Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gray ME
1026 PM EDT Monday Sep 1 2014
a cold front will approach from the west tonight and Tuesday and
will cross the area Tuesday night. High pressure will build in
from the west Wednesday through Thursday and will shift offshore
Thursday night. High pressure will hold off the East Coast on
Friday as a cold front approaches from the west. The front will
stall over the region on Saturday as a weak area of low pressure
tracks east along it. Low pressure will push off to the east
Saturday night and high pressure will build in from the west on
Near term /until 6 am Tuesday morning/...
1025 PM...Flash Flood Warning cancelled as showers wind down and
exit the County Warning Area. Overnight probability of precipitation generally brought down to 10 percent
in or less...although given low level moisture and a few boundaries
lurking around form convection this afternoon...cant rule out a
brief rain showers popping up. Otherwise...look for patchy fog most
everywhere...with more locally dens valley fog and perhaps another
round of more widespread fog and low stratus along the coast.
840 PM...grids have been updated several waves over the last hour
to cover the rain showers/thunderstorms and rain that are moving slowly and regenerating on
old outflow boundary from Jay...Livermore fall region east into
the Belgrade Lakes. Will have to make sure these do fall apart or
move on in the next hour or so as radar EST rainfall rates around
2 inches in the last hour in some spots. Otherwise made some temperature
adjustments...mins a little higher on the coast and in southern New Hampshire and
hit the fog a little harder.
Showers and a few thunderstorms popping in northern zones this
afternoon will gradually die out with the loss of heating by this
evening. Ocean stratus lurking offshore will quickly move
inland this evening in coastal and southern interior portions of
Maine. Elsewhere valley fog will affect the usual spots. Lows
overnight will bottom out in the middle 50s to lower 60s.
Short term /6 am Tuesday morning through Tuesday night/...
hot and muggy Tuesday ahead of an approaching cold front. Expect
morning fog and stratus to give way to hazy sun which will quickly
destabilize the airmass. Should see airmass type showers and
thunderstorms developing by late morning and early afternoon. Not
looking for a lot in the way of shear until later in the day but
some storms in the north could approach severe limits by middle
afternoon. Onshore flow will keep coastal Maine from Portland to
the middle coast in the 70s to near 80. Elsewhere highs will range
through the 80s to near 90.
More organized convection will be likely Tuesday evening into
Tuesday night as the front crosses the area. Expect wind damage to
be the main threat with these storms which may last into the
early morning hours in far eastern zones. Low temperatures will range
from the upper 50s to middle 60s.
Long term /Wednesday through Monday/...
model guidance is in good agreement that rising heights and surface
high pressure will be working into the area by Wednesday morning. Any
remaining showers should quickly end by middle morning...even for eastern
High pressure will reestablish southeast of the area...bringing SW flow
aloft and a return to above normal temperatures. Friday should be the
warmest of these days...with 800 mb temperatures climbing into the middle to
upper teens and some compressional warming ahead of the
approaching fnt. Still look to fall shy of records in the low
90s...but readings should be comfortably into the 80s for much of
Shortwave trough ejects out of larger western trough...and races up through Canada
to Quebec by Sat. This will drag a cold fnt slowly towards the
area for the weekend. Model guidance again is in fairly good
agreement with a frontal passage Sat...clearing the coast by sun. As usual
multi-model blend tends to smooth out the pop and prolong chance
of precipitation...so I have tried to narrow the time window for pop as
best as possible at this time range. The result is mostly dry Friday
and sun...with highest pop Sat.
A more seasonable air mass builds in with Canadian high pressure
behind frontal passage. Normal temperatures and dry air will be the rule for a few
days...before ridging and heat from the central part of the
country builds our way again.
Aviation /03z Tuesday through Saturday/...
short term...IFR/LIFR ceilings and visibility developing overnight.
Becoming VFR of Tuesday. Areas of MVFR/IFR ceilings and visibility in
showers and thunderstorms Tuesday night.
Long term...generally VFR for the extended. Exception will be in
nocturnal valley fog as high pressure dominates the forecast. Cold
frontal passage Sat into Sun morning could bring areas of MVFR in
short term...no flags.
Long term...winds and seas expected to remain below Small Craft Advisory
thresholds. Ahead of cold fnt on the weekend...sustained southwesterly flow
may build seas to near 5 feet...but model guidance tends to
overforecast wave height under these conditions.