067
FXUS61 KALY 260901
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
501 AM EDT Wed Jun 26 2024

.SYNOPSIS...
After a few light early showers mainly north of Albany, clouds
give way to sunny, warm, and slightly breezy conditions today.
A period of moderate to heavy rain and embedded thunderstorms
overspread the region this evening along an incoming cold front.
Storms south of Interstate 90 will be capable of producing
gusty winds and heavy downpours that may result in localized
flooding. Cooler and even breezier conditions arrive for
Thursday as high pressure builds into the Northeast.

&&

.NEAR TERM /THROUGH TONIGHT/...
Temperatures early this morning remain quite warm ranging from
the upper 60s to mid 70s thanks to fairly widespread mid and
upper level clouds. Regional radar shows a small area of rain
tracking across Lake Ontario and high res guidance suggests
these showers will continue weakening as they cross into NY but
some showers should spill into the western Adirondacks by 09
- 12 UTC so maintained chance POPs there with even slight
chance POPs extending into the Upper Hudson Valley to account
for a few light sprinkles early this morning before all showers
end.

Then, early clouds give way to mainly sunny skies as zonal flow
strengthens aloft in response to an incoming potent shortwave
that will amplify as it swings into the Great Lakes. A dew
point boundary settles just south of I-90 this afternoon with
dew points north of this boundary across the Greater Capital
District, southern VT, Upper Hudson Valley, and SW Adirondacks
actually only rising into the upper 50s to low 60s as a pocket
of dry air in the mid-levels tracks overhead and supports deep
boundary layer mixing. Not only will the deep mixing result in
temperatures warming into the mid to upper 80s but westerly
winds should also turn a bit breezy with gusts reaching up to
20kts at times. South of this boundary temperatures will be a
bit warmer reaching into the low to mid 90s and higher dew
points in the low to mid 60s will make it feel even warmer. A
few pockets of heat index values reaching 95 degrees likely in
the mid-Hudson Valley but not enough coverage to warrant a heat
advisory.

Clouds increase late this afternoon from southwest to northeast
as sfc winds back to the south and warm air and moisture
advection increase ahead of an approaching cold front. Guidance
remains in good agreement that the majority of the incoming
rain and possible thunderstorms hold off until after 21 UTC but
given the strong dynamics, forcing for ascent, and moisture
fetch, rain may arrive a few hours earlier than high res
guidance suggests so we still introduce likely POPs for the mid-
Hudson Valley, the eastern Catskills, and Litchfield County by
21 - 00 UTC.

We continue to closely monitor this evening from 00 - 06 UTC
Thursday for a period of potentially more impactful weather
mainly south of I-90, including periods of moderate to heavy
rain and damaging winds gusts from strong to severe
thunderstorms. The aforementioned potent shortwave from the
Ohio Valley and Great Lakes will continue amplifying, even
taking on a neutral to slightly negative tilt, with increasingly
stronger height falls occurring downstream. The Northeast will
be positioned in the favorable equatorward entrance region on
the anti-cyclonic side of 300hPa jet reaching 100 - 110kts. This
will support increasing upper level divergence and the
development of a sfc low along the incoming cold front as it
tracks through west/central NY this evening. The front will
feature a tight thermal and moisture gradient with a notable
wind core in the 850 - 700hPa layer immediately ahead of the
front reaching 40 - 50kts advecting a rich plume of PWATs
nearing 2" into the mid-Hudson Valley and southern New England.

While this event will occur in the evening and past peak
heating, dew points in the 60s in this region should
contribute to sufficient instability to support thunderstorm
activity with SB CAPE values ranging 500 - 1500J/kg. Such a
strong moisture fetch, low-level convergence along the
boundary/theta-e gradient, and forcing for ascent including mid-
level FGEN in an environment with high freezing heights ~13kft
will easily support very efficient warm rain processes and
potential for high rainfall rates. Along the leading edge of the
incoming cold front, a period of high rainfall rates is looking
likely for areas mainly south of I-90 as an area of moderate to
heavy rain and embedded thunderstorms overspreads the region.
In fact, HREF probabilistic guidance shows a swatch of 15 - 30%
for 3-hourly rainfall amounts >2" and 70 - 80% probabilities for
>1" in 3 hours across Ulster, Dutchess, Litchfield, southern
Columbia/Berkshire County from 00 - 03 UTC Thurs. Fast mid-
level winds means the heavy rain should be progressive so high
rainfall rates should only last for a few hours this evening but
could still result in a quick 1-2" of rain resulting in some
poor drainage or urban flooding. Isolated flash flooding cannot
be ruled out and WPC maintains its marginal risk for excessive
rainfall noting this event is on the higher end of its marginal
risk category.

Besides the heavy rain potential, the storms along the leading
edge of the cold front may grow upscale as the reach the
moisture rich environment where sfc - 6km shear values ranging
40-45kts can help storms organize into cluster or even bowing
segments. Damaging winds is the primary hazard from any severe
storms and SPC maintains its "slight risk" (level 2 of 5) for
severe weather in Dutchess, Ulster, and southern Greene County.

Since the period for high rainfall rates and potential severe
weather is mainly along the leading edge of the incoming cold
front during the evening hours, the window for any flooding or
damaging winds is rather short-lived and should end by 03 - 06
UTC. After this time, a period of stratiform rain will likely
follow after Midnight with temperatures cooling into the mid 50
to low 60s as drier air advects eastward and rain winds down
shortly before sunrise from west to east. Total rainfall amounts
range 0.50 to 2 inches with highest amounts in the mid- Hudson
Valley and Litchfield County.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...

Cooler and tranquil weather follows for Thursday into Friday
thanks to subsidence building across the Northeast in the wake
of the departing shortwave. Some lingering clouds and morning
showers Thursday, especially in the high terrain areas, will
diminish by midday into the afternoon as the upper level trough
axis shifts eastward. A tight sfc pressure gradient develops
over the Northeast between an incoming high to our west and
departing sfc low and results in gusty winds reaching up to
25kts. The strongest winds likely occur down the Mohawk Valley,
Capital District into Berkshire County. Otherwise, cool air
advection may support some lake effect rain showers that spill
into the western Adirondacks but the valley should remain dry
as skies give way to increasing sun through the afternoon.
Daytime highs should reach into the mid to upper 70s with low
80s in the mid-Hudson valley. Cooler in the mid to upper 60s in
the southern Adirondacks and southern VT.

Expect chilly temperatures Thursday night as skies remain clear
and winds turning calm supports ideal radiational cooling. Overnight
lows drop into the low 50s in the valley with mid to upper 40s
in the hill towns and high terrain. The higher peaks of the
southern Adirondacks may even approach 40.

High pressure builds over the Northeast for Friday giving us a
beautiful and seasonably cool day. Expect abundant sunshine and
temperatures warming into the mid to upper 70s with rather low
dew points by late June standard. Luckily winds will be much
lighter. Clouds return Friday night which will keep temperatures
milder with lows only in the mid 50s to low 60s. Chances for
showers approach out western zones late Friday night but the
higher probabilities hold off until daytime Saturday ahead of
our next disturbance.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Unsettled conditions return for the weekend, as an upper level
trough and surface low approach from the Great Lakes region. A warm
front associated with this system looks to bring showers and
thunderstorms Saturday into Saturday night, with scattered
showers/thunderstorms possible Sunday as the system`s cold front
tracks through the region. Locally heavy rainfall is possible
Saturday-Saturday night as 00Z/26 GEFs suggest PWAT`s increase to
1.5-2 inches (+2 to +3 SD).

A trailing upper level disturbance could bring isolated
showers/thunderstorms to portions of the region Monday, with fair
weather returning by Tuesday.

Slightly below normal temperatures are expected Saturday and again
Monday with highs mainly in the mid 70s to around 80. Seasonable
warmth is expected Sunday and Tuesday, with highs mainly in the
upper 70s to lower/mid 80s. Overnight lows will be warm Saturday
night, mainly in the 60s to lower 70s, then cooling into the 50s to
lower 60s for Sunday/Monday night, with some 40s possible across
higher elevations.

&&

.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
Through 06Z/Thu...VFR conditions are expected through daybreak,
despite a few showers tracking southeast and affecting KGFL/KALB
between 09Z-13Z/Wed as a warm front approaches.

There could be borderline MVFR Cigs for a brief time between 13Z-
16Z/Wed at KALB and KPSF, otherwise mainly VFR conditions through at
least mid afternoon. Later this afternoon, scattered
showers/thunderstorms may develop at KPOU, with more widespread
showers and thunderstorms expected after 00Z/Thu at KALB, KPOU and
KPSF as a wave of low pressure tracks just south of the region.
Occasional MVFR/IFR Vsbys/Cigs will be possible within any heavier
showers/thunderstorms this evening. The best chance of thunderstorms
will be at KPOU and KPSF, although some chance that thunderstorms
reach as far north as KALB.

South to southwest winds 5-10 KT with a few gusts of 15-20 KT
through daybreak will then shift into the west by late morning at
similar speeds/gusts. West to northwest winds will decrease to less
than 5 KT toward and after sunset, although may become southeast at
KPOU around 5 KT.

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

Outlook...

Thursday Night: No Operational Impact. NO SIG WX.
Friday: No Operational Impact. NO SIG WX.
Friday Night: No Operational Impact. NO SIG WX.
Saturday: High Operational Impact. Likely SHRA...TSRA.
Saturday Night: High Operational Impact. Definite SHRA...TSRA.
Sunday: Moderate Operational Impact. Breezy. Scattered SHRA...TSRA.
Sunday Night: No Operational Impact. NO SIG WX.
Monday: No Operational Impact. NO SIG WX.

&&

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

&&

$$

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