Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Burlington Vermont
335 am EST Wednesday Mar 4 2015
temperatures will climb into the middle 30s to near 40 today with an
air mass of Pacific origin briefly in place today. Winds shift
from southwest into the northwest tonight with a cold frontal
passage...allowing for a return of much colder temperatures and
dry weather conditions with high pressure in place Thursday and
Friday. No significant precipitation systems are foreseen over the
next 7 days. Temperatures will gradually moderate through the
weekend and into next week.
Near term /until 7 PM this evening/...
as of 320 am EST Wednesday...Pacific origin airstream making a rare
appearance across the north country today...with deep-layer
west-west-southwesterly flow in place in the wake of yesterday evening/S shortwave
trough...and south of next thermal trough across northwestern Ontario. Surface
temperatures have been slowly rising through the 20s and lower 30s
during the pre-dawn hours on gusty S- SW surface winds (locally up
to 35 miles per hour in the Champlain valley). Winds will cause some
continued minor blowing and drifting of the 1-3" of snow that
fell during the 00-04z period Wednesday. Still a chance for an
isolated flurry or patchy freezing drizzle early this morning...but
otherwise anticipating partly sunny conditions to develop later
this morning through the afternoon as low-levels mix out. Have
dropped the Winter Weather Advisory with this forecast package.
Already getting some low-level cold air advection upstream...but insolational
heating should offset for much of today. Will see temperatures briefly
reach 35-40f range most valley locations late morning/early
afternoon...and then begin to fall. The west-southwesterly flow will have an
upslope component...especially into the northern Adirondacks. Will
leave a chance of a flurry or sprinkle across the higher terrain.
P-gradient gradually subsides...but steep lapse rates will keep
winds 10-15 miles per hour with gusts 20-25 miles per hour through much of the daylight
Short term /7 PM this evening through Friday/...
as of 320 am EST Wednesday...low-level winds shift northwesterly this evening
and overnight allowing for continued low-level cold air advection and return of
seasonably cold temperatures. Lows tonight will fall back into the
single digits across northern New York...and generally into the low-middle teens
across Vermont. Arctic high pressure will be in control through
the remainder of the period...with highs only in the upper teens to
lower 20s on Thursday and generally 20-25f for Friday. Stalled frontal
zone south of New England may yield some middle-upper clouds Wednesday
night and Thursday across central/S-central Vermont...but any
precipitation is expected to remain well to the South.
Ridge axis slides to the east Friday afternoon...so will see a
S-SW return flow develop during the afternoon hours. In the St. Lawrence
Valley...could see some SW wind gusts to 25 miles per hour middle-late Friday
afternoon. All in all, a dry and seasonably cold short-term period.
Long term /Friday night through Tuesday/...
as of 320 am EST Wednesday...several upper level disturbances will
affect the north country, mainly late Saturday-Saturday night and
again Monday. Upper level flow will become more zonal across the
eastern half of the country, contributing to model differences in
timing of each upper level wave. This zonal pattern will also allow
for moderating temperatures, as maximum temperatures on Saturday range
from the l20s-l30s and warm into the u20s to near 40 in the valleys
on Tuesday. Overnight minimum temperatures will experience the same
trend with Friday night/Saturday morning lows in the single digits
to low teens, warming to general teens Saturday night through the
rest of the period. More moderate temperatures possible Tuesday
night into Wednesday morning with lows staying in the 20s.
These warmer temperatures will provide chance for rain/snow mix in
the southern valleys with Monday/S disturbance and again Tuesday
Aviation /09z Wednesday through Sunday/...
through 06z Thursday...widespread MVFR/IFR conditions in snow and
blowing snow early this morning will gradually improve to VFR in
the middle to late morning hours. Snow continues to taper off with
only scattered snow showers and/or areas of light freezing drizzle
or light sleet possibly persisting through 12z, especially at
kslk/kmss. South to southwest winds persist into the daytime with
funneling up the Champlain Valley producing gusts of 25-35kts at
kbtv through about 10z, when gusts decrease to 20-25kts throughout
the day Wednesday, shifting out of the west middle morning.
Elsewhere...winds become westerly and gust around 20-27 kts.
Ceilings lift or scatter out to VFR at most taf sites...exception
being slk where some terrain enhancement may lead to continued
broken MVFR stratus through midday.
This afternoon and evening, gusty winds continue with VFR
conditions and scattered middle-high level clouds. Heading into evening,
winds will decrease out of the west at 5-10kts.
Outlook 06z Thursday through Sunday...
06z Thursday through 00z Friday...mainly VFR although some
periods of MVFR/IFR are possible in light snow showers as system
slides to the south.
00z Friday through 12z Saturday...VFR under ridge of high
12z Saturday Onward...MVFR/IFR possible in snow showers with