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Area forecast discussion 
National Weather Service Albany New York
339 am EDT Tuesday Jul 22 2014

Synopsis...
Summer warmth and humidity returns today...and especially
Wednesday. A cold front will approach during the afternoon hours
Wednesday...bringing showers and thunderstorms. A cooler and less
humid air mass filters behind the cold front for the remainder of
the work week.

&&

Near term /through tonight/...
as of 330 am...variable cloud cover across the region with patches
of fog per regional metars along with light winds. The surface
high over the middle Atlantic region will continue to slide
offshore today. The return flow around this high will increase the
southerly winds and allow for higher low level moisture content
and a warmer thermal profile. This will all result in a rather
warm and humid afternoon for the region. Forecast profiles
continue to suggest rather steep lapse rates below the inversion
around h700 so cumulus cloud development is expected. As for
convective precipitation potential...the aforementioned inversion is
rather low and below the freezing level so no expecting any
thunder. Experiential reflectivity forecasts from Storm Prediction Center/local-
WRF/hrrr still advertise isolated to widely scattered showers this
afternoon as we will continue with the slight chance-isolated
probability of precipitation. Highs today should climb well into the 80s for valley
locations to around 80f for the higher terrain.

Any convection should subside rather quickly this evening. The
surface gradient remains tight enough to keep the southerly flow
of moisture transport into the region overnight. It will be muggy
indeed as dewpoints climb well into the 60s for many locations.
Upstream cold front approaches the central Great Lakes region
setting the stage for an active weather day on Wednesday.

&&

Short term /Wednesday through Thursday/...
the Storm Prediction Center /spc/ continues to highlight an area
of slight risk for severe weather from the capital region and
locations to the north and east. Forecast instability parameters
are rather high and consistent with a severe weather episode for
the region. Sbcapes climb at or above 2k j/kg...precipitable waters up to 2
inches...bulk shears of 30-40kts and the timing of this front
coincides with the maximum daytime heating for the region. Local
mesoscale low level winds up the Hudson River could assist with
enhancing the low level helicity for a few of these cells to
exhibit potential rotation. Nevertheless...the main threat from
these thunderstorms will be from damaging wind gusts and cloud to
ground lightning strikes. High temperatures in advance of the cold
front should climb into the middle and upper 80s for many
locations...with the exception across the Adirondacks region where
clouds will likely increase early and cut down on the insolation.

The cold front is rather progressive and should continue to
progress southeast during the evening hours Wednesday. Convective
threat should diminish rather quickly with frontal passage as we will time
a decrease in probability of precipitation from northwest to southeast through the night.
A low level wind shift from the west-northwest will usher in drier
and more stable atmosphere. In fact...h850 temperatures drop near 10c
during the night. Lows will range from the upper 40s across
portions of the dacks to middle 60s for the middle Hudson
Valley...southern Berks and northwest CT.

On Thursday...cold front continues to track further southeast
leaving behind a very dry middle levels. However...very steep low
level lapse rates at or below h800 and still cyclonic flow aloft should
allow for scattered cumulus to develop through the day. Highs on Thursday
will average 10 degrees cooler with many locations remaining in
the 70s and some upper 60s for the higher terrain of the dacks.

&&

Long term /Thursday night through Monday/...
a broad area of high pressure over the Ohio Valley and Middle
Atlantic States will extend into our region for Thursday night
through Saturday. This will provide several days of dry
weather...with comfortable humidity levels and seasonable temperatures
/highs mainly in the middle 70s to middle 80s...and lows in the 50s to
low 60s/. The only exception may be across the Adirondacks on
Friday...when a brief rain shower may be possible thanks to an
upper level disturbance situated north of the region over Quebec.
Otherwise...skies will be partly to mostly sunny throughout the
region with dry conditions.

The next chance for showers and thunderstorms will return for later
in the weekend and into early next week as a slow moving closed off
upper level low drops into the northern tier of the US from Canada.
With diffluent flow aloft ahead of this feature and a moist flow out
of the south...some showers and thunderstorms look possible for Sat
night through Tuesday. The best chance will be during the diurnally
favored afternoon and evening hours. Eventually...this system will lifts
back into Canada towards middle week...ending the threat for widespread
showers and thunderstorms.

&&

Aviation /07z Tuesday through Saturday/...
infrared satellite imagery shows mainly clear skies over the region with
just a few patches of some middle and high level cloudiness passing
over the area. With light winds in place and higher low level
moisture than recent nights...some IFR radiational fog will develop
at kgfl/kpsf. This fog will be in place through the remainder of
the night until shortly after sunrise. Elsewhere...enough of a T/dew point
spread should prevent any fog from developing.

During the day on Tuesday...VFR conditions are expected to dominate.
Some passing high clouds will be in place...along with few-scattered
diurnal cumulus. The highest coverage of the cumulus will be over the higher
elevations. An isolated rain shower cannot be ruled out...but
coverage looks too small to include in the taf at this time. S-southeast
winds will be light...generally 6 kts or less.

Middle level clouds will increase on Tuesday night...as a storm system
begins to approach from the west. This increasing cloud cover should
prevent widespread IFR fog from occurring for Tuesday night with
light to calm winds.

Outlook...

Tuesday night: no operational impact. No sig weather.
Wednesday: moderate operational impact. Likely rain showers...tsra.
Wednesday night: moderate operational impact. Likely rain showers...tsra.
Thursday: low operational impact. Slight chance of rain showers.
Thursday night to saturday: no operational impact. No sig weather.

&&

Fire weather...
mainly dry weather is expected through early Wednesday. A stray
shower or thunderstorm cannot be ruled out during the afternoon and
early evening hours.

Relative humidity values will be elevated through Wednesday with minimum values
generally at or above the 40-50 percentile range and overnight
lows generally at or above 90 percent.

By Wednesday...shower and thunderstorm activity will increase as a
cold front begins to impact the region...which will interact with a hot
and humid air mass.

The surface wind will be light or calm this early morning...becoming
west to southwesterly at 5 to 10 miles per hour this afternoon into tonight.

&&

Hydrology...
mainly dry weather expected through Wednesday morning with just a
low chance for a brief rain shower this afternoon.

By Wednesday...the threat for more widespread showers and
thunderstorms by afternoon...lingering into early Thursday. The
higher moisture content across the region...the chance for heavy
rainfall from thunderstorms will increase.

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...bgm
near term...bgm
short term...bgm
long term...frugis
aviation...frugis
fire weather...bgm
hydrology...bgm



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