Area Forecast Discussion
Issued by NWS Burlington, VT

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FXUS61 KBTV 241340
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
940 AM EDT Fri Mar 24 2017

.SYNOPSIS...
An active weather pattern is expected for the next several
days across the entire North Country. A wide variety of
precipitation types are also expected with snow changing to rain
today through tonight...but not before some light snow
accumulations occur. There may even be some sleet mixed in. The
precipitation will push south of the area on Saturday...but then
returns late Saturday night and continues Sunday into Monday.
Once again we will be looking at a mix of rain...sleet...and
snow.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 940 AM EDT Friday...Some modest adjustments to current
forecast to speed of timing/arrival of snows across the area.
Also nudged QPF/snowfall amounts up just slightly from prior
forecast, though still offer a general 0.5 to 2 inches for
valleys today, 2 to 4 inches in the mountains with localized
totals to perhaps 6 inches in the highest elevations. Didn`t get
too carried away with some of the higher model QPF output given
a distinct high bias during warm advective events. Used latest
RAP model for mid level thermal profiles and slightly cooler
model-blended hourly temperature trends given expected wet
bulbing processes. This would offer highs mainly in the lower to
mid 30s across north central/northeastern VT and upper 30s to
lower 40s elsewhere.

Prior discussion...
Clouds will continue to be on the increase today as a warm
front approaches the region. Favorable warm air advection will
take place for widespread precipitation to develop across the
area...especially this afternoon into the first half of tonight.
However...there will be one narrow band of snow that moves
across the area this morning. Low dew points across the area
this morning should help temperatures cool briefly at the onset
of precipitation before warming above freezing later today into
early tonight. Thus looking at snow changing to rain later
today...with temperatures remaining cold enough over parts of
eastern Vermont for the precipitation to remain as snow with
even some sleet mixing in as warmer temperatures aloft move
across the region. Most locations should see a half to two
inches...with higher amounts in the mountains and over north
central and northeast Vermont where two to four inches is more
likely. Northwest flow aloft takes over late tonight and warm
front will begin to get shunted to the south after midnight
tonight and colder and drier air will begin to move out of
Canada and down into the far northern portions of New York and
Vermont. High temperatures today will be in the mid 30s to lower
40s with lows tonight in the mid 20s north to mid 30s south.

On Saturday...colder and drier air continues to push south
during the day and any precipitation will be most concentrated
over the central and southern sections of our area with front
pushing southward. Highs will be in the mid 30s to lower 40s and
thermal profile suggests a mix of precipitation types once again
with rain...sleet...and snow possible.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 415 AM EDT Friday....Initially Saturday evening the cold
front that will have caused the precip on Friday will sag south
of the North Country and should lead to a brief period of dry
weather. However that will be short lived as the high pressure
over the Hudson Bay builds east. As that does, the flow will
become southerly and push the front back to the north with a
reinvigorating shot of cold air and precip. Expect snow
initially as we wet bulb down and cool however the southerly
warm air will eventually win out, and we see a transition from
snow with wintry mix, and then to plain rain but Sunday during
the daytime hours. There could be a few pockets of freezing rain
but with the warm air pushing in from the south and the high
sun angle its climatologically difficult to see much freezing
rain in late March.

While  boundary layer temps melt all the precip to mainly rain
during the day on Sunday, as we cool overnight we return to the
mixed bag of precip.  The warm nose looks strongest over the Saint
Lawrence and Champlain valleys however east of the Greens 925mb
temps stay below zero.  The result is that I anticipate mainly rain
with some ice pellets for the Greens and west however east of the
spine of the Greens we`ll be looking at a messy wintry mix.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 415 AM EDT Friday...The pattern continues to be messy
moving into the work week next week. As the first of a series of
upper level troughs swings through off and on rain/snow will
persist through Monday night before briefly subsiding. Then the
next trough swings through bringing more rain and snow Tuesday
into Wednesday. The difficulty in the forecast is that the
thermal profiles are very close to the rain or snow line so
slight movement north or south of the low pressure systems will
have dramatic impacts on precip type. So I`ve gone with the
boundary layer idea of rain/snow based primarily on surface temp
for now but will update as temps aloft become clearer.

The general trend in temperatures is that we are finally truly
coming out of winter as the airmasses are becoming more Pacific than
Arctic.  Thus we will see a generally warming trend that puts out
temps near normal with highs in the 40s and lows in the 30s. With
the exception of Monday night and temps in the mid to upper 30s
overnight, the diurnal swings should be good for the maple sap
runs.

&&

.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
Through 12Z Saturday...Overall expect VFR conditions through
about 14z before ceilings and visibilities lower through the
remainder of the period. However...there will be a narrow band
of snow moving across the area that reduces visibilities down
to a mile and ceilings to around 1000 feet for less than one
hour through 13z. Otherwise looking at MVFR/IFR conditions
developing over the entire area...especially after 18z and
continuing through the remainder of the period. Precipitation
will begin as snow and then transition over to rain between 21z
and 00z. Light winds through 12z before increasing out of the
south with gusts in the 15 to 20 knot range at most locations
later this morning and afternoon. Winds will start to shift to
the west and north after 06z.

Outlook 12Z Saturday through Tuesday...

12Z Saturday through 18Z Saturday...MVFR/IFR conditions
expected to improve as precipitation settles southward and
lessening in coverage by Saturday afternoon affecting mainly
southern terminals at that point. Highest threat of mix to occur
at northern terminals.

18Z Saturday through 12Z Sunday...trending mainly VFR
/precipitation-free as Canadian high pressure noses briefly
southward into the area.

12Z Sunday through 12Z Tuesday...widespread mixed precipitation
and/or rain return to the region.

12Z Tuesday onward...light and spotty mixed precipitation
transitions toward a period of steadier rains by Wednesday.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.

&&

$$
SYNOPSIS...Evenson
NEAR TERM...Evenson/JMG
SHORT TERM...Evenson
LONG TERM...Deal
AVIATION...Evenson/KGM



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