Area Forecast Discussion
Issued by NWS Portland, ME-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KGYX 242356 AAA
Area Forecast Discussion...UPDATED
National Weather Service Gray ME
756 PM EDT SUN JUL 24 2016
-- Changed Discussion --A cold front will approach from the west on Monday and will cross
the region Monday night, providing another round of showers and
thunderstorms. High pressure will build in from the west Tuesday
through Wednesday. A weak frontal boundary will settle south from
Canada Wednesday night and will stall over the region on Thursday
and perhaps Friday. The weekend may dry out if high pressure from
the north suppresses the frontal boundary far enough south.
-- End Changed Discussion --
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
-- Changed Discussion --7:50 PM Update...
Temperatures are in the 70s except for a few exceptions over
southern NH. Dew points have dropped into the 50s to near 60s
along the coast. Models are entertaining a few spots of fog
possible in the mountain valleys and have added patchy non-dense
fog to these areas and also near Rockland. This will really depend
on how far temperatures and dew points fall overnight...but
Rockland is already carrying fog.
Otherwise forecast is on track. Winds are already light and
Sunny skies will continue this afternoon in the wake of yesterdays
front. Radar returns show the seabreeze just beginning to push
onshore at 18Z. Expect the seabreeze to make it to the middle of
Cumberland county...allowing temperatures to cool a bit this
-- End Changed Discussion --
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
This evening skies will remain mostly clear. With considerable
dry air aloft and dewpoints generally in the upper 50s expect
little to no fog for the morning.
After sunrise on Monday increasing clouds will move in as a short
wave currently located over the great lakes approaches the region.
Increasing southerly flow ahead of the front will push dewpoints
back into the mid 60s across the area by afternoon...with southern
New Hampshire seeing highs near 90 giving a heat index in the mid
Hot and sticky airmass, and an approaching short wave will once
again set the stage for thunderstorms Monday afternoon. Moisture
will be plentiful as the higher dewpoints advect northwards. As
far as instability most guidance hints at a region of steep lapse
rates aloft approaching ahead of the short wave. Timing for the
instability and trigger may be the critical issue. Fairly good
agreement in the models of the short wave and accompanying jet
streak and not arriving into western NH until around 5pm or
later...which would result in limited instability by the time the
shear and trigger arrives. The best chance for strong to severe
storms will be across western New Hampshire in late afternoon. Dry
mid levels will make gusty and potentially damaging winds the main
threat although small hail is also possible as freezing levels
drop back to around 10,000ft. Further east into Maine shower
activity will likely hold off until after sunset, and while some
thunder may develop the strongest storms will remain in NH for the
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Cold front will move offshore Monday night bringing and end to
shower and thunderstorm activity during the evening or early
overnight hours. A drier air mass works in for Tuesday with fair
weather likely except perhaps for a period of clouds and spotty
showers near the Canadian border where there will be a little more
influence from cooler cyclonic flow aloft. Wednesday should b e
fair as well but perhaps a bit more humid. Above normal
temperatures continue both Tuesday and Wednesday. Chances for
showers and thunderstorms look to increase Thu and Fri as a
frontal boundary nears and slows down.
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
Short Term...VFR conditions expected through tonight. Looks like
dewpoints will remain low enough to prevent fog formation. Monday
afternoon increasing clouds but remaining VFR. HIE and LEB will
see thunderstorms in the afternoon.
Long Term...Some valley fog possible Monday night in the wake of
showers and thunderstorms. Otherwise, VFR conditions are expected
Tuesday and Wednesday, with increasing chances for some
restrictions Thursday and Friday as a frontal boundary nears with
increased chances for showers and thunderstorms as well as
possible nighttime fog and stratus near the coast.
Short Term...All quiet on the waters through Monday. Only issue
will be thunderstorms late Monday afternoon.
Long Term...Winds and seas look to remain below SCA thresholds
Tuesday through the end of the week.