FXUS61 KBTV 192034
AREA FORECAST DISCUSSION
National Weather Service Burlington VT
334 PM EST Tue Feb 19 2019
High pressure building into the Northeast will supply another
dry but seasonably cold night tonight before warm air advection
commences Wednesday morning. A quick moving low pressure system
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 4 inches of snow and sleet
expected across north-central into northeastern Vermont.
Precipitation will end Thursday morning through early Thursday
afternoon, followed by drier weather and seasonably warm
temperatures to finish out the week.
.NEAR TERM /THROUGH WEDNESDAY/...
As of 318 PM EST Tuesday...High pressure will crest overhead tonight,
allowing for one last crisp night with mostly clear skies and
seasonably cold temperatures under effective radiational cooling
conditions. Weak warm air advection will be ongoing through the
night under light southerly return flow, especially over
northern New York west of the center of the high, which will
counter radiational cooling and prevent temperatures from
plummeting quite as much as last night. However, still looking
at lows well below normal in the -10 to +5 range...warmest in
the Champlain Valley and coldest in northeastern Vermont closer
to the core of the high.
High pressure will shift east of the area during the day Wednesday,
prompting winds to turn southerly with increasing warm air advection
through the day. While the morning will start off mostly sunny,
high and mid-level clouds will increase through the day in advance
of the next system, which will impact the area Wednesday night.
Still looking like the majority of the area will stay dry through
Wednesday afternoon into early Wednesday evening (including dry for
the Wednesday afternoon commute) before precipitation arrives later
Wednesday evening/Wednesday night. Highs Wednesday will be in the
mid to upper 20s.
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 318 PM EST Tuesday...A low pressure system tracking through
the Great Lakes Region will push a warm front through the North
Country Wednesday night. Isentropic upglide along and ahead of
the front will spread precipitation over the forecast area
starting as light snow in the early overnight hours Wednesday
night. Warm air advection will continue through the night, and a
weak warm nose will develop in response to a southwesterly 850
mb jet pushing in. The warm air advection will allow for snow to
progressively change over to a wintry mix (primarily sleet)
through the night from west to east. A brief period of freezing
rain is possible during this transition time, however with
maximum temperatures in the warm layer aloft only progged
between 0 and 2 degrees C, the overall freezing rain threat
looks low. As far as timing of the snow to wintry mix
transition goes, northern New York will switch over between
midnight and sunrise Thursday morning, while Vermont will hold
onto primarily snow through the early morning hours. Thus, there
will be a west to east gradient of snow/sleet totals for
Wednesday night/Thursday morning, with generally 1-3" expected
in northern New York and the Champlain Valley, and 2-4" expected
along and east of the Green Mountains in Vermont.
Temperatures will quickly rise to above freezing Thursday
morning, and any residual snow or sleet will become light rain.
A rapidly advancing dry slot will quickly end most of the rain
through the morning, and a general drying trend will be observed
for the remainder of the day. The exception will be western
slopes of the northern Adirondacks and northern Greens, which
could hold on to some light showers through the day. Highs
Thursday will warm into the low to mid 40s, and winds will
become gusty in response to steepening lapse rates during the
daytime hours, particularly after precipitation ends. Westerly
winds 15-25 mph can be expected during the day, with gusts to
up to 35 mph possible.
Thursday night will be mostly dry with diminishing winds.
Temperatures will be fairly mild with lows in the 20s.
.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 318 PM EST Tuesday...Friday starts out mostly dry with
some lingering mountain snow showers under light northwest flow.
The snow showers shouldn`t account for much in the way of
accumulation and will likely taper off in the early evening as
the the flow turns more zonal aloft. High pressure builds in to
start the weekend as both Friday and Saturday should be fairly
pleasant with highs in the mid 30s Friday and mid to upper 30s
The quiet weather is short lived as a system will push into the
Great Lakes region Saturday night and will bring widespread
precipitation to the North Country Sunday through Monday. A
vertically phased low pressure system will develop off the lee edge
of the Rockies. The system will push northeast over the Great Lakes
and will bring continuous warm southerly flow. Warm advection snow
will start before changing over to potentially mixed precip and then
rain for much of the North Country by Sunday afternoon. As with this
morning`s global suite there is some subtle hint of a coastal trough
developing which would act to keep some of the low level air near
freezing east of the Greens which would complicate the precip type
A dry slot then provides a brief lull in the precipitation Sunday
evening before a cold front starts to push through transitioning
everything back to snow on the back side Monday. High pressure and
quiet weather return for Monday evening into Tuesday.
Based on the latest suite of guidance I`m not real bullish on any
flooding threats outside any river locations that are not currently
jammed with no channels. 24 hour rainfall totals appear to be on the
order of a half to three quarters of an inch and absent quite a bit
warmer temperatures I dont see significant snow melt running off.
Thus there shouldn`t be enough water added to the basins to lift and
break ice. That said, we`ll continue to monitor for any changes and
specifically for those locations that already have an ice jam in
.AVIATION /20Z 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.