Area Forecast Discussion
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FXUS61 KBTV 270721
Area Forecast Discussion
National Weather Service Burlington VT
321 AM EDT Mon Mar 27 2017
Unsettled and warmer weather moves into the North Country for
tonight and Monday as developing low pressure over the central
U.S. pushes a warm front northward through the region. Periods
of freezing rain tonight into Monday will transition to all rain
by Monday afternoon, briefly tapering off Monday night before
returning for Tuesday and ending as snow Tuesday night.
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
As of 1021 PM EDT Sunday...Have increased pops along and north
of a potsdam to Burlington to white river junction line thru
06z...for mainly light rain with pockets of freezing rain.
Surface temps continue to be several degrees warmer than
expected guidances...so have bumped hourly temps up and
decreased overall areal coverage of freezing rain thru 06z.
Still expect some pockets of freezing rain to develop as temps
drop btwn 29-32 across the deeper valleys of central/eastern
vt...including the northeast kingdom. Temps continue to be
challenging as Whiteface is 39F while Mansfield is 25f with BTV
36F and 1V4 is 35F. Most of central/southern Vt remains dry
this evening...but additional moisture will advect back into
this region after 06z...based on upstream radar trends.
Also...have trimmed back total qpf grids with amounts generally
between 0.33 and 0.66 expected by Monday Afternoon.
Previous discussion below: Better
slug of moisture with deeper saturation will move into the area
after 6z. Warm air aloft continues to push into the area and
temperatures have risen into the mid to upper 30s across our
area. Temperatures will not drop too far overnight with clouds
and precipitation moving into the area, as well as warm air
advection with warm front lifting across the area. Still
concerns across the Eastern Dacks and Eastern Vermont for
freezing rain and headlines for freezing rain advisory remains
For tonight into Monday, concerns remain from the previous
forecast thinking in regards to freezing rain potential as deep
low pressure pushes a warm front across the area. Thermal
profiles are as such that freezing rain will be the dominant
ptype across Essex County of New York and from the western
slopes of the Green Mountains eastward where surface temps will
hover a freezing or just below as warmer air aloft moves over
the area. In the deeper Champlain and St. Lawrence Valleys
surface temps remain in the low/mid 30s overnight so while
pockets of freezing rain are certainly possible, the overall
impacts will be minimal. On the impact side of things, under the
advisory area, there is some concern that impacts will be on
the low side through much of the event as modeled road
temperatures show surfaces warming well above freezing during
the day, and only right to freezing during the overnight. The
expected ice accumulations won`t have an impact on powerlines as
only up to a tenth of an inch is expected at the lower
elevations, and even though higher up on the mid-slopes
increased amounts could accumulate onto the larger transmission
lines, they can usually handle a little more without failing.
Freezing rain will be falling during the Monday morning commute
though so any ice on area roadways will be a concern.
By mid-day Monday the warm front pushes closer to the Canadian
border allowing surface temps to warm into the mid-30s east to
upper 40s west transitioning ptype to plain rain and ending the
threat of ice accumulation. Rain will be ending by about 00z
across our entire forecast area.
.SHORT TERM /7 PM THIS EVENING THROUGH WEDNESDAY/...
As of 321 AM EDT Monday....Background flow trends bodily to the
northwest in all areas by Tuesday night as northern stream
upper trough builds southward into the area. This will drive a
cold front through the region and with boundary layer
temperatures cooling a transition to scattered snow showers is
expected as coverage gradually wanes. Some minor accumulations
possible across elevated terrain to perhaps an inch or two.
By Wednesday main push of upper trough swings through the region as
surface high pressure builds south and east from central Ontario. A
continued threat for scattered rain/snow shower activity will exist,
mainly across the northern high terrain as temperatures top out in
the upper 30s to lower 40s for most. A fairly deep boundary layer to
850 mb under modest cold thermal advection aloft should ensure a
breezy day with northwesterly gusts in the 15 to 25 mph range as
skies trend partly sunny for all but the northern Green Mountains by
the afternoon hours.
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 321 AM EDT Monday...Any lingering northern mountain snow
showers end Wednesday evening with dry weather expected Thursday
into Thursday night as southern nose of Canadian high pressure
traverses the area. Low temperatures on both nights mainly in
the 20s with a few upper teens in favored northern mountain
hollows. Highs on Thursday similar to Wednesday - upper 30s to
Next precipitation maker then arrives by Friday into Friday night as
additional energy tracks northeast from the Ohio Valley/Great Lakes
area. Global models have trended toward taking this system
further northward than prior indications and as such have raised
precipitation probabilities accordingly - especially during the
Friday afternoon to Saturday morning time frame. Boundary layer
thermal profiles suggest this will mainly fall as a rain event
for lower elevations, though with 850 mb temps hovering around
0C some mix with snow or even all snow may occur across the
higher terrain above 1500 feet or so, especially Friday night
when a mix may even reach the valley floors. Time will tell. By
Saturday steadier precipitation exits east during the morning
hours as skies remain variably cloudy. Temperatures average near
late March norms with highs Friday/Saturday generally in the
lower to mid 40s with Friday night lows from the upper 20s to
Looking further out a gradual drying trend is expected by the latter
half of the weekend as surface high pressure is bridged aloft by
modest upper troughing. Temperatures should remain within 5 degrees
of typical early April values with highs ranging through the 40s and
overnight lows from 25 to 35.
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
Through 06Z Tuesday...MVFR conditions to persist through the
next 24 hours with IFR possible towards the tail end. Warm
frontal precipitation moves into the region in the next few
hours predominantly as rain except for FZRA at KMPV through 15Z.
Precip clears the area to the east after 18Z. For winds, mainly
south/southeast except northeast at KMSS at 5-10kts. Some gusts
up to 20-24kts in the Champlain Valley at KRUT/KBTV through
Outlook 06Z Tuesday through Friday...
00Z Tuesday through 00Z Thursday...MVFR/IFR in scattered rain
showers Monday night, becoming prevailing rain Tuesday, and
rain/snow Tuesday night and Wednesday. Moderately gusty NW winds
00Z Thursday through 00Z Saturday...Mainly VFR, except for some
scattered MVFR snow showers over the Adirondacks and Green
Mountains, mainly 00Z Thursday until 00Z Friday.
VT...Freezing Rain Advisory until 11 AM EDT this morning for VTZ003-
NY...Freezing Rain Advisory until 11 AM EDT this morning for NYZ034.