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000
FXUS61 KALY 081742
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
142 PM EDT Sat Aug 8 2020

.SYNOPSIS...
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Today will be mostly sunny and warm, with an isolated shower or
thunderstorm. High pressure builds back in tonight into Sunday
with dry weather and temperatures rising back above normal
Sunday afternoon. An upper level disturbance may bring a shower
or thunderstorm to the northern part of the area Sunday evening.
The heat and humidity increases for Monday into the mid week
along with the chances for afternoon showers and thunderstorms.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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As of 141 PM EDT...radar showing some widely isolated showers
over central NY, the Tug hill and the high peaks of the
Adirondacks. Cell movement has been almost west to east. Skies
have almost cleared out in valley locations with sct to bkn
cumulus over the high terrain. Still looking for a modest
increase in coverage of showers later today, but showers/storms
still remaining generally isolated. Temperatures have warmed
into the 70s in the hills to 80s in the valleys.

Previous...
There is a risk for isolated/scattered showers or thunderstorms
in the afternoon, as the mid and upper level trough axis moves
well downstream over New England and northwest flow sets up
aloft. The latest 00Z HREFs has mean SBCAPEs of 250-750 J/kg
with weak 0-6 km shear of 15-20 kts. Some loosely organized or
pulse type thunderstorms may be possible.

The isolated shower/thunderstorms will be tied to the diurnal
heating and likely will set up due to differential heating
between the mtns/valleys. It does not look like a washout, and
coverage looks very limited on the CAMS. PWATs will be in the
1-1.4" range which are near or slightly above normal for early
AUG. A locally heavy downpour is possible.

Max temps should be near normal with 850 hPa temps in the +13C
to +15C range. High temps will range from the upper 60s to
upper 70s over the mtns, and upper 70s to lower 80s in the
valley areas with partly sunny conditions. Sfc dewpts will be in
the upper 50s to mid 60s, so humidity levels will not be
oppressive.
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&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
Tonight...The 00Z NAM/GFS/ECMWF/CMC all show some mid and upper
level height rises over eastern NY and western New England with
a 1020 hPa sfc high building in. Any diurnally driven
convection should dissipate in the late pm/early pm, as the
skies will become mostly clear/partly cloudy and some
radiational cooling is possible with light to calm winds. Patchy
fog formation is likely especially along and near the major
river valley. Lows in the mid 50s to around 60F are likely over
the higher terrain and lower to mid 60s in the valleys.

Sunday...High pressure continues to still be in control at the
sfc and aloft. The sfc anticyclone begins to drift off the
southern New England Coast late in the day. Model soundings show
a low to mid level cap which should limit convective
development. We maintained a dry forecast with subsidence from
the ridge dominating. Some weak warm advection occurs with H850
temps increasing to +15C to +17C. Max temps should be a few
degrees warmer than SAT. Max temps will be in the mid and upper
80s in the lower elevations, and mid 70s to lower 80s over the
hills and mtns.  Humidity levels will continue to creep up.

Sunday night into Monday...A short-wave trough passing north of
the region over northern NY and New England may kick off a few
showers or thunderstorms over the southern Adirondacks into the
Lake George Region. It will become warmer and more humid/sticky
with variable cloudiness. Lows will range form the upper 50s to
lower 60s over the higher terrain, and mid and upper 60s over
the valleys. A hotter air mass continues to ridge in from the
south and west. H850 temps increase to +1 to +2 STDEVS above
normal based on the latest 00Z GEFS. The actual H850 temps rise
to +17C to +18C. Sfc dewpts increase into the 60s to around 70F
in a few spots in the mid Hudson Valley. The combination of the
high air temps /upper 80s to lower 90s/ and dewpts will allow
apparent temps or heat indices to rise into the mid 90s in the
mid Hudson Valley. We may need a Heat Advisory for the mid
Hudson Valley. Max temps will get into the mid 80s to lower 90s
in the valley areas, and upper 70s to mid 80s over the hills and
mtns. Some terrain/differential heating diurnally timed pop-up
showers/thunderstorms are possible outside the Hudson River
Valley and NW CT are possible. We kept an isolated threat in.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Tuesday looks to be the peak day of the upcoming heat, as mixed
layer winds are forecast to shift to the southwest and 850 mb
positive temperature anomalies are forecast to be greatest.
Downsloping off the Catskills/Helderbergs in the SW flow should
result in the warmest temps occurring in the Hudson Valley,
especially from the Capital District southward. Combined with
dewpoints in the upper 60s/lower 70s, maximum heat index values
should be in the mid/upper 90s in the Hudson Valley. Will continue
to mention a Heat Advisory may be needed in the Hazardous Weather
Outlook. Values may even be approach 95 in the Mohawk Valley, so
will monitor trends. There is a chance for showers and thunderstorms
mainly in the afternoon to early evening, as a weak disturbance and
surface trough move across the region. Best chances look to be west
of the Hudson Valley.

While slightly cooler compared to Tuesday, it will still be very
warm and humid on Wednesday as our region will still be under the
influence of upper level ridging extending NW from the western
Atlantic. The main focus for convection will be a slow-moving front
that may become quasi-stationary somewhere across or our area. So
will continue to mention a chance of showers/storms, mainly during
the afternoon to early evening hours.

No discernible change in air mass expected for Thursday and Friday,
with the 00Z guidance indicating the aforementioned front to shift
slightly southward, but remaining nearly stationary. Will limit
chance pops to the southern half of the area each day (from the
Mohawk valley/Capital District/southern VT southward), with only
slight chance to the north. Again, the most favorable times for
convection will be tied to the diurnal heating cycle. Temps expected
to remain above normal, with humid conditions persisting as
well.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
Through 18z/Sun...VFR conditions remain with fair weather cu around
5000 ft continuing throughout the afternoon before gradually
dissipating this evening. Isolated showers/t-storms will develop
this afternoon, mainly across the higher terrain. Latest guidance
continues to support none impacting any TAF sites so will omit VCSH
with this update.

With a mostly clear sky tonight, patchy low clouds and fog may
develop. Best fog chances will be at KGFL/KPSF with cigs/vsbys
lowering to MVFR or possibly even down to IFR/LIFR. Patchy low
clouds, if any, are more likely at KALB/KPOU, where VFR
conditions should continue. Any fog or low clouds gradually lift
Sunday morning with few-sct fair weather cu developing by
midday.

Wind will be variable at 5 kt or less this afternoon, then go calm
tonight. Wind will then be out of the south to southwest at 4-8 kt
tomorrow.

Outlook...

Sunday Night: No Operational Impact. NO SIG WX.
Monday: Low Operational Impact. NO SIG WX.
Monday Night: No Operational Impact. NO SIG WX.
Tuesday: Moderate Operational Impact. Chance of SHRA...TSRA.
Tuesday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Wednesday: Moderate Operational Impact. Chance of SHRA...TSRA.

&&

.FIRE WEATHER...
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Today will be mostly sunny and warm, with an isolated shower or
thunderstorm. High pressure builds back in tonight into Sunday
with dry weather and temperatures rising back above normal
Sunday afternoon. An upper level disturbance may bring a shower
or thunderstorm to the northern part of the area Sunday evening.
The heat and humidity increases for Monday into the mid week
along with the chances for afternoon showers and thunderstorms.
-- End Changed Discussion --

The RH values will increase to 90 to 100 percent with areas of
dew and fog formation Sunday morning. The RH values will lower
to 45 to 55 percent Sunday afternoon. The RH values will again
increase to 90 to 100 percent with areas of dew and fog
formation Monday morning.

The winds will be  light and variable in direction at 10 mph or
less today. They will become light to calm tonight, and then
increase from the south to southwest at 5 to 10 mph on Sunday.
On Sunday night, winds will remain 5 to 10 mph on the hills but
become near calm in valley locations.

&&

.HYDROLOGY...
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No widespread hydrological problems on expected in the ALY Hydro
Service Area /HSA/ the next several days through the end of next
week.

Forecast rainfall across the HSA the next 7 days ranges from
around a tenth of an inch to around an inch and a half.
Rainfall will be variable during this period due to isolated to
scattered thunderstorms, but the highest amounts look to be in
the eastern Catskills. The most widespread threat of showers and
thunderstorms looks to be Tuesday into Thursday with a slow
moving cold front. Localized ponding of water or poor drainage
flooding is possible where thunderstorms produce locally heavy
downpours. No river flooding is forecast.

For details on specific area rivers and lakes, including
observed and forecast river stages and lake elevations, please
visit the Advanced Hydrologic Prediction Service /AHPS/ graphs
on our website.
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&&

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

&&

$$
SYNOPSIS...SND
NEAR TERM...SND
SHORT TERM...SND
LONG TERM...KL
AVIATION...Rathbun
FIRE WEATHER...SND
HYDROLOGY...SND