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fxus61 kaly 271036 
afdaly

Area forecast discussion
National Weather Service Albany New York
636 am EDT Thu Jul 27 2017

Synopsis...
a cold front will bring some showers and thunderstorms to the
area today. Dry weather is expected for most of the area Friday
into the weekend; however, some rainfall is possible across far
southern areas as low pressure passes by to the south.
Temperatures will remain a bit cooler than normal.

&&

Near term /through tonight/...
as of 610 am EDT, rain showers will continue to traverse the
area this morning under cloudy skies with mild temperatures. A
few spots in southern New York dipped below the 60 degree mark but
otherwise, locations stayed in the 60s overnight. In terms of
the forecast, updated pops to reflect current radar trends and
freshened up the hourly temps. Sent updates to ndfd and web
servers.

Prev disc...
the area will remain under broad west-southwest flow at upper
levels as a broad upper trough sweeps into the region. Low level
clouds associated with the upper trough, as seen this morning
in the GOES-16 nighttime microphysics channel over northern New
York, will continue to spread southward through the morning.
Light showers embedded in the broad westerly flow will continue
across the forecast area through the morning hours with a few
hundredths of an inch possible.

A weak surface cold front, tied to a surface low in northern
Quebec, will also push into the forecast area today. A
seasonably moist airmass is washing into the region from the
west ahead of the front, characterized by pwats in the 1.50-1.75
inch range. Model consensus suggests areas of
rainfall/thunderstorms associated with Theta-E advection and
midlevel height falls to expand southeastward and impact most of
our forecast area between 12-21z today. The increasing cloud
cover and rainfall from this morning will limit destabilization.
Though, the namnest suggests cape in excess of 1300 j/kg mainly
across the eastern Catskills into the Mid-Hudson valley for a
limited time this afternoon. Even if some instability develops
with muted surface heating, convergence along the front appears
to weaken by the afternoon hours as the front washes out. So,
while an isolated stronger storm cannot be ruled out, especially
in the afternoon, an organized severe weather event appears
unlikely. Locally heavy rainfall will be a threat, given
midlevel winds nearly parallel to low-level boundary, along with
the moist atmosphere. However, uncertainty with respect to
convective coverage as well as fairly fast precip motion should
mitigate the threat somewhat. Highs today will generally be in
the 70s.

Lingering showers and isolated thunderstorms will remain
possible early tonight as a secondary boundary drops into the
region. Drier air quickly builds in tonight on northwest flow
as high pressure begins to nose in. Can't rule out some fog if
clearing develops, especially in areas that see rainfall
this afternoon. Lows in the upper 50s in the high terrain to the
mid 60s in the valley locations.

&&

Short term /Friday through Friday night/...
Friday, a vigorous, compact upper low will move from the
western Great Lakes towards the mid-Atlantic coast. A seasonably
strong surface low will develop ahead of this feature in the
Lee of the mid-Atlantic Appalachians Friday night. As this
system takes shape, some showers could squeeze into southern New
York Friday night. However, most of Friday looks dry and
seasonably cool with high pressure in place. Highs on Friday
will generally be in the 70s.

&&

Long term /Saturday through Wednesday/...
for this weekend, rather tranquil for most of the region. However,
some subtle changes and trends are possible south of Albany as
latest NCEP model suite and international global guidance suggest
the tail end of the departing trough becomes cut-off from the
westerlies and develops an upper low over the mid-Atlantic region
for the start of the weekend. While this overall trend was further
south, now there are signals of a little further north with the
placement of this low and the slower departure through the weekend
(and perhaps into Monday as well). Ensemble trends also favor a
little northward trend as well so we will take the pops/wx a little
northward with this forecast package through Monday. Overall
confidence is lower than normal through Monday.

Conditions should improve along with warming temperatures through
Tuesday and Wednesday as ridge axis builds across the eastern Continental U.S..
with an increase in temperatures and the approach of another
boundary across the Great Lakes region, the low level moisture
should also increase and the slight chance for some diurnally driven
convection.

Temperatures through the period will average near normal through the
long term.

&&

Aviation /12z Thursday through Monday/...
band of showers continues to slowly advance southward with flight
conditions remaining in the VFR category but bordering MVFR
thresholds. Expectations are for at least the ceilings to drop
back to MVFR through the day as these showers continue to
advance southward and moisten up the lower levels. Kgfl will be
the first to see flight condition restrictions with kpou
experiencing it last.

Then with daytime heating additional isolated to scattered
convection is expected. As with convection, difficult to
highlight the best timing for impacting tafs as we will place a
vcsh with a combination of MVFR to some IFR for kpsf with
favorable upslope conditions and moist lower levels.

Winds will generally be light and variable with a tendency to
become westerly through the daylight hours at speeds 10kts or
less. Then winds become light and variable again tonight. Along
with those light winds the chance of low stratus or fog
formation becomes increasingly probable.

Outlook...

Friday night: no operational impact. No sig weather.
Saturday: no operational impact. No sig weather.
Saturday night: no operational impact. No sig weather.
Sunday: no operational impact. No sig weather.
Sunday night: no operational impact. No sig weather.
Monday: no operational impact. No sig weather.
Monday night: no operational impact. No sig weather.
Tuesday: low operational impact. Slight chance of rain showers...tsra.

&&

Fire weather...
showers and thunderstorms will become likely once again
today, especially north of the Mid-Hudson valley. Drier weather
takes hold Friday into the weekend, although periods of
rainfall may impact areas south of the capital district Friday
and Friday night. Temperatures will come up short of normal
values. Relative humidity values will bottom out in the 55 to 65 percent range
Friday, and become drier Saturday in the 40 to 50 percent range.
Northerly winds may become a bit gusty Saturday to near 25 mph.

&&

Hydrology...
periods of showers and thunderstorms are expected today into early
tonight. Basin average rainfall is expected to remain below a
half inch; however, locally heavy rainfall will be possible in
any thunderstorm. Isolated urban and poor- drainage flooding
cannot be ruled out in areas that see repeated rounds of
rainfall.

Conditions will generally be dry Friday into the weekend, but
some periods of rainfall may impact areas south of the capital
district Friday afternoon into Friday night. Latest indications
are that amounts will remain on the light side; however, there
is a low probability that the associated storm track will shift
north and bring more of a soaking rain to southern portions of
the forecast area.

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...Thompson/jvm
near term...NAS/Thompson/jvm
short term...Thompson/jvm

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