383
FXUS61 KALY 031118
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
718 AM EDT Mon Jun 3 2024

.SYNOPSIS...
Early morning isolated showers will give way to a
primarily dry day as a weak disturbances passes and high pressure
builds in across the region. Fair weather persists into Tuesday,
though minor increases in instability and humidity could lead to
widely scattered showers and thunderstorms over higher terrain
regions in the afternoon and evening. A strong upper-level system
will then move in from the west by late Wednesday, bringing periods
of widespread showers and scattered thunderstorms through the
remainder of the work week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
.UPDATE...As of 645 AM...There remains a few lingering showers
mainly in the lower Mid-Hudson Valley this morning, which should
dissipate within the next hour or so. Water vapor imagery shows
the mid-level shortwave traversing through the area, so skies
remain partly cloudy. Made minor adjustments to PoPs and sky
cover to account for these latest trends. Also made minor
adjustments to temperatures to reflect latest obs, but all
remaining elements of the forecast remain on track. See the
previous discussion below for additional details on today`s
forecast...

.PREVIOUS DISCUSSION [439 AM]...
Light, isolated showers continue in portions of the Eastern
Catskills and Hudson Valley this morning as a mid- level
shortwave tracks south and east through the region as seen on
water vapor imagery. Weak reflectivity seen on the KENX radar
and lack of accumulation seen in NYS Mesonet ground truth obs
indicate that little may indeed be reaching the ground, but
maintained scattered chance PoPs for the next couple hours as a
light sprinkle remains possible mainly in the Eastern Catskills.


Skies continue to retain a fair amount of cloud cover this
morning as a result of the aforementioned disturbance, but some
patchy clearing in the Southwest Adirondacks, Upper-Hudson
Valley, and Northwest Connecticut has aided in temperatures
cooling to the low to mid 50s in these areas. Elsewhere, upper
50s to low 60s and pockets of mid to upper 60s throughout the
Mid-Hudson Valley are common where cloud coverage has remained
rather extensive.

The shortwave disturbance will push fully through the region
later this morning, giving way to surface high pressure
building in across the region from the northwest and shortwave
ridging nosing in aloft. As a result, subsidence will begin to
entrain dry air into the mid and upper levels throughout the day
such that skies will gradually follow along a clearing
trend. Subsequently, little in the way of precipitation will be
expected today outside of a stray shower or sprinkle in upslope
regions of the Southwest Adirondacks and Eastern Catskills
later this afternoon.

With the building high providing clearing and 850 mb temps
remaining around +13 to +14 C, high temperatures today will
reach the upper 70s to mid 80s with pockets of mid 70s above
1500 ft.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
Clouds continue to decrease into this evening with any
shower/sprinkle that develops over the higher terrain regions of
the Eastern Catskills and Southwest Adirondacks swiftly
dissipating upon the loss of diurnal heating. The aforementioned
shortwave ridge will amplify across the region slightly
overnight tonight allowing radiational cooling to drop
temperatures into the mid to upper 50s across the region.

Throughout the day Tuesday, the surface high will begin to drift
eastward, leading the ridge aloft to begin to weaken. Clouds
will begin to increase a bit from northwest to southeast as an
upper-level system begins to take shape and strengthen
upstream, but plenty of sunshine will still be present
throughout the morning and even into the afternoon as skies only
become partly cloudy. Humidity will increase a bit throughout
the region Tuesday as winds take on a more southerly direction,
but with highs anticipated to reach the mid/upper 70s to mid
(and pockets of upper) 80s and dewpoints rising into the mid 50s
to low 60s, conditions will still be relatively comfortable.

While most areas will remain dry Tuesday, some additional high-
terrain, scattered showers and isolated thunderstorms are
possible in the afternoon. Breaks of sun paired with higher
humidity will aid in instability maximizing at about 500-1000
J/kg, but shear looks to be low. Therefore, the probability of
severe convection is very low. However, any thunderstorms that
develop could be capable of producing a brief downpour and
lightning that could pose a threat to outdoor activities.

Once again, any showers or thunderstorms that develop will
quickly dissipate with the loss of daytime heating Tuesday
night. Skies will remain partly cloudy throughout the overnight
period Tuesday, yielding more mild low temperatures primarily in
the upper 50s to low 60s.

Attention then turns to Wednesday as the aforementioned upstream
system begins to approach the region from the west. High
pressure at the surface and shortwave ridging aloft continue to
make their exit east as heights fall ahead of potent troughing
extending south and east ahead of its parent closed low
deepening in Southern Canada. As a result, clouds remain
prominent across the region with environmental moisture
increasing as a southwest to northeast moisture fetch develops
off the Gulf of Mexico. There remain some model discrepancies in
the evolution of the system as a whole which has added some
uncertainty in conditions Wednesday, but maintained scattered to
chance PoPs to account for the possibility of some initial
showers and possibly some embedded thunderstorms as the leading
edge of the upper trough tracks into the region Wednesday
afternoon into the evening. At this time, instability looks to
generally fall within 500-1000 J/kg with pockets of 1500 J/kg or
so and low shear. However, with lack of HiRes guidance coverage
of the beginning stages of this event and medium-range model
disagreement in some of the finer details that would allude to
thunderstorm severity, confidence is low in the possibility of
severe convection. For now, continuing to mention slight chance
to chance thunder beginning Wednesday afternoon. Highs Wednesday
will be a few degrees cooler than Tuesday given more extensive
cloud cover. Anticipate mid 70s to low 80s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Unsettled weather expected through the period. A closed upper low
will track out of the Great Lakes and into the northeastern U.S.
This closed low will become an upper cut off low and drift very
slowly through the northeastern U.S. Thursday through the weekend.

Past CSTAR research suggests that there could be considerable strong
thunderstorm activity ahead of the upper low and associated cold
front, with strong to severe thunderstorms and locally heavy rain.
However, there is a lot of uncertainty about where the upper low
will cut off and track.

If the upper low cuts off and drifts along the U.S./Canada border,
then that would favor stronger thunderstorms in our region. If the
upper cut off tracks over or just south of our region, then more
showery with locally heavy rain and less chances for severe weather.

Once the upper cut off and associated upper cold pool is in our
region, breaks in the clouds at night but instability and
considerable coverage of showers and thunderstorms during the day,
especially in the afternoon, each day Thursday through the weekend.

Highs Thursday and Friday in the mid 70s to near 80 with around 70
higher terrain. Highs Saturday and Sunday around 70 to mid 70s with
mid 60s higher terrain, with again, showers and thunderstorms
developing in the daytime instability.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
Weak high pressure controls the weather through tonight. Intervals
of ceilings around 9000-12000 feet this morning. Clouds will
tend to become scattered by midday, remaining scattered through
the afternoon and night. Visibilities should remain VFR as well.

Light to near calm winds through about 14Z-15Z. Then, winds become
north to northeast at 6 Kt or less and continue through the
afternoon and evening. Winds will go calm again for tonight.

Outlook...

Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: Moderate Operational Impact. Chance of SHRA...TSRA.
Wednesday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Thursday: High Operational Impact. Definite SHRA...TSRA.
Thursday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Friday: Moderate Operational Impact. Chance of SHRA...TSRA.
Friday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Saturday: Moderate Operational Impact. Chance of SHRA.

&&

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

&&

$$

SYNOPSIS...Gant/Wasula
NEAR TERM...Gant
SHORT TERM...Gant
LONG TERM...NAS
AVIATION...Frugis/NAS