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Area forecast discussion 
National Weather Service Albany New York
344 PM EDT Tuesday Sep 2 2014

Synopsis...
a cold front will approach the region late into the evening
bringing showers and thunderstorms...some of which could contain
heavy rainfall and gusty winds. Slightly cooler and noticeably
drier air will follow on Wednesday. The dry weather is expected to
continue the rest of the work week with warming temperatures once
more.

&&

Near term /until 6 am Wednesday morning/...
isolated thunderstorm activity just east of the capital district
heading toward the Berkshires through the late afternoon. More
isolated thunderstorms headed for parts of the southern
Adirondacks. It is quite warm aloft and storms have not been able
to build in enough vertical extent to become strong...at least in
our forecast area. The storms seem to strengthen as they head in
to central and eastern New England.

Band of deeper moisture...clouds...showers and isolated
thunderstorms in western New York/PA ahead of the cold front still
making progress east. Sources of guidance...including the
mesoscale short term models suggest convection develops and
strengthens in western NY/PA...then tracks through our region
through the evening. Current analysis of instability shows small
regions of strong surface based instability where showers have not
occurred and most sunshine has occurred...but instability
considerably less where showers have occurred and surface
temperatures have not recovered as much.

So...will keep watching for the development of organized
convection in western NY/PA...and if/when it develops...could have
some embedded strong to marginally severe wind gusts. Decent low
level jet energy still predicted to track through the region. High
precipitable water values suggest locally heavy rain and possible standing water
in low lying areas and poor drainage areas. Any showers and storms
should exit later tonight and partial clearing should take place.
Winds will shift to the west and northwest before sunrise as
boundary layer winds are expected to remain somewhat strong behind
the front. Lows tonight in the upper 50s to middle 60s...depending on
how quickly we clear and how much of the dryer air can build in.

&&

Short term /6 am Wednesday morning through Friday/...

Drying and clearing through the day Wednesday...with a steady
west to north breeze. Highs Wednesday in the upper 70s to middle 80s.
Dry weather continues Thursday with light winds as high pressure
centers itself over the region. Some weak warm advection could
begin late Thursday afternoon. Highs Thursday in the lower to middle
80s. Warm advection continues Friday and based on boundary layer
temperatures and southwest boundary layer flow...temperatures
should reach the middle to upper 80s...a little cooler in higher
terrain. There could be an isolated thunderstorm in the southern
Adirondacks and western Mohawk Valley late Friday afternoon well
ahead of the next cold front.

&&

Long term /Friday night through Tuesday/...
the long term period will be characterized by unsettled weather
early in the period...but followed by dry and tranquil conditions to
end the weekend and into early next week.

At the start of the long term period...a cold front will be
approaching the forecast area from the Great Lakes region Friday
night into early Saturday...bringing the threat of showers and
thunderstorms to the region. Long range guidance still has some
timing differences regarding the timing of the cold front passage
across the forecast area...but are converging on a solution that
would feature the cold front moving through the region during the
day Saturday.

With south/southwesterly flow ahead of the cold front thanks in part
to a return flow setup from departing high pressure moving to the
east...low-level moisture will once again be transported across the
region as dewpoints surge back into the low and middle 60s. Lows Friday
night will be muggy...generally in the 60s for most locations except
for upper 50s across the higher terrain of the southern Adirondacks.
Accompanying the increase in humidity should be extensive cloud
cover which may limit overall instability Saturday
afternoon/evening. Midlevel lapse rates are not overly impressive
either...generally around 6.0 c/km which should also hamper the
potency of any thunderstorms...despite bulk shear values in the
0-6km layer of 30-40 knots.

Regardless...expect a period of scattered showers and thunderstorms
beginning late Friday night across western areas and across the
entire forecast area during the day Saturday as the cold front
pushes through the region. The greatest threat for any localized
stronger storms looks to be for areas south of the capital
region...where enough breaks in the cloud cover could occur to
increase instability and enhance destabilization. The thunderstorm
threat should rapidly diminish by the late evening hours with the
loss of daytime heating.

Showers may linger especially for areas south and east of the
capital region Saturday night as the cold front slowly exits to the
east. Behind the cold front...a sprawling area of high pressure will
build across the region resulting in an extended period of dry
weather and partly cloudy skies beginning Sunday and continuing into
early next week.

High temperatures for the remainder of the long term period will
generally range from the middle 60s to middle 70s with lows generally
ranging from the middle 40s to to middle 50s.

&&

Aviation /19z Tuesday through Sunday/...
a cold front moves across the region this evening with scattered showers
and thunderstorms. The front should be south of eastern New York and western New
England by daybreak tomorrow with high pressure building in from
the Ohio Valley.

VFR conditions will persist this afternoon with scattered cumulus and
scattered-broken cirrus. An isolated shower or thunderstorm is possible prior
to sunset. An organized band of showers and scattered thunderstorms will
reach the Hudson Valley between 01z/Wednesday and 04z/Wed. This frontal band
of showers and thunderstorms will produce MVFR ceilings/visibilities with
isolated IFR conditions. Thunderstorms may be needed to be added to
the taf later. It has been placed in kpou at this time.

In the wake of the front some MVFR/IFR visibilities/ceilings may linger at
kpsf/kgfl/kalb until the stronger cold advection arrives towards 12z/Wed.
VFR conditions should arrive between 11z-13z/Wed.

The winds will be from the S/SW at 5-10 kts shifting to the west/SW
at 5-12 kts 00z-04z/Wednesday with the front. The winds will continue to be
from west/northwest at 6-12 kts after 12z/Wed.

Outlook...

Wednesday night: no operational impact. No sig weather.
Thursday: no operational impact. No sig weather.
Thursday night: no operational impact. No sig weather.
Friday: no operational impact. No sig weather.
Friday night: moderate operational impact. Chance of rain showers...tsra.
Saturday: moderate operational impact. Chance of rain showers...tsra.
Saturday night: moderate operational impact. Chance of rain showers.
Sunday: no operational impact. No sig weather.

&&

Fire weather...
a cold front will approach the region late into the evening
bringing showers and thunderstorms...some of which could contain
heavy rainfall and gusty winds. Slightly cooler and noticeably
drier air will follow on Wednesday. The dry weather is expected to
continue the rest of the work week with warming temperatures once
more.

Relative humidity values tonight and tomorrow night will be 80 to 100 percent.
Minimum relative humidity values Wednesday will be 35 to 45 percent and on
Thursday 40 to 50 percent.

Winds will be southwest at 15 miles per hour or less this evening...shifting
to northwest after midnight. Winds will be west to north tomorrow
at around 15 miles per hour...with possible gusts in the afternoon to 20 miles per hour.
Will will decrease Wednesday night to less than 15 miles per hour then shift
to south and southwest Thursday afternoon at 15 miles per hour or less.

&&

Hydrology...
shower and thunderstorm coverage should increase from northwest
to southeast through the evening. The showers and thunderstorms
should exit the region late in the evening and through the early
morning hours. Average basin rainfall with these storms is
projected to be around half an inch across northern areas north
of Albany. Look for around half an inch in and around the capital
region...and lesser amounts of a quarter inch or less further
south.

Any thunderstorms could produce locally heavy rainfall...possibly
exceeding an inch and this rain could fall in a short time.
Therefore there is the potential for ponding of water on roadways
and areas of poor drainage.

Drier weather returns by Wednesday...lasting through the remainder
of the workweek.

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...NAS
near term...NAS
short term...NAS
long term...bgm/irl
aviation...wasula
fire weather...NAS
hydrology...NAS

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