FXUS61 KBTV 121739
Area Forecast Discussion
National Weather Service Burlington VT
1239 PM EST Mon Nov 12 2018
The week will start with dry conditions today as high pressure
slides off the eastern seaboard, but unsettled weather returns early
Tuesday morning as another low pressure system moving up the east
coast will bring another round of widespread precipitation through
Tuesday evening. Precipitation will begin as snow, but will
transition to mainly rain across much of Vermont during the mid-day
hours, with mostly snow anticipated across northern New York. Rain
and snow will end as all snow Tuesday evening with drier conditions
developing Tuesday night. A reinforcing shot of cold air is expected
behind this low pressure system, with temperatures well below
average on Wednesday with gusty northwesterly winds.
.NEAR TERM /THROUGH TUESDAY/...
As of 933 AM EST Monday...Mid-level clouds continue to reside
over the North Country this morning and should continue to
slowly erode throughout the day. As this happens, cloud cover
out ahead of the next system will move into the region.
Temperatures this morning are once again over-performing which
means temperatures will likely be in the upper 30s to mid 40s
today. Some sun is expected to peak out periodically through the
day so enjoy another nice fall-like day ahead of the messy
weather expected throughout the week.
Previous Discussion...The forecast remains on track for the
next 36 hours beginning with dirty high pressure over the region
this morning slowly sliding off the eastern seaboard through
the day. Low clouds shifted into the region overnight and we`ll
start the day cloudy, but as southerly return flow develops
behind the departing high we should see partly sunny skies
develop by the afternoon with temps rising into the mid 30s to
low 40s, which is about 5 degrees below normal for mid-
More active period of weather starts tonight as a well advertised
low pressure system develops off the mid-Atlantic coast and tracks
northeast through eastern New England Tuesday and into New Brunswick
by Tuesday night. Model consensus on the low track has zeroed in
Long Island to Rhode Island mid-day, then to near Portland Maine by
the afternoon which will make for some ptype issues due to a warming
boundary layer across much of central and southern Vermont.
Initially, soundings support precipitation beginning as all snow
across the area during the pre-dawn hours, but by mid-morning snow
will transition to a mix of rain and snow and eventually all rain
across all of Vermont except areas north of Route 15 in eastern
Franklin, Lamoille, Orleans and Essex counties where snow will
remain the predominant ptype. Across northern New York, snow will
mix with rain locally along the Adirondack coast and in portions of
southern Essex county, but areas northwest will remain all snow.
As the low rapidly shifts northeast over the Maine coast in the
afternoon, precipitation will change back to all snow across the
region but will quickly come to an end as deeper moisture lifts east
of the region. A quick burst of snow is possible during the evening
commute especially in the Champlain Valley where a brief period of
blocked upslope flow will support some additional enhancement. All
in all, by the end of the day we`re expecting to see a general 3-6"
across the Adirondacks and central/northeast Vermont, with 2-4" in
the St. Lawrence Valley and only a dusting-2" elsewhere. Main impact
will be travel during the morning and afternoon commutes with the
potential for snow covered roads and low visibility. A winter
weather advisory has been posted.
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 221 AM EST Monday...Sfc low pres quickly lifts into
eastern Canada with brisk northwest winds and strong low level
caa developing. Any leftover snow showers will quickly end by
00z as moisture profiles are limited and soundings show no
available moisture in the favorable snow growth area. Brisk
850mb winds of 35 to 50 knots will advect the coldest airmass of
the early winter season across our cwa on Weds, as progged
850mb temps drop btwn -16c and -18c. These values combined with
sfc winds 15 to 30 mph with some higher gusts will create wind
chill values well below zero summits to single digits/lower
teens valleys on Weds morning. Advection cold will result in
coldest overnight lows summits with single digits to near 20f
warmest valley, while highs on Weds struggle in the teens and
20s. Have noted extreme instability off Lake Champlain with
northwest flow, so would anticipate plenty of clouds downwind
with some flurries possible on the east side of the Lake.
Soundings are dry, which should limit overall impacts. 1036mb
high pres overhead by Thurs morning will result in a mainly
clear and cold night with lows single digits to mid/upper teens.
Winds should be mainly light and driven trrn.
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 221 AM EST Monday...Forecast period starts out quiet with
sfc high pres and modifying temps on Thurs. Highs generally mid
20s to mid 30s. Next potential coast system moves toward the ne
conus on Friday into Saturday. Guidance still shows a large
spread in solutions, but GFS ensemble mean has trended westward
toward the coast with low pres. The UKMET/FV3/ICON weaken closed
mid/upper level circulation lifting across the southern Conus
into the mid Atlantic States while sfc high pres remains
stationary over northern New England. These solutions would
provide our southern cwa with best chc for precip on Friday.
Meanwhile, ECMWF and GEM are much deeper with closed 5h/7h
circulation lifting north and placed 985mb low pres over
southern New England by Friday evening. Favorable 5h/7h track
and sfc low pres would result in a widespread precip event
across most of our fa. GFS is a compromise between the two camps
and shows a shearing system to our south, but still enough
moisture/lift to produce some precip across our fa. Once again
thermal profiles are complex and challenging, so have just
mentioned rain/snow based on sfc temps attm. Have continued to
mention likely pops most of our cwa and will wait for better
agreement before making significant changes. Temps mainly in the
upper 20s to mid/upper 30s Friday into Saturday. Additional
snow showers and potential snow squalls are possible Saturday
Night/Sunday Morning as guidance in good agreement showing
potent s/w energy, sharp boundary, and good mid level moisture
to produce additional precip. Temps drop back into the 20s by
Sunday with blustery conditions.
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
Through 18Z Tuesday...VFR conditions with SCT-BKN040-080 will
prevail thru 05Z. No vsby restrictions foreseen this aftn/eve.
Thereafter, will begin to see a mix of rain and snow overspread
the region from south to north during the pre-dawn hours
Tuesday. Anticipate periods of 1SM -SN 08-15Z, with potential
for periods of a rain/snow mix from the Champlain Valley ewd.
During mixed rain and snow, vsby will likely improve to 3-5SM.
Ceilings will generally lower to MVFR by 07-08Z, with periods of
IFR ceilings and TRRN OBSCD between 09-15Z. Should see
precipitation begin to wind down from SW-NE during the 15-18Z
time frame on Tuesday.
Tuesday Night: VFR. Slight chance SHSN.
Wednesday: VFR. NO SIG WX.
Wednesday Night: VFR. NO SIG WX.
Thursday: VFR. NO SIG WX.
Thursday Night: Mainly VFR, with local MVFR possible. Chance SN.
Friday: MVFR and IFR. Definite SN, Definite RA.
Friday Night: Mainly MVFR, with local IFR possible. Likely SHSN.
Saturday: Mainly MVFR, with areas VFR possible. Chance SHSN,
VT...Winter Weather Advisory from 1 AM to 6 PM EST Tuesday for
NY...Winter Weather Advisory from 1 AM to 6 PM EST Tuesday for