Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Burlington Vermont
issued by National Weather Service Albany New York
1012 am EDT Tuesday Oct 6 2015
high pressure will move east of New England this afternoon
allowing a weak cold front to move across the north country on
Wednesday...but remaining dry with the exception of a few
northern mountain sprinkles. A better chance of rain will approach
Thursday night and Friday.
Near term /until 6 PM this evening/...
as of 1011 am EDT Tuesday...the visible satellite picture late
this morning continues to show plenty of clouds over the St
Lawrence River Valley...North country of New York...and much of northern Vermont.
The latest kalb sounding shows some low-level moisture trapped
below an inversion at 850 hpa. The clouds have eroded nicely
across portions of southern-central Vermont due to the subsidence from the
anticyclone and mixing from aloft. The cloud cover/sky grids have
been retooled for a gradual clearing by the early to middle afternoon
/partly to mostly sunny conditions/. Otherwise the inherited forecast
is in very good shape.
850 mb temperatures are slightly milder than yesterday and if we
see enough sunshine...then maximum temperatures should be a few
degrees milder than Monday with u50s to near 60f in the valley
areas...and u40s to m50s over the higher terrain.
Short term /6 PM this evening through Thursday/...
as of 327 am EDT Tuesday...mainly dominated northern jet zonal
flow across US/Canadian border with a weak shortwave/cold front
Wednesday followed by a deeper...stronger system Thursday
Tonight...it will be dry tonight but clouds associated with
approaching shortwave/surface cold front will keep temperatures a few
degrees above normal but may be colder in eastern Vermont and will need
to monitor in later forecasts.
On Wednesday...mainly clouds associated with shortwave/cold front
with perhaps a few northern mountain sprinkles. Temperatures very
similar to today...perhaps a degree/two cooler in northern New York after
cold front passage.
Wednesday night...surface high moves into area with skies clearing and new
colder airmass which will allow temperatures to drop into the 30s
across much of the region with some scattered frost but close to
Thursday...surface high in control with middle-level flow backing in advance
of stronger/deeper short wave will bring about increasing clouds
during the afternoon but staying dry. Maximum temperatures slightly
cooler than normal.
Long term /Thursday night through Monday/...
as of 324 am EDT Tuesday...overall very little change to previous
forecast thinking as medium-range global models are in good
agreement for the extended period from Thursday night through
Monday night. Main weather feature of interest continues to be a
fairly robust shortwave trough and associated surface low pressure
and cold front swinging through the north country late Thursday
night through Friday night. Bulk of the precipitation associated
with system comes during the daylight hours on Friday where a
healthy amount of rainfall looks possible owing to slightly above
normal precipitable waters averaging around 1.25". Early indications are for a
widespread 0.50-1" with some higher/lower amounts possible in
upsloped/downsloped areas due to a modest southwesterly jet of
40kts at 850mb coinciding with the frontal passage.
Behind the front high pressure builds back into the region making
for a nice cool/crisp fall weekend with temperatures running
slightly below normal, highs in the 50s, lows in the 30s/40s. For
the later part of the weekend into early next week still seeing some
differences between the GFS and European model (ecmwf) in regards to some additional
shortwave energy encroaching from the north, mainly on Sunday. European model (ecmwf)
offers a stronger middle-level ridge and drier conditions while the GFS
has a weak low shifting east through Ontario/Quebec dragging a weak
cold front through the btv County Warning Area. This far out, will play some slight
chance probability of precipitation and see how guidance fairs over the next few days before
penciling anything in for certain.
Aviation /14z Tuesday through Saturday/...
through 12z Wednesday...mainly VFR conditions are expected
through the next 24 hours. Broken-overcast VFR deck around mountain top
levels will persist through at least middle-day before scattering out
after 18z. Only exception will be MVFR ceilings and kslk and possibly
at kmss this morning, but they too will trend to VFR. Calm winds
early this morning increase to around 5kts from the SW at
kmss/kslk, northwest at kbtv/krut/kmpv and NE at kpbg after 15-16z, going
calm again after 23-00z.
Outlook 12z Wednesday through Saturday...
12z Wednesday - 06z Friday...mainly VFR. Late night/early morning IFR fog
possible at mpv/slk 07-13z each day.
06z Friday - 12z Sat...VFR trending to MVFR in rain.
12z Sat - 00z sun...MVFR trending VFR with high pressure.