302
FXUS61 KALY 160527
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
127 AM EDT Tue Jul 16 2024

.SYNOPSIS...
Scattered showers and isolated thunderstorms will
diminish overnight with patchy fog developing.  High heat and
humidity continue Tuesday 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 THIS MORNING/...
.UPDATE...As of 115 AM EDT, remnant MCV/low level circulation
noted on regional radars centered over SW Adirondacks and
slowly tracking east/northeast. Cluster of showers/thunderstorms
across Litchfield County extending into Berkshire County
tracking east/northeast, and should be shifting east of these
areas within the next 1-2 hours. However, locally heavy
downpours will remain possible across portions of
Litchfield/southeast Berkshire County during this time.

Elsewhere, spotty light showers and drizzle was occurring across
the Mohawk Valley and SW Adirondacks. This should continue
tracking east over the next 2-3 hours, remaining mainly just
north of I-90.

Isolated showers/thunderstorms developing upstream north of the
Tug Hill may affect northern Herkimer/Hamilton Cos over the next
several hours.

Temps will generally hold fairly steady through daybreak, in the
mid 60s to lower 70s.

[PREVIOUS UPDATE 1042 PM EDT]...Severe Thunderstorm Watch #540
for most of eastern NY, except Warren and Washington Counties is
canceled.

Heat Advisories remain up overnight in the Mohawk and Hudson
River Valleys, Capital Region, Lake George Saratoga Region and
NW CT.

The impressive QLCS and MCV weakened the past few hours over
eastern and northern NY that the severe thunderstorm watch was
canceled in coordination with SPC. Some downed trees were
reported in southern Herkimer County, and the eastern Catskills
of western Ulster and Greene Counties. Overall, wind gusts have
been in the 30-45 mph range with the waning instability and the
parcels becoming elevated the past hour or so.

Expect the scattered showers and isolated thunderstorms to
diminish between 11 pm and 2 am with some patchy fog developing
north of the Mohawk Valley and Capital Region. Some lower
stratus clouds will likely form in the wake of the upper level
disturbance and the sfc trough. Lows will be muggy in the 60s to
lower 70s.

&&

.SHORT TERM /6 AM THIS 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 /06Z TUESDAY THROUGH SATURDAY/...
Through 06z/Wed...An upper-level disturbance will cross the
region overnight and will bring at least some MVFR
stratus/stratocu to some TAF sites, especially KALB/KGFL/KPSF.
Cigs may lower to IFR levels at KPSF but there is not enough
confidence to include it in the TAF at this time. TEMPOs have
been included to address the likely transition. KPOU should
trend mostly clear which may result in some patchy fog toward
daybreak.

Cigs will gradually lift back to VFR levels Tuesday morning at
all sites. Another disturbance will bring a round of showers
and thunderstorms later in the afternoon into the early evening.
Some of these storms could be strong to locally severe. Will
continue with PROB30 groups and fine tune timing as this event
gets closer. Some lower level stratus/stratocu may develop in
the wake of these storms Tuesday evening; otherwise, looking at
a return to VFR conditions.

Wind will be south to southwesterly at 4-8 kt through the
overnight, then increase to 7 to 15 kt on Tuesday with a few
gusts to around 20 kt. Wind will decrease to less than 10 kt
Tuesday night.

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 this evening for CTZ001-013.
NY...Heat Advisory until 8 PM EDT this evening for NYZ038>041-043-
     049-050-052-053-059-060-064>066-083-084.
MA...None.
VT...Heat Advisory from noon today to 8 PM EDT this evening for
     VTZ015.

&&

$$

SYNOPSIS...Gant/Wasula
NEAR TERM...KL/Wasula
SHORT TERM...Gant
LONG TERM...Speck
AVIATION...Rathbun