Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Albany New York
1018 am EST Sat Mar 8 2014
multiple fast moving weather systems will race across the region
the next few days. A cold front will push south across the region
today. High pressure will briefly crest over the northeast overnight
into Sunday. Late Sunday into Tuesday a warm front will push into
the region and stall in or near New York and the Middle Atlantic
States. A weather disturbance moves through Tuesday...dragging
this frontal system out of the region...and is then followed by a
strong cold front...which stalls from the Tennessee Valley to the
Virginia convective available potential energy Tuesday night. Middle week a storm will organize along
this front and move to the East Coast.
Near term /through tonight/...
as of 945 am...clouds have moved in faster than earlier forecast so
have increased the sky cover grids to reflect this. Have also
adjusted the hourly temperature grids to reflect curretn conditions.
clouds associated with the advancing cold front are moving across
the region from the west and northwest. The middle and high clouds are
spreading relatively quickly east...but there are breaks in the
clouds and most areas should be mostly cloudy to cloudy by middle
There is not much moisture associated with the cold front...but
the higher terrain of the southern Adirondacks and eastern
Catskills should see isolated to scattered snow showers...maybe a
few rain sprinkles mixed in during the afternoon. Temperatures
should reach the lower to middle 40s in many areas this afternoon...
some 30s in higher elevations.
Some gradually decreasing cloud cover through tonight with cold
advection. The winds may not go completely calm tonight...and with
some mixed clouds at times...temperatures may not fall as much as
they could. Lows in the lower to middle 20s...single numbers in the
southern Adirondacks and teens in the Lake George Saratoga region
to southern Vermont.
Short term /Sunday through Tuesday night/...
this period will be characterized by a fast moving mainly northwest
500hpa flow...with embedded short waves and multiple surface systems
racing through in a low to moisture started environment.
For the most part the model suite is in agreement with some spread
in amount of cloudiness and quantitative precipitation forecast with series of weak fronts that
impact the region.
Sunday begins with surface high pressure cresting over fca in wake of
departing cold front. Most of day will be MS to plus...cold air advection will be sharp and
brief ending by afternoon sun...but knock temperatures back to 10 degree below
normals...as h850 temperatures drop back to -11 to -16c.
Sun after surface high press ridge shifts east of region...and warm air advection ahead of
approaching warm front begins with clouds arriving by evening. The
warm front settles in or just S of fca into Monday nt as it parallels
500hpa flow and weak short waves pass at 500hpa and surface waves propagate
southeast. Result will be an unsettled period with considerable clouds
and chance -shra/shsn. Given lack of forcing and precipitable water around 0.50 inch
quantitative precipitation forecast will be in the 0.10 to 0.30 range with hiest amounts across north
tier over several periods.
The most significant 500 hpa short WV races southeast in fast flow on
Tuesday...dragging surface low offshore...and one cold front through early
Tuesday and a much stronger cold front Tuesday nt. Given even less
moisture this regime may trigger a scattering of rain showers/shsn on the
light side...but generally during this period there will be
considerable clouds...scattered rain showers/shsn around...and temperatures returning
to near normals Monday and Tuesday.
Long term /Wednesday through Friday/...
the GFS/ECMWF/Gem are moving to consensus with the Wednesday/Thursday storm
with system weaker...further S and considerably less threatening
then pvs runs.
Cold front has stalled from tenn to Virginia convective available potential energy by Wednesday mrng, strong cold air advection in
its wake has pushed temperatures back to 10 degree below norms. Wednesday and Wednesday nt
series of 500 hpa short waves act to dig trough from Great Lakes to lower miss
valley. However is whats becoming clear in these runs is while the larger
trough is carved out there much less phasing of short waves...and it
never closes off.
Result is garden variety cyclogen along the stalled frontal
boundary...with surface low ejecting east-northeast to New Jersey CST Wednesday nt and straight
out to sea Thursday morning.
Quantitative precipitation forecast for entire event ranges from European model (ecmwf) 0 north fca to 0.80 southeast
corner of fca...GFS/Gem near miss everywhere excpt extreme southeast.
While pvs GFS ensembles still had considerable spread with several
members as wet as an even wetter 12utc European model (ecmwf)...the trend here is
to less quantitative precipitation forecast across the board...and an event that's trending in
the guidance like last weekends miss.
Given trending...will not use HPC guidance. Will populate with
GFS...but nudge quantitative precipitation forecast and precipitation chance further north...but not as far north as
HPC or European model (ecmwf). S areas could still see several in of snow...and if hi
end European model (ecmwf) is correct could still be looking at marginal ws
criteria...but outside the outliers...could be a few inches of snow
to a near miss with best chances S and east of alb.
The Gem/GFS have system well offshore by daybreak Thursday...and European model (ecmwf)
just 6 hours behind. In its wake the progressive 500hpa trough
moves offshore and is followed by ridging...with surface high building
along eastern Seaboard Thursday into Friday.
Friday into Sat strong/dynamic but moisture starved clipper type short
WV/surface low pair race across North Ontario into qb...dragging a warm front
through region Friday and a trough or weak cold front Sat. Regardless fca will be
in wm sector with just a scattered -shra/shsn threat and temperatures rebounding
to near or above normals to end the efp.
Aviation /11z Saturday through Wednesday/...
a cold front will cross the local area Saturday with
mainly an increase in clouds as moisture is rather limited.
High clouds above 9000 feet will dominate through this afternoon
and evening. Ceilings will lower as the front moves through but
should remain above 3000 feet. However...have not included any
mention of showers in tafs as chances are so low.
Calm to light and variable winds through the morning with a
northwesterly flow developing with the passage of the cold front.
Sunday night/monday: moderate operational impact. Chance of shsn.
Monday night: low operational impact. Slight chance of rain showers...shsn.
Tuesday: low operational impact. Slight chance of rain showers.
Tuesday night: no operational impact. No sig weather.
Wednesday-thursday: moderate operational impact. Chance of
no widespread Hydro problems are anticipated over the next five
Temperatures generally be near or above normal over the next
week...except for short cool Downs...Sunday...Wed and Thursday.
Overnight lows will still be below freezing...and dew points
remaining rather low. Limited snow and ice melt is anticipated
with little to no effect on river and stream flows.
Little or no precipitation is expected over the next five days.
Any precipitation that does occur will mainly be in the form of
light snow or rain showers...until Wednesday when a more
significant precipitation event is possible mainly south.
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.