Area Forecast Discussion
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FXUS61 KBTV 230627
Area Forecast Discussion
National Weather Service Burlington VT
227 AM EDT Thu Mar 23 2017
A strong area of high pressure will crest over the North Country
this afternoon bringing mostly sunny conditions and light winds.
Temperatures will moderate a bit, with daytime highs mainly in
the upper 20s to lower 30s. A warm front will approach from the
southwest on Friday, with overcast skies and a developing wintry
mix across the North Country. Some light accumulations of snow
and sleet are expected Friday morning before transitioning to
mostly rain later in the day. The frontal zone will become
quasi-stationary near or just south of our region over the
weekend, with the potential for additional mixed wintry
precipitation later in the weekend.
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
As of 152 AM EDT Thursday...Strong sfc anticyclone (1036mb) in
control today as it translates ewd across the nern CONUS. This
feature will bring generally clear skies and lighter NW winds
(5-10mph). A chilly start at sunrise with readings mainly in the
single digits, and locally below zero in the Adirondacks (-12F
at SLK) and far nern VT. Air mass will undergo some moderation
today, aided by relatively high late March sun angle. Looking
for afternoon highs 27-32F, warmest in the Champlain/St.
Lawrence/CT river valleys. PoPs NIL, but will see some
increasing cirrus clouds late this afternoon into this evening.
.SHORT TERM /8 PM THIS EVENING THROUGH FRIDAY NIGHT/...
As of 200 AM EDT Thursday....High pressure shifts east of our
longitude overnight and into the Gulf of Maine by 09-12z Friday.
This will allow for a light S-SW return flow to develop. Aloft,
will see a warm front approaching from wrn NY and sern Ontario,
and increasing 850-700mb WAA will result in thickening mid-level
overcast. These factors will keep overnight temperatures
generally in the mid teens to lower 20s, with a tendency for a
slow rise in temps toward daybreak Friday, especially west of
the Green Mtns.
Moderately strong 850-700mb WAA with approaching warm front
brings developing stratiform precipitation beginning during
Friday morning from SW-NE. It appears thermal profiles will
initially support snow, with a transition to sleet/rain as the
day progresses. Subfreezing thermal profiles will persist
longest across central/ern VT and in the nrn Adirondacks, where
1-3" of wet snow/sleet are forecast. Should see generally 1" or
less wet snow in the Champlain Valley as PBL temperatures warm
more quickly thru the 30s. Could see some minor impacts to
travel especially around the time of onset of the mixed wintry
precipitation (and especially away from the Champlain Valley),
and will continue to highlight in the Hazardous Weather Outlook.
Afternoon highs on Friday generally 36-39F, except 33-34F
across portions of ern/nern VT.
First wave of low-level WAA passes to our east Friday
evening/night, but E-W oriented low-level frontal zone will
become quasi-stationary across nrn NY/nrn VT. May be a tendency
for a shallow nly wind shift after midnight with strong high
pressure building into wrn Quebec, so we`ll need to monitor
trends with the frontal position overnight with possible shallow
CAA near the intl border. Anticipate continued overcast skies,
but with just very light rain/drizzle or isolated pockets of
snow/sleet/freezing drizzle across far nrn areas. Temperatures
will generally hold in the low-mid 30s.
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 245 PM EDT Wednesday...Best day of the 7-day forecast
period appears to be on Saturday as aforementioned Canadian high
pressure noses briefly southward into the area. Skies should
trend partly sunny north and variably cloudy south under light
northerly flow. Some lingering light mixed precipitation may be
possible during the first half of the day south but shouldn`t be
a big deal. Temperatures generally 35 to 40 north and 40 to 45
The forecast then becomes increasingly complex from Sunday onward
into early next week as waves of modest advection of warmth and
moisture ripple through the area with continued chances of
precipitation. Boundary layer thermal profiles will again be
critical in determining eventual p-type through the period, with
subtle differences of just a few degrees potentially having a large
impact. Other factors such as time of day and precipitation
intensity/wet bulb cooling processes will likely play a role as
well. For now will maintain highest threat of precipitation during
the Sunday/Monday time frame, and potentially again toward the
middle of next week. Temperatures should exhibit a narrower than
normal diurnal range given the expected abundance of clouds with
highs from 35 to 45 and overnight lows 25 to 35.
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
Through 12Z Friday...VFR conditions through the period. Strong
surface high pressure will crest over NY and New England during
the daylight hours Thursday. Will see light (5-10kt) NW winds
redevelop after sunrise, and then switch into the S-SE tonight
once the ridge axis shifts to our east. Will see an increase in
mid-upr level clouds this evening through tonight, with ceilings
falling to near 7-8kft toward 12Z Friday. Any precipitation
with approaching warm front is expected to hold off until during
the daylight hours on Friday.
Outlook 12Z Friday through Monday...A warm front will bring
mixed wintry precipitation to the North Country Friday morning,
with a trend toward mainly rain by afternoon. Looking for
widespread MVFR conditions with intervals of IFR and HIR TRRN
OBSCD. Frontal zone becomes quasi-stationary across our region
over the weekend. It may settle southward just enough to allow
for VFR conditions Saturday, followed by a redevelopment of a
wintry mix Sunday into Sunday night with mainly MVFR/IFR conds.