FXUS61 KBTV 211810
Area Forecast Discussion
National Weather Service Burlington VT
210 PM EDT Tue Mar 21 2023
A weak boundary will produce more clouds today with a chance of
rain and mountain snow showers, with just some minor snow
accumulation possible. Temperatures will warm into the upper 30s
to upper 40s across the region with a few spots reaching near
50 degrees. A quiet weather day is on tap for Wednesday, before
more showers return on Thursday with temperatures warming back
into the 40s to near 50 degrees.
.NEAR TERM /THROUGH WEDNESDAY/...
As of 210 PM EDT Tuesday...Little further change needed with
the afternoon update. Destabilization and lift in the vicinity
of a weak surface cold front has resulting in rapid increase in
cumulus, now expanding into south central Vermont. However, with
limited moisture, still are not seeing any precipitation fall
out of the clouds and the low chance idea, primarily in the
northern mountains, looks good through the rest of the day,
peaking late this afternoon along and behind the surface cold
front. The front is oriented from southwest to northeast, draped
roughly 10 to 30 miles south of the International Border in
northern New York and up into Highgate, Vermont as of 1:30 PM
based on pressure and wind data from surface observations.
Clouds will tend to lower and thicken a bit behind the boundary,
helping see better chances for at least flurry activity on the
north side of the boundary.
Previous Discussion as of 6:30 AM...
Updated to throttle back pops/qpf and snowfall acrs northern
cwa, as radar is indicating light precip but web cams and sfc
obs still show no precip is reaching the ground. Have reduced
pops to chc for mainly the mtns of northern NY and VT today with
best chance along and just behind weak boundary crossing our
region btwn 16z-22z this aftn. The modest caa and developing
upslope flow, combined with steepening lapse rates/instability
from cooling aloft maybe enough to produce a few stronger
reflectivities to support precip reaching the ground. Otherwise,
qpf/snowfall wl be minor with no impacts anticipated.
Water vapor shows weak embedded 700 to 500mb vorticity moving
acrs the eastern Great Lakes with some enhanced mid lvl
moisture. Radar continues to indicate light rain/snow showers
acrs northern NY, but sfc obs and web cams continue to indicate
no precip is reaching the ground, as bl layer remains pretty
dry. Based on this and upstream obs, along with latest guidance
have trimmed back pops/qpf and snowfall acrs the northern Dacks
into the mtns of central/northern VT today. Best lobe of 850 to
700mb rh and weak embedded 5h vort slides along the
International Border btwn 10z and 16z today, while best llvl
convergence associated with weak cold frnt arrives aft 18z.
Also, minimizing qpf/pops here in the CPV wl be westerly 850mb
wind component of 25 to 35 knots and weak convergence along sfc
boundary. Bottom line have schc/chc pops valleys to high
chc/spot likely in the mtns for a period of time today, before
decreasing activity toward sunset. Any qpf wl be confined to the
higher trrn with values generally <0.10 and just a minor
snowfall accumulation possible above 2000 ft. Temps are
challenging today, as we are starting near 40F here in the CPV,
while east of the Greens in protected valleys are in the upper
teens to lower 20s. 925mb thermal profiles show values ranging
from near -4C northern SLV to +2C southern VT, indicating the
best llvl caa is acrs our northern CWA. Boundary continues to
sink south btwn 16z-20z this aftn with modest llvl caa and winds
shifting to the west/northwest. As a result wl indicate highs
ranging from the mid 30s to lower 40s northern cwa to mid
40s/lower 50s southern valleys today.
For tonight, 1034mb high pres anchored near Hudson Bay tries to
nose into northern NY/VT with some drier bl moisture and
clearing skies. However, boundary that pushes acrs our cwa this
aftn becomes stationary over central NY and slowly begins to
approach our southern cwa with increasing mid lvl moisture by
06z. This axis of moisture and potential impacts on clouds,
along with a sharpening 925mb thermal profiles results in a
tricky overnight low fcst. Based on potential for clearing/lower
dwpts and lighter winds have temps mid/upper teens NEK to lower
30s southern VT/southern SLV for tonight with dry conditions
Weds wl feature above normal temps with developing southerly
flow and moderately strong llvl waa as warm frnt lifts acrs our
cwa. Progged 925mb temps warm btwn 0C NEK to 4 to 6C southern
SLV/Western Dacks and southern VT zns, supporting highs mid 40s
to l/m 50s most locations, while summits hold in the mid/upper
30s. Weak embedded 5h vort and better 850 to 500mb moisture
profiles arrive aft 21z acrs our western cwa, so have continued
with the idea of chc pops toward sunset. Any qpf wl fall in the
form of rain, given very warm bl temps on Weds aftn with amounts
< 0.10 of an inch anticipated. Light and variable winds wl
become south 5 to 10 mph during the aftn hours, as clouds
redevelop from sw to ne acrs our fa.
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/...
As of 400 AM EDT Tuesday...A warm front will lift northward
through the region Wednesday night with some scattered valley
rain and mountain snow showers, but better forcing arrives
Thursday with shortwave energy ejecting from a decaying upper
trough over the northern plains riding eastward along a fast
westerly flow aloft and brings numerous rain showers to the
region as the aforementioned warm front sags back south as a
cold front. Latest model guidance looks like QPF will range from
around a tenth of an inch up to half an inch from Wednesday
night through Thursday.
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 415 AM EDT Tuesday...Showers taper off Thursday night as
the front drops south of the forecast area. Strong surface high
pressure centered over Quebec will bring a partly sunny and dry
day for Friday with highs back to seasonal normals. By Friday
night, low pressure develops over the lower Mississippi River
Valley and tracks into the Ohio Valley by Saturday morning.
Thereafter, there is a general consensus in the long range
guidance that this primary low will continue northward through
the Great Lakes Saturday and Saturday night, while secondary
cyclogenesis occurs along the mid- Atlantic coast. As is to be
expected this far out, just how deep this secondary low can
develop and it`s track is highly uncertain, and will play a
large role in the precipitation type forecast heading into
Saturday night and Sunday. At this time mostly likely scenario
looks like rain showers in the valleys and mountain snow
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Through 18z Wednesday...Mainly VFR conditions expected with
main element of interest being wind. Breezy south/southwest
winds ahead of a cold front will continue south of the boundary.
A wind shift to the northwest has already occurred at MSS and
PBG, and this shift will progress south and east through 23Z.
The developing upslope flow may result in some mvfr cigs at SLK
thru the early evening hours, before conditions improve to VFR,
but a very low chance of snow showers is expected. Wind speeds
will fall to 5 knots or less overnight, and only increase
through the remainder of the TAF period at MSS where northeast
flow increases to around 10 knots by 12Z.
Wednesday Night: Mainly VFR, with local MVFR possible. Chance
Thursday: Mainly MVFR, with local IFR possible. Definite SHRA.
Thursday Night: MVFR/IFR conditions possible. Chance SHRA, Chance
Friday: Mainly VFR, with areas MVFR possible. NO SIG WX.
Friday Night: VFR. NO SIG WX.
Saturday: VFR. Definite SHRA, Likely SHSN.
Saturday Night: Mainly MVFR, with local IFR possible. Likely
SHSN, Likely SHRA.
Sunday: Mainly MVFR, with local IFR possible. Chance SHRA, Chance