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515
FXUS61 KALY 211836
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
236 PM EDT Fri Jun 21 2024

.SYNOPSIS...
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Warm and humid conditions will continue across the area this
weekend, with shower and storm chances each day. Strong to
severe storms will be possible on Sunday as a cold front moves
through the area, with quieter conditions expected early next
week.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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** Heat Advisory in effect for the mid Hudson Valley and all of
 Litchfield County, CT through 8 PM today.

Regional observations to include the NYS Mesonet showing a
backdoor cold front draped just south of the Mohawk River early
this afternoon, with latest radar trends showing widespread
shwr and storm coverage both north and south of this boundary.
Activity has really picked up in the last hour or so, with some
support being provided by a weak impulse noted on upper-level
water vapor imagery and SPC Mesoanalysis data. With high PWAT
values (>90% of normal for today`s date), efficient rainfall
production and isolated flooding will be possible with any
storms that linger of an area for a period of time. That said,
storms so far have shown enough east-southeast movement to limit
residence time for now, however trends will have to be
monitored as the afternoon hours progress. WPC did upgrade
southern portions of our forecast area into the SLGT risk
category for excessive rainfall, which seems reasonable given
the high PWAT values currently in place. In terms of severe
potential, overall threat remains marginal this afternoon as
best deep-layered shear remains across northern NY and southern
Canada, with better instability located further south along
the I-90 corridor and points south. That said, steep low-level
lapse rates along with heavy precip loading may result in a few
isolated strong wind gusts with collapsing storms.

Convective coverage should begin to decrease later this evening
with loss of daytime heating. As this occurs, upper ridge
responsible for the excessive heat these past few days will
begin to deamplify with time. Have maintained mention of early
morning fog for valley locations early Saturday morning, however
uncertainty exist due to possible increased cloud as compared
to this morning. Lows tonight should range from the lower to
middle 60s across the southern Dacks, to low 70s further south
across the mid Hudson Valley.
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&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
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**Heat Advisory for the mid-Hudson Valley and Litchfield County,
 CT through 8PM Sunday.**

Very similar conditions expected across the area on Saturday as
aforementioned backdoor front remains hung up across our area.
As a result, another day of late morning shwrs and storms is
expected, with activity becoming more widespread during peak
heating in the afternoon. Overall severe threat again looks
marginal as best deep layered shear remains displaced to the
north and displaced from the main instability axis which again
will be positioned along the Mohawk Valley and points south.
SPC has our area in another marginal risk for Saturday, with
isolated strong wind gusts again being the biggest concern.
Another warm day is expected for the mid Hudson Valley and
Litchfield County, CT as these locations will remain south of
the backdoor front. Have expanded the heat advisory further east
to eastern Dutchess and Litchfield Counties in collaboration
with adjacent offices.

Diurnal shwr/storm activity will begin to come to an end early
Saturday evening with loss of daytime heating. Attention then
begins to turn to Sunday, as large-scale upper wave begins
digging into the western and central Great Lakes, before sliding
into our region and gradually taking on a more neutral to
slightly negative tilt with time. As this occurs, much if not
all our forecast area will quickly move back into the warm
sector with increasing southwesterly low-level flow. Model MSLP
field suggest there could be a pre-frontal trough that leads to
an initial round of convection late Sunday morning and early
afternoon, with another round possible later in the day as main
cold front approaches from the west.

As of right now, deep layered shear of 30-40 kts appears likely
as the main upper trough approaches from the west with time.
Shear magnitudes will likely be a bit better than what we`re
seeing both today and Saturday, however the biggest caveat
appears to be just how unstable the atmosphere becomes later in
the day behind the early round of convection. That said,
kinematics and large-scale forcing will definitely be present,
and Sunday into early Sunday night definitely warrants continued
focus.
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&&

.LONG TERM /MONDAY THROUGH THURSDAY/...

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Main upper trough will slide through the region on Monday in a
post-frontal airmass with instability shwrs/iso storms possible
across the area. This will finally result in cooler temps for
the start of next week with highs on Monday expected to warm
into the upper 70s to lower 80s down south. Weak upper ridging
will lead to dry conditions across the area on Tuesday before
next upper trough approaches from the west on Wednesday. Shwrs
and storms look to move back into the area Wednesday afternoon
with activity possibly lasting through Thursday morning. This
looks to be followed by the arrival of high pressure Thursday
night with drier weather expected through the early weekend.
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&&

.AVIATION /18Z FRIDAY THROUGH TUESDAY/...

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Through 18z Saturday...VFR conditions currently prevail at all
terminals, though scattered showers and thunderstorms threaten to
disrupt the peace. Included TEMPOs between 18-23z for showers and
thunderstorms which will likely reduce visibility and lower ceilings
to MVFR to IFR thresholds due to heavy downpours.

Showers and thunderstorms should subside upon the loss of daytime
heating this evening, yielding another dry overnight period. VFR
conditions will, therefore, be returned at all terminals for a brief
time. There is, however, an increased likelihood of mist/fog
formation especially at KGFL and KPSF courtesy of light to calm
winds and elevated low-level relative humidity. For now, maintained
MVFR conditions since there is a little bit of uncertainty in terms
of cloud cover overnight. IFR visibilities and ceilings cannot be
ruled out, though, and will make adjustments with future updates if
necessary. Any fog should burn off relatively quickly after sunrise
tomorrow.

Winds throughout the period will be light at sustained speeds of 3-6
kt. While winds will generally begin to hold a northeast direction,
a gradual shift to a more southerly direction will occur throughout
the period.

Outlook...

Saturday Night: Moderate Operational Impact. Scattered SHRA...TSRA.
Sunday: High Operational Impact. Breezy. Definite SHRA...TSRA.
Sunday Night: Moderate Operational Impact. Numerous SHRA...TSRA.
Monday: Moderate Operational Impact. Chance of SHRA...TSRA.
Monday Night: Low Operational Impact. NO SIG WX.
Tuesday: No Operational Impact. NO SIG WX.
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: Moderate Operational Impact. Chance of SHRA...TSRA.
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&&

.ALY WATCHES/WARNINGS/ADVISORIES...
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CT...Heat Advisory until 8 PM EDT Sunday for CTZ001-013.
NY...Heat Advisory until 8 PM EDT Sunday for NYZ064>066.
MA...None.
VT...None.
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&&

$$

SYNOPSIS...32
NEAR TERM...32
SHORT TERM...32
LONG TERM...32
AVIATION...Gant