Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Burlington Vermont
148 am EST Friday Dec 6 2013
a cold front will move across the region tonight into Friday
morning. It will bring rain showers to the north country...which
will transition to a wintry mix and then snow showers late tonight
into Friday morning before ending. More snow showers are possible
Friday night...especially over southern Vermont...as a weak wave of
low pressure passes south of New England. Dry and cold weather is
then expected over the weekend.
Near term /until 6 am this morning/...
as of 1249 am EST Friday...cold front slow to progress across the
area...with associated precipitation starting to move into the slv and
northern adks...as we continue to be in the warm sector with temperatures
generally in the 40s to l50s. Have slowed increase of probability of precipitation across
the area...starting as showers and becoming more stratiform towards
morning hours. Expect rain to be the primary form of ptype through
approx 08z/09z as colder temperatures look to filter into the adks and
slv. These areas will see mix of sn/ra/ip. Cold air may have
tough time filtering in before main precipitation shield exits region. So
expecting the bulk of the precipitation to fall in the form of
rain before the colder air arrives. Not anticipating more than a
coating of ice anywhere...and any snow/sleet accumulations by
morning will be light as well (a dusting to 2 inches) and
confined to northern areas. Southern and central Vermont can
expect mainly rain as cold air arrives very late.
Short term /6 am this morning through Saturday night/...
as of 341 PM EST Thursday...cold air continues to filter into forecast
area during Friday as front pushes slowly southeast. Temperatures
not expected to climb much above the early morning lows over
northern areas...with temperatures falling a bit over the south.
Changeover from rain showers to sleet/snow continues across
Vermont during the morning before precipitation comes to an end as
drier air works into the region. Any snow/sleet accumulations will
be limited to a dusting to around an inch. Cloud cover will also
decrease briefly before a weak wave of low pressure moves along
the cold front and passes out south of New England Friday night.
Moisture associated with this disturbance returns north into
forecast area Friday evening...before exiting by Saturday morning.
The result will be some light snow...which will affect mostly
southern half of Vermont with 1 to 3 inches of snow. Lower probability of precipitation
and less snow expected across the north. Outside of perhaps a few
mountain snow showers or flurries on Saturday...it will be dry
with partly sunny skies. Temperatures expected to be several
degrees below normal with valley highs mostly in the lower 30s.
Continued dry and Cold Saturday night as a ridge of high pressure
builds into the north country.
Long term /Sunday through Thursday/...
as of 318 PM EST Thursday...overall trends of all extended range
guidance continue to favor another mixed precipitation event to
begin the work week...followed by generally quiet conditions
thereafter. Model consensus remains very good...and thus
forecaster confidence is high.
Extended forecast begins on Sunday with a ridge of high pressure
over the region and dry conditions but cool temperatures with highs only
in the 20s...about 10 degrees below normal. Forecast then becomes
more active going into Sunday night as the high drifts east off
the Atlantic coast and a developing low coming out of the Midwest
approaches the Great Lakes. As the low tracks northeastward into
southern Ontario/Quebec the north country will once again be put
into the warm sector with mixed precipitation likely. Precipitation
should begin as snow late Sunday night into Monday
morning...before transitioning a mix of rain/sleet/snow Monday
afternoon...and back to snow Monday night. Vertical temperature profiles
even support some areas of freezing rain...but confidence is low
on those exact details at this time.
For the remainder of the forecast period for Tuesday through
Thursday...colder temperature profiles return as a broad upper trough
settles over the northeast. We'll be under fast west/southwest
upper flow with several weak shortwaves moving through supporting
some low chance probability of precipitation here and there for snow...but no real big
accumulations on the horizon...sigh. Highs during the period will
generally be in the 20s...and lows in the lower teens to single
numbers...all well below normal for mid-December.
Aviation /07z Friday through Tuesday/...
through 06z Saturday...a weak cold front is moving through the
region at this time with surface winds shifting to the west and northwest.
However...composite radar loop showing precipitation behind the
front across most of northern...central and western New York state
at this time. Conditions ranging from VFR to MVFR/IFR across the
region at this time. Expecting ceilings to rise later this morning
as precipitation winds down across the region. Expecting mainly VFR
ceilings across Vermont and northern New York by 16z Friday. Model
guidance showing more precipitation moving into central and
southern Vermont after 03z Saturday...mainly in the form of snow.
Outlook 06z Saturday through Tuesday...
06z Saturday through 12z Saturday...generally VFR with areas of
MVFR/IFR in light snow...mainly south and east of kbtv.
12z Saturday through 06z Monday...becoming VFR under high
06z Monday through 12z Tuesday...IFR/MVFR in developing snow and
mixed precipitation...as surface low pressure area moves into the
Tuesday...generally MVFR with isolated to scattered snow showers.