Area Forecast Discussion
Issued by NWS Burlington, VT-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KBTV 160755
Area Forecast Discussion
National Weather Service Burlington VT
255 AM EST Mon Jan 16 2017
A ridge of high pressure will build east from the Great Lakes
overnight and will remain over the north country through Tuesday
morning. A mixed precipitation event is expected from late
Tuesday afternoon through Wednesday, followed by warmer and
drier weather from Thursday through the weekend.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 1145 PM EST Sunday...No significant change made to current
forecast with this update. Refreshed some cloud grids to capture
lake effect moisture lifting into Southern Saint Lawrence Valley
and mid/upper level clouds across northern VT. Otherwise...temps
ranging from near 0f at slk/nek to 20f immediate cpv. All
covered well in current grids.
1031mb high pres centered directly over the Champlain Valley
this evening is providing most of the area with clear skies and
light winds. Still some clouds lingering across the NEK and
watching some lake effect clouds moving toward southern SLV
attm. This lake clouds and increasing southerly winds on
backside of departing high pres will result in temps slowly
warming across the SLV and dacks by 06z and across the CPV by
early Monday morning. Have trimmed back lows by several degrees
based on current temps. Generally thinking lows range from -5f
SLK/NEK to 10 to 15F Saint Lawrence and Champlain Valleys.
Otherwise...rest of forecast in good shape.
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
As of 205 PM EST Sunday...Generally quiet conditions are
expected for Monday night through the morning on Tuesday as
surface high pressure persists over the North Country. For
Monday night, weak shortwave energy passing north of the area
combined with some lingering low level moisture may spark a few
snow showers across our northern tier zones, but most of the
area should remain dry under partly cloudy skies. Tuesday begins
a warming trend that we`ll see through the week with highs
pushing well into the 30`s area-wide with southerly flow
increasing ahead of our next system.
Surface low pressure lifts northward through the Great Lakes
region Tuesday and precipitation will spread across our forecast
area from Southwest to Northeast during the late afternoon and
evening. Strong vorticity advection and deep moisture, therefore
expect precipitation to be widespread. Early Wednesday morning
a secondary low will form off the New England coast and bulk of
the energy shifts to this low center and wraps colder air back
into the system. Have continued with previous forecaster`s
thinking that will see more of a sleet and snow mix rather than
freezing rain...only exception being the Saint Lawrence valley
where some low level Northeasterly flow will get trapped. From
Tuesday evening through the overnight feel that we`ll see a mix
of sleet and snow with some rain at the onset Tuesday afternoon
and evening. Best chance for sleet and snow will be across
Eastern Vermont and the Eastern Dacks. We`ll probably see more
rain in the Champlain and Saint Lawrence valleys, perhaps
freezing rain in the Saint Lawrence valley as I previously
mentioned. Warm air advection continues Wednesday with original
low lifting north of the region and precipitation should change
to all rain during this timeframe. As secondary low strengthens
later in the day Wednesday and overnight colder air aloft will
wrap into the system and precipitation should change over to
Still several days away so will iron out the details as we get
closer and have better higher resolution data to look at. At
this stage, looks like Wednesday morning will have a messy
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
-- Changed Discussion --As of 255 AM EST Monday...The middle to later portions of the
week will generally feature high pressure with very mild
temperatures, variable clouds and mainly dry weather. This idea
is broadly supported by a variety of global ensemble guidance so
forecast confidence remains above average. A weak upper trough
passage Wednesday night/Thursday morning will bring the best
shot at scattered snow/rain showers during the period, otherwise
minimal pops will be offered through Sunday. Mean 925 mb
temperatures generally average from -1 to -3C through Saturday,
then climb slightly by Sunday. Adding a customary +7C to these
values for January yields max temps from the mid 30s to lower
40s through the 4 day period with overnight lows in the 20s to
around 30 in milder valley locales. Of course, any radiative
effects that do develop during overnight periods of partial
clearing could yield higher variability in the overnight lows
than currently shown, but this is not an uncommon occurrence.
Regardless, daily mean departures should average some +8 to +15
deg above normal for this time of year continuing the larger
background trend throughout the winter so far.
-- End Changed Discussion --
.AVIATION /08Z Monday THROUGH Friday/...
Through 06Z Tuesday...High pressure is over the North Country
and will remain over the area through the rest of Monday. Mainly
VFR conditions with scattered high clouds expected through the
period. Only exception will be a period of SCT/BKN MVFR cigs
possible at KSLK and to a lesser extent KMSS in the 07-13Z time
frame as lingering lake moisture from Lake Ontario is advected
northward on developing light southerly return flow. These
clouds will be thinning over time so after sunrise should be in
the dissipation process.
Winds will be light and variable overnight and then increase to
10-15 knots out of the south-southwest with the St Lawrence
Valley seeing gusts up to 20 knots.
06Z Tuesday - 18Z Tuesday...VFR with surface high pressure
18Z Tuesday - 00Z Friday...Trending MVFR with intervals of IFR
in widespread precipitation
00z Friday onwards...VFR as high pressure builds into the