Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Burlington Vermont
341 PM EDT Monday Mar 30 2015
rain and snow showers end for most this evening with some mountain
snow showers continuing overnight. Cool and drier conditions move in
for Tuesday and Wednesday as a system passes south of the region and
high pressure builds in overhead. This will be followed by a warming
trend for the end of the week ahead of an approaching low pressure
system with temperatures rising into the 40s and 50s. This will
also provide the area with its next chance of widespread
Near term /until 8 am Tuesday morning/...
as of 336 PM EDT Monday...initial frontal feature and wind shift
to the southwest has crossed the area this afternoon. A second
wind shift to the northwest and a stronger surge of colder air
lies back near Ottawa and will progress southeastward across the
region this evening. There are some scattered rain and snow
showers across the north country this afternoon and coverage
should increase at least somewhat ahead of the secondary front.
Some of the hi-res models also indicating a little more organized
line of rain/snow showers may develop directly with the front and
cross the area from 21-03z. Behind front as winds turn
northwest...a period of unblocked upslope flow will ensue with
snow showers continuing in the Green Mountains/Adirondacks through
the overnight hours. No accumulations expected in the larger
Champlain...Saint Lawrence...and Connecticut River valleys...and
only a T-1" at most in the remainder of the lower terrain. However
some of the highest mountains may find several inches by morning.
Lows will occur late...generally in the 20s.
Short term /8 am Tuesday morning through Wednesday night/...
as of 336 PM EDT Monday...default ridging develops on Tuesday
between the exiting system and another low diving south of the
region. Northwest flow will be briefly weakening through the
day...so some morning lingering orographic clouds and perhaps a
few flurries early will give way to partly/mostly sunny skies for
most in the afternoon. Some high clouds across southern Vermont
also likely from the system passing south. Highs generally in the
30s to near 40.
Northwest flow re-strengthens for Tuesday night as the low moves
offshore...but will be drier...so only some clouds expected.
Temperatures will be a little tricky depending if the winds and any
clouds allow for locations to decouple or not. Right now running
with lows in the teens for most...with some single digits in the
far Northeast Kingdom and Adirondacks.
High pressure builds in on Wednesday with mostly sunny skies.
Temperatures still on the cool side with highs in the 30s area-wide.
Our next system will approach the region from the west on Wednesday
night. The night will start calm and clear...but southerly flow and
clouds will increase after midnight ahead of a warm frontal feature.
Lows occur early...in the teens/20s before rising towards morning.
Long term /Thursday through Monday/...
as of 340 PM EDT Monday...global model output showing a rather
active and progressive pattern across the north
central/northeastern tier of the country still looks on track
during the Thursday to Sunday time frame. Thus prior forecast idea
of the typical early Spring ups and Downs in temperature and
frequent bouts of light to occasionally moderate precipitation
will be maintained with this package. Most active stretch in the
period will occur Thursday night into the first half of Saturday
when the combination of a cold frontal passage and a potential
frontal wave will bring scattered/numerous rain/snow showers and a
possible period of steadier wet snow. Boundary layer temperatures
mild enough for mainly rain showers Thursday into Friday with the
best shot at a steadier accumulating light snows to occur Friday
night when aforementioned frontal wave tracks to our immediate
south. GFS has trended further north from its prior runs, in
closer agreement with last nights (and current) Euro output,
though admittedly the Euro is considerably milder with its
boundary layer temperatures. Time will tell in regard to ptype. As
mentioned earlier, temperatures will tend to exhibit a typical up
and down pattern of early springtime with mildest values (40s to
lower 50s) occurring Thursday/Friday followed by a steady cooldown by next
weekend when highs should hold in the 30s to around 40 and
overnight lows fall back into the teens/20s.
Aviation /20z Monday through Saturday/...
through 18z Tuesday...mix of broken/overcast VFR/MVFR with scattered
rain/snow showers through 06z with cold front/upper trough
passage. Some IFR likely at kslk terminal during this period. Precipitation
ends after 06z but with lingering broken/overcast VFR/MVFR ceilings. Winds
gusty south to southwesterly to 30 kts through 00z, trending west
to northwesterly thereafter and slowly abating behind front/trough
Outlook 18z Tuesday through Saturday...
18z Tuesday through 00z Friday...mainly VFR with high pressure.
00z Friday through 12z Friday...scattered rain showers with
frontal passage. MVFR/scattered IFR possible.
12z Friday Onward...confidence moderate. Indications of some
moisture return with light snows/rains possible, especially from
00z Saturday Onward with MVFR/IFR implications, especially at
southern terminals of kmpv/krut.