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Area forecast discussion 
National Weather Service Albany New York
423 PM EDT Friday Aug 28 2015

Synopsis...
high pressure will be over New York and New England
tonight into tomorrow with tranquil weather and high temperatures
rebounding to slightly above normal levels. The surface high will
drift off the coast Saturday night...and a weak upper level
disturbance...and a warm front will bring some isolated showers or
thunderstorms mainly north and west of the capital region on Sunday.
Above normal temperatures and more humid conditions will continue
into the middle of next week.

&&

Near term /until 6 am Saturday morning/...
as of 423 PM EDT...the fair weather cumulus over the forecast area
should quickly dissipate with the loss of the diurnal heating...as
high pressure builds in from Pennsylvania tonight. This surface
anticyclone will be in control overnight with clearing skies and
the winds becoming calm. Ideal radiational cooling is expected
with temperatures falling into the middle 40s to around 50f over the hills
and mountains lows in the valleys will be in the lower 50s with some
spotty upper 40s in the Lake George region.

Some patchy radiational mist/fog is also possible in the major
river valleys especially between 06z-12z. The fog in the forecast will
be mainly at elevations less than 1000 feet.

&&

Short term /6 am Saturday morning through Sunday night/...
tomorrow...a pleasant start to the last weekend of August is
expected...as high pressure over New York and New England begins to
drift off the coast. The middle level flow transitions from zonal to
weak ridging aloft. H850 temperatures increase to +13c to +15c in the
warm advection pattern. Good mixing from aloft...and abundant
sunshine will allow high temperatures to rise a few degrees above normal.
High temperatures will generally be in the u70s to l80s in the valley
areas...and middle and u70s over the mountains humidity levels will
remain on the comfortable side with surface dewpoints mainly in the 50s.

Saturday night...weak ridging continues aloft off the Atlantic
coast with the surface high drifting further off the coast. A weak
warm front or thermal trough will approach the region with some
increasing middle and high clouds late. The GFS actually has a weak
h500 trough axis moving across northern New York/southeast Quebec/northern New England. We
kept this part of the forecast period dry with temperatures possibly falling
off again with the light winds in the boundary layer. It should
not be as cool as Friday night. Lows will range from the m50s to
l60s across the forecast area.

Sunday into Sunday night...the NAM is a bit of an outlier compared
to the GFS/ECMWF/Canadian guidance for Sunday. The NAM would have
a weak disturbance with a weakening upper level trough move along
the rim of the middle and upper level ridge setting up over the middle
Atlantic region. Any synoptic forcing looks weak...but the NAM
would have isolated-scattered showers...perhaps some isolated thunderstorms
over most of the forecast area by the afternoon. The majority of the
other guidance would keep it fairly dry...except for some isolated
showers mainly north and west of the capital region...especially
tied to the diurnal heating. We have placed some slight chance probability of precipitation
mainly north and west of the capital region. The instability looks
very weak on the GFS with less than 250 j/kg of instability. The
NAM has a bit more due to much higher dewpoints especially over the
eastern Catskills...and Schoharie valley /mid 60s to around 70f/.
These look too high...but even some surface instability amounts of 500
j/kg or less may focus an isolated thunderstorm over the west-central
Mohawk Valley/eastern Catskills. We placed a slight chance of thunder
here. Only a slight chance of showers were used north of the Tri
Cities due more stable conditions.

Overall...humidity levels will slightly increase and h850
temperatures of +14c to +16c will allow highs to get into the middle 80s
over the capital district...middle Hudson Valley and northwest CT...and m70s
to l80s over the rest of the forecast area.

The isolated showers and thunderstorms should diminish early in the
evening...with high pressure building in from the south and east.
A warming trend will continue into early next week. Lows Sunday
night will be in the middle 50s to l60s.

&&

Long term /Monday through Friday/...
the long term period will be characterized by mainly tranquil...but
very warm and muggy conditions as high pressure and upper-level
ridging dominate the weather across the region.

At the start of the long term period...high pressure at the surface
will be ridging in across the region...with increasing heights aloft
as upper-level ridging establishes itself across the eastern Continental U.S..
this upper-level ridging and surface high pressure will remain
established across the region for much of the long term period
resulting in mainly dry and tranquil weather. The best chance for
precipitation across the region looks to occur possibly Thursday
and/or Friday as convection riding across the top of the upper-level
ridging/northwest flow regime may impact the region...but have only
indicated slight chance probability of precipitation at this time.

The main weather factor dominating the long term period will be a
return of Summer-like heat and humidity across the region...with
well above normal temperatures for early September along with muggy
conditions as dewpoints return back into the middle and upper 60s
across most of the region. High temperatures throughout the long
term period will generally range from the upper 70s to lower 80s
across the southern Adirondacks to upper 80s and low 90s across
valley areas. Low temperatures will generally range from the upper
50s to the middle 60s.

&&

Aviation /19z Friday through Wednesday/...
diurnal cumulus will dissipate with loss of heating late in the
day/early this evening. Mainly clear skies expected for tonight
and along with light winds conditions will be favorable for
radiational fog to develop after 06z/Saturday. IFR conditions are
expected to develop by around 09z/Saturday at kgfl and kpsf. Fog
will burn off after sunrise. Some cumulus clouds will develop
with heating plus cirrus clouds will stream in Saturday morning.

Light westerly winds will diminish this evening and become calm
for the overnight. A light southerly flow will develop Saturday.

Outlook...
Sat night-Wed: other than some patchy early morning fog...no
operational impact. No sig weather.

&&

Fire weather...
high pressure will be over New York and New England
tonight into tomorrow with tranquil weather and high temperatures
rebounding to slightly above normal levels. The surface high will
drift off the coast Saturday night...and a weak upper level
disturbance...and a warm front will bring some isolated showers or
thunderstorms mainly north and west of the capital region on Sunday.
Above normal temperatures and more humid conditions will continue
into the middle of next week.

The relative humidity values will increase to near 100 percent tonight with some
dew formation...and they will lower to 35 to 50 percent Saturday
afternoon. Expect another excellent relative humidity recovery to 90 to 100
percent with dew formation Sunday morning again.

The winds will be light to calm tonight...and south to southeast
on Saturday at 5 to 10 miles per hour...before becoming light to calm at
Saturday night.

&&

Hydrology...
no hydrologic issues are anticipated over the next five days.

No widespread rainfall is forecast to fall for at least the next
five days as a ridge of high pressure builds in.

Some isolated showers or thunderstorms may product light rainfall
amounts of a few hundredths to a tenth of an inch on
Sunday...mainly north and west of the capital region.

River levels will continue to run at normal to below normal
levels for August.

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.

&&

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

&&

$$
Synopsis...wasula
near term...iaa/wasula
short term...wasula
long term...irl
aviation...iaa
fire weather...hwjiv/wasula
hydrology...hwjiv/wasula

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