Scientific Forecaster Discussion
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Area forecast discussion...updated
National Weather Service Gray ME
1059 PM EDT Mon Jun 26 2017
a series of upper level disturbances will cross the region this
week, bringing chances for showers or thunderstorms, especially
in the mountains. Otherwise temperatures will be near normal
with lower humidity into mid week. Warmer and more humid
conditions move in at the end of the week, with a chance of
showers and thunderstorms Thursday night into Friday. More
chances for some storms will accompany a low pressure system
Near term /until 6 am Tuesday morning/...
update...some decaying showers are left over srn New Hampshire...while the
next batch associated with the main S/WV trof are approaching
from the Hudson Valley. For the most part cloud tops are
warming...especially the trailing end of the line that will clip
parts of New Hampshire. Given the weakening I will not put widespread
thunder in the grids...but keep it at slight chance as there are
still some strikes detected.
Previous discussion...a short wave trough will approach from
the west for the rest of this afternoon and evening triggering
scattered showers and possibly a thunderstorm, mainly across New Hampshire.
This scattered precipitation will continue to progress east
with time, bringing the chance for a shower to western ME and
the mountains during the overnight period.
Cloud cover and low surface dew points may prevent fog in many
areas. However, have added patchy fog over some of the more
vulnerable inland valleys, especially in New Hampshire.
Overnight lows will be mostly in the 50s, but it will be chilly
with some mid to upper 40s in the mountains.
Short term /6 am Tuesday morning through Tuesday night/...
low level lapse rates increase on Tuesday along with cape
values. This will be in response to a mid level short wave which
will be more vigorous than the previous impulses over the last
day or two. Showers and scattered thunderstorms will be more
widespread on Tuesday. With a cold pool aloft, there remains
the potential for small hail or gusty winds in a few of the
stronger storms. Will continue to highlight this possibility in
the hwo, however confidence not sufficiently high enough at this
time to add this hazard categorically to the afternoon forecast.
Temperatures will continue to remain below normal for this time
of the year. Look for highs in the 70s, except it will be chilly
with 60s along the midcoast region and in the mountains.
Showers and scattered storms will continue through Tuesday
evening. Thereafter, any chance for precipitation will be
limited to the region of best dynamics which will once again be
the northern mountain regions. Temperatures will remain below
normal with overnight lows in the mid 40s north to mid 50s
Long term /Wednesday through Monday/...
the deterministic models are in decent agreement on the longwave
pattern into the upcoming Holiday weekend. We begin the period
with an upper trough draped across the northeast Continental U.S.. this
trough lifts out by early Thursday and is replaced by a low
amplitude nearly zonal flow with several difficult to time weak
embedded shortwave impulses. By early in the upcoming Holiday
weekend...one of these impulses will carve out a broad low
amplitude trough centered over the eastern plains/western Great
Lakes. This trough axis will gradually migrate eastward into the
Great Lakes and New England by the tail end of the Holiday
weekend. In the dailies...a weak surface trough crosses the area
Wednesday accompanied by scattered convection. For Thursday and
Thursday night a warm front will advance into New England as low
pressure approaches from the Great Lakes. This east-west oriented
boundary will stall across northern New England...then meander a
bit north and south across the forecast area Friday through Monday
as a series of weak lows track along it. This will be a period of
warm and humid weather...with daytime heating and passing shortwave
energy contributing to several rounds of convection during the
Aviation /03z Tuesday through Saturday/...
short term...VFR conditions are expected most areas overnight
although there will be scattered showers and possibly a
thunderstorm over New Hampshire and westernmost ME. There may be some
patchy valley fog, mainly over New Hampshire and in the western mountains
Showers and scattered thunderstorms will be a little more
widespread on Tuesday into Tuesday evening with brief periods
of conditions in the precipitation.
Wed - Thu...sct MVFR in -shra/-tsra.
Fri - Sat...areas of MVFR in rain showers/thunderstorms and rain with LCL IFR psb vcnty of
the coast in fog.
short term...winds and seas will remain below Small Craft Advisory thresholds in
the near/short term portion of the forecast.
Thu PM - Fri...small craft conditions are possible outside the