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Area forecast discussion 
National Weather Service Albany New York
514 PM EDT Tuesday Jun 30 2015

Synopsis...
showers and isolated to scattered thunderstorms will
continue tonight ahead of a warm front and an upper level
disturbance. The threat for showers and thunderstorms continues
tomorrow...as a cold front will move across the region. High
pressure builds in from the upper Midwest and Great Lakes region
Wednesday night into Thursday with fair and drier weather returning
to eastern New York and western New England.

&&

Near term /until 6 am Wednesday morning/...
as of 427 PM EDT...a warm front remains south of most of the forecast
area over PA...northern New Jersey...Long Island and southern England. An upper
level disturbance in the SW flow aloft coupled with the warm
advection ahead of the front has produced an area of widespread
showers across the region in the middle to late afternoon. This
activity has become more scattered over western and central New York. The
better organized strong to potentially severe convection is over
central-eastern PA moving into parts of New Jersey. This area has been in the
warm sector...and had more time to destabilize coupled with more
effective bulk shear.

Further north into our forecast area...the shower coverage will tend
to be most numerous from the Hudson River valley westward into the
evening hours. Another weak vorticity maximum/short-wave energy in the SW
flow aloft will be moving out of west-central PA...and keep a threat
of isolated to scattered thunderstorms. There will still be a chance
east of the Hudson River valley...especially for the ongoing
convection over eastern PA/northern New Jersey...as some of the remnants of this
convection may migrate into the middle Hudson Valley...southern
Berks...and northwest CT based on the latest hrrr layer maximum reference product
indicating this possibility southeast of the forecast area prior to
midnight.

A lull in the showers may occur around or shortly after
midnight...but then will increase again between 09z-12z...as another
short-wave impulse/weak surface low will move along the warm front
south of the region and impact southern New York and New England. We have
increased the probability of precipitation to likely and low categorical values east of
the Hudson River valley at this time. Not expecting any bonafide
severe threats with very little surface based instability /generally
less than 250 j/kg/. There are pockets of weak elevated
instability across the region with showalter values between 0c and
-1c...so a slight chance of thunderstorms was kept in the forecast
everywhere tonight. Precipitable waters will tend to be in the 1-1.50 inch range
with the higher values S/southeast of the immediate greater capital
region. Some bursts of MDT-heavy rain will be possible there. The
question will be how quickly the warm front moves through parts of
the forecast area.

Lows tonight with be on the muggier side with increased humidity
levels with u50s to m60s over the forecast area.

&&

Short term /6 am Wednesday morning through Thursday night/...
tomorrow...complicated forecast with multiple short-waves moving through
the upper- level trough. The trough shifts from being neutral-
tilted to negatively tilted...which will help a cold front to
move across the region during the afternoon.

In the morning...ongoing showers and thunderstorms will occur ahead
of the cold front in the warm sector...as the weak surface low/surface
trough moves through in the morning. The better deep shear across
the eastern half of the forecast area will be in the morning or prior to
18z tomorrow with 0-6 km bulk shear values of 40-55 kts. Some
bands of convection may form in the strongly sheared environment.
The 0-1 km bulk shear values are generally in the 15-25 knots
range...but the instability is limited in the morning initially at
less than 500 j/kg...but it may increase to 1000-1500 j/kg based
on the latest GFS by 18z...and the NAM is similar with roughly
sbcapes of 1000-1500 j/kg with surface dewpoints in the 60s.
However...the NAM lingers the moderate amounts of instability
until 21z ahead of the cold front...and another short-wave. The
left front quadrant of an h500/h250 jet streak will also be
approaching central-eastern New York between 18z-00z. This would be mean some
strong thunderstorms...possibly isolated or scattered severe would
be possible in the middle to late PM...if enough surface heating occurs.

The better shear is departing in the morning...but ahead of the
front...the 0-6 km shear should increase again to 30-40 kts for
some multi-cell clusters/lines with damaging winds /bowing
segments/ the main threat...as the middle level lapse rates are
generally 5-6 c/km in the afternoon...but steeper in the
morning/very early PM. Hail looks like it would be a secondary
threat. Storm Prediction Center keeps most of the forecast area in a marginal risk. We
keep mention in the severe weather potential statement of gusty winds and hail. No enhanced
wording in the zones/grids until this becomes a bit clearer. If
the cloud cover remains in place the threat will be greatly
diminished for the severe potential. Temperatures tomorrow will be in the
u70s to l80s /mainly the middle Hudson Valley and northwest CT/ in many of
the valley areas...and u60s to m70s over the hills and mountains

Wednesday night...better agreement with the NAM/GFS/ECMWF and ensembles
that the short-wave and cold front move through the forecast area in
the early evening. The showers and isolated-scattered thunderstorms should
end in the early evening. Some isolated showers may linger north and
west of the capital region until midnight. Cooler and drier air
will start to filter into the region with the cold advection in
the wake of the front. H850 temperatures lower to -6c to -8c north and
west of the capital district...and -8c to -11c to the south and
east. Lows will be mainly in the middle to u50s with some u40s to
l50s over the higher terrain.

Thursday-Thursday night...high pressure begins to ridge in from the upper
Midwest and west-central Great Lakes region. The latest consensus from
guidance is for the front to sag far enough south for a drier
forecast for Thursday. The probability of precipitation have been removed for Thursday. Clouds will
be more prevalent south of the capital district with partly to
mostly sunny conditions to the northern half. Cyclonic flow will
persist aloft for a cool second day for July. The GFS continues to
have h850 temperatures of +8c to +12c over the forecast area from northwest to southeast.
Highs on Thursday will range from the middle and u70s in many of the
valley areas...with a few 80f readings in the middle Hudson
Valley...and m60s to m70s over the hills and mountains clearing skies
and cool conditions are expected Thursday night with the surface ridge
building eastward. Lows in the u40s to l50s will be common north
and west of the immediate capital district...and middle and u50s from
the capital district south and east.

&&

Long term /Friday through Tuesday/...
heights will be on the rise as we head into the Holiday
weekend. Looking at a dry day with highs temperatures
expected to fall just short of normal...in the 70s.

Another short wave trough is expected to pass to our north
across eastern Canada on Saturday with the upper flow fairly
zonal across New York state. The European model (ecmwf) is stronger with the
feature with an upper low closing off to our north...while
the GFS keeps the wave open. Either way weak forcing is
indicated by the models across our area so just have slight
chance probability of precipitation across most of the forecast area with the heating
of the day. Temperatures are anticipated to be a couple degrees
warmer than Friday.

There are differences in the models as we head into the latter
part of the weekend and into next week with timing and amplitude
of systems.

At this time...Sunday is looking dry with seasonable warm temperatures
with heights ridging. Sunday will be even warmer with highs forecast
in the middle 70s to middle 80s.

The weather will turn unsettled as we head into next week as a low
pressure system gradually approaches. We could have another dry day
Monday with better chances for storms Tuesday. Temperatures will be at
or bit above normal with southerly slow ahead of the approaching system.

&&

Aviation /21z Tuesday through Sunday/...
a warm front and associated rain will affect the taf sites this
afternoon through about 21z-22z...with some intervals of MVFR
ceilings and visibilities. Once the main area of rain exits...there
will still be some isolated to scattered showers over the region
that will continue into this evening. New showers and thunderstorms
are developing west and south of the region that could track through
our region overnight...so keeping vcsh overnight with MVFR ceilings
and visibilities...until showers and thunderstorms actually develop
and movement can be tracked. Again...wherever there are no showers
and thunderstorms...there should be some areas of MVFR...and
borderline IFR at kpsf...fog and ceilings...through about 13z.
Conditions should return to VFR after 13z...but still vcsh as a cold
front approaches with additional scattered showers and thunderstorms.

Light/variable winds will trend into the south later this afternoon
at less than 10 knots. Winds will remain from the south to southeast
after through the night and Wednesday morning...at generally less
than 10 knots.

Outlook...

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

&&

Fire weather...
showers and isolated to scattered thunderstorms will
continue tonight ahead of a warm front and an upper level
disturbance. The threat for showers and thunderstorms continues
tomorrow...as a cold front will move across the region. High
pressure builds in from the upper Midwest and Great Lakes region
Wednesday night into Thursday with fair and drier weather returning
to eastern New York and western New England.

&&

Hydrology...
showers and isolated to scattered thunderstorms will continue
into Wednesday ahead of multiple upper level disturbances...and a
cold front. Some of the thunderstorms may produce locally heavy
rainfall tonight into Wednesday...but overall widespread Hydro
problems are not expected aside from ponding of water on
roadways...and isolated poor drainage flooding of low lying or
urban areas. Total rainfall through Wednesday looks to be in the
third of an inch to inch range. Locally higher amounts are
possible with any convection.

A period of drier weather returns Wednesday night into the
Holiday weekend. This stretch of drier weather will allow for
river flows to lower from the past week of rain.

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.



&&

Climate...
June precipitation through 4 PM June 30 (departure from normal)

Albany ny: 6.70 inches (+2.91 inches)
glens falls: 6.16 inches (+2.61 inches)
Poughkeepsie ny: 4.06 inches (-0.37 inches)
Bennington vt: 2.94 inches (-1.19 inches)
Pittsfield ma: 8.13 inches (+3.73 inches)

Albany needs more 0.55 inches to make it into the top 10 wettest
junes since 1826. The wettest is 8.74 inches set back in 2006.

June 2015 is already the 6th wettest for Glens Falls since 1949.
The wettest is 8.20 inches set back in 1998.

Poughkeepsie needs more 1.20 inches to make it into the top 10
wettest junes since 1949. The wettest is 9.82 inches set back in
2013.

&&

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

&&

$$
Synopsis...wasula
near term...wasula
short term...wasula
long term...iaa
aviation...NAS
fire weather...11/wasula
hydrology...11/wasula
climate...iaa/wasula

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