-- Discussion containing changed information from previous version are highlighted. --
754
FXUS61 KALY 300531
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
131 AM EDT Sun Jun 30 2024

.SYNOPSIS...
A moist southwest flow will bring periods of rain with a chance
for thunderstorms into tonight. A cold front will bring
additional scattered showers and thunderstorms Sunday, some of
which could be strong to severe, mainly south and east of
Albany. Fair weather with cool and breezy conditions return for
Monday.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
.UPDATE...As of 125 AM EDT, one cluster of showers and embedded
thunderstorms is tracking east/northeast across the northern mid
Hudson Valley/southern Taconics region into southern Berkshire
County, with a broken band of showers/thunderstorms across
northern Herkimer/Hamilton/Warren Cos. Bursts of heavy rain have
occurred within these showers/storms, with NYS Mesonet obs
indicating hourly rainfall rates of 0.50-0.75"/hour within the
heaviest cores.

Over the next few hours, will have to watch the broken band of
showers/storms across the southern Adirondacks extending along
the south shore of Lake Ontario. Latest CAMs suggest this band
continues sagging southeast, with a general weakening trend.
However, there will be increasing elevated instability across
western areas, so it is possible that some stronger storms with
gusty winds and heavy downpours reach portions of the SW
Adirondacks (south of location) and western Mohawk Valley
region within the next 2-3 hours.

Also, initial cluster of heavy showers/embedded thunderstorms
across southern areas back tend to backbuild into the SE
Catskills over the next 1-2 hours with locally heavy rain
possible.

Elsewhere, isolated showers/thunderstorms will remain possible
through daybreak. It will remain warm and humid, with
temperatures either holding steady, or even rising slightly in
some areas through daybreak, with lower/mid 70s within many
valley areas and 65-70 across higher elevations.

.PREVIOUS UPDATE...As of 1035 PM...According to the ALY 00z
sounding, we officially broke today`s maximum daily PWAT value
of 1.98" with a new value of 2.06"! Needless to say, we remain
highly saturated throughout the area this evening. Despite this,
showers continue to decrease in coverage with the main coverage
in the Southwest Adirondacks. Higher reflectivity noted on the
KENX radar indicates some heavier downpours embedded within
these showers, but with rapid flow keeping them from remaining
in one place for too long, accumulations have not been too
impressive. In fact, the Old Forge Mesonet site only has about
0.34" for the latest 1-hour accumulation.

Few updates were necessary with this update outside of minor
updates to PoPs and temperatures to reflect latest obs and
trends. The warm front now rests comfortably to the northeast
with the surface trough approaching the region. Additional
showers and possibly some embedded rumbles of thunder in the
Southwest Adirondacks are possible throughout the night as the
surface trough continues to push eastward. See the previous
discussion for additional details.

.PREVIOUS DISCUSSION...
The area of rain that dominated much of the region this
afternoon has decreased to mere scattered showers across the
area this evening with the heaviest rainfall embedded within
showers to the north and west of Albany. The latest SPC
Mesoanalysis indicates increasing instability mainly to the west
of the Hudson River with SBCAPE values at about 100-250 J/kg.
This aligns well with the latest HRRR that depicts SBCAPE
continuing to increase throughout the evening and into the
overnight period especially in the Southwest Adirondacks.

Speaking of the HRRR, this has been the model of choice for the
evening as other sources of HiRes guidance have struggled to
accurately resolve convection. According to the latest run,
shower activity should continue to decrease such that coverage
should become widely scattered over the coming hours. However,
maintained thunder in the forecast especially after midnight for
embedded rumbles of thunder as instability increases with almost
stagnant low temperatures and sustained elevated dewpoints. Low
temperatures overnight will primarily span the 60s with pockets
near 70 mainly in the Mid-Hudson Valley and southwest New
England.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/...
On Sunday, The Storm Prediction Center has placed the southeast
part of our forecast area in a slight risk for severe weather
with the rest of the area in a marginal risk. The cold front is
forecast to move from northwest to southeast across the area.
Ahead of the front the airmass will be unstable.

We expect a band of showers/thunderstorms to develop and
cross the region during the day Sunday. Heavy downpours and
gusty winds could accompany some of these storms, as instability
peaks in the afternoon with CAPES 1500-2000 J/kg and 0-6 km
shear of 40-50 KT. Damaging wind gusts will be the primary
severe threat, however can not rule a tornado or two across the
Slight Risk area given the strong shear, potentially high
instability and low LCL`s ahead of the cold front. High temps
should reach the 80s for most valley areas and 70s across higher
terrain areas. Heat indices will approach the mid 90s across
portions of the mid Hudson Valley, but look to be below heat
advisory thresholds.

A few showers and storms may linger Sunday evening over the far
southeastern areas and a few showers and storms may redevelop
over the southern adirondacks in the evening with the upper
level trough and cold pool moving southeastward.

Monday looks cooler and breezy, but with the upper level trough
overhead, a shower is possible over western New England.
Otherwise clearing and cooler for Monday with highs mainly in
the 70s.

Mainly clear and cool for Monday night, with low temperatures in
the 40s to lower 50s.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Surface high pressure will be centered over the region on
Tuesday resulting in sunny, warm and dry weather. This high
will push southeastward on Wednesday resulting in a southwest
return flow of milder air. Wednesday should also remain mostly
dry. Highs will rise well into the 80s across the valleys and
the upper 70s to lower 80s in the higher elevations.

A cold front associated with an area of low pressure tracking
well northward into Quebec will slowly cross the region
Wednesday night into Thursday, Independence Day. Showers and a
few thunderstorms will likely accompany the front during this
time. There remains a bit of uncertainty with the movement of
the front. Best case scenario, the front moves through the area
early thursday leaving a mostly fair Independence Day before
the front returns northward Thursday night into Friday bringing
additional showers and storms. Worse case the front stalls over
the area with showers and storms on Independence day. Will
monitor trends over the coming days. Otherwise, it looks to be a
very warm and humid day on Thursday with heat index values
reaching the 90s in the valley areas.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
Through 06z/Mon...IFR/MVFR cigs will linger into the start of
the TAF period at all sites before trending back to VFR levels
toward daybreak or later Sunday morning. Rain showers should
approach the TAF sites between 08-12z/Sun from the west. Have
included VCSH at KALB/KGFL/KPSF. There is some uncertainty on
how heavy these showers will be and if vsbys will be reduced.
Will monitor and amend if necessary.

Additional rain showers are possible Sunday afternoon,
especially from KALB and points south and east. Best
thunderstorm chances are at KPOU/KPSF and maintained PROB30
groups there. Trended KGFL/KALB to VCSH with more isolated
coverage at these sites. Cigs should remain VFR Sunday
afternoon, but cigs/vsbys may lower in any shower or
thunderstorm.

Mixed VFR/MVFR cigs are possible in the wake of the frontal
passage Sunday evening with MVFR most favored at KPSF at this
time.

Wind will remain south to southwesterly at around 10 kt
overnight into Sunday morning with a few higher gusts. Wind
will become west to northwesterly behind the cold front passage
Sunday afternoon and early evening at 10 to 15 kt with gusts 20
to 25 kt.

Outlook...

Sunday Night: Low Operational Impact. Breezy. NO SIG WX.
Monday: Low Operational Impact. Breezy. NO SIG WX.
Monday Night: No Operational Impact. NO SIG WX.
Tuesday: No Operational Impact. NO SIG WX.
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: Low Operational Impact. Breezy. NO SIG WX.
Wednesday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Independence Day: Low Operational Impact. Slight Chance of SHRA...TSRA.
-- End Changed Discussion --

&&

.HYDROLOGY...
There is a marginal risk for excessive rainfall today and
tonight across all but Litchfield County CT. Showers will
continue to overspread the region tonight, with embedded
thunderstorms developing later today into tonight. High PWAT`s
of ~2", warm cloud depth and some potential training of
thunderstorms could lead to heavy rainfall and localized
flooding tonight into Sunday. The greatest potential for this
looks to be across the southern Adirondacks and western Mohawk
Valley for tonight, where some areas have already received over
an inch of rain.

Localized flooding of urban, low lying and poor drainage areas
is possible from any thunderstorms.

&&

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

&&

$$

SYNOPSIS...SND
NEAR TERM...Gant/KL
SHORT TERM...SND
LONG TERM...SND
AVIATION...Rathbun
HYDROLOGY...SND/KL