Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Burlington Vermont
701 PM EST Wednesday Nov 25 2015
a ridge of high pressure will remain over the north country
through early Friday. A cold front will move south from Canada on
Friday and bring rain showers to the region later Friday and
Friday night...with a chance of snow showers over the higher
elevations Friday night. Another ridge of high pressure will build
into the region on Saturday and will remain over the north country
Near term /through Thursday/...
as of 700 PM EST Wednesday...generally small changes to hourly
temperatures, winds and lows with this update.
Southwest deep-layer flow aloft and associated low-level warm
advection regime expected for the north country tonight. At
surface, pressure gradient continues to increase from west to
east between an anomalously strong/1045 mb surface anticyclone over
Nova Scotia and slow-approaching cold front over the upper
Midwest. Given strengthening gradient and low-level flow
increasing in turn, expect south winds to further increase
through the overnight hours.
Despite the warming temperatures aloft, combination of radiative
cooling effects under clear skies and local drainage flows will
make for a complicated temperature forecast this evening. While
areas in the southern St. Lawrence Valley are in the upper 30s to
near 40, northeast winds are making it some 10 degrees colder in
the northern St. Lawrence Valley early this evening. Expect to see
the strongest cooling rates east of The Greens through midnight,
but temperatures probably will begin to level off/rise into the
overnight in the face of the warm advection aloft and sustained
south winds. Lows will generally be warmest in the Champlain and
southern St. Lawrence valleys (mid/upper 30s) and coldest in the
Adirondacks and eastern Vermont (mid/upper 20s).
Short term /Thursday night through Friday night/...
as of 321 PM EST Wednesday...increased pressure gradient remains
for Thursday night keeping winds brisk out of the south. This will
help to keep min temperatures fairly mild...40s. A cold front approaches
from the west on Friday...with rain showers reaching the north
country Friday afternoon. Low pressure system passes well to our
north. Temperatures on Friday will also be mild ahead of the cold
front...50s. Conditions will also remain breezy ahead of the front
on Friday. Cold front will finally cross our area Friday
night...mainly rain showers expected with just a quick change over
to snow showers as the precipitation is ending towards early Saturday
morning. Min temperatures Friday night will be much cooler...generally
upper 20s and lower 30s...coldest temperatures north and west where the
front passes first.
Long term /Saturday through Wednesday/...
as of 321 PM EST Wednesday...some upslope snow showers on
Saturday as region is under northwest flow following cold frontal
passage which occurred overnight. General surface high pressure
will then be over our area through early Tuesday morning. GFS and
European model (ecmwf) both show some sort of Great Lakes low pressure system to
then impact the northeast in the Tuesday night into Wednesday
timeframe. Right now that is very far out in the forecast. Right
now looks like some rain showers are expected for the middle of
the week with generally near normal temperatures through the
Aviation /00z Thursday through Monday/...
through 00z Friday...VFR through the period. Low level wind shear and increasing
southerly wind gusts to be the primary aviation concern for the
Expect generally clear skies this evening. Southerly winds will
continue to gradually strengthen up to around 10-12 knots through
overnight. Increasing low- level winds will also yield some areas
of llws, particularly at pbg and slk. A general west-east
lowering/thickening trend of VFR ceilings expected for
Thanksgiving, with southerly winds 12-15 kts gusts up to 28 kts
(highest at btv).
Outlook 00z Friday through Monday...
00z Friday through 18z Friday...VFR under high pressure.
18z Friday through 18z Saturday...trending to MVFR in rain
showers as a cold front drops south into the region from Canada.
Some MVFR/IFR in snow showers possible 00z-18z Saturday as
18z Saturday through 00z Tuesday...VFR conditions expected as
another ridge of high pressure builds into Vermont and northern
a lake Wind Advisory is in effect...
A lake Wind Advisory is in effect tonight as southerly winds
increase to 25 to 30 knots after midnight. These strong winds will
continue through at least the early afternoon tomorrow,
Thanksgiving day. Waves will build from 1 to 3 feet this evening,
to 3 to 5 feet after midnight. Strongest winds and highest waves
are expected across the Broad Lake and along southern facing