Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Burlington Vermont
1006 am EDT sun Mar 9 2014
high pressure will move over the region today for a nice day
across the area. This ridge of high pressure will give way to a
couple of quick moving lows in succession tonight through
Tuesday...to be followed by a coastal storm to affect the entire
region...with the potential of wet and heavy snow Wednesday into
Near term /until 11 PM this evening/...
as of 1006 am EDT Sunday...relatively quiescent conditions as surface
ridge of high pressure in place across the north country leading
to mostly sunny skies and dry air. Current forecast in good shape
overall with just minor adjustments to hourly temperatures and dewpoints.
Hourly temperatures likely to be tough to pin down over the next
few hours as temperatures rise quickly under strong insolation.
Low- level thermal profiles show modest 925-850 mb cold advection
weakening/becoming more neutral with time through the day today.
No changes to current temperatures which are in the 20s to lower
today (warmest in southern vermont).
Looking ahead toward later today/tonight...noted the latest 12z
NAM/WRF shows a slower ramp- up in timing of probability of precipitation/weather into northern
New York associated with the approaching clipper-type system later
today into tonight (generally near/after 00z monday). Certainly
expect an increase in clouds late in the day and I may need to
adjust these back some with later updates...but for now will await
latest GFS before making any changes.
Previous near-term discussion issued at 731 am EDT Sunday
Cloud cover from exiting frontal boundary continues to move away
from the region this morning...setting up ridge of high pressure
over the Great Lakes region to mv over the northeast for much of
today. Nice sunny/mostly sunny day on tap for the entire County Warning Area with temperatures
ranging mainly in the 20s which will be several degrees above
current temperatures with full sun today...but below normal as approach
of ridge will allow for cold air advection from central Quebec/Ontario. Going
into tonight though...shortwave energy over the northern plains
will dive southeast across the Great Lakes and into the County Warning Area from the west
by 00z tonight. This will be the first of two shortwaves models have
been showing to affect the area over the past several days. Bulk
of dynamic/energy with this system will slide just south of the
County Warning Area overngt...but with 0.10-0.15' quantitative precipitation forecast potential...1-2" of snow is
possible overngt...highest totals of hir terrain of dacks/western
slopes. Overngt lows will drop into the teens mainly with some
single numbers in dacks...aided by radiational cooling tonight before
clouds set in with system.
Short term /11 PM this evening through Tuesday/...
as of 433 am EST Sunday...going into Monday morning...shortwave
energy continues to slide S and east of the area. County Warning Area will see -SW to
continue through the day with northerly flow on backside of exiting
system aiding in an additional inch or so...especially over hir
terrain...before ending. County Warning Area will see Little Break in action Monday night
through Tuesday as second shortwave right on heels of exiting first
one. This system will track a bit further north than first system
and will allow for more broad coverage of light snow over the
area. Will be looking for 1 to 3 inch accumulate potential with highest
totals over hir terrain northwest facing slopes. -SW will taper from west to east
during the day Tuesday as westerly upper flow behind shortwave
will aid in pushing system east of area by nightfall. --SW still
possible during the day as clouds will linger over area...especially
over hir terrain. Temperatures Monday/Tuesday will be near to just above normal as
west-southwest flow will bring in warm air advection air to have middle 30s mainly for highs
with some u30s possible in cvly. Overngt lows look to be near/to above
normal as cloud cover between systems will not allow for radiational
cooling. Lows will be in the 20s with some spots teens in NE
Long term /Tuesday night through Saturday/...
as of 503 am EDT Sunday...a weak disturbance will bring a slight
to low chance probability of precipitation for snow showers Tuesday night.
Wednesday and Wednesday night...models are in better agreement in
bringing a surface low over the Ohio Valley early Wednesday and
moving it just north of the benchmark (40n 70w) by late Wednesday night.
Thus...forecaster confidence is also higher. This low track will
bring a significant snowfall for Vermont and northern New York
Wednesday...Wednesday night and early Thursday. Have raised probability of precipitation
for Wednesday and Wednesday night to likely across the entire
forecast area. All the models...ECMWF...GFS and Canadian global
model all show the track of the low just north of the benchmark on
Wednesday. The European model (ecmwf) model has the highest quantitative precipitation forecast with this
system...with the GFS and Canadian global models showing less quantitative precipitation forecast.
Thus...at this time it is still too early to forecast how much
snow will fall...but it does look like a significant and plowable
snowfall for the region Wednesday and Wednesday night. If later
model trends continue to show this potential...then a Winter Storm
Watch may need to be issued. Models show snow will continue into
Thursday morning before tapering off Thursday afternoon.
A weak ridge of high pressure will build into the region Thursday night.
Some weak clipper systems will move southeast from the western
Great Lakes and Canada Friday and Saturday with a chance of snow
showers and a chance of rain or snow showers on Saturday.
Aviation /14z Sunday through Thursday/...
through 12z Monday...mainly VFR conditions expected through most
of the period as a weak ridge of high pressure builds into Vermont
and northern New York today...with just some high thin cirrus
clouds expected. A warm front will approach the region late this
afternoon and tonight with ceilings lowering to around 10000 feet
by 00z Monday. Expecting some light snow to develop across
northern New York between 02z-04z Monday and then across the
remainder of Vermont between 03z-05z Monday with conditions
lowering to MVFR/IFR in light snow.
Outlook 12z Monday through Thursday...
12z Monday through 00z Wednesday...MVFR...tempo IFR in snow showers.
00z Wednesday through 18z Wednesday...mainly VFR under high pressure.
18z Wednesday through 12z Thursday...possible IFR/snow in NE coast storm.
12z Thursday through 00z Friday...improving to VFR.