793
FXUS61 KALY 172055
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
Issued by National Weather Service Burlington VT
455 PM EDT Tue Jun 17 2025

.SYNOPSIS...
Cloudy skies through tonight with scattered areas of showers. As
our warm front begins to lift north of the area tomorrow, clouds
finally break for some sun resulting in warmer temperatures and additional
scattered showers and potential storms with any storm capable
of heavy downpours. Potential dangerous heat and humidity
returns for Thursday ahead of a strong cold front which can
result in strong to severe thunderstorms with damaging winds the
main hazard.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Widespread cloudy skies late this afternoon into tonight with
additional scattered areas of showers tracking through PA
heading into the Catskills and areas south of I-90 in response
to continued southwest flow and weak low and mid-level warm air
and moisture advection. With our sfc warm front slowly pushing
towards the MD/PA border, much of the Northeast and mid-
Atlantic remains within the cool conveyor belt ahead of the
front. Luckily, this air mass has also limited instability so
not expecting thunderstorms through tonight. We maintained
chance POPs for scattered showers from I-90 southward through
tonight with likely POPs after Midnight as additional shortwave
track north/eastward.

The clouds and increased humidity/muggy conditions will keep it
mild tonight with overnight lows only falling into the mid-60s.


&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/...
Key Message:

- The Storm Prediction Center has upgraded to a slight risk
  (level 2 to 5) for severe weather on Thursday as a potent
  cold front tracks eastward across the Northeast with damaging
  winds the primary hazard.

- Confidence is increasing that the combination of hot
  temperatures and uncomfortable humidity on Thursday will
  necessitate heat advisories, especially in the mid-Hudson
  Valley, Litchfield County, CT, into the Capital Region. There
  is a 30 to 50% chance for high temperatures to reach or exceed
  90 degrees in these areas, which would result in heat index
  values or the "feel-like temperatures" climbing into the mid
  to upper 90s.

Discussion:

Cloudy skies continue in Wednesday morning with a few scattered
showers as our mid-level warm front lifts north across the
region as mid-level shortwaves track overhead while our sfc
warm front continues to slowly lift north through the mid-
Atlantic. By midday into the afternoon, the sfc warm front will
finally begin lifting from south to north across eastern NY and
western New England. This will allow sfc winds to shift from the
southeast and become more southerly with low stratus clouds
lifting and even giving way to breaks of afternoon sun. Given
ongoing southwest flow aloft advecting moisture from the Gulf
into the Northeast, PWATs will remain quite high with values
from both the NAEFS and ENS ~2 inches which ranks in the 99th
percentile of the CFSR climatology. Such values also exceed the
90th of the SPC sounding climatology for June 18. Thus, such a
moisture environment will easily generate instability as breaks
of sun develop, especially areas west of the Hudson which should
break for sun first and thus have more time to recover. Forecast
soundings continue to favor a "tall-skinny" signature with FZ
levels nearing 13kft and rather slow unidirectional shear
(~20-30kts) through the column supportive of more of a heavy
rain rather than severe weather hazard from any storms that
develop. WPC has introduced a "marginal risk" in its Day 2
Excessive Rainfall Outlook covering the mid-Atlantic into the
mid-Hudson Valley, eastern Catskills and NW CT which matches up
with areas where the highest instability can develop. Given that
breaks of sun hold off until the afternoon hours, overall
instability values are meager, generally limited to around 500
maxing out near 1000 J/kg and again favored south/west of the
Capital District. Any thunderstorm can produce heavy downpours
resulting localized poor drainage and urbanized flooding.
Otherwise, it will be warmer and very humid tomorrow with
temperatures warming quickly once clouds break for sun rising
into the upper 70s to low 80s in valley areas.

Storms/showers diminish with the loss of daytime heating and
we should trend drier Wednesday night. The sfc warm front finally
lifts north of the area Wed night but given such a muggy air
mass, temperatures will not cool much only falling into the mid
to upper 60s with patchy fog developing where rain occurred
during the day and skies can at least partially clear.

Attention then turns to Thursday when confidence has increased
for both heat and severe weather impacts. An intensifying
shortwave trough and deepening sfc low tracking northeastward
through Ontario and strengthening southwesterly winds ahead of
the low will advect an even warmer air mass into the Northeast
with 850 hPa isotherms +17C to +20C. Any early fog/stratus
quickly give way to morning sun and as southerly winds turn a
bit breezy supporting deep boundary layer mixing, temperatures
will likely rise into the mid to upper 80s, topping out in the
low 90s in immediate valley areas in the afternoon. Probabilistic
guidance has trended upward showing a 30 to 50% chance for
temperatures to exceed 90 in valley areas Thurs afternoon. The
combination of high humidity and very warm temperatures will
result in heat index values around or slightly above 95 degrees
in valley areas Thursday P.M which likely will necessitate heat
advisories. Will continue to monitor but heat sensitive
populations should be mindful of potential heat related impacts
(heat stroke/heat exhaustion) on Thursday and limit unnecessary
or strenuous outdoor activities. WPC`s HeatRisk continues to
show much of our valley areas in its "moderate" or level 2
categories as well.

As such a warm and humid air mass spreads across the
Northeast, we will monitor an approaching cold front and upper
level parent trough tracking through Ontario. There remains
discrepancies on timing and amplitude of the trough as some
guidance is more robust with the trough, suggesting it takes on
a neutral to even negative tilt resulting in rapid height falls
downwind extending into eastern NY and western New England
during peak heating. Needless to say, the air mass ahead of it
will be primed with plenty of sfc based instability available as
mid-level lapse steepen and strong southwesterlies aloft
support deep layer shear values 40-45kts. Straight line
hodographs and shear vectors oriented parallel to the forcing
mechanism support a linear storm mode but some storms cluster
could develop ahead of the main cold front. Again, the timing
of the front will be key as we ascertain the severe weather
potential as an earlier arrival during afternoon peak heating
would increase the potential for severe weather. Damaging winds
is the primary hazard from severe thunderstorms (especially if a
squall line develops ahead of the front) as well as heavy
downpours given the high PWATs. Given the favorable set-up and
strong forcing for ascent, SPC introduced a slight risk (level 2
to 5) its Day 3 Convective Outlook over much of eastern NY and
western New England for Thursday. WPC has blanketed much of the
Northeast in its "marginal risk" (level 1 of 4) for potential
localized flash flooding, mainly from storms that train/persist
over an area.

The trough axis/sfc cold front should quickly push through the
region by Thursday evening, ending the severe weather potential.
Winds shift to the northwest in the wake of the front, advecting
relatively cooler and less humid air into the region. Overnight
lows fall into the mid to upper 50s with low 60s in valley
areas. Breezy northwest winds in the wake of the front/trough on
Friday will result in much more comfortable conditions as
subsidence builds overhead and high temperatures only rise into
the 70s to low 80s.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Key Messages:

- Increasing confidence for a period of dangerous heat and
  humidity early to mid next week. Probabilistic guidance shows
  50 to 90% chance for temperatures to exceed 90 degrees in
  valley areas on Monday and 30 to 50% chance on Tuesday. Heat
  index values may exceed 100 degrees both days.

Discussion:


High pressure builds overhead for Saturday giving us a pleasant
start to the weekend as large scale subsidence from the Midwest
builds eastward. As the ridge builds into the Northeast, the
conveyor belt of strong westerly winds along its northern
periphery tracks overhead. Temperatures trend warmer and
humidity levels rise higher on Saturday under partly sunny
skies thanks to residual mid-level moisture in the conveyor
belt. We continue to monitor the Saturday night into early
Sunday period of a potential "ridge roller" as guidance
continues to show shortwaves riding within the fast westerly
flow aloft which could support additional areas of
showers/thunderstorms or even an MCS (depending on the track).

Then, our focus turns to a prolonged period of hot and humid
weather Sunday through Tuesday as the large anti-cyclone from
the Midwest/Ohio Valley builds eastward with the hot air dome at
its core extending into the Northeast. With guidance in good
agreement for 700 and 850 hPa isotherms reaching 3.5 - 3
standard deviations above normal per the NAEFS. Probabilistic
guidance shows the highest confidence for temperatures exceeding
90 degrees on Monday with greater than 75% confidence throughout
valley areas and even 50 to 75% confidence for greater than 95
degrees. Such high temperatures conbined with higher humidity
values will likely result in dangerous heat index values or
"feel-like temperatures" closer to 100 - 105 degrees.
Probabilistic guidance trends slightly lower for Tuesday with 30
to 60% chance for temperatures exceeding 95 degrees but
regardless, dangerous heat is still expected to be a concern.
WPC HeatRisk graphics show "moderate" and even "major" heat-
related impacts for Sunday and Monday, respectively. Sensitive
populations including the very young, elderly, and those with
pre-existing conditions should limit time outdoors and avoid any
strenuous outdoor activities. Stay hydrated (even if you are not
thirsty) and stay in air-conditioning, if available. Visit
weather.gov/heat for more preparedness information.

&&

.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
Mix of MVFR and IFR conditions, along with a cluster
of light showers affecting ALB and PSF, are currently being
observed. Moving forward, primarily IFR conditions can be expected
at all sites as ample low level moisture remains in place, with
additional periodic showers through about 12Z. Thereafter, a warm
front will have lifted to the northeast of our region, supporting
some increased mixing out of the low clouds with a trend towards
MVFR ceilings and P6SM visibilities. Winds generally southerly and
light through the period, increasing a bit towards the end of the
period; however, southeasterly winds near 10 knots with a few gusts
to 20 knots at PSF may persist for a few hours this afternoon.

Outlook...

Wednesday Night: Low Operational Impact. Chance of SHRA.
Thursday: High Operational Impact. Breezy. Likely SHRA...TSRA.
Thursday Night: Moderate Operational Impact. Breezy. Chance of SHRA.
Friday: No Operational Impact. NO SIG WX.
Friday Night: No Operational Impact. NO SIG WX.
Saturday: Low Operational Impact. Slight Chance of SHRA...TSRA.
Saturday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Sunday: 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...Speciale
AVIATION...BTV