Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Burlington Vermont
734 am EST Friday Mar 6 2015
sunny but chilly conditions are expected today...as surface high
pressure remains in control across New York and New England. An
upper level disturbance will bring increasing clouds with periods
of light snow shower activity Saturday into Saturday night. Snow
accumulations are expected to be light...generally a dusting to 2
inches. No significant precipitation systems are foreseen over
the next seven days...but temperatures are expected to moderate
closer to seasonal levels during the early to middle part of next
Near term /until 7 PM this evening/...
as of 733 am EST Friday...Arctic high pressure providing for a frigid
start this morning under clear skies and light wind conditions.
Readings at 12z include -33f at Canaan Vermont...-27f at Saranac Lake
New York...and an overnight low of 10f at btv. Strong surface ridge
overhead this morning slides to the Gulf of Maine by 00z Sat while
maintaining dry/sunny conditions today. Light S-SW return flow
will develop on western periphery of surface ridge...and locally SW
10-15mph with gusts to 25 miles per hour middle-late afternoon across the St.
Lawrence Valley with some valley channeled flow. Otherwise...just
looking at continued chilly conditions with valley highs mainly in
the lower 20s. Went a couple of degrees above MOS consensus given
full sun and increasing March sun angle...but forecast highs still
14-18deg below the climatological average for this point in March.
Short term /7 PM this evening through Sunday/...
as of 302 am EST Friday...a weak clipper system will approach from
the northern Great Lakes late tonight...resulting in increasing
middle-upper clouds tonight. Combined with continued light south-SW
winds (5-10 miles per hour in the Champlain/St. Lawrence valleys)...it won't
be nearly as cold tonight with lows mainly in the upper single
digits to lower teens. Later arrival of cloud cover anticipated in
the Northeast Kingdom...and that could result in some local spots
near zero to slightly below zero before leveling off during the
Scattered snow showers are expected on Saturday into the first
half of Saturday night associated with weak clipper system/northern
stream shortwave trough. Activity should be most widespread middle
afternoon through early evening based on NAM and local btv mesoscale
WRF runs, and passage of best middle-level differential vorticity
advection. Consistent with previous forecasts...overall moisture
is quite limited with precipitable water values 0.2-0.25". Thus...only looking at
a dusting to 2" of snow...with the highest accumulations likely
across St. Lawrence/Franklin New York counties and the higher
elevations of Vermont (isold 3" amount possible across the northern
summits). Highs on Saturday generally 25-30f.
BUFKIT profiles suggest stratus layer will likely linger in most
sections on Sunday following passage of the shortwave trough.
Relatively quiet otherwise with weak surface high pressure in place.
Despite clouds...should see high temperatures in the upper 20s to lower 30s
in most valley sections.
Long term /Sunday night through Thursday/...
as of 302 am EST Friday...work week starts with chance of snow
showers as several upper level waves moves across in the north
country in mostly zonal flow aloft. Heading into the middle of the
week, some weak ridging at the surface to our south and slight
ridging aloft will keep chance for precipitation minimal. More significant
upper trough will move across hudsons Bay, but associated moisture
will only skirt the international border. However behind this system
will be colder air and northwest flow.
Generally low level south/southwest flow will keep influx of warmer
air through the first half of the week, allowing temperatures to
moderate into the m30s Monday, into the 40s Tuesday and Wednesday.
Min temperatures will experience a similar trend with teens Sunday night
and Monday night warming into the 20s Tuesday night. Aforementioned
northwest flow arriving Wednesday night and persisting into Thursday.
Temperatures will be noticeably colder in the 30s on Thursday and
back into the teens Thursday night.
Aviation /13z Friday through Tuesday/...
through 12z Saturday...high pressure providing VFR conditions
through the next 24 hours. South to southwest winds develop middle to
late morning at 5-10kts with gusts developing at kmss up to 20kts
in the afternoon as winds are funneled down the St Lawrence
Valley. Increasing VFR clouds expected after 06z ahead of
scattered snow showers that will move in from west to east. Have
included vcsh at kmss and kslk starting around 09z/10z as the snow
showers will be scattered in coverage. Increasing chance for snow
showers to affect terminals after 12z and IFR/MVFR conditions
possible within snow showers.
Outlook 06z Saturday through Tuesday...
12z Saturday - 06z Tuesday...periods of MVFR/IFR in light snow as
several systems track through the region.
06z Tuesday - 00z Wednesday...VFR under high pressure.