FXUS61 KBTV 211435
Area Forecast Discussion
National Weather Service Burlington VT
1035 AM 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 1035 AM EDT Tuesday...Further adjustments were made to
PoPs, as well as to elements including dewpoint and sky cover
to match recent observations better. General idea from this
morning is right on track with best chances of showers this
afternoon and across the northern mountains. Quite extensive
shower activity is evident in MRMS composite reflectivity in
southern Canada associated with the weak cold front slowly
sliding southward. The degree of low level moisture needed to
see precipitation out ahead of the front has indeed been too
low so far today in our region, as some virga occurred earlier
this morning over even the higher terrain. However, as the front
approaches, lift and moisture will be increasing from north to
south and so increasing precipitation chances looks good. Sunny
skies ahead of the front also is leading to some
destabilization and convective clouds have formed, which could
also aid in some shower development in our northern counties.
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 /15Z TUESDAY THROUGH SATURDAY/...
Through 12z Wednesday...Mainly VFR conditions expected the next
12 to 24 hours with brief periods of MVFR at EFK, MSS and SLK.
Crnt radar shows light precip acrs the northern NY, but sfc
obs/web cams indicate no precip is actually reaching the ground
attm. Have utilized tempo at EFK, MSS and SLK for MVFR VIS/CIGS
with light snow/rain with just vcsh elsewhere. Any lingering
precip should shift east of taf sites by mid aftn, with
expected winds shift to the northwest btwn 5 to 10 knots btwn
18z-21z today. This developing upslope flow may result in some
mvfr cigs at SLK/EFK and MPV thru the early evening hours,
before improving conditions to VFR is likely. Have noted on the
06z guidance, increase llvl moisture at EFK/SLK tonight,
supporting some lower cigs and potential brief IFR conditions in
stratus/fog. At this time, feel the potential and confidence is
pretty low and wl not include in tafs but mention in afd.
Wednesday: VFR. NO SIG WX.
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.
Friday: Mainly VFR, with local MVFR possible. NO SIG WX.
Friday Night: Mainly VFR, with local MVFR possible. NO SIG WX.
Saturday: VFR. Likely SHRA, Chance SHSN.