Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Burlington Vermont
723 am EDT Wednesday Sep 2 2015
a mean upper level ridge across the central and eastern U.S. Will
bring generally dry weather with above normal temperatures across
the north country over the next 7 days. The only exception will be a
chance for showers and a possible thunderstorm tonight into Thursday
as an upper level disturbance drops south across the region.
Near term /until 8 PM this evening/...
as of 713 am EDT Wednesday...high pressure remains in control of
north country weather today. Some early morning fog and low
clouds...then plenty of sunshine expected although there will be
an increase in clouds late in the day near the international
border. This due to approach of middle level shortwave from north of
the border. The sunshine combined with 850mb temperatures of 17-18c this
afternoon support maximum temperatures well into the 80s...with perhaps a few
isolated 90 degree readings. A bit more humid than recent days
with dewpoints climbing into the middle and upper 60s.
Short term /8 PM this evening through Friday/...
as of 358 am EDT Wednesday...will see a temporary weakness in the
mean upper ridge tonight into Thursday as shortwave trough moves
south from Ontario and southwest Quebec. This will be accompanied
by weak backdoor cold front...which will make its way into
northern portion of forecast area late tonight and then drop south
across rest of forecast area through about 18z Thursday.
Chances for a few showers and perhaps a thunderstorm increase across
northern tier of zones this evening as this system approaches...but
chances diminish overnight due loss of daytime heating and
instability. Have kept 15-30 probability of precipitation for tonight...mainly across the
northern half of the forecast area. An increase in cloud cover will
keep temperatures relatively warm with lows mainly in the 60s. Clouds
should also preclude fog development in most areas.
Convective showers and possible thunderstorm activity redevelops
Thursday...mainly across south-central Vermont before exiting southward
during Thursday afternoon. Have included 40-50 probability of precipitation across southern
zones Thursday...but only around 20 pop for northern tier of zones.
Drier northerly flow develops early in the day across northern areas
and spreads south during the afternoon. It will be accompanied by
decreasing humidity and increasing sunshine. Temperatures on Thursday will
be several degrees cooler but still above average...with highs
generally in the lower to middle 80s in valley locations. High pressure
brings fair and tranquil conditions Thursday night...with fog
expected in the favored locations 06-12z Friday along with low
temperatures mainly in the 50s.
High pressure settles over forecast area on Friday...allowing for an
abundance of sunshine. Temperatures will be slightly cooler...although
still a few degrees above normal with readings in the upper 70s and
lower 80s along with comfortable humidity levels.
Long term /Friday night through Tuesday/...
as of 300 am EDT Wednesday...really no change from previous
forecast thinking for the extended period as a high amplitude
ridge will be over the eastern Continental U.S. Through the period. Apex of
the upper ridge and surface high move over the north country for
Friday night through Sunday, but drift south/southeastward over
the Middle-Atlantic States Sunday night allowing the middle-level flow
to turn more zonal going into next week. The resulting weather
will be sunny/dry conditions through the weekend and into Monday
with increasing chances for precipitation Tuesday and Tuesday
night as a weak frontal boundary approaches. Highlight of the
forecast period will be abnormally warm temperatures for early September
which will start out with highs in the low/middle 80s for Saturday,
bumping into the middle/upper 80s for Sunday through Tuesday. Even
have a couple shots at a few 90 degree readings in the valleys
Monday/Tuesday. Lows follow suit starting out near normal for
Friday night in the 50s, but become milder thereafter ranging from
the upper 50s to middle 60s.
Aviation /12z Wednesday through Sunday/...
through 12z Wednesday...IFR to vlifr will persist at
kmss/kslk/kmpv until 14z when thereafter conditions return to VFR
under relatively clear skies and light winds. After 00z, an
approaching frontal boundary will bring increasing low/middle clouds
and the chance for showers. Timing and coverage uncertain at this
time so will allow next taf cycle to address.
Outlook 12z Wednesday through Sunday...
mainly VFR. Early morning vlifr/IFR likely at kmpv/kslk, and
possible at kmss. Chance thunderstorms and rain Thursday, mainly across