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fxus61 kaly 272006 
afdaly

Area forecast discussion
National Weather Service Albany New York
406 PM EDT Sat may 27 2017

Synopsis...
another dry and seasonable day under variable cloud cover is
likely Sunday before a frontal system brings rainfall to the
forecast area Sunday night. Showers will persist into Memorial
Day along with plenty of clouds and cool temperatures. Several
quick-moving systems will keep precipitation chances in the
forecast through mid-week with temperatures near normal.

&&

Near term /until 6 am Sunday morning/...
as of 4 PM, fairly thick high clouds have spread across areas
south of the capital district associated with a remnant MCV,
while diurnal clouds have blossomed across portions of the
Catskills/Adirondacks. Current forecast continues mostly cloudy
skies with the exception of the Mohawk/upper Hudson Valley where
comparatively more sunshine is occurring. A couple of sprinkles
remain possible over the higher terrain through the daylight
hours.

Tonight, upper-level drying and subsidence will spread across
the region in the wake of the mesoscale convective vortex. A good deal of cu/stratocu
upstream, but the presence of lake shadowing suggests these will
diminish after sunset once the boundary layer cools, so have
worked a clearing trend into the forecast. With a weak surface
high overhead and light winds, if substantial clearing does
indeed occur, some fog is possible. Forecast soundings indicate
the near-surface moist layer will be shallow, so have just
included patchy mention for lower/River Valley areas.

&&

Short term /6 am Sunday morning through Monday night/...
Sunday, shortwave ridging will crest over the forecast area, and
the surface high will shift east of the area ahead of a broad
area of lower pressure over the upper Midwest and Great Lakes.
Mid/upper-level flow will turn southwesterly as a couple of
impulses swing into the forecast area along the periphery of a
large upper low setting up across southwestern Ontario. Fair
weather and partial sunshine is expected after any morning fog
Burns off, though we will probably see a fair amount of diurnal
cumulus. Developing south-southeasterly flow will advect some
marine air northward, so relatively cooler temperatures are
likely to be found across the southern Catskills/Mid-Hudson
valley/northwest CT along with possibly a bit more cloud cover.
Otherwise, temperatures should reach near to a bit above
seasonal normals. The leading weak impulse will track through
toward 00z, which may act to increase midlevel clouds toward the
evening.

A stronger impulse will approach the forecast area late Sunday
night, with low-level moist inflow increasing ahead of this
feature. Models are in fairly good agreement in spreading
rainfall from west to east across the forecast area especially
after 06z, although the GFS is slower. Enough confidence exists
for likely/categorical pops over eastern/western portions of the
forecast area, respectively. Will have to watch wind gusts over
the favored southeast flow regions of The
Greens/Berkshires/Taconics as NAM indicates 925 mb winds of near
40 kt, although ability to mix these winds to the surface is
questionable given the expected rainfall. Precipitation is
expected to be ongoing during the morning of Memorial Day, with
coverage diminishing past 18z as the upper wave passes. However,
forecast soundings indicate a good deal of moisture lingering,
so we are unlikely to see much sunshine and temperatures will be
below normal. Showalter values go slightly negative, so have
kept slight chance thunder in the forecast 06-18z Memorial Day.

&&

Long term /Tuesday through Saturday/...
much of the long term portion of the forecast looks to be rather
unsettled with periodic chances for showers and some thunder, along
with slightly below normal temperatures with a mean upper level
trough expected to persist over the region.

The period starts out on Tuesday with a broad upper level trough
already in place across the Great Lakes. Our region will be on the
southeast periphery of the upper level trough, which will allow for
some breaks of sunshine and resulting surface heating with a
southwest flow aloft. A short wave trough and associated jet streak
area forecast to round the base of the trough and approach from the
lower Great Lakes Tuesday afternoon into the evening. This setup
should result in scattered to numerous showers and thunderstorms
developing. NAM/GFS indicating SBCAPE values approaching or possibly
exceeding 1000 j/kg especially from around the capital district
westward, along with 40-50 kt of 0-6 km bulk shear. Will have to
watch the potential for a few stronger storms, especially if surface
heating and resulting instability is realized.

Showers and thunderstorms should generally taper off Tuesday night,
but could linger well into the evening depending on the eventual
speed of movement of the short wave. Will still mention pops
overnight though due to the broad upper trough digging across the
region.

Then, multiple disturbances will move through the mean trough as it
settles in across the region through the rest of the work week
Wednesday through Friday. Very difficult to time disturbances and
resulting precipitation chances in the days 4-7 time frame. So will
mention higher chances for showers during the more diurnally favored
daylight hours, with slightly lower pops at night. Models not
indicating any appreciable instability Wednesday and Thursday, but
there could be at least modest instability on Friday as a potential
cold pool within the deepening trough moves overhead so will mention
slight chance thunder for now.

It appears we may get a break in the unsettled weather by next
Saturday, as a weak area of surface high pressure builds in and the
flow regime aloft is forecast to transition from cyclonic to more
neutral. Again, temperatures should generally be slightly below
normal with the trough in place through much of the long term.

&&

Aviation /19z Saturday through Thursday/...
have some weak ridging over the region at the surface with an
upper level ridge axis located to our west. A short wave which
is overtopping the ridge will approach late in the day and move
off to the southeast overnight. Have variable cloudy skies
across the local area with multiple cloud layers with diurnal
driven clouds and clouds from remnants of a mesoscale convective vortex moving across
region. VFR conditions are expected with MVFR conditions
possible late tonight/early Sunday morning especially at kpou
due to both ceilings and visibility. An improvement to
widespread VFR is expected to develop after sunrise Sunday.

Winds will be mainly light and variable with calm conditions for
a period overnight.

Outlook...

Sunday night: high operational impact. Likely rain showers...tsra.
Memorial day: high operational impact. Definite rain showers...tsra.
Monday night: low operational impact. Slight chance of rain showers.
Tuesday: moderate operational impact. Likely rain showers...tsra.
Tuesday night: moderate operational impact. Chance of rain showers...tsra.
Wednesday: moderate operational impact. Chance of rain showers.
Wednesday night: low operational impact. Slight chance of rain showers.
Thursday: moderate operational impact. Chance of rain showers.

&&

Fire weather...
seasonably mild temps Sunday with relative humidity values mainly bottoming out
in the 50s with light to moderate southeasterly winds. An
approaching system will bring rainfall to the region Sunday
night into Memorial Day, along with cool temperatures. Showers
and thunderstorms will be likely again on Tuesday with seasonable
temperatures.

&&

Hydrology...
after a dry day Sunday, an approaching system will bring
showers and a few thunderstorms Sunday night into Memorial Day,
with total quantitative precipitation forecast ranging from 0.25-0.75" expected. Additional
periods of showers and thunderstorms are likely Tuesday and
Wednesday, with basin average quantitative precipitation forecast likely remaining less than an
additional half inch.

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...
the ASOS at the Floyd Bennett Memorial Airport in Glens Falls,
New York and Pittsfield Airport, Massachusetts continue to experience outages
with hourly metars occasionally missing. This will continue
until communications are fully restored.

&&

Aly watches/warnings/advisories...
CT...none.
New York...none.
Massachusetts...none.
Vermont...none.

&&

$$
Synopsis...Thompson
near term...Thompson
short term...Thompson
long term...jpv

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