FXUS61 KBTV 111805
Area Forecast Discussion
National Weather Service Burlington VT
105 PM EST Tue Dec 11 2018
Relatively quiet mid December weather conditions will persist
through the end of the work week. Increasing cloudiness is
expected today as a weak upper level disturbance over the
northern Great Lakes shifts eastward. This system will bring
periods of light snow tonight into Wednesday morning, with just
a dusting to an inch expected in most areas. A cold front in the
wake of this disturbance will result in high temperatures on
Wednesday 10 to 15 degrees below normal. Temperatures will
gradually moderate on Thursday and Friday, with highs likely
reaching 35 to 40 degrees for Friday.
.NEAR TERM /THROUGH WEDNESDAY/...
As of 1247 PM EST Tuesday...Forecast remains on track with only
minor changes needed. Continuing to see some light snow enhanced
off of Lake Ontario over portions of northern New York, but
accumulations are minimal.
Previous discussion...Another chilly start this morning with
08Z readings generally in the single digits above zero, except
locally zero to -10F in the nrn Adirondacks and across far nern
VT. Bands of mid and upper level clouds streaming ewd ahead of
shortwave trough across the nrn Great Lakes acting as a bit of a
brake on longwave cooling, so we should be near the pre-dawn
lows at this point. Relatively quiet day ahead with weak south
to SW winds (5-10 mph) in advance of sfc low across the nrn
Great Lakes. Will see a gradual increase in cloud cover through
the daylight period from west to east, resulting in lows a few
degrees cooler than yesterday. Generally looking for highs in
the mid-upr 20s.
Shortwave trough traverses the region this evening and
overnight from west to east, with increasing chances for light
snow showers, especially across nrn NY. Have indicated PoPs of
30-40% before diminishing during the morning hours on Wednesday
as sfc reflection dissipates across VT. Limited moisture
availability with this system, and should limit snowfall amts to
a dusting to 0.5" in most sections. Some modest moisture
advection from Lake Ontario and orographic ascent into the
Adirondacks may yield around 1" or so of light fluffy (20:1 SLR)
snow accumulation across nrn NY. Will see lows tonight mainly
in the mid-upr teens under overcast skies. A shallow surge of
low-level CAA and northerly winds around 10 mph behind the
trough will bring colder temps on Wednesday, with daytime
temperatures generally in the upr teens to lower 20s. Should see
a gradual clearing of low stratus...especially during the
afternoon and evening hours on Wednesday.
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 316 AM EST Tuesday...Very quiet conditions are expected mid-
week as surface high pressure and a building ridge aloft dominate
over the Northeast. As such, PoPs are nil with the main forecast
challenge being clouds and temps. As the high centers over the
region Wednesday night we should see ideal conditions for
radiational cooling develop with temps area- wide in the single
digits above to teens below zero. For Thursday the high begins to
ever so slowly shift east allowing for a good rebound in temps into
the mid/upper 20s by the afternoon. Increasing south/southwesterly
return flow will also allow for some increasing mid/high clouds
which will make for a cloudy sunset and overnight, moderating lows
in the teens to low 20s.
.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 316 AM EST Tuesday...Still a bunch of uncertainty going into
the weekend in regards to precip chances, but the trend appears to
be towards drier conditions. Latest FV3 and ECMWF are in rather good
agreement showing surface high pressure holding strong over the
Atlantic coast for Friday and into Friday night while cutoff low
pressure over the Ark-La-Tex region slowly trudges east. Meanwhile
to the north, an upper trough begins to take shape over the Canadian
Prairies and drops through the forecast area on Saturday with no
phasing with the southern stream system. This is in stark contrast
to the operational GFS which shows the northern and southern streams
phasing and significant chances for precipitation come Sunday, but
it appears to be the outlier even amongst the GEFS. With that in
mind, the forecast highlights the best chance for precipitation
being late Friday night through Saturday being mainly rain early
with a chance for snow showers late as a cold front drops into the
region Saturday night. Drier and cooler conditions would return for
Sunday under a weakening upper ridge with additional chances for
snow showers Monday associated with another upper trough passage.
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Through 18Z Wednesday...VFR clouds (generally 3500 to 6000 ft)
continue to spread from west to east over the forecast area in
advance of a shortwave trough. These clouds will thicken and
lower through the night, with MVFR ceilings developing. Some
light snow showers enhanced off of Lake Ontario are currently
being reported over areas of northern New York, locally reducing
visibilities/ceilings at KMSS and KSLK to MVFR/occasional IFR.
These light showers will weaken as they spread west and further
from Lake Ontario this evening/overnight, but still could see a
few vicinity snow showers in the Vermont TAF sites overnight
that may temporarily reduce visibility to under 6sm. After 15Z,
any residual showers will end, and ceilings and visibilities
will improve to widespread VFR through 18Z. Southerly winds will
continue this afternoon under 10 kts, then become light and
variable overnight, then become northerly under 10 kts after
06Z. After 15Z, ceilings and visibilities will improve to
widespread VFR through 18Z.
Wednesday Night: VFR. NO SIG WX.
Thursday: VFR. NO SIG WX.
Thursday Night: VFR. NO SIG WX.
Friday: VFR. NO SIG WX.
Friday Night: Mainly MVFR, with local IFR possible. Chance RA.
Saturday: Mainly VFR, with local IFR possible. Chance RA, Chance
Saturday Night: VFR. Chance SHSN.
Sunday: VFR. Slight chance SHSN.