377
FXUS61 KALY 152322
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
722 PM EDT Mon Jul 15 2024

.SYNOPSIS...
Scattered showers and thunderstorms are anticipated
tonight as a result of a nearing upper level disturbance. Some of
the thunderstorms may produce damaging winds along and west of the
Hudson River Valley prior to midnight. High heat and humidity
continue tomorrow with additional chances for showers and
thunderstorms, some strong to severe. A cold front will
then cross the region Wednesday to bring some relief from the heat,
but additional showers and thunderstorms will be possible.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
.UPDATE as of 715...Severe Watch #540 in effect for most of
eastern NY except Warren and Washington Counties until 0400
UTC/midnight.

Impressive squall line/QCLS with an MCV is moving across central
NY towards the WFO ALY forecast area this hour. Lots of wind
damage upstream with a 61 mph gust recorded at KELM. 59 mph gust
recorded at Burdett in the NYS Mesonet. MLCAPE of 1000-2000 J/kg
is in place over the forecast area with DCAPEs in excess of
1000 J/kg. Low-level lapse rates are steep. Damaging winds are
the main threat. The question will be if the line can maintain
itself. Greatest threat look like it will be west of the Hudson
River Valley 730-9 pm or so, then 9-11 pm to the east. KALY
sounding is underway and will give a good snapshot of the
troposphere.

PREV DISCUSSION [0436 EDT]...

Most areas remain dry this afternoon as mid/upper-level ridging
persists across the region. However, some showers and
thunderstorms have popped up in the lower Mid-Hudson Valley and
northwest Connecticut with plenty of instability due to
sufficient heating and high dewpoints.

Well upstream, a mature MCS associated with a potent mid-level
shortwave and vorticity maximum continues to traverse western
New York. Latest CAMs indicate this complex driving eastward
into the CWA by this evening with most of the convective
activity remaining north and west of Albany. With peak heating
hours being long-since over by the time the anticipated line of
storms arrives, there should be a limited risk of storms
maintaining severe strength of becoming severe in the target
areas of the Southwest Adirondacks, Mohawk Valley and Lake
George-Saratoga Region. However, with modest instability
remaining in these areas (on the order of 1000 to 1500 J/kg), 25
to 35kt of 0-6 km shear, and stronger upper-level divergence
present with these areas falling near the favored region of the
curved upper jet maximum, showers and thunderstorms should be
able to be supported through at least midnight before completely
dissipating.

Once the main line of thunderstorms weaken to the point of
ultimate dissipation tonight as instability is lost and the
aforementioned disturbance weakens, dry conditions should
return across eastern New York and western New England. Low
temperatures will fall to the 60s to low 70s across the region
and, with dewpoints in the 60s, a respite from muggy conditions
is not anticipated.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
*Heat Advisory remains in effect for the Hudson Valley including
 the Capital Region, the Mohawk Valley, Lake George Saratoga
 Region, northwest Connecticut and now eastern Windham County
 until 8 PM Tuesday.*

Upon the full passage of the aforementioned shortwave tonight,
geopotential heights increase slightly across the area with the
brief build of a shortwave ridge across the region tomorrow
morning into tomorrow afternoon. While the morning into the
beginning of the afternoon looks to remain dry for most areas,
shower and thunderstorm chances increase beginning tomorrow
afternoon as a positively-tilted, upper-level trough digs
farther south and east into the Great Lakes and Ohio Valley
Regions from southern Ontario. At the surface, low pressure
will settle south of the Hudson Bay, with a southwest-extending
cold front draped through the eastern Great Lakes upstream.

Along the leading edge of a pre-frontal trough, latest CAMs
indicate a potentially strong line of thunderstorms that will
develop and track west to east across the region tomorrow
afternoon into tomorrow evening. With moderate instability
across much of the region courtesy of sufficient heating out
ahead of the convection intersecting 30 to 35 kt of 0-6km shear,
anticipated steep low-level lapse rates, DCAPE near 1000 J/kg,
and mean wind near 25-30 kt, the main threat from thunderstorms
tomorrow will be strong to potentially damaging wind gusts.
Additionally, effective inflow storm relative helicity near 150
to 200 m2/s2 north of Albany could aid in the threat for an
isolated tornado. Isolated instances of large hail also cannot
be ruled out, though is not a high probability due to very warm
surface conditions and high freezing levels. The Storm
Prediction Center has, therefore, placed most of the region in a
Slight Risk for severe thunderstorms for tomorrow.

Outside of the risk for severe thunderstorms, heat will continue
to pose a concern for tomorrow. High temperatures look to range
from the upper 70s/mid 80s at higher elevations with upper 80s
to mid 90s in valley areas. Dewpoints in the upper 60s and low
70s will make for feel like temperatures in the mid/upper 90s to
low 100s (Mid-Hudson Valley) so heat advisories were continued
for valley areas, northwest Connecticut and issued for eastern
Windham County.

The anticipated line of thunderstorms should move out of our
area by tomorrow evening, yielding dry conditions for a brief
period overnight Tuesday night. Low temperatures will fall to
the mid 60s to low 70s with muggy conditions continuing.

Wednesday will see the northwest to southeast progression of the
cold front which will once again bring the chances for showers
and thunderstorms across the region. Higher heat and humidity
will once again be present on Wednesday, though heat indices
will likely not reach as high as Tuesday. High temperatures will
range from the upper 70s to low 80s at higher elevations with
mid/upper 80s to low 90s in valley areas. Maximum apparent
temperatures will likely be in the mid to upper 90s, but decided
to delay the potential expansion of heat advisories by another
day to ensure high confidence. Low temperatures Wednesday will
fall to the upper 50s to upper 60s with lower humidity making
for more comfortable conditions than previous nights.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Key Messages:

1) Dry and more comfortable weather favored for the end of the work
week into the early weekend

2) Chances for showers & storms return to close the weekend into
early next week

Discussion:

Thursday through Saturday...

We start off the period with lingering rain showers mainly across
the mid Hudson Valley and northwest CT associated with a passing
front attached to a passing trough aloft. This front, along with a
building surface high, will help advect a dry, comfortable air mass
across eastern New York and western New England to close out the
work week. 925-850 hPa temps are progged to fall to around 10-15 C
behind the front Thursday, with these values expected to linger into
Saturday. Fcst soundings suggest we will be well mixed in the low
levels, which should allow us to take full advantage of this air
down at the surface. The current forecast has afternoon highs
Thursday and Friday maxing out in the lower to middle 80s in the
valleys, and in the 70s across the terrain, which is around normal
for mid July. Dewpoints will remain confined in the 50s/low 60s as
we mix down the dry air aloft during the afternoon hours. For
Saturday, temperatures in the valleys will be warmer in the mid to
upper 80s with increasing southerly flow behind the high.
Thankfully, dew points will remain in the comfortable range.

Sunday on...

Flow will briefly increase out of the southwest Sunday as ridging
mid-level ridging strengthens across the Mid-Atlantic. These higher
heights will allow temperatures to increase with highs Sunday maxing
out in the upper 80s in valley locations. Sunday afternoon, another
cold front will move across the region from the northwest with
cooler temperatures in tow. This front could provide some forcing
for scattered showers and storms across the region late Sunday into
Monday. Confidence is low on any potential for severe weather or
heavy rain at this time.

Another round of high pressure looks to build into eastern New York
and western New England early next week, with dry conditions
and near normal temperatures favored going into midweek.

&&

.AVIATION /23Z MONDAY THROUGH SATURDAY/...
Isolated to scattered thunderstorms will continue across the lower
Hudson valley with a low chance of operational impacts at POU/PSF
over the next 2-4 hours. A line of thunderstorms will progress east
across the state this afternoon and approach the region this
evening. These storms are expected to be weakening as they approach
area TAF sites. Therefore, elected to only include VCTS during the
most likely timeframe for thunderstorms and will amend the forecast
should confidence in operational impacts increase. Thunderstorms are
expected to quickly end from 04z-06z.

Outlook...

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

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory until 8 PM EDT Tuesday for CTZ001-013.
NY...Heat Advisory until 8 PM EDT Tuesday for NYZ038>041-043-049-
     050-052-053-059-060-064>066-083-084.
MA...None.
VT...Heat Advisory from noon to 8 PM EDT Tuesday for VTZ015.

&&

$$

SYNOPSIS...Gant/Wasula
NEAR TERM...Gant/Wasula
SHORT TERM...Gant
LONG TERM...Speck
AVIATION...Humphrey