Area Forecast Discussion
Issued by NWS Portland, ME-- Remove Highlighting --
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FXUS61 KGYX 231525
Area Forecast Discussion
National Weather Service Gray ME
1125 AM EDT Sun Oct 23 2016
Low pressure in Quebec will gradually move further north today. In
its wake rain and snow showers will continue in the mountains
while elsewhere cloudy skies in the morning will give way to some
sun in the afternoon. Windy conditions are expected today. Tonight
clearing occurs across all areas as the dry west flow continues
but diminishes. The cool cyclonic flow will continue through
midweek. By the end of the week another upper trough will approach
and move through the area with more unsettled weather.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --Update...
Have updated the grids based on current conditions and latest
mesoscale model information. We continue to transition from a
synoptically driven precip environment to purely an upslope flow
event. Rain and snow showers will continue today, mainly across
the west-northwest facing higher terrain. Current radar imagery
continues to show a very good upslope signature, however some of
these echoes are not reaching the ground downwind of the
Made minor adjustments to temperature forecast and tweaks to the
wind forecast. Winds continue to be very strong over the high
terrain with over 100 mph winds on top of Mount Washington.
The center of low pressure is now located north of
Maine along the St Lawrence river valley and moving north. In the
systems wake a broad cyclonic flow will continue across the area
today keeping rain and snow showers in the mountains and
foothills. above 3000 feet a few inches of snow may accumulate.
Over southern and downslope areas conditions will gradually dry
out and the clouds will give way to some sun in the afternoon.
With the strong westerly pressure gradient lined up vertically
combined with cold advection aloft, mixing down of winds expected
thus strong gusty winds today but should remain just below wind
advisory criteria. Some exceptions will be over the higher terrain
but will be localized. Temperatures will remain steady during the
day or only rise a few degrees due to the strong cold air
advection. Used a blend of models for max temps and for wind
forecast relied on the WRFEMS which appeared better.
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.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
The cool west flow continues tonight and Monday and all areas
are expected to clear out except for some lingering clouds in the
mountains due to orographics. Temperatures will be cool tonight through
Monday. Winds will diminish some overnight but then increase and
become gusty once again during Monday as a weak short wave exits
to our south Monday.
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
In the 500mb hemispheric pattern, any signs of of possible +PNA
pattern break down toward the end of the week, although the ridging
in the west and the troughing in east do set up a cool spell through
Wed before large scale troughing over the ern CONUS breaks down and
troughs become more mobile. This will allow for some warmer and
cooler periods, but generally 850 temps stay with a few degrees C of
normal late this week into next weekend.
Mon night and Tue will see decent shot of energy swinging around
base of the large scale trough, and deepening it while pulling even
cooler air southward into New England. This will pull sfc and 850
mb low over the maritimes a little bit to the south and west and
will keep decent gradient in the low to mid levels, so look for NW
flow to persist with upslope showers continuing in the mountains.
In fact, will likely see the upslope surge a little bit late Monday
night into Tuesday as the wave moves through. Lows Mon night will
be around 30 in the north to the mid 30s along the coast and In
srn NH with highs on Tue ranging from the low 40s in the N to near 50
in the south.
Tue night will see the NW flow slacken off a bit and with colder air
place will see mins drop to the upper 20 N to the mid 30s S, but
still too much flow to allow for any real rad cooling. Wed should
be partly to mostly sunny with weakening NW flow as sfc high builds
in, and max temps not all that different from Tue. Next system
arrives late Thu into Friday, as sfc low tracks to our N and allows
for some warning, buit also the threat for showers, mainly thu
night into Friday.
Sat remains uncertain with possible weak closed 500mb low in the
vicinity, but it should cool down a bit for next weekend.
.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
Short Term...VFR conditions expected in all southern and downslope
areas today while in the mountains mvfr conditions are expected
in scattered rain and snow showers. Conditions will improve to VFR
in the mountains tonight. All areas will be VFR on Monday.
Long Term...Mainly VFR Mon night through Thu. KHIE could see some
periods of flight restrictions in SHRASN Mon night into Tue.
Short Term...A persistent West flow will keep Gales over the
outer waters into tonight. Strong SCA conditions are expected in
the bays through tonight. On Monday the west gradient winds will
continue but will not be as strong. A SCA for the outer waters on
Monday will likely be needed while in the bays, conditions should
remain just below criteria.
Long Term...SCA conds likely to persist through Tuesday and maybe
into Tue night, but winds should subside for Wed and Thu.
MARINE...Small Craft Advisory until 11 PM EDT this evening for ANZ151-
Gale Warning until 11 PM EDT this evening for ANZ150-152-154.