Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gray ME
953 PM EDT Tuesday Sep 1 2015
a large blocking high pressure system will be in control the rest
of the week and through the weekend into next week with an
extended period of quiet weather expected. Temperatures will be
above normal through the period...with gradually increasing
humidity. The only exception being Thursday and Friday where a
brief cool down may occur behind a weak cold front.
Near term /until 6 am Wednesday morning/...
950 PM...this update mostly makes some adjustments to temperatures as
Delaware-coupled locations...especially in the elevated valleys...have
dropped quickly this evening. Their fall should slow as boundary
layer flow increases as bit...as do cirrus....and mins in the mountains
may be closer to midnight than daybreak.
630 PM...just a quick update to temperatures top account for marine
influence making for cooler temperatures along the coast early this
evening before temperatures drop there slows toward midnight.
Also...adjusted sky to account for slightly more cirrus.
Previously...quiet night on tap across the forecast area...as
center of surface high pressure slides southeast. Increasingly humid air will
lead to another round of valley fog tonight...which could be dense
at times in the CT River Valley. Have added 1/4sm visibilities to the
grids after 06z tonight in that area. Otherwise temperatures will be
above normal...as warmest part of the air mass moves in for Wednesday.
Short term /6 am Wednesday morning through Wednesday night/...
Wednesday looks to be the warmest of the recent hot stretch. 800 mb temperatures
climb to plus 18 to 20 degrees c across the entire forecast area.
Forecast soundings indicate we should be able to mix to this
height...and resulting temperatures would top out in the low 90s for much
of southern New Hampshire and southwestern ME. We are missing a few things that could push
temperatures even higher...namely advection will be neutral
tomorrow...and flow is rather weak in the boundary layer so we
lack much downslope warming on SW flow. The latter will also mean
that a sea breeze could force its way inland on the coast. Still
expecting temperatures to climb well into the 80s before any marine
influence takes over though.
Weak cold front again tries to push southward into the forecast area
from Canada late in the day. Much like Monday...this front is
moisture starved. Coupled with a bit of a cap above
800 mb...convection will have a hard time getting going and sustaining
through the evening. Hi-res convection allowing models do fire
showers/storms in Canada during the afternoon...but weaken
everything as it enters northern zones. Will have isolated thunderstorms for
far north around and after 00z Wednesday...but dry elsewhere until Thursday. With
front crossing the area Wednesday night...valley fog should be a little
Long term /Thursday through Tuesday/...
a cold front will continue to slowly move south through southern
areas by Thursday morning and moving south of the area in the
afternoon. There may be widely scattered showers on Thursday along
and behind this this front.
A brief cool down to seasonal temperatures expected for Thursday
and into Friday as Canadian high pressure builds south into the
By the weekend the large blocking high pressure system will
gradually build and allow a southwest flow to develop as its
center gets aligned along the coast. A return to very warm and
even hot conditions with higher humidities are expected over the
weekend and into next week with plenty of sunshine as strong
subsidence will be the rule under this large dome of blocking high
Superblend model will be generally accepted...temperatures over
the weekend into early next week may be a little low due to the
weights of climatology into the models.
Aviation /02z Wednesday through Sunday/...
short term...VFR conditions are expected to prevail during the day
through Wednesday night. Valley fog will be likely again tonight...with
conditions quickly dropping to LIFR at leb and hie after 06z.
Leaned mainly on persistence from last night to time fog at
terminals. Late Wednesday evening very isolated rain showers are possible at
hie...but chances are lower than 30 percent.
Long term...VFR through the outlook period.
short term...winds and seas will remain below Small Craft Advisory thresholds.
Long term...winds and seas to remain light.
while temperatures will soar into the 80s along the coast to the
lower 90s inland on Wednesday...this will be well above normal
but likely not set records for sept 2nd. The record high at
Concord on Wednesday is 98 degrees...while it is 94 degrees at