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afdaly

Area forecast discussion
National Weather Service Albany New York
1207 am EST Thu Feb 23 2017

Synopsis...
mild conditions with well above normal temperatures are expected to
persist for the remainder of the week. A weak cold front will cross
the region Thursday evening bringing some showers. The front will
stall just south of the region Thursday night, before lifting back
northward as a warm front on Friday. There will be increasing
chances for heavy rainfall associated with a strong cold front
passage late Saturday into Saturday night.

&&

Near term /through today/...
as of 930 PM EST...not much change to ongoing forecast as upstream
showers have dissipated as we are left in a diffuse synoptic flow
across the region. 11u-3.9u satellite imagery and infrared bands show a
variety of cloud decks across the region and as dewpoints slowly
climb, so will the potential for some fog. So with at least partly
cloudy skies early, temperatures should cool into the mid to upper
30s across much of the region tonight. Patchy fog may also develop,
especially for areas where snow remains on the ground.

Thursday will be another day of well above normal temperatures, as
we will be in a mini warm sector ahead of a weak cold front
approaching from the eastern Great Lakes. Temperatures expected to
even warmer than Wednesday, as there will be a stronger S-SW flow
ahead of the cold front resulting better mixing potential. Will
forecast highs in the upper 50s to lower 60s for much of the area,
except slightly cooler mid 50s in the western Adirondacks due to
more extensive cloud cover. The record high temp for Albany is 62
set back in 1984 and there is a good chance of tying or possibly
breaking this record. Chances for isolated-scattered showers will
increase during the day, mainly limited to areas north and west of
the capital district before sunset.

&&

Short term /tonight through Saturday/...
the aforementioned cold front is expected to stall along or just
south of the region Thursday night. So will hold on to mentioning
slight to low chances for showers along and just north of the front.
There will not be much moisture associated with the stalling front,
so only light showers are expected. With slightly cooler air behind
the front, temperatures will cool into the lower to mid 30s mainly
north of I-90, with milder upper 30s to mid 40s south.

Chances for showers will increase again on Friday, as the front
lifts back northward as a warm front in response to a strong storm
system digging across the Midwest and downstream ridging developing
across the eastern Continental U.S.. again, expecting light rainfall amounts
with the warm front Friday. Temperatures will still be very mild,
although slightly cooler than Thursday due to extra clouds/showers
around.

A tricky forecast period setting up for Friday night, as some
sources of guidance (especially the nam) indicating a side-door cold
front approaching from northern/eastern New England with a highly
amplified pattern. GFS/European model (ecmwf) less aggressive with this feature, so
will lean towards warmer guidance for Friday night. Still, this is
something to watch if trends develop.

The westward progression of the possible side-door cold front and
how cool temperatures get Friday night into Saturday morning could
have significant implications for eventual high temperatures for
Saturday. With increasing southerly flow and a strengthening sub-
990mb cyclone tracking into southeast Canada on Saturday, warmer air is
expected to surge into the region...at least aloft. If colder denser
air at the surface takes hold, this could result in a slow warmup.
Also this could have implications with regards to the degree of snow
melt and subsequent runoff that may occur. Will conservatively
forecast highs in the upper 50s to lower 60s, but could end up being
cooler or warmer depending on factors mentioned above.

Will continue to mention a slight chance for thunder ahead of the
system's cold front, with the potential for a period of moderate to
heavy rainfall Saturday afternoon into Saturday evening. A ribbon of
high precipitable waters of +2 to +3 stdev is forecast to move through just ahead
of the cold front. Quantitative precipitation forecast will be another factor to consider for
possible flooding issues. See hydrology section below for more
details.

&&

Long term /Saturday night through Wednesday/...
the period will be marked by an abrupt return to sharply colder
temperatures. Daytime highs on Sunday and Monday will be some 15 to
30 degrees colder than for Saturday with more moderation back into
the 40s and 50s by mid-week. Lows Saturday night will be about 15
to 20 degrees colder than for Friday night...with all lows Sunday
and Monday nights down in the mid teens to upper 20s range.

A strong cold front will push through the region late Saturday and
Saturday night. Rain showers will mix with or change to snow after
midnight. Mixed precip and snow will linger across the higher
elevations of the Adirondacks and greens on Sunday...with some light
snow accumulations possible. A reinforcing shot of cold air
overnight into Sunday will keep most of this period dry, with yet a
third cold front passing through on Monday.

Tuesday night and Wednesday will be the next best chance for
precipitation with a storm forming over the nation's bread basket
and heading toward the Great Lakes. Passing to our west, this
system will bring a return flow of mild air back across our
region.

&&

Aviation /05z Thursday through Monday/...
VFR conditions will prevail until late tonight as a warm front
lifts through our region. This will allow for good low level
moisture advection late this evening/overnight and increased fog
potential after 08z. Combined with calm winds and snowpack on
the ground, MVFR fog is possible. Since this is more of an
advective fog event, cloud cover shouldn't impact the potential
for fog development overnight. Have placed a tempo group in the
tafs between 08z and 12z for MVFR conditions in fog. Conditions
should gradually improve after daybreak Thursday although
ceilings will be borderline MVFR/VFR for much of the day.

Winds will be mainly light at less than 10 kts from the south
for much of the taf period.

Outlook...

Thursday night: moderate operational impact. Chance of rain showers.
Friday: moderate operational impact. Chance of rain showers.
Friday night: moderate operational impact. Chance of rain showers.
Saturday: high operational impact. Breezy likely rain showers...ra...tsra.
Saturday night: moderate operational impact. Chance of rain showers.
Sunday: no operational impact. No sig weather.
Sunday night: no operational impact. No sig weather.
Monday: no operational impact. No sig weather.

&&

Hydrology...
no widespread Hydro problems are expected through the rest of the
work week, with just light rainfall forecast and overnight
temperatures falling into the 30s to lower 40s the next few nights.

However, mild temperatures that will be well above normal, are
expected during the day Thursday and from Friday through Saturday.
This will cause snow melt and subsequent runoff. Also, a strong
storm system may bring a period of moderate to heavy rainfall
Saturday afternoon and evening. The meteorological model ensemble
river forecasts /mmefs/ continue to suggest significant river rises
will occur, with flooding possible Saturday into Sunday due to the
combination of snow melt and moderate to heavy rain.

At this time, at least minor flooding appears likely for at least a
few points along main Stem rivers. Depending on the degree of snow
melt, flooding could reach moderate levels in some locations. We
will have more specific information as the weekend draws nearer. A
Flood Watch may eventually be needed if confidence increases.

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...11/jpv
near term...bgm/jpv

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