Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Burlington Vermont
709 PM EDT sun Oct 23 2016

a departing low pressure across eastern Quebec will allow for
continued clearing this evening, along with diminishing wind
speeds. A secondary trough moving into the region from the
northwest late Monday into Monday night will bring a chance of
light rain showers, with snow showers possible across the northern
Adirondacks and northern Green Mountains. A more significant wave
of low pressure approaching from the Great Lakes and Ohio Valley
will bring the next chance for rain, generally late Thursday,
Thursday night, into early Friday.


Near term /through Monday/...
as of 709 PM EDT Sunday...mostly clear skies continue across most
of the north country early this evening with a west-northwest
gradient wind around 10-15 mph with gusts up to 25 mph. However, a
mid-level shortwave trough and associated weak surface low over
the eastern Great Lakes is already beginning to overspread low to
mid-level cloud cover across the central Adirondacks and western
New York state. These clouds are associated with 925-700 mb warm thermal
advection and will continue to advance east-southeast, tending to
be the lowest and thickest across southern Vermont and into
southern St. Lawrence, Franklin and Essex counties in New York.
Mostly clear to a few high clouds anticipated elsewhere in the
overnight. No significant changes were made to the forecast except
to account for current observations and to lower dewpoints by a
few degrees. Lows in the 30s still appear on track, trending
coldest in northeast Vermont, the Adirondacks, and at elevations
above 1000' with a fresh snow pack.

Previous near-term discussion issued at 337 PM Sunday follows...

See summary public information statement and local storm report
for reports on snowfall yesterday through this morning. At mid-
afternoon, lingering light flurries/sprinkles have generally ended
across the Northeast Kingdom. Strong low- level drying underway,
and has allowed for mostly clear skies to develop from the
Champlain Valley wwd...and also across S-central Vermont. Should
gradually see sunny breaks develop across N-central and nern Vermont
late this aftn. Afternoon highs generally upr 40s to lower 50s for
the Champlain/St. Lawrence and CT river valleys. Elsewhere, steep
lapse rates (and clouds across N-central/nern Vermont yielding colder
readings in the low-mid 40s most locations. Gradient flow will
remain moderately strong through sunset, as 980mb sfc low across
ern Quebec slowly fills while drifting ewd north of the St.
Lawrence Valley tonight. Will keep 15-25mph with a few gusts to
35mph next 1-3 hrs, before gradually diminishing with slow
weakening of p-gradient and loss of steep lapse rates as planetary boundary layer
cooling occurs toward sunset.

Generally quiet conditions tonight. A minor shortwave trough in
fast west-northwest flow 700-500mb layer will pass to our south across the
srn tier of New York and PA. This will yield some increase in mid-level
clouds, especially across the srn half of the forecast area. That
said, associated light pcpn should remain south of our area. West
winds continue 5-10 mph overnight, which will mitigate radiative
cooling and keep overnight lows mainly mid-upr 30s, except low 30s
in the 1-2kft elevational band.

Generally quiet weather expected Monday. Broad cyclonic flow
remains in place aloft, and it appears we'll have another surge of
low-level cold air advection and possible passage of weak mid-level shortwave
trough. Shallow instability layer will produce clouds by afternoon
and possible light upslope precipitation into the Adirondacks and
nrn green mtns. Freezing levels generally 2000-2500ft, so can't
rule out some flurries down to about 1000ft in elevation Monday
aftn, especially wrn slopes. May see passing sprinkles in the
valley locations, and kept pops generally less than 20%. High
temps generally low-mid 40s, except upr 40s near Lake Champlain
and with downslope warning effects across ern Windsor County/vsf
area. Winds will be west-northwest winds 8-15kts with gusts developing in
the afternoon with presence of steeper lapse rates.


Short term /Monday night through Tuesday night/...
as of 302 PM EDT Sunday...cold, cyclonic flow continues across area
with still a few spokes of energy flowing across northern areas
for fall/winter like chance of mtn sprinkles/flurries during this
period. The influence of this trof weakens Wed. It will be
unseasonably cold with highs in the 30s/40s and lows in the 20s.


Long term /Wednesday through Sunday/...
as of 302 PM EDT Sunday...trof axis sliding east on Wednesday with
lessening influence and some shortwave ridging going into Wed ngt
before another shortwave in overall northwest flow pattern impacts our
region late Thu thru Fri.

Slowly increasing sunshine on Wed but cold with highs only in
30s/40s with high pressure Wed ngt for a chilly one with lows in
teens/20s. Morning sunshine will try to offset chilly temperatures
with clouds advancing with the next system previously advertised.
Precipitation shouldn't threaten western zones until 18z or later
and Vermont aft 21z Thu. Ptype should be mainly liquid with some mixed
rain/snow in highest elevations. Highs in the 40s.

Surface low and accompanying front should be across Vermont by 12z Fri
and moving east out of area thus wettest in ern Vermont during morning
with leftover shoer threat in upslope terrain Fri and Fri ngt.
Mildest day of stretch with highs around 50 degrees.

Thereafter...northwest flow persists but their are difference between
European model (ecmwf)/GFS with another disturbance in the flow or not. GFS..yes
while European model (ecmwf) does not. Wpc has this feature...cold front as well as
our superblend ensemble thus will go for chance of showers Sat and
dry for sun although confidence is lower in this timeframe.


Aviation /00z Monday through Friday/...
through 00z Tuesday...generally VFR conditions through the
evening across the tafs. Potential for intervals of MVFR/VFR
ceilings generally after 05z at rut and slk as a frontal system
passes to the southeast. Winds will remain northwest 8-12 kts
through 12z Monday, with gusts to 21 kts gradually abating by 03z.

Variable VFR cloudiness anticipated for at least the first part
of Monday. A mid-level trough in the northwest flow aloft
traverses the tafs later in the day, resulting in a gradual lower
of ceilings to VFR/MVFR, particularly in The Greens and
Adirondacks. Possibility of rain/higher elevation snow showers
toward 00z Tuesday as well but for now have left out of the tafs.
Northwest winds 10-12 kts with gusts to 24 kts during the day.

Outlook 00z Tuesday through Friday...

00z Tuesday through 00z wednesday: broad upper trough in place
bringing variable cloudiness. Generally VFR ceilings, with
possible MVFR showers and higher elevation snow showers late
Monday afternoon through Tuesday vcnty of the nrn mts. Increasing
chances for MVFR ceilings at mpv/slk later Monday night through
Tuesday, with periods of light precipitation and MVFR cigs/vsby

00z Wednesday through 00z saturday: next low pressure system
approaching from the Great Lakes/Ohio Valley brings chances for
widespread showers and periods of MVFR conditions late Thursday
through the first half of Friday.


Btv watches/warnings/advisories...
New York...none.


near term...banacos/loconto
short term...slw
long term...slw

National Weather Service Glossary of Abbreviations