Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Albany New York
452 am EDT sun Mar 9 2014
high pressure will briefly crest over the region today. Tonight
into Tuesday a warm front will push into the region...and stall
near New York and the Middle Atlantic States. A weather disturbance
moves through the Ottawa Valley Tuesday...dragging this frontal
system out of the region...and is then followed by a strong cold
front. This front stalls from the Tennessee Valley to the
Virginia coast Tuesday night. Middle week a storm will organize along
this front and move up the East Coast.
Near term /through Monday/...
a weak cold front is in the process of exiting and clouds
gradually moving out. Southern and western areas could take part
of the morning to see a meaningful decrease in clouds as the
boundary layer thermal gradient is still a bit tight and some
forcing along with lingering boundary layer moisture could keep
the clouds in in those areas. Highs today should be mainly in
the 30s...some 20s higher elevations.
Another little upper impulse tracks across the Great Lakes tonight
and tomorrow with some additional boundary layer frontogenesis and
forcing as boundary layer temperatures warm. Some enhanced
isentropic lift and upslope boundary layer flow suggests the best
coverage of snow showers...mixed snow and rain showers during the
day Monday...in areas of higher terrain...especially the southern
Adirondacks...parts of the southern Green Mountains and parts of
the eastern Catskills. However...acknowledging scattered activity
in all areas...but very light precipitation amounts with little
impact if any.
Lows tonight in the lower 20s...teens in the southern Adirondacks
and Lake George Saratoga area. Highs Monday with the warming
boundary layer temperatures...but mostly cloudy sky...in the
lower to middle 40s...with middle to upper 30s southern Adirondacks.
Short term /Monday night through Wednesday night/...
a strong 500hpa short WV and surface low pressure move through the
Ottawa Valley Monday night dragging its trailing frontal system
through the region. In this moisture starved environment...only
scattered -shra/shsn. Tuesday this system will slide east of region with
initially strong northwest wind gradient behind it.
Weak bubble ridge of surface high pressure passes over region Tuesday...bfe a
much strong cold front drops S Tuesday evening...and merges with stalled
front from Ohio Valley to Delaware-Maryland-Virginia.
At this point this gets complex. For several days the model suite
has had a signal of a significant cyclone impacting the east.
Tracks have varied with fca in and out of affected area. Last
nights model suite had event largely to our south. Tonight's has fca
in the bulls eye.
Storm forms on the stalled front in the Ohio Valley Tuesday
night...and moves east-northeast and deepens as several 500hpa short waves
phases into full latitude trough over east USA. By Wednesday afternoon the center
is near dca...with a track just S of Long Island and past the
benchmark over Cape Cod.
Tngts GFS/Gem have exact same track as 12utc European model (ecmwf). At this point
we certainly have consistency among the guidance...and we've had run
to run consistency since last nights 06utc GFS. Qfp amounts still
vary some among the models suite...but indications are now centered
around a largely winter storm potential event. Ptype should be
mainly snow north...but complex ptype scenario S as precipitation could
begin as rn S change to snow as ageo winds drive cold air advection and temperatures
actually fall during Wednesday afternoon.
While confidence in an event is increasing...it is still dependent
on the phasing of 2-4 short waves that are currently in the North
Pacific...and north of Alaska. Some guidance shears off a piece of
vorticity and leaves it behind in the 4 corners...weakening the
trough...others collect all the energy/dynamics and hurl it
eastward. The next few periods are the last where this event can
be broad brushed as chance or likely snow or rn to snow.
As such snow/rn should overspread the area Wednesday morning...change
to mostly snow... and end by Thursday morning. Since the 500hpa
trough never cuts off the surface low will move quickly under
progressive 500hpa trough.
Temperatures will be near normals during this period...temperatures will be non
diurnal Wed/Wed...with highs early Wednesday bfe onset of precipitation...and
falling as cold air advection increase over fca as storm deepens to our S.
Long term /Thursday through Saturday/...
fair amount of agreement with European model (ecmwf) and GFS...which is reflected
in HPC guidance. Coastal storm and its full latitude 500hpa trough
depart the eastern Seaboard quickly Thursday...however they keep a very
significant 24mb wind gradient across New York state...in cold air advection pattern. Temperatures
will go nowhere fast Thursday in what will be a cold blustery day.
Rest of efp will be characterized by fast northwest 500hpa flow and fast
moving surface weather systems. High pressure will build over eastern
states Thursday afternoon and nt...and winds will subside.
Friday morning and again Sat morning a 500hpa short WV and a surface clipper
low race across S ont/qb. They drag a warm front which Ushers a
quick return to near normal temperatures Fri/Sat. Sun and sun nt two cdfnts
drop S through region with a return to below or much below normal
temperatures at the end of the efp.
Otherwise its a regime of variable clouds...scattered -snsh as systems pass
through fca and as well as fluctuating temperatures. Efp populated with
Aviation /09z Sunday through Thursday/...
a cold front continues to move south of Long Island...northern New Jersey...and
PA this evening. High pressure will ridge in from the Great Lakes
region and Midwest tonight into tomorrow.
Other than some flurries and snow showers at kalb and kpsf through
about 07z-08z with periodic MVFR ceilings and visibilities...VFR
conditions will continue the next 24 hours for
kalb/kpsf/kgfl/kpou. Some gradual clearing from north to south
after through the early morning hours. By 1200 UTC...the skies
will be clear or mostly clear due to the strong subsidence from
the surface anticyclone. Some high clouds will increase from the north
and west towards 00z/Mon.
The winds will be variable but mostly north to northwest at less
than 8 kts overnight. Expect the winds to increase from the west
to northwest at 8-13 kts during the late morning into the
afternoon with some gusts around 20 kts at kalb and kpsf. Winds
will diminish to less than 10 knots by 00z and shift to west or
southwest for this evening.
onday night: moderate operational impact. Chance of rain showers...shsn.
Tuesday: no operational impact. No sig weather.
Tuesday night: moderate operational impact. Chance of shsn.
Wednesday: high operational impact. Likely shsn...ra...sn.
Wednesday night: high operational impact.Breezy likely snow.
Thursday: moderate operational impact. Chance of shsn.
Thursday night/friday: no operational impact. No sig weather.
no widespread Hydro problems are anticipated over the next week
Much of the period will be characterized by fast moving weather
systems...with only scattered -shra/shsn...and temperatures fluctuating between
days 5-10 degree above normal and days 10 below normals. While there some
melting in the afternoon temperatures will return to below freezing most nights
precluding significant runoff.
The exception to this pattern will be the potential for a significant
storm Wednesday and Wednesday nt. While the precipitation may start as rain in S
areas...temperatures will fall Wednesday afternoon and nt and should change ptype
all over to snow...with little contributing to runoff.
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.