238
FXUS61 KALY 070805
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
405 AM EDT Mon Jul 7 2025

.SYNOPSIS...
Very humid and hot today with chances for showers and
thunderstorms capable of producing heavy downpours and gusty
winds mainly in the western Mohawk Valley and western and
southern Adirondacks as a cold front slowly sinks out of
Canada. Additional showers are possible south of I-90 as the
remnants of tropical cyclone Chantal track into the mid-
Atlantic. Muggy and very warm again tomorrow with additional
showers and thunderstorms capable of producing heavy downpours
mainly south of I-90 as our cold front continues slowly tracking
southward.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Key Message:

- Dangerous heat expected from the Capital District into the
  Mohawk Valley and Upper Hudson Valley today due to the
  combination of high temperatures in the upper 80s to low 90s
  and very humid conditions.

- Areas of heavy rain and embedded thunderstorms likely in the
  Southwest Adirondacks and Mohawk Valley later this afternoon
  into this evening. Localized flooding possible where heavy
  rain can repeatedly impact a given area and locally damaging
  winds possible should storms become strong to severe.

- Locally heavy rain possible in the mid-Hudson Valley, eastern
  Catskills into parts of western New England as the remnants of
  Chantal track into the mid-Atlantic today.

Discussion:

We start the day under mainly sunny skies as broad ridging
persists over the Northeast while a cold front positioned well
to out north in southern Canada slowly tracks southward. Latest
water vapor and IR imagery also shows the remnants of tropical
cyclone Chantal rapidly weakening as it tracks northward into
VA and the mid-Atlantic. Southwest flow aloft will advect cirrus
clouds from Chantal northeastward into the our region this
morning and especially this afternoon so expect sun to fade
behind thickening cirrus. Otherwise, it will be uncomfortably
humid today as PWATs rise to 1.5 - 2.25 inches and dew points
reach into the upper 60s to low 70s. The combination of high
humidity, sufficient insolation and weak capping will easily
allow instability to develop across the region through the day
with ML CAPE values rising to 1.5k to 2k J/kg by this afternoon.
In addition, 850hPa isotherms again ranging +17C to +18C will
result in daytime highs rising into the upper 80s to low 90s.
When combined with the high humidity, expect dangerous heat
index values or "feel-like" temperatures reaching into the mid
to upper 90s. Highest confidence for heat index values to reach
or slightly exceed the 95F criteria is in the Capital District,
Mohawk Valley, and Upper Hudson Valley where we issued the heat
advisory. Sensitive populations should limit strenuous outdoor
activities and drink plenty of water, even if not thirsty, to
stay hydrated. Areas further south in the mid-Hudson Valley were
close to the criteria but given increased cloud coverage and
shower potential from the remnants of Chantal, held off on heat
advisories there.

There will be two main regions to monitor for potential heavy
rain/localized flooding and thunderstorm development. The first
area will across the western and southern Adirondacks into the
western Mohawk Valley later this afternoon (18 - 21 UTC) into
early evening. Our cold front sinking out of southern Canada
will be very slow moving and therefore will give ample time for
this region to destabilize in response to the high humidity and
insolation. In fact, there is good consensus that such conditions
should generate SB CAPE values exceeding 2k J/kg. By the time
the front approaches by mid to late P.M and erodes any minimal
cap, high res guidance shows thunderstorms/areas of heavy rain
quickly becoming focused along the boundary given weak deep
layer shear values around 20-25kt oriented parallel to the
front. With high FZ heights/warm cloud depths 13-14kft and high
PWATs ~2", heavy downpours can easily occur and could
train/repeatedly impact over an area as cloud layer winds remain
parallel to 850hPa winds. The HREF shows a broad region of
30-50% probabilities for 3-hrly QPF amounts to exceed 1 inch
between 18 - 00 UTC oriented along the front and these
probabilities extend into parts of the western Mohawk Valley.
WPC expanded its slight risk (level 2 of 4) in its Day 1 ERO
across the Southern Tier into parts of Oneida County but stops
right at the Herkimer County border where the marginal risk
(level 1 of 4) continues. This makes sense as 3-hrly flash flood
guidance is quite high at 2.25 - 3 inches so any flooding
impacts should be limited to the typical trouble spots/poor
drainage and urban areas. Regardless, we will maintain a close
eye on potential localized flooding late this afternoon into
this evening. A few storms could grow upscale enough to result
in localized damaging winds mainly from wet microbursts given
DCAPE values >500 J/kg but with forecast soundings showing mid-
level lapse rates limited to 5.5 - 6C/km, any strong to severe
storms should be isolated. SPC expanded its marginal risk (level
1 of 5) in its Day 1 Convective Outlook to cover more of the
southwest Adirondacks and Mohawk Valley but given the late
arrival of the front, severe storms should be isolated.

The second area to monitor for heavy downpour potential will be
south of I-90 mainly in the eastern Catskills, mid-Hudson Valley
and NW CT/southern Berkshire where moisture streaming ahead of
the remnants of Chantal may result in disorganized areas of
rain and embedded isolated thunderstorms. While the remnant
circulation of Chantal will continue to quickly become sheared
out and remain well to our south crossing into the DelMarVa,
southwest flow aloft will direct leftover weak troughing towards
southern New England. Sufficient weak forcing ahead of the
trough combined with mid- level moisture within a region of very
high PWATs (ranking among the highest values in the 30 yr CFSR
model climo) looks to result in a few areas of rain and
thunderstorms with heavy downpours certainly possible given high
warm cloud depths ~13-14kft that can easily support efficient
warm rain processes. While there is rather good consensus on
showers reaching our southern zones, there is discrepancy on the
resultant QPF. The HREF probabilistic guidance shows nearly 50%
chance that 3-hrly QPF exceeds 1 inch this afternoon while QPF
spread from the NBM during this window is limited to between 0
and 0.25". The potential for heavy rain is certainly there given
the moisture rich environment but weak forcing may limit the
coverage. WPC maintained a broad brushed marginal risk in its
Day 1 ERO that includes these southern zones. We maintained the
heavy rain potential wording in the forecast for this afternoon
into the early evening and given very weak flow through the
column <20kts, localized flooding may occur from slow moving
storms or where storms repeatedly impact.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...

Key Message:

- Locally heavy downpours and isolated severe thunderstorms
  potential continues into Tuesday mainly focused south of I-90
  as a slow moving cold front pushes south/east through the
  region.

Discussion:

Oppressive humidity continues into tonight as our cold front
continues its slow progression south and eastward across the
forecast area. Additional areas of rain and locally heavy
downpours with isolated thunderstorms likely continue into the
overnight hours along the front with storms diminishing after
Midnight. By Tuesday morning, the front should be positioned
across the Capital District and continuing to push south/east.
The air mass ahead of the front mainly south of I-90 will remain
very warm and very humid as PWATs remain high around 2". While
the 850hPa isotherms will still be elevated at +17C to +18C,
increased cloud coverage and shower activity should limit
daytime heating and therefore we are not as confident in
temperatures becoming warm enough to warrant additional heat
advisories. It will be close though as our latest forecast shows
highs reaching into the upper 80s to around 90 with dew points
in the upper 60s to low 70s resulting in heat index values or
"feel-like" temperatures in the mid to upper 90s in far southern
Ulster/Dutchess/Litchfield. Such a warm and humid air mass
combined with daytime heating will also result in SB CAPE values
ranging 1000 - 2000 J/kg across the mid-Hudson Valley, NW CT,
southern Berkshire and eastern Catskills and with deep layer
shear values 20-30kts and slightly steeper mid-level lapse rates
around 6C/km, we will once again need to monitor severe weather
and heavy downpour potential as the front pushes southward
through the day resulting in areas of showers and thunderstorms.
The SPC Day 2 Convective Outlook maintains its marginal risk
(level 1 of 5) across these southern zones with damaging winds
the primary hazard from any severe storm and WPC continues it
marginal risk focused across far southern zones in its Day 2
ERO. Again, high PWATs/high warm cloud depths and cloud layer
mean winds oriented parallel to the boundary will support heavy
rain focused along the front which could result in localized
flooding. Areas behind the front from the Capital District
north/west will experience lowering humidity through the day as
northwest winds advect a drier air mass into the area but
temperatures will still be very warm reaching into the mid to
upper 80s with upper 70s in the southern/western Adirondacks.
POPs trend lower Tuesday night as the front finally pushes to
our south with drier air arriving in its wake leading to
partial clearing skies and more comfortable temperatures/humidity.

We finally get a break from the wet weather by Wednesday as the
front settles to our south and high pressure briefly builds over
the Northeast. However, it will still be quite warm albeit not
as humid as weak southwest flow continues aloft supporting
high temperatures rising into the mid to upper 80s with upper
70s in the higher terrain. Troughing becomes re-established
across southern Canada by Wed night with the main trough axis
remaining well to our north/west. We maintained slight chance
POPs with chance POPs across far southern zones as the front
remains stalled to our south and weak height falls ahead of the
trough may result in additional shower development along the
boundary. Some members of guidance even suggest a weak sfc low
develops along the boundary resulting in more organized areas
of rain but not enough confidence to include anything more than
chance POPs in southern zones at this time. Otherwise, Wed
night remains warm and a bit muggy with overnight lows and dew
points in the 60s.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Coming soon.

&&

.AVIATION /07Z MONDAY THROUGH FRIDAY/...
Through 06z Tuesday...VFR conditions will prevail through much of
the night with just a few mid and high clouds around. Scattered low
ceilings in the MVFR range will be possible at KPSF/KPOU early this
morning, along with patchy fog at KGFL. However, confidence for both
these impacts are low due to guidance backing off on low stratus
development, and stronger surface winds limiting fog coverage. Going
into the daytime Monday, expect continuation of VFR conditions with
the exception of KPOU/KPSF/KALB where PROB30 groups have been
maintained for a low potential for afternoon showers and storms.
COnfidence for showers/storms at KGFL is low at this time as
majority of guidance weakens the storms before entering the
vicinity, but this may be adjusted in later TAFs. Late in the
period, MVFR ceilings will be possible at all terminals with the
approach of a frontal boundary from the northwest, but impacts
should hold until after 08/06z. Winds will be around 5 kt from the
S/SE tonight, increasing to 5-10 kt tomorrow with gusts up to 15-20
kt during the afternoon.

Outlook...

Tuesday Night: Low Operational Impact. Slight Chance of SHRA.
Wednesday: Low Operational Impact. Slight Chance of SHRA...TSRA.
Wednesday Night: Low Operational Impact. Slight Chance of SHRA.
Thursday: Moderate Operational Impact. Likely SHRA...TSRA.
Thursday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Friday: Moderate Operational Impact. Chance of SHRA...TSRA.
Friday Night: Low Operational Impact. NO SIG WX.
Saturday: Low Operational Impact. Slight Chance of SHRA...TSRA.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...Air Quality Alert from 11 AM this morning to 11 PM EDT this
     evening for CTZ001-013.
NY...Heat Advisory from noon today to 8 PM EDT this evening for
     NYZ038-040-041-043-049-050-052-053-083-084.
MA...None.
VT...None.

&&

$$

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