FXUS61 KBTV 191807
AREA FORECAST DISCUSSION
National Weather Service Burlington VT
107 PM EST Tue Feb 19 2019
A large area of high pressure across the Great Lakes region will
build eastward into the Northeast, bringing dry, mostly clear,
and seasonable cold conditions through Wednesday. Quick moving
low pressure passing to the north and west of the St. Lawrence
River will bring developing snowfall Wednesday night, ending as
a wintry mix early Thursday morning. Snow and sleet amounts
will range up to a couple of inches from the Champlain Valley
westward across northern New York, with 2 to 5 inches of snow
and sleet excepted across north-central into northeastern
Vermont. Some melting of this snow and sleet is expected as
Thursday afternoon valley temperatures rise into the 40s.
Temperatures will remain above normal with drier weather to end
.NEAR TERM /THROUGH WEDNESDAY/...
As of 1239 PM EST Tuesday...Forecast in good shape with high
pressure remaining in control. Updated the sky forecast to
reflect the clear skies in place. Should be a beautiful, sunny
late winter afternoon, but bundle up if headed outdoors as wind
chills are in the single digits. Previous discussion follows.
Synoptically quiescent conditions prevail across the North
Country as large sfc anticyclone builds ewd from the Great Lakes
into the nern CONUS, and eventually shifts east of New England
on Wednesday. Some residual stratus clouds persist across
n-central into nern VT early this morning per GOES-16 fog
product, and could see a few lingering flurries in Vermont`s
Northeast Kingdom. However, dry N-NW low-level flow will result
in clearing conditions areawide toward daybreak with sunny skies
expected today. NW winds increasing to 10-15mph will keep
temperatures on the chilly side, with highs only in the 15-20F
range, except 20-25F across the srn valleys.
High pressure builds directly overheard tonight with
diminishing winds. Should be ideal radiative cooling conditions
with lows in the single digits above zero, and locally zero to
minus 10F across the northern Adirondacks and Vermont`s
Northeast Kingdom. As high pressure shifts to our east on
Wednesday, a southerly return flow develops, allowing afternoon
highs to reach the mid- upr 20s. Should see a trend toward
filtered sunshine Wednesday aftn as mid-upr level cloudiness
increases from SW-NE late. PoPs NIL through the near-term
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/...
As of 104 AM EST Tuesday...Little overall change in expected
minor snow to mixed precipitation event expected Wednesday night
into early Thursday morning. Primary low is still expected to
track to our north and west, and secondary low development
occurs late and too far east to have any significant impact on
our forecast area. Thus, strong 850-700mb WAA will drive
isentropic ascent with developing snowfall from SW-NE, likely
during the 00-03Z period from BTV south and west, and between
03-06Z across north-central into nern VT. Periods of WAA snows
will continue during the overnight hours (PoPs 80-90%), but
will see SW 850-750mb winds of 50-60kt advect above
freezing/warm layer into the region late. This warm layer
results in a transition to sleet across nrn NY and south-
central VT 06-09Z, and into the Champlain Valley 09-12Z. Far
northeastern VT remains mainly snow based on current NAM/GFS
vertical profiles. May see a few pockets of light freezing rain
as well, but not expecting much in the way of ice accumulation
(trace to a few hundreths). Also appears that synoptic mid-
level dry slot works into the region quickly 10-13Z, with a
rapid end to any steady precipitation from W-E around or just
after daybreak Thursday. The remainder of Thursday will feature
isold rain/summit snow showers, with valley temperatures warming
well into the 40s.
With overall QPF mainly 0.20-0.35", not looking at a major
winter event Wednesday night early Thursday morning. General
snow/sleet totals of 1-2" expected from the Champlain Valley wwd
across nrn NY, and 2-5" of snow/sleet for central into nern VT
with colder temperature profiles expected. May see some slow
travel for the morning commute on Thursday, especially east of
the Greens. Current trends suggest Winter Weather Advisories may
be needed for Wednesday night into the morning commute time
frame, mainly for central into nern VT. Should see melting and
improving road conditions with partial sunshine later Thursday
morning into the aftn and temperatures rising into the 40s.
Gusty south to southwest winds are also expected Thursday. In
the Champlain Valley and nrn NY, will see S-SW winds 15-25 mph
with gusts to 35 mph possible with steepening lapse rates and
good low-level mixing.
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 301 AM EST Tuesday...Surface cold front and shortwave energy
aloft shift through the region Thursday night with precipitation
generally waning through the night with some upslope snow showers
possible across the higher terrain. High pressure follows for Friday
and Saturday with dry and pleasant weather expected with temps
ranging through the 30s for highs and teens/20s for lows.
Next system moves in for Saturday night through Monday and appears
to be a rinse and repeat from the mid-week storm with primary low
pressure once again tracking from the lee of the Rockies northeast
through the Great Lakes Sunday and into southern Quebec Sunday
night. Latest GFS/FV3/ECMWF are all in fairly good agreement showing
little coastal development which leads to warm air intruding into
the region on strong south/southwesterly flow creating some ptype
issues. Soundings indicate precip starts as snow Saturday night and
briefly changes to a mix of sleet/snow and perhaps freezing rain
Sunday morning before transitioning rapidly to all rain by the noon
hour as surface temps rise into the 40s area-wide. Could see a break
in precip in the warm sector depending on the strength of the mid-
level dry slot post warm front passage, and if that does occur it
could allow for a period of gusty winds to mix to the surface before
the cold front passes Sunday night. Behind the cold front
precipitation transitions back to snow and gradually becomes more
terrain focused heading into Monday.
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Through 18z Wednesday...Dry/VFR conditions expected at the TAF
sites through the TAF period with the lone exception some MVFR
ceilings overnight at SLK. Winds will continue N-NW 7-10kts
today and at times gusty east of the Greens, becoming light and
variable tonight. Westerly flow aloft will bring some low level
moisture into SLK which will lead to a 3-6 hour window of some
BKN/OVC 1500 foot ceilings between 03-08z this evening.
Wednesday Night: Mainly MVFR and IFR, with areas VFR possible.
Definite SN, Definite PL, Definite FZRA.
Thursday: Mainly MVFR, with areas VFR possible. Chance RA, Chance
FZRA, Slight chance SHRA.
Thursday Night: Mainly VFR, with local MVFR possible. Slight
Friday: Mainly VFR, with local MVFR possible. NO SIG WX.
Friday Night: Mainly VFR, with local MVFR possible. NO SIG WX.
Saturday: VFR. NO SIG WX.
Saturday Night: VFR. Likely RA, Likely FZRA, Slight chance SN,
Slight chance PL.
Sunday: MVFR. Definite RA, Definite FZRA.