Area Forecast Discussion
Issued by NWS Portland, ME-- Highlight Changed Discussion --
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FXUS61 KGYX 270323
Area Forecast Discussion
National Weather Service Gray ME
1123 PM EDT TUE JUL 26 2016
Warm high pressure remains over the area through Wednesday with
temperatures warming into the 80s and 90s. A weak frontal boundary
will drop south out of Canada and into northern New England
Wednesday night into Thursday, bringing a chance for showers and
thunderstorms as it does so. The front slowly slips offshore on
Friday as low pressure track easts along the front offshore of
Cape Cod. This will bring another chance of rain Friday into
Friday night. Cooler, more seasonable temperatures return for the
.NEAR TERM /TONIGHT/...
-- Changed Discussion --1130PM UPDATE...
Temperatures have been a little slow to cool in some spots,
particularly over southern New Hampshire where it was in the low
90s this afternoon. Otherwise temperature forecast appears to be
on track tonight with very few adjustments needed.
Have made a few minor adjustments to hourly temperature and
dewpoints and removed all precipitation chances. Afternoon cumulus
clouds continue to dissipate this evening, setting the stage for a
mostly clear night with good radiational cooling conditions.
Expect fog in the favored valleys.
A short wave trough will move away from northern New England
tonight. Any diurnal showers or isolated thunderstorms from Coos
County NH southeastward to the Midcoast of Maine should dissipate
early this evening with the loss of daytime heating. Otherwise, a
mostly clear night is expected tonight with radiational cooling
taking place. This will result in local valley fog, especially in
areas that have received a good amount of rainfall over the last
couple of days.
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.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
Another very warm to hot day expected on Wednesday with weak high
pressure sinking to the southwest of the region. The opposing
westerly flow in the boundary layer will likely be weaker on
Wednesday and should allow an afternoon seabreeze to form. The day
should be dry except perhaps near the Canadian border where there
is a low prob of a very late afternoon shower or thunderstorm as a
weak short wave trough approaches that area from the west. This
trough will help push a weak cold front across northern zones
during Wednesday night and may allow for a few showers or spot
thunderstorms during the night in the far north. Elsewhere, we
expected dry weather.
.LONG TERM /THURSDAY THROUGH TUESDAY/...
A weak cold front accompanied by showers and thunderstorms will
drop south across the region Thursday and Thursday night and then
stall to the south of the area Friday as high pressure builds in
from the north. High pressure should hold over the region through
most of the weekend as a frontal boundary remains just to our
south. Most of the models suggest this scenario, although it is a
low confidence forecast for the weekend as the EURO model
continues to be somewhat an outlier suggesting northern/southern
stream energy phasing and thus taking a considerably further north
With the above reasoning for the weekend, the safe play is to
stick with the superblend model and see how the models play out
the development of the system for the weekend.
Temperatures will be comfortable late in the week and through the
weekend as the heat remains to our south.
.AVIATION /23Z TUESDAY THROUGH SUNDAY/...
Short Term...VFR conditions are expected tonight through Wednesday
night except for perhaps a few hours of valley fog late at night
tonight and Wednesday night.
Long Term...MVFR conditions in scattered showers and thunderstorms
Thursday into early Friday associated with a frontal passage from
the north. Mainly vfr conditions expected for Friday into the
weekend. Late in the weekend conditions may lower to MVFR
depending on the track of low pressure to the south.
Short Term...Conditions are expected to remain below small craft
thresholds through Wednesday night.
Long Term...Conditions to remain below SCA criteria through the
NEAR TERM UPDATE...Kimble