000
FXUS61 KBTV 231432
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
932 AM EST Thu Jan 23 2020
.SYNOPSIS...
Above normal temperature are expected across the North Country
today and Friday as high pressure remains anchored across the
Northeast US. A system is poised to impact the region late Saturday
into Sunday, however uncertainty remains in exact precipitation
type with chances for a mix of wintry precipitation and
snowfall.
&&
.NEAR TERM /THROUGH FRIDAY/...
As of 927 AM EST Thursday... After remaining steady for much of
the night, temperatures abruptly fell 5-10 F across much of
Vermont and in cold hollows of the Adirondacks around 7 to 8
AM. As a result, had to tweak hourly temps blending in some
guidance with colder temperatures, mainly over the valleys.
Otherwise, going forecast remains in good shape. Enjoy the
pleasant day!
Previous Discussion...No real changes made to the forecast with
surface high pressure cresting over the region today. Despite
some chillier readings in the deeper hollows this morning,
temperatures should warm nicely into the mid to upper 30s by
this afternoon. Expect mainly sunny skies with passing cirrus
overhead. As upper level ridging begins to dampen Thursday
afternoon, coverage of high clouds will increase which will have
potential implications once again on overnight low
temperatures. Have trended above MOS guidance slightly despite
surface high pressure and calm winds across the area due to
cloud cover. Upstream obs show thicker cloud cover across
Indiana/Ohio area with lots of temperatures remaining in the mid
20s to low 30s. Per model guidance this area of clouds is what
will advect over our region tonight. At this time, expect low
temperatures generally in the upper teens to low 20s with colder
readings across eastern Vermont where ridging will hold
stronger longer (and therefore limit cloud cover). Just to note,
however, these temperatures could easily be ~5 degrees warmer
(which is suggested by some deterministic guidance) if cloud
cover remains thick enough to limit radiational processes.
For Friday, another warm January day is on the docket with
temperatures warming another degree or two from Thursday`s highs.
Heights will build once again Thursday night into Friday as upper
level pattern amplifies ahead of the system for the weekend. 925mb
temperatures warm to around 1-2C before cold air damming sets up
across eastern Vermont by Friday night. Continued passing high
cirrus clouds are expected with increasing coverage by Friday
evening from west to east.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
As of 435 AM EST Thursday...Still anticipate a wintry event to occur
over the weekend. Model guidance continues to be in disagreement
with the details, however. Low pressure across the Great Lakes will
give way to a secondary low which will develop over the Mid Atlantic
states, then lift north or northeast. The question will be exactly
where and when this secondary low tracks and how quickly its cold
air moves into our area. This has big implications on precip type
and amounts. Warm advection precip will move in during the day
Saturday, becoming heaviest during the evening hours as a band of
strong frontogenetical forcing lifts across the region. The NAM
takes the secondary low to our south, while the GFS and CMC actually
lift northward through NY, keeping it to our west. The NAM solution
would mean a wintry mix of snow, freezing rain, and rain as east-
southeast flow would keep low-level cold air locked up on the
eastern side of the Greens and portions of the Adirondacks. However,
it should be noted that the warm nose aloft could well be eroded
away as evaporational cooling brings the temp aloft down to the wet-
bulb temperature which would mean more of a rain/snow type of
profile. Meanwhile, the the CMC and GFS solutions would mean snow
going to rain with perhaps just a bit of freezing rain or sleet
mixed in at the transition. Also noted that the SREF p-type plumes
are indicating the most likely p-type east of the Greens will be
rain, followed closely by freezing rain at 30-35%. Given all
this...have stayed with mainly a rain/snow precip type based on
surface temps, but added a slight chance of freezing rain for areas
below 32F. This and the warmer GFS and CMC solutions ended up
cutting back on snow amounts; now anticipate 2 to 4 inches across
much of northern NY where the colder air is more likely to hang in.
Much of VT would get 1 to 3 inches of snow, with higher amounts in
the higher terrain in the south central Greens. The aforementioned
east-southeast flow would result in shadowing in the Northeast
Kingdom, so for now expect an inch or less there. Regardless of
where the low tracks, colder air will spread from west to east on
Sunday once the secondary moves to our east. Flow turns to the
north-northwest, which will allow snow showers to become focused
along the western slopes of the higher terrain. Temperatures through
this entire period will likely be within 5 degrees of freezing,
making the precip type and amount forecast even more challenging.
Lots of details still need to be ironed out, so stay tuned for later
forecasts.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
As of 435 AM EST Thursday...Low pressure pulls away to the east
Sunday night and Monday, but mountain snow showers will linger into
Monday evening as we will be under northwest flow. Weak ridging
builds in thereafter, but low chances for snow showers will continue
through the middle of the week as an upper shortwave trough moves
through. Stronger high pressure will spread across the region for
Thursday, finally drying things out. Temperatures will remain near
or just above seasonal normal through the week.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
Through 12Z Friday...VFR conditions expected through the TAF
period with only passing high clouds. Winds will generally be
under 10 knots during the day Thursday with winds slackening
areawide as high pressure crests overhead. Expect mostly calm
winds Thursday night with light SE drainage wind at KRUT.
Outlook...
Friday: VFR. NO SIG WX.
Friday Night: Mainly VFR, with local MVFR possible. Slight chance
FZRA.
Saturday: Mainly VFR, with local MVFR possible. Chance SN, Chance
RA, Slight chance FZRA.
Saturday Night: Mainly MVFR, with local IFR possible. Definite
SN, Definite RA, Slight chance FZRA.
Sunday: Mainly MVFR, with areas IFR possible. Likely SN, Likely
RA.
Sunday Night: Mainly MVFR, with areas IFR possible. Chance SHSN.
Monday: Mainly MVFR, with areas IFR possible. Slight chance SHSN.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...LaRocca
NEAR TERM...Haynes/LaRocca
SHORT TERM...Hastings
LONG TERM...Hastings
AVIATION...LaRocca
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