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Area forecast discussion 
National Weather Service Albany New York
159 am EDT Wednesday Aug 20 2014

high pressure will loosen its grip across the region as our weather
will turn unsettled for the later half of this week. A slow moving
and weak low pressure system will begin to impact our region
Wednesday with clouds and the chance for showers. The best chances
for wet weather will be along and west of the Hudson River
valley...especially across the western Adirondacks...western and
central Mohawk Valley and Catskills.


Near term /until 6 am this morning/...
as of 930 PM EDT...high clouds have worked into the area. IFR
11.9u-3.9u indicated that some patches of stratus have formed as
well across central New York into northern PA.

Dewpoints have been rising a little...and will do so overnight. Even
with only a partly cloudy sky...we believe overnight temperatures
needed to be raised a couple of degrees and therefore we did that
with this update.

Otherwise...only minor tweaking of the hourly grids including the
cloud grids.

Overnight lows will generally range from 50 north and well east of
the capital the middle and upper 50s over the remainder of
the area. It should remain completely dry.


Short term /6 am this morning through Friday/...
most of the short term period of weather will be under increasing
cloud cover...higher surface dewpoints and the raising the
probabilities for showers. The 12z model suite and ensembles are a
little higher with the overall quantitative precipitation forecast field along and west of the
Hudson River as precipitable waters climb 1-2 Standard deviations above normal.
The culprit was the upper low seen in the water vapor loop over the
u.P. Of Michigan. As this low tracks further east...the upper ridge over
northeast Canada strengthens. This will result in a squeeze between
this upper low and the surface ridge reattempting to build

As the case leading into this forecast...the best moisture
transport and isentropic lift remain along or west of the Hudson
River. As low level southerly flow increases through
Thursday...favorable upslope conditions for the Catskills and
dacks may experience enhance rainfall. We will place these areas
into likely probability of precipitation beginning later Wednesday and continuing into all
of Thursday. Quantitative precipitation forecast amounts could approach one inch but flood
concerns are low at this time per coordination with nerfc.

As for thunderstorm potential...while lapse rates are not too
conducive...the h850 Li/S /Aka showalter index/ drop to or just
below 0c over most of eastern New York. This will warrant the
continuation with the slight chance for thunderstorms.

As for temperatures through the period...MOS guidance is rather
close with average highs into the middle-upper 70s and some lower 80s
in the middle Hudson Valley...and overnight lows generally well into
the 50s and lower 60s.


Long term /Friday night through Tuesday/...
model guidance suggests that our area might be sandwiched between a
cutoff low to our south and east...and upper latitude middle level
ridge to our north throughout the extended period. This scenario
might keep our area dry with only some clouds from time to time. The
Canadian model does bring some showers into our region Saturday
night into Sunday but is really not supported by the latest European
and GFS extended model guidance.

We have followed wpc/S thinking and have kept our area rainfree
Saturday night through Tuesday. Temperatures look to be
seasonable...with highs 75-80 in the valleys...70-75 higher terrain
each day. Overnight lows looks to be mainly in the 50s...upper 50s
locally in the capital region.


Aviation /06z Wednesday through Sunday/...
high pressure has moved offshore...and a weak warm front is
approaching the region this morning. Another frontal boundary with
a surface wave over the Great Lakes region will slowly approach from
the west tonight into Thursday.

VFR conditions will lower to MVFR and possibly IFR levels this
morning with some low stratus forming with the increasing low-
level moisture in the boundary layer. Kpsf has the best chance for
IFR ceilings/visibilities with some radiational mist or fog forming...and
then stratus. The low-level stratus is forecasted in the 1.5-2.5
kft above ground level range at kgfl/kalb/kpou between 09z-12z...and should burn off
shortly thereafter. Kpsf may have it linger until 15z. VFR
conditions will return thereafter with scattered-broken cumulus 4-5 kft above ground level
and middle and high clouds around. The best chance of showers with a
middle level disturbance ahead of the occluded front will be after
22z today. Vcsh groups were placed in the forecast at all the taf
sites between 22z to 00z/Thu.

The winds will be light to calm this morning...and then increase
from the southeast to south at 4-8 kts. They will become light and
variable tonight.


Wednesday nt - Thursday nt: moderate operational impact. Chance of rain showers.
Friday-Sun: no operational impact. No sig weather.


Fire weather...
another dry night as high pressure remains in control. The
weather will turn unsettled for the middle of the week as a slow
moving and weak low pressure system impacts the region. The best
chances for storms will be to the west of the Hudson River
valley...especially across the western Adirondacks...and western
and central Mohawk Valley Wednesday afternoon and night.

Relative humidity values will recover toward 90 and near 100 percent
tonight. Minimum values Wednesday afternoon will be mainly in the
50s percentile.


no Hydro problems are expected on the main Stem rivers at this time.
The weather will turn unsettled for the middle of the week as a
slow moving and weak low pressure system impacts the region. The
high quantitative precipitation forecast amounts will occur to the west of the Hudson River
valley...especially across the western Adirondacks...and western
and central Mohawk Valley including the Catskills. Model quantitative precipitation forecast has
increase with up to one inch basin average west of the Hudson
River. Due to low river levels at the present time...most of this
rain should remain within river banks.

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...
New York...none.


near term...hwjiv/bgm
short term...bgm
long term...hwjiv
fire weather...iaa/bgm

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