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Area forecast discussion 
National Weather Service Albany New York
645 am EDT Monday Mar 30 2015

Synopsis...
a fast moving clipper will bring a little snow mainly
north and west of the capital region...mainly early today. A cold
front will whip across the region this afternoon offering more
scattered showers of rain...graupel or mountain snow. There will
also be some gusty winds as well. High pressure briefly builds in
tonight...but a disturbance will bring more clouds and perhaps a
little more precipitation to mainly areas south of Interstate 90 on
Tuesday. High pressure regains control of our weather for Wednesday.

&&

Near term /until 6 PM this evening/...

As of 630 am EST...snow showers were reported throughout our County
Warning Area (cwa) which in some cases was coating the ground. This
first line of snow showers was already in the process of moving west
of the Hudson Valley. There were more scattered showers upstream
across the Adirondacks due to broad ascent and increasing low level
instability.



The latest hrrr indicated not much activity behind this batch.
However...upstream a cold front will cross the region by
afternoon...and the atmosphere will continue to destabilize
(increasing cold aloft). Therefore...we feel pretty confident
additional scattered showers of rain...graupel will develop. This is
hinted by the hrrr. As it turns colder aloft...any of these showers
could turn back to snow showers across elevations higher than 2500
feet later this afternoon. Also...there could actually be lake
effect snow showers briefly off of Ontario...down the Mohawk Valley
by late in the day.

So for this update...just finagled with hourly probability of precipitation...but keep
isolated to scattered showers into the afternoon...diminishing to no
probability of precipitation in the middle Hudson Valley by late in the day.



Any snow accumulations this morning will localized and confined to
the higher terrain where an inch or two could accumulate. Nothing
more than a dusting to an inch (if that) is expected in any valley
areas.

This afternoon...there should be no real additional
accumulations...even over the mountains.

High temperatures will tricky to forecast. They will be highly
dependent on cloud cover and precipitation coverage. Less
precipitation...more breaks of sunshine and a brief gusty SW wind
could propel temperatures past 50 in the capital district for the
first time in 92 days. However...we leaned more with the clouds and
enough shower activity to hold high temperatures to the upper 40s in
and around the capital region...but reaching 50 or a little higher
south of the capital region...40-45 higher terrain.

The wind will be brisk out of the south this morning 10-20 miles per hour with
some higher gusts...especially at the onset of any shower activity
as evaporative cooling could mix a pretty strong west-southwest low level jet
to the surface. As the cold front slides through...the wind will
shift to the west at similar speeds. The potential is there for
gusts 35-45 miles per hour...just below Wind Advisory thresholds...but we will
monitor. The quantitative precipitation forecast will light this system...well under a quarter of
an inch...and in some places from Albany southward...perhaps not
even measuring.

&&

Short term /6 PM this evening through Wednesday night/...
tonight high pressure will briefly build in resulting in a clearing
sky and a gradual diminishing wind (after some gusty winds in the
evening)...but probably not go completely calm. Night time lows will
generally be in the 20s...except upper teens across the Adirondacks.

A trailing piece of northern stream upper energy tracks southeast
out of the Great Lakes Tuesday and tracks off the Middle Atlantic
States Tuesday...with the northern edge of a precipitation
shield...possibly extending just south of I-90. Clouds will extend
northward through the entire County Warning Area. While on paper it looks cold
enough for this precipitation to be snow...that fact that it is
nearly April...the air mass will not be all that cold...and much of
the precipitation will fall during the day allowing solar influence
through the clouds...ptype will be a challenge. If the precipitation
is light enough (which we believe will be the case) we would
probably be looking at snow at elevations higher than 1500
feet...and rain or rain snow mix in the valley with very little if
any accumulation. Even over the higher terrain accumulations (if
any) look light but again we will have to monitor later trends to
see if there signals ramping up the quantitative precipitation forecast (which would favor more snow
over rain and of course more accumulation). We kept probability of precipitation in the
chance category for now...even though some guidance indicates
higher chances than that to our south.

Project high temperatures look to be 40-45 in the valleys (possibly
highest north of Albany where the clouds will be the thinnest). High
temperatures will be in the 30s over the higher terrain. Again...if
precipitation turns out to be heavier...these highs would have to be
lowered several degrees.

The disturbance will move on Tuesday evening...leaving high pressure
to build back in. The sky should clear and with light wind
temperatures Will Tank (especially in any areas that pick up even
fresh coating of snow). Lows will dip back into the lower to middle 20s
Albany southward...15-20 further north and west.

Wednesday looks like a fairly decent day (at least by this Spring
standards). Bright sunshine will bolster temperatures back into the
lower to middle 40s in the valleys...middle to upper 30s higher terrain.
These values are still a bit below normal for this time of year.

&&

Long term /Thursday through Sunday/...
considerable uncertainty in the long term portion of the
forecast...especially regarding the handling of fast moving
Pacific shortwave energy during the Friday-Sat time period.

The overall pattern will be deamplifying at the start of the
extended across the u... the persistent polar vortex relaxes and
reorients a bit further north and west across Canada. This will allow for
fast moving Pacific systems to track across the central and eastern
U.S. Ridging ahead of one of these disturbances should bring a
period of milder temperatures for Thu-Fri...before temperatures trend back
to below normal by next weekend as middle/upper level heights once
again fall across eastern Canada and the Great Lakes region.

Thursday-Sat nt...a pair of upper level impulses will track east from
the western U.S. During this time period...with a northern piece
tracking into central Canada...while a southern one tracks into
the Southern Plains. Frontal systems associated with the northern
one should impact our region Thursday...with a warm front
initially...then a cold front sometime Thursday nt or Friday. This should
bring rain showers to the region Thursday afternoon-early Friday. Then...as
the southern piece of energy tracks into the Southern Plains and
eventually the eastern u... wave of low pressure may develop
along the cold front...and allow precipitation to linger/redevelop
later Friday and possibly into Sat. Depending on how the upper level
energy and timing of associated surface boundaries track Friday-
Sat...there could be enough cold air for p-type issues with any
lingering precipitation Friday night. In addition...some guidance
suggests that any southern pieces of energy and waves of low
pressure track further south with less impacts on our region.
So...at this time...generally have indicated only chance probability of precipitation for
this time period...mainly for rain showers...although some snow
could occur Friday nt into Sat morning depending on the exact timing
and track of systems.

Sun...a return to below...to potentially well below normal temperatures is
quite possible in the wake of any previous system. It should be
generally dry...although can not rule out some showers of snow or
rain depending on instability and overall progression of upper level
energy.

Temperature wise...highs Thursday will be in the upper 40s and
50s. Lows Thursday night in the middle 30s to middle 40s. Highs Friday
generally in the 50s to lower 60s...with upper 40s over the
Adirondacks. Lows Friday night as colder air moves in will be in
the upper 20s and 30s. Highs Saturday in the upper 30s and 40s.
Lows Saturday night in the middle teens to the 20s. Highs Sunday in
the middle 30s to middle 40s.

&&

Aviation /12z Monday through Friday/...
as of 630 am...the initial band of scattered snow showers
associated with a warm front was already moving through the taf
sites and will likely be east of the region by 12z (the start of
the taf period). Even after the warm front moves through...the
threat of showers (mainly rain showers later in the day...will
continue ahead of a cold front that will cross the region during
the middle afternoon period. Behind the cold front there will still
be a chance of showers as an upper level disturbance also affects
the region.

Although there will be a few weather features affecting the region
during the taf period ending at 12z Tuesday...moisture is limited
and forcing is relatively weak...so for the kgfl/kalb/kpou/kpsf
taf sites have generally forecast VFR conditions for most of the
taf period. The exception is at kgfl...where a tempo group for
MVFR ceilings/visibilities due to snow showers has been forecast between 12z
and 15z. Otherwise...the threat of showers is low and timing
difficult...so have only indicated vcsh during the day at the
other taf sites and during other times of the tafs.

Surface winds will be southerly ahead of the warm front at 8 to 12
kts with gusts of 15 to 20 kts. After the warm front the winds
will shift to southwesterly and increase to 10 to 15 kts with
gusts of 18 to 25 kts during middle/late Monday morning. By middle
afternoon the winds will shift to westerly after the cold front
moves through with speeds of 12 to 18 kts and gusts of 20 to 30
kts. After 00z Tuesday...the speeds will begin to slowly
diminish...dropping to 5 to 10 kts by late tonight...with some
gusts to 15 kts.

Outlook...

Tuesday: low operational impact. Slight chance of rain showers.
Tuesday night: low operational impact. Slight chance of snow.
Wednesday and Wednesday night: no operational impact. No sig weather.
Thursday and friday: low operational impact. Chance of rain showers.

&&

Fire weather...
gusty winds up to 40 miles per hour today...

A fast moving clipper will some snow showers mainly north and
west of the capital region early Monday...with mostly rain showers
from Albany south and east. A cold front could bring a few more
showers Monday afternoon. High pressure will build back
in tonight. Another clipper tracking mainly south of the region
could bring light rain or snow to southern areas Tuesday.
High pressure builds into the region Wednesday.

Relative humidity values will range between 30 and 55 percent Monday and Tuesday
afternoon. Relative humidity values will range between 70 and 100 percent tonight
and Monday night.

A south wind average 10 to 20 miles per hour...then become west to
northwest by with gusts to 40 miles per hour by afternoon. The wind will
diminishing down 5-15 miles per hour late Monday night...light and variable
Tuesday.

&&

Hydrology...
no Hydro related problems are anticipated through at least the
middle of the upcoming week.

Recent rainfall and snow melt has allowed for some minor rises on
rivers and streams but colder weather will continue slow any rises.

During the first portion of next week...some scattered rain
and snow showers are expected today. Precipitation
amounts of a tenth of an inch or less is expected with this
activity...and some areas may not see precipitation. Some of the
precipitation will fall as snow shower activity.

Another disturbance could bring a little more rain or snow to mainly areas south
of Interstate 90 Tuesday. Quantitative precipitation forecast amounts look light...under a quarter of an inch
which should have little if any impact on our hsa.

Temperatures will be above freezing this afternoon. This
will allow for a slow but gradual melt on the snowpack in place...
and river ice will continue to slowly decrease and rotate away.

A rapid warmup or significant rainfall isn/T expected through the
middle of the upcoming week.

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...hwjiv
near term...hwjiv
short term...hwjiv
long term...kl/gjm
aviation...gjm
fire weather...hwjiv/NAS
hydrology...hwjiv

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