National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
760
FXUS61 KBTV 090936
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
436 AM EST Mon Dec 9 2019

.SYNOPSIS...
Light wintry mixed precipitation is ongoing this morning, and
we may have some light icing or snow accumulation. This mornings
commute may be impacted, but temperatures warm during the day
changing precipitation over to rain showers. Winds will continue
to be gusty out of the South until surface cold front finally
pushes through later in the day Tuesday. Drier weather returns
Tuesday night through Friday night with colder than normal
temperatures anticipated. Saturday will bring our next chance
for rain.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 400 AM EST Monday...Strong warm air advection over our
area and gusty southerly winds as well as strong low level jet
have helped to push temperatures into the mid 30s to around 40,
except for areas East of the Greens where temperatures remain in
the upper 20s. So far this morning most observations have been
rain or snow, but isolated pockets of sleet are possible. Areas
east of the Greens where the temperatures have remained colder
will still have some freezing rain resulting in light icing.
Untreated surfaces elsewhere may take some time for the pavement
temperatures to come up and a light glaze will be possible as
well. Precipitation this morning will mainly impact areas of VT
north of I-89. We`ll have a brief break in precipitation, then
more rain moves into the area from the South around 17z across
Southern VT, spreading northward all the way to the
international border by about 21z. With low level jet over the
area, QPF will be terrain driven with highest amounts in the
southeast upslope regions of the eastern Dacks and
central/southern Greens. Downslope flow will limit QPF in the
Champlain Valley and parts of the Northern New York north of the
Dacks. Maximum temperatures today will reach the 40s areawide,
then not fall too drastically overnight with strong winds,
clouds and showers continuing, mainly lower 40s. Precipitation
will become more showery following 00z tonight, and eventually
ending from west to east towards early Tuesday morning. Areas of
fog are possible through the period with rainfall on top of
snowpack, especially deeper/protected valleys. Still not
expecting any significant hydrology issues, though with heaviest
rain in southern Vermont and some snowmelt as well, Otter Creek
at Center Rutland is forecast to rise above flood stage. With
low pressure system lifting through Great Lakes and then well to
our Northwest, surface cold front will finally push through our
area on Tuesday. Winds will veer from Southerly to Westerly,
then eventually Northwest behind the departing front. Any
remaining rain showers will change over to snow showers on
Tuesday, with early morning high temperatures established in the
40s then dropping through the day. Temperatures will drop a
good 15 degrees or so during the day Tuesday. As midlevel dry
air settles in behind the front Tuesday afternoon, chances of
precipitation will be decreasing.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY/...
As of 345 AM EST Monday...Cold air advection will continue
Tuesday night behind the aforementioned cold frontal passage.
Precipitation will come to an end across much of the region as
best moisture and forcing move to our south and east, with
northern areas seeing some breaks in the clouds as well.
However, far southern/southeastern areas may see snow showers
continuing as a weak wave of low pressure traverses along the
front positioned off the New England coast. This southern focus
to the precip will continue Wednesday morning, but snow chances
will increase, particularly over northern NY, Wednesday
afternoon as winds turn to the southwest ahead of a secondary
cold front moving south out of Ontario. This will lead to lake
effect snow over the favored areas east of Lake Ontario, with
around an inch of accumulation possible through the daylight
hours. Temperatures Tuesday night are a bit tricky as they will
depend on extent of cloud cover and whether locations can
decouple, but regardless, it`ll be turning colder. Lows look to
be in the 10 to 20 range, with southern valley locations
remaining in the lower 20s. Wednesday`s temperatures will
rebound a bit owing to the south- southwest winds; highs will be
in the mid 20s to around 30.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 345 AM EST Monday...A secondary cold front will move
across the region early Wednesday night, turning winds to the
west/northwest and shunting any lingering lake effect snow
south. High pressure will settle over New England Thursday,
making for a dry but cold day with highs only in the teens and
20s. Thursday night will be cold as well, though radiational
cooling potential might not be fully realized as the ridge axis
shifts east, placing us under southwest flow and increasing
cloud cover by early Friday. This continues through Friday,
which will be dry but quite a bit warmer than Thursday. The
weekend continues to look wet, though the exact details remain
in question. The latest GFS is stronger with an upper trough
swinging across the Upper Midwest and through the Great Lakes,
developing surface low pressure over the Ohio River Valley and
pushing it northeastward through the St Lawrence River Valley
Saturday and Saturday night. Meanwhile, the ECMWF is weaker with
the upper shortwave and slower and further south with the
surface low, taking it over Long Island Saturday evening and
into coastal Maine on Sunday. Either way, would expect
precipitation to move in Friday night or Saturday. Though it may
start out as a bit of snow or perhaps a wintry mix,
precipitation would change over to all rain Saturday and
continue into the evening, then perhaps wind down overnight
before showery conditions resume on Sunday as the main upper
trough moves through. Have stayed close to a model blend for
this time frame given the discrepancies between model solutions.
Trends will need to be monitored through this week as the event
draws nearer.

&&

.AVIATION /09Z MONDAY THROUGH FRIDAY/...
Through 06Z Tuesday...Wind shear will continue to be an issue
across much of the area through about 12z Monday with a lull in
the winds between 12z and 18z on Monday and then a second low
level jet moving in and creating low level wind shear once again
across the area from 18z to the end of the period. During both
periods of low level wind shear winds will be from the south at
2000 feet at speeds in the 40 to 50 knot range. This will result
in areas of moderate to severe turbulence. Otherwise looking at
VFR conditions with respect to ceilings and visibilities
through about 12z. After 12z ceilings will be lowering into the
MVFR category and possibly into the IFR category after 20z.
Visibilities will be lowering as precipitation becomes
widespread after 12z. Precipitation prior to 12z will be light
and may be a mix of snow, sleet, freezing rain, and rain before
becoming all rain between 12z and 18z. Visibilities will lower
into the MVFR category after 12z and could briefly reach the IFR
category.

Outlook...

Tuesday: Mainly VFR, with local MVFR possible. Chance SHRA,
Chance SHSN.
Tuesday Night: VFR. Chance SHSN.
Wednesday: VFR. Chance SHSN.
Wednesday Night: VFR. Slight chance SHSN.
Thursday: VFR. NO SIG WX.
Thursday Night: VFR. NO SIG WX.
Friday: VFR. NO SIG WX.

&&

.MARINE...
A period of very strong winds will impact Lake Champlain through
the day. South winds of 25 to 35 knots and frequent gusts to 40
knots will occur, creating very difficult boating conditions,
especially on the north end of the lake where waves of 5 to 7
feet will occur because of the strong winds. Winds will
eventually taper off a bit on Monday, but remain in the 20 to
30 knot range and waves of 4 to 6 feet.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.

&&

$$
SYNOPSIS...Neiles
NEAR TERM...Neiles
SHORT TERM...Hastings
LONG TERM...Hastings
AVIATION...Neiles
MARINE...Evenson