139
FXUS61 KALY 131040
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
640 AM EDT Tue Aug 13 2024

.SYNOPSIS...
High pressure building eastward into the region will bring
pleasant conditions today. Chances for isolated to scattered
showers and thunderstorms increase Wednesday and Thursday
afternoon due to a nearby disturbance. Additional chances for
showers and thunderstorms come this weekend with the approach of
a frontal system. Temperatures remain on the cooler side for
mid-August today before nearing normal values for the middle and
end of the work week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
.UPDATE...The forecast remains on track with this update. Minor
updates were made to ensure consistency of temperatures and sky
cover with recent obs and trends, but elsewhere all remains
status quo. See the previous discussion below for additional
details on today`s forecast.

.PREVIOUS DISCUSSION...
Water vapor imagery shows an upper low spinning just inside the
Gulf of Maine with its associated upper shortwave attempting to
exit the Northeast in tandem with its eastward progression. Our
region remains under cyclonic flow on the rear flank of the
trough with northwest flow advecting cool air and making for a
chilly night for most by August standards as temperatures
currently range primarily from the upper 40s/low 50s at higher
elevations to mid/upper 50s in valley areas. With high pressure
building in from the west at the surface, subsidence has kept
skies clear in most areas, though some low-level clouds have
been allowed to form and have remained persistent at the higher
peaks of the Eastern Catskills, Southern Greens, and Berkshires
thanks to upslope flow. Infrared satellite imagery also shows
light fog formation in some sheltered areas courtesy of ample
radiational cooling so maintained fog in the forecast through
daybreak.

Throughout the day today, the aforementioned shortwave will
continue to track farther eastward as high pressure pushes
farther into the region. Plenty of sunshine and dry conditions
can be expected as subsidence persists with the building high.
Temperatures will remain on the cooler side for mid-August
standards, but will fair a few degrees higher than yesterday
with widespread 70s and pockets of upper 60s above 1500 ft.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
Dry conditions persist throughout the evening and into the
overnight period tonight with high pressure dominant across the
region. Mainly clear skies will lead to another night of prime
radiational cooling conditions, yielding low temperatures in the
50s with isolated pockets of upper 40s in the Southwest
Adirondacks and Eastern Catskills. Light fog development will
also be possible again in sheltered, low-lying areas.

Wednesday will begin dry before chances for isolated to scattered
showers and thunderstorms increase for the afternoon and
evening hours courtesy of the previously mentioned upper low
beginning to retrograde westward. With little forcing and
counteracting subsidence, thunderstorms that develop are not
anticipated to become severe. However, thermal profiles from the
latest CAMs indicate 500 to 1000 J/kg SBCAPE with steepening
low-level lapse rates, so a couple of stronger wind gusts cannot
be ruled out. High temperatures Wednesday will warm closer to
August normals with mid/upper 70s to low 80s anticipated.

Any showers and thunderstorms that develop should
dissipate rather quickly Wednesday evening with the loss of
daytime heating, yielding a mainly dry night Wednesday night.
Thursday will more or less be a rinse and repeat of Wednesday in
terms of afternoon convection, but with increased coverage of
showers and thunderstorms as the upper low backs farther west
closer to the Northeast Coast. Once again, modest instability
(500 to 1000 J/kg SBCAPE), limited shear (~15 to 25 kt from
0-6km), and an overall lack of strong forcing will lead to the
low probability of thunderstorms becoming severe. However, with
a cool pool aloft extending inland from the system helping to
increase low- level and mid- level lapse rates and DCAPE looking
to be around 600 J/kg, some gusty winds are possible with
thunderstorms that may form. High temperatures Thursday will be
a few degrees cooler than Wednesday, though mid/upper 70s to low
80s can also be anticipated.

Loss of daytime heating in addition to the low beginning to move
back east will allow convection to rapidly die off Thursday
night, bringing dry conditions for the overnight period. With
more cloud cover around, lows will fall to the upper 50s to low
60s with mid 50s at higher elevations.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
The period starts out on Fri with surface high pressure shifting
east off the New England coast, with an upper level ridge axis
forecast to be in place through the day. This should result in dry
conditions and near normal temperatures across our area.

The pattern then becomes unsettled during the upcoming weekend, as
an upper level trough approaching from the Great Lakes slowly moves
east across the region. Low level southerly flow will increase ahead
of the trough, which will transport anomalous moisture (PWAT
anomalies increase to +1 to +2 STDEV) northward. Along with forcing
from the upper trough, a frontal system/triple point at the surface
looks to gradually push eastward through Sun. So will mention 50-70%
PoPs Sat through Sun night, with the highest values during the
diurnally favored times for convection (afternoon/evening). Locally
heavy rainfall may occur, especially within any persistent
convective showers/T-storms. Temperatures look near normal for
highs, but above normal for lows due to mostly cloudy and humid
conditions at night.

The main upper level trough axis may still be over or even west of
our area on Mon, so will linger mention 30-60% PoPs. There will be
chances for thunder again during the afternoon/evening hours.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
Through 12z Wednesday...Any patchy fog should dissipate by
11z-12z, with VFR conditions then expected to prevail through
the rest of the day. FEW-SCT clouds around 5-6 kft will develop
due to diurnal effects, but no showers are anticipated today.

There is a low probability for fog tonight with mainly clear
skies, but confidence is low since there looks to be just enough
of a pressure gradient for a light northerly breeze at the
surface or just above the mixed layer. Will mention MVFR vsby
for now at KGFL/KPSF and will re-evaluate potential for
subsequent TAF issuances today.

Winds will range from calm to westerly around 3-6 kt through
the rest of the night, then becoming northwest and increasing to
6-8 kt by late this morning.


Outlook...

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

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.

&&

$$

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