Scientific Forecaster Discussion
fxus61 kgyx 280137
Area forecast discussion
National Weather Service Gray ME
937 PM EDT Tue Jun 27 2017
a cold front will approach from the west through this evening
and will likely aid in the development of showers and
thunderstorms, a few of which may be strong to severe. The
front will eventually move off the coast on Wednesday and will
bring a few showers. A warm front will approach on Thursday and
bring increasing chances of showers and thunderstorms during the
afternoon and nighttime hours. Another low pressure system may
affect the region on Saturday with more showers and
Near term /until 6 am Wednesday morning/...
935 PM...threat of hail and gusty winds has diminished at this
time, and even lightning is waning at the moment, so once
showers with a few storms winds down this evening should be
farily quiet overnight. Patchy fog will develop as cooler air
moves in behind the front over moist ground from the rain. Lows
should be mostly in the 50s.
550 PM...minor estf update to reflect the current mesonet in
near term grids.
for the remainder of this afternoon and evening, showers and
scattered thunderstorms will continue. The atmosphere is not
overly destabilized, however good dynamics aloft with an upper
level low pressure system will allow for steep lapse rates
through sunset. The primary threat is for hail, however a few
stronger wind gusts are possible.
The greatest threat for severe weather will be over southern
portions of New Hampshire and southwest Maine where highest
surface based CAPES will be in place in conjunction with upper
air dynamics. The hrrr and other mesoscale models suggest the
convection will be off the coast between 00z and 03z.
Have introduced patchy fog for late tonight with low level
moisture in place. Areas that receive rainfall will also be
prone to some fog.
Short term /6 am Wednesday morning through Wednesday night/...
the upper level low pressure system will be exiting the region
Wednesday. Nevertheless, sufficient moisture and instability
will still be in place, albeit not nearly as much as today, to
trigger a couple showers and perhaps a thunderstorm.
Will mainly be confined to the north and mountains.
Cool, widespread 70s, below normal for this time of the year
will be the highs tomorrow. Patchy fog possible as temperatures
fall towards the dew point values. It will be chilly again with
mid 40s to mid 50s for lows.
Long term /Thursday through Tuesday/...
the deterministic models remain in decent agreement on the
longwave pattern into the upcoming Holiday weekend. We begin the
period with a low amplitude and nearly zonal flow with several
difficult to time weak embedded shortwave impulses. By early in
the upcoming Holiday weekend...one of these upstream impulses
will carve out a broad low amplitude trough centered over the
eastern plains and 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. Of note is that during the
past several model runs the deterministic models have trended
towards a higher amplitude trough. In the dailies...a warm front
will advance into New England Thursday and Thursday night 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 Sunday as a series of weak lows track along it. This
will be an extended period of warm and humid weather...with
daytime heating and passing shortwave energy contributing to
several rounds of convection during the period. By early
Monday...the surface boundary and higher humidity levels have
been swept offshore. Rising heights and weak ridging should
provide a dry day with seasonable temperatures and decreasing
humidity levels to wind out the Holiday weekend.
Aviation /02z Wednesday through Sunday/...
short term...expect VFR conditions to prevail for the rest of
this afternoon and evening with a developing light southerly
wind. Showers and thunderstorms are likely until about sunset,
forming in New Hampshire and progressing eastward through the
evening hours. Any areas that get significant rainfall could
have a potential for fog tonight. More showers are possible on
Wednesday, mainly in northern areas.
Thu - Fri...areas of MVFR in shra/tsra.
Sat - sun...areas of MVFR in rain showers/thunderstorms and rain with LCL IFR psb vcnty of
the Maine coast in nighttime fog and stratus.
short term...light southerly flow expected over the waters
tonight, shifting to the west or southwest on Wednesday.
Thu PM - sun...small craft conditions are possible outside the