
milder for Sunday rising into the low to mid 60s in the valley
with mid to upper 50s in the higher terrain and hill towns.

There remains some uncertainty on how the pattern evolves for
Monday into Tuesday as weak shortwaves continue to track aloft
while weak high pressure builds at the surface. Therefore, we
maintained low end chance POPs for Monday into Tuesday but this
may change as guidance becomes into better agreement. Despite
the uncertainty in the evolution of shortwaves aloft, there is
better agreement for temperatures to trend milder and more
seasonable as a milder air mass from the Ohio Valley spills
eastward.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
A warm front will approach from the west Wednesday morning,
followed by a cold front passing through from the northwest in
the late afternoon.

VFR conditions are expected through at least 08Z/Wed. Showers
and a few thunderstorms currently developing across western New
York will reach the TAF sites between 09Z-12Z/Wed, and may
linger until 14Z-16Z/Wed. A period of low MVFR Cigs and brief
MVFR/IFR Vsbys will be possible within heavier downpours.

Showers/thunderstorms should become isolated/scattered between
15Z-19Z/Wed, then taper off. VFR conditions are then expected
later this afternoon through early evening.

Light/variable winds will become south to southwest at 5-10 KT
by mid morning, then will shift into the west after 19Z/Wed and
increase to 10-15 KT with some gusts up to 25 KT, strongest at
KALB and KPSF. Winds will become west to northwest and decrease
to 8-12 KT toward and after 00Z/Thu.

Winds will be stronger, and variable in direction in and near
any thunderstorms.

Outlook...

Wednesday Night: Low Operational Impact. Slight Chance of SHRA...TSRA.
Thursday: Moderate Operational Impact. Likely SHRA.
Thursday Night: High Operational Impact. Likely SHRA.
Friday: High Operational Impact. Likely SHRA.
Friday Night: Moderate Operational Impact. Chance of SHRA.
Saturday: Moderate Operational Impact. Chance of SHRA.
Saturday Night: Low Operational Impact. Slight Chance of SHRA.
Sunday: Moderate Operational Impact. Likely SHRA.

&&

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

&&

$$

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