Area Forecast Discussion Issued by NWS Portland, ME
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FXUS61 KGYX 080118
AFDGYX
Area Forecast Discussion
National Weather Service Gray ME
818 PM EST Sun Mar 7 2021
.SYNOPSIS...
Cool and fair weather continues tonight as high pressure builds
in from the west. A warming trend will start Monday into the
second half of the week. Much of the week will be precipitation
free with the exception of isolated mountain snow showers Monday
night and rain showers towards the end of the week as a front
approaches.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Update...
Clear skies continue across the forecast area per latest
satellite imagery. With easing winds and very dry air in place
for the overnight hours, the instinct is to lower temperatures
due to radiational cooling, especially across the north.
However, satellite imagery does show some low and mid level
moisture over Quebec Province moving southeast this evening.
Latest HREF guidance does bring a period of cloudiness across
northern and eastern zones after midnight. This would reduce the
rate of cooling in some areas.
Because of the discussion above, have allowed for clear skies
through the late evening hours, but have added clouds to the
forecast after midnight. Have lowered the wind forecast for the
near term portion of the forecast and left forecast mins as is.
Prev Disc...
Beautiful day across northern New England, with satellite
showing only a few stray clouds over the Gulf of Maine. The
strong March sun has allowed temperatures to climb above
freezing in the south even as the temperatures aloft remain
relatively cool. That cold pool aloft will remain overhead
through tonight, and the clear skies should allow for some good
radiational cooling. Have pushed low temperatures to the bottom
quarter of the range, with a few below zero spots expected
across the northern valleys.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
Monday will see the start of what will become a week long warming
trend. The cold air aloft will pull out to the east with moderating
temperatures. Highs will again reach above freezing, this time with
the thawing temperatures pushing northwards into the foothills. With
the sun have leaned warm on the highs. A weak wave will pass to the
north of us late Monday afternoon. While most of the precip looks to
stay in southern Quebec the mountains of Maine may eek out a few
snow showers from this, and have increased both pop and cloud cover
overnight in support of this. That cloud cover and the warming
temperatures will significantly moderate the overnight lows, pulling
them back into the teens north to mid 20s south.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Overview...The warming trend begins in earnest on Tuesday with
temperatures looking to peak on Wednesday and Thursday. While we
will not be setting any records, temperatures will be some 10-20
degrees above normal for mid-week. Significant precipitation
continues to look elusive in the long term, but a frontal system
could bring isolated to scattered showers to the region toward the
latter part of next week along with a return to near-normal
temperatures.
Impacts...Minimal. The warm temperatures mid-week in southern areas,
especially southern NH, could lead to some ice movement on rivers
and that could ultimately lead to ice jams.
Forecast Details...A shortwave is expected to brush northern
portions of the region Monday night into Tuesday morning while
crossing through Quebec. However, not expecting any significant
impacts from this system other than isolated to scattered snow
showers in the mountains and foothills with very light accumulations
possible.
The big story in the long term is the warm temperatures expected for
mid-week. From Tuesday through Thursday, surface high pressure
builds over the eastern U.S. while mid-upper level ridging also
builds into New England. This setup will allow deep southwest flow
to develop and funnel warmer air into the region. Parts of southern
NH and southwestern ME should reach 50 degrees on Tuesday, but
Wednesday and Thursday look like the warmest days as the high shifts
east and the southwest flow really gets going. Highs on Wednesday
are expected to range from the upper 40s to upper 50s, and Thursday
generally looks to be about 5 or so degrees warmer than
Wednesday....which gives much of southern NH a real shot at reaching
60 degrees. The only impact this taste of spring may have is on area
rivers, especially in southern NH; there could be some ice movement
that could ultimately lead to ice jams. A final note on temperatures
for this period concerns Tuesday night as the high crests over New
England; did go a bit lower than NBM here, blending in some cooler
guidance for what could ultimately be favorable radiational cooling
conditions.
By Thursday morning, the high should be holding firm off the
Atlantic coast and a developing frontal system looks to approach
from the west. This could be our next chance for significant
precipitation, but it continues to look like isolated to
scattered showers at best for late Thursday night into Friday.
High temperatures on Friday will be interesting depending on the
timing of the frontal passage; some areas could still reach the
lower to mid 50s. A cooler air mass arrives in the wake of the
front, bringing down high temperatures closer to normal for
Saturday.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
Short Term...VFR as far as the eye can see with cold clear high
pressure over the region. That high will shift eastwards overnight
and by Monday evening a weak wave passing to the north through
Quebec may bring brief periods of MVFR in SHSN to the mountains.
Long Term...Widespread VFR conditions expected through Thursday.
Could see a few snow showers at HIE Tuesday morning with
associated MVFR/IFR conditions possible. Light northwesterly
winds on Tuesday will become light and southerly on Wednesday
and a little stronger but more southwesterly on Thursday. A
frontal system could bring showers Thursday night into Friday
morning with winds shifting to westerly behind the front.
&&
.MARINE...
Short Term...It`s been quite a while since we had a prolonged stretch
without at least SCA on the waters, but that`s what`s ahead. High
pressure well crest across the region tonight with southerly
slow slowly moving in to start next weeks warming trend.
Long Term...Broad high pressure dominates the waters through
Wednesday,keeping winds and seas below SCA criteria. Southerly
winds increase on Wednesday as high pressure slides east and
increase again and become more southwesterly on Thursday as a
frontal system approaches from the west and impinges on the
high. Marginal SCA conditions look likely from Wednesday night
through Friday night, especially over the outer waters, with a
return to quieter conditions on Saturday.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
&&
$$
Cannon