Area Forecast Discussion
Issued by NWS Albany, NY

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000
FXUS61 KALY 191505
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
1105 AM EDT Sat Aug 19 2017

.SYNOPSIS...
This afternoon will feature sunshine mixed with clouds with a few
showers and isolated thunderstorms especially from the Hudson River
Valley westward into the early evening associated with a secondary
cold front. Fair weather and seasonable temperatures are forecast
for Sunday and a warm up is expected Monday and Tuesday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 1105 AM EDT...An upper level trough axis remains upstream
over the central and eastern Great Lakes Region with a short-
wave swinging across the OH Valley according to the latest RAP.
Some lake enhanced isolated showers continue downstream of Lake
Ontario across the western Adirondacks, especially north of Old
Forge based on the KTYX radar. Further downstream, the low
clouds and fog have burned off across the region, and scattered
cumulus and mid-level clouds continue to form in the wake of the
cold/occluded frontal passage overnight into this morning. The
latest experimental GOES-16 satellite imagery continues to show
plenty of cumulus and mid clouds in increase with the 12Z KALY
sounding having the convective Temp around 75F. We have trended
for partly sunny conditions in most locations.

The approaching short-wave looks to move close to the region
late this afternoon, and we increased the slight to low chc pops
for isolated-scattered showers and isolated thunderstorms. The
latest NAM12 has SBCAPES generally 250-750 J/kg with sfc dewpts
in the upper 50s to mid 60s despite some steepening of the mid-
level lapse rates. Expecting general thunderstorms with a
locally heavy downpour possible in a few spots. The instability
should be waning early this evening. Some retooling of the POPS
was done with the latest 3-km NAM and HRRR trends.

Deep west flow will limit the low level convergence and mid and
upper moisture will be lacking for widespread coverage of the
showers/t-storms. However, again, there may be enough low level
moisture and thermal forcing along the low level cold front to
support isolated showers and thunderstorms until about midnight.
It will breezy at times this afternoon which will support
decent mixing and highs in the lower to mid 80s in many areas,
70s in higher terrain.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
Any lingering isolated showers and thunderstorms will end late this
evening and the sky will become mostly clear. There could be
some patchy fog in some areas near water and swamps around
daybreak Sunday. Sunday looks dry and sunny with highs in the
80s and some 70s in higher terrain.

Some warm advection begins Monday and there should be good
viewing of the eclipse. Will the reduced sunlight during the
eclipse for the time period that is usually the peak sun angle
of the day cause high temperatures to be a little cooler than
guidance? Well, 33% sunshine in our region at the time when we
are supposed to have peak heating during the mid afternoon might
modify the atmosphere a little. Still, highs maybe a degree or
two cooler than guidance, but still in the 80s many areas and
around 80 higher terrain. It will be interesting to see just how
the eclipse does affect the atmosphere over the entire U.S.
with varying percentages of the sun on either side of the path
of the total eclipse.

A mostly clear sky is expected Monday night with slowly
increasing warm advection and low level moisture. Lows mainly in
the 60s with around 60 higher terrain.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
The long term portion of the forecast starts out with summer-like
warmth, as a ridge of high pressure moves off the mid Atlantic
coast. Relatively high mid level heights and subsidence should allow
daytime highs to reach 85-90 for valleys, and 80-85 across higher
elevations Tuesday. An approaching cold front, combined with late
day mid/upper-tropospheric height falls, and perhaps a pre-frontal
trough could spark some showers/thunderstorms late Tuesday
afternoon, especially for areas north and west of the immediate
Capital District. Some of these thunderstorms could be strong, as
mid level wind fields increase to 30-40 KT or stronger.

For Tuesday night-Wednesday, a cold front is expected to approach
from the northwest. Both 00Z/19 deterministic global models and
ensembles suggest that a wave develops along the incoming front,
somewhere across the eastern Great Lakes or western NYS, before
strengthening and moving northeast into southern Quebec. Model
consensus continues to favor a late night/early morning frontal
passage. This would tend to decrease the overall threat for severe
weather with the main front, after any initial convection Tuesday
afternoon. So, have sided with consensus with best chances for
showers/thunderstorms Tuesday night into Wed morning, then
decreasing chances Wednesday afternoon. However, changes to frontal
timing remain possible over the next few days as upper level
features and their evolution become better resolved within various
sources of guidance. It should be warm/humid Tue night ahead of the
front, with lows mainly in the 60s, then highs Wednesday mainly in
the 70s to around 80 for valleys, and 60s to lower 70s across higher
terrain.

Wednesday night-Friday, assuming the aforementioned cold front does
not slow down, high pressure is expected to build in from southern
Canada and the Great Lakes region with cooler and less humid
conditions. There could be a few showers across mainly higher
elevations of the southern Adirondacks/southern VT Thursday due to
lingering cold air aloft and some mid/upper level cyclonic flow.
Expect lows Wed night in the 50s, with some 40s possible for higher
elevations; highs Thursday and Friday mainly in the 70s for lower
elevations, and 60s across higher terrain. Even cooler temperatures
are expected for Thursday night, with lows in the 40s across higher
elevations, and lower/mid 50s in valleys. It is even possible that
some sheltered areas of the southern Adirondacks fall into the upper
30s by daybreak Friday.

&&

.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
A cold front will move east of the region today. A secondary
cold front and upper level trough will sweep across the
tonight, leaving the local area between the features for
today.

Any low stratus/fog should lift between 11Z-13Z/Sat, with VFR
conditions then prevailing through Saturday evening. The low
clouds/fog may linger at KPOU longest.

Additional patchy fog may develop between 06Z-12Z/Sun,
especially at climatologically favored KGFL and KPSF, where
periods of IFR conditions will be possible.

An isolated shower will be possible this evening as the
aforementioned secondary cold front/upper level trough moves
through.

Light.variable winds will increase from the west at 5-10 KT by
later this morning, with some gusts possibly reaching the 15-20
KT range at KALB and KPSF this afternoon. West winds will
decrease to less than 8 KT after sunset.

Outlook...

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

&&

.FIRE WEATHER...
Today looks fair and breezy before a second cold front crosses
the area late this afternoon and tonight with just isolated
showers and thunderstorms. Fair weather and seasonable
temperatures are forecast for Sunday and a warm up is expected
Monday and Tuesday.

RH values will be near 100 percent at night. RH values will be
45 to 65 percent this afternoon and Sunday afternoon.

Winds will be west at 15 mph or less Saturday, but a few gusts
to 20 mph are possible during the afternoon. Winds diminish to
less than 15 mph tonight. Winds will be northwest at 15 mph or
less on Sunday.

&&

.HYDROLOGY...
Isolated to scattered thunderstorms are possible late this
afternoon and tonight along a reinforcing cold front. Less
humid air will start to work its way into the region after the
cold front tracks through. Drier weather is expected Sunday into
Monday.

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.

&&

.EQUIPMENT...
While repairing the azimuthal gear box, radar technicians have
determined that the bull gear on KENX radar needs to be
replaced. This will require the radar to be out of service until
at least next Friday, August 25th.

&&

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

&&

$$
SYNOPSIS...NAS/Wasula
NEAR TERM...NAS/Wasula
SHORT TERM...NAS
LONG TERM...KL
AVIATION...KL
FIRE WEATHER...NAS
HYDROLOGY...NAS
EQUIPMENT...



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