584
FXUS61 KALY 060156
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
956 PM EDT Wed Jun 5 2024

.SYNOPSIS...
Tonight will be warm and muggy, with some showers and a few
thunderstorms expected as we head towards sunrise. Tomorrow will be
a few degrees cooler with some showers and thunderstorms likely,
especially during the afternoon and evening. Things continue to
trend cooler and unsettled for Friday through the weekend, with a
chance for showers and a few rumbles of thunder each afternoon and
evening.
&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
1000 PM Update...
Lingering shwr/storm activity persisting this hour across the
southern Adirondacks and Saratoga regions. Have made a few minor
changes to pop and wx grids based on these trends. Otherwise,
everything else remains on track with additional shwrs/isolated
storms expected to develop during the early morning hours as
mid-level shortwave energy approaches.

730 PM Update...
Isolated shwrs/storms currently moving through the southern and
western Adirondacks, with latest radar scans now showing some
gradual weakening. This activity will likely continue to weaken
with loss of daytime heating. Otherwise, low status beginning to
develop over Long Island, which with time, will advance north
into our region during the overnight hours. This will coincide
with early morning shower activity as a weak upper shortwave
advances towards our area.

Previous Discussion...

As of 3:50 PM EDT...Our region remains under an upper
ridge, with surface high pressure located well to our southeast
over the Atlantic. Southerly return flow around the periphery of
the surface high has lead to warm and muggy conditions this
afternoon, with some of our valley areas seeing temperatures in
the upper 80s and dew points in the low 60s. Temperatures are
slightly cooler south and east of the Capital District where
there is more of a marine influence due to the southerly flow.
Skies remain partly to mostly clear. Without much vertical
development to the cu field, expecting mainly dry conditions
through this evening, although a couple stray showers and
possibly a rumble of thunder can`t be ruled out across the
western Mohawk Valley or ADKs with the upper ridge beginning to
weaken.

Tonight starts off mainly dry, with any showers or thunderstorms
diminishing after sunset with the loss of daytime heating.
However, the upper ridge continues to deamplify as an upper low
tracks into the Great Lakes region. A separate upper impulse
out ahead of the upper low tracks across the southern portion of
our region late tonight, which will likely lead to a period of
showers tracking through our southern areas as we head towards
daybreak. Showalter indices between 0 and -1 suggest that there
could be a few embedded rumbles of thunder, and locally heavy
rain is possible with any thunderstorms as PWATs climb to
1.5-1.8". Further north, some lighter showers are possible with
a warm front lifting north through our region. With increasing
clouds and high dew points, tonight will be warm and muggy with
lows mainly in the 60s.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
Tomorrow, the upper low settles over the Great Lakes region,
with a surface cold front and associated wind shift
boundary/pre-frontal trough expected to track through the region
in the afternoon. Guidance is now good agreement that earl AM
showers should diminish by mid morning, which may allow the
atmosphere time to recover and destabilize before another round
of showers and thunderstorms tomorrow afternoon...

CAMs suggest that we may see 500-1000J/kg of CAPE ahead of the
cold front tomorrow afternoon, although exactly how much
instability we see will depend on how much (if any) sun can
break through the clouds tomorrow morning. The best instability
looks to be south of the Capital District, while the best
forcing will be north and west, closer to the upper low.
However, with strong low-level convergence along the wind shift
boundary and 25-30 kt of deep-layer shear, we are expecting to
see a line or cluster(s) of storms tracks across the region from
west to east tomorrow afternoon into early evening. Given the
above parameters, we collaborated with SPC to have a marginal
risk for severe weather across our region. Current thinking is
that the best chance for sever weather will be north and west of
the Capital District, but the intensity of storms will
ultimately depend on how much instability we see.

The other threat with any storms tomorrow, especially during the
afternoon, is for locally heavy rainfall. PWATs look to be at or
above the 90th percentile per the SPC sounding climatology, with
warm cloud depths of 10-11 kft. However, we have been quite dry
lately, and storms should be moving at an "average" pace so they
are not expected to sit in any one place for too long.
Therefore, maximum rainfall amounts look to be more on the order
of 1-2" per the HREF PMM. Finally, flow aloft is relatively
perpendicular to the wind shift boundary, which should help
reduce the risk of training storms. We could certainly see some
ponding of water in the typical urban/poor drainage areas with
any storms, although the threat for more widespread or flash
flooding looks to be on the low side. Highs tomorrow will be
cooler than today, mainly in the 70s and 80s.

Tomorrow evening, thunderstorms come to and end in the evening
as the cold front tracks through our region. There could still
be a few lingering showers overnight with the upper low nearby
over the Great Lakes, but the severe and hydro threats should
end as the sun sets. Behind the front, it will be cooler with
lows dropping into the 50s to around 60s.

Friday through Saturday...The upper low tracks eastwards from
the Great Lakes into southern Canada, just north of the
international border. This will lead to several rounds of
showers and perhaps a few rumbles of thunder, with the best
chance each afternoon and evening with diurnal heating.
Additionally, an secondary cold frontal passage late Friday
afternoon and evening and the left exit region of the upper jet
being overhead Saturday afternoon will enhance coverage of
showers. Instability generally looks unimpressive at <500 J/kg
and the deeper moisture will be off to our east, so severe
weather and/or hydro do not look to be a concern during this
time period. With plenty of clouds and showers around, it will
be much cooler with daytime highs in the 60s to 70s each day and
overnight lows mainly in the 50s, with some upper 40s for the
high terrain.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Long term period will start off cool and unsettled, but we should
see a trend towards drier and slightly warmer weather by the middle
of next week...

Long term period begins at 00z Sunday with the upper low still
centered just north of our forecast area in southern Canada. Where
exactly it tracks Sunday and Monday remains somewhat uncertain, as
we are still seeing some rather large run-to-run jumps with the
various sources of guidance. This makes sense given the tendency for
models to struggle with upper low placement several days out, and we
have therefore taken an ensemble/continuity approach to this portion
of the long term forecast. Even with the uncertainty in the exact
placement of the upper low, this feature is large enough that we
should still be under its influence Sunday with diurnally-driven
scattered showers developing by late morning and lasting through the
evening, with the best chances north of I-90 closer to the cold pool
aloft. A few rumbles of thunder can`t be ruled out, but we are not
expecting any severe weather or hydro concerns. The upper low
finally begins to slide to the east Monday, although a piece of the
upper low may break off and drift southwards over our area. Will
still mention slight chance to chance PoPs Monday, but will note
that coverage of showers will probably be lower than on Sunday. With
plenty of clouds and showers and a cool airmass aloft, daytime highs
Sunday and Monday will range from 60s in the terrain to 70s in the
valleys with overnight lows in the upper 40s (terrain) to 50s
(valleys) each night.

Tuesday and Wednesday...By Tuesday, the upper low should slide
further to our east. Upper ridging builds to the west of our area,
putting us in a drier northwest flow regime. Surface high pressure
builds towards our area from the west, so things should dry out
Tuesday. It will be a few degrees warmer, with highs near normal for
early to mid June. Forecast confidence decreases for Wednesday, as
some sources of guidance show additional upper troughing approaching
from the west while other sources of guidance delay this until later
in the week. So, will mention slight chance to chance PoPs with
temperatures a few degrees warmer than on Tuesday. Looking forward
to days 8-14, the CPC is leaning slightly towards temperatures and
precip being above normal.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
VFR conditions this evening will give way to increasing chances
for MVFR cigs at all terminals during the early morning hours as
return flow moisture advances northward with time. For now,
current fcsts for all sites show MVFR cigs developing at the 06z
timeframe, however trends will have to be monitored as IFR
conditions cannot be ruled out at PSF and possibly POU. In
addition, shwrs will likely begin moving into the region after
the 09z timeframe as well, as an upper-level disturbance moves
overhead. After 18z, attention then turns to developing
shwrs/storms as a cold front approaches. For now, have included
TEMPO groups at all locations beginning at 20 or 21z. This
activity will likely be east of area terminals by the conclusion
of the TAF valid time with a return to VFR conditions.

Outlook...

Thursday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Friday: High Operational Impact. Likely SHRA...TSRA.
Friday Night: Low Operational Impact. NO SIG WX.
Saturday: High Operational Impact. Likely SHRA...TSRA.
Saturday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Sunday: Moderate Operational Impact. Chance of SHRA...TSRA.
Sunday Night: Low Operational Impact. Slight Chance of SHRA...TSRA.
Monday: Moderate Operational Impact. Chance of SHRA...TSRA

&&

.HYDROLOGY...
Showers and scattered thunderstorms are expected late tonight
through Thursday. Rainfall amounts of around 1 inch are expected
with localized amounts up to 2 inches. Some thunderstorms will
contain heavy rain and could produce localized ponding of water
on roadways, urban and small stream flooding and standing water
in low lying areas.

No flooding of main stem rivers is expected. Additional showers
and thunderstorms will occur Friday through the weekend but
less widespread and lighter, with additional amounts of perhaps
up to a half inch of rain through the weekend.

&&

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

&&

$$

SYNOPSIS...Main
NEAR TERM...32/Main
SHORT TERM...Main
LONG TERM...Main
AVIATION...32
HYDROLOGY...NAS