Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 191055 AAA
AFDGYX

Area Forecast Discussion...UPDATED
National Weather Service Gray ME
655 AM EDT Tue Oct 19 2021

.SYNOPSIS...
Northwest flow will keep clouds and showers going over the the
higher terrain for much of the day today. South of the mountains
while it may be drier will still be raw and gusty with
temperatures struggling into the 50s. Above normal temperatures
will return Wednesday into Friday, but the rollercoaster
continues with another cool down over the weekend. Chances for
widespread precipitation through the end of the week are low as
any rain remains showery across the north Thursday and with the
passage of a series of cold fronts Friday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Update...Minor changes to PoP to account for latest radar
observational trends. We are in the middle of one of those
relative maxes in upslope shower coverage. I anticipate a lull
mid morning...followed by another increase this afternoon.

Previous discussion...The local area remains well under the
influence of upper low pressure. Cyclonic flow over the higher
terrain is producing a fairly classic upslope precip event.
Based on forecast soundings and cloud presentation on IR
satellite...air is not free flowing over the terrain at the
moment. Forecast Froude numbers suggest the bulk of the upslope
shower activity will keep QPF max near the peaks. Temps solidly
at or below freezing from about 2500 ft...so some minor snow
accumulations continue today for those summits. Forecasts also
suggest a double max in activity today. One with an embedded
S/WV trof occurring right now...and a second embedded trof this
afternoon. In addition to the increase in showers...wind gusts
will also see a little uptick as well. Temps will struggle into
the 50s...so between that the wind gusts...and showers it will
feel like another raw day.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
As upper low starts to shift Ewd...any PoP will also start to
become more confined to Wrn ME vs NH. With return flow starting
overnight temps will be similar if not a couple degrees warmer
than this morning.

Wed will see warm front lifting into the area. Srn half of the
forecast area could get quite warm...with readings back around
10 degrees above normal. Once the warm front lifts thru the area
any chance of precip will be quite low.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Wednesday night, clouds increase as low pressure passes through
the eastern Great Lakes. The outreaching warm front will remain
over central NH and southern ME through the day, with another
warm day set for these locations. The coolest spots will be
across the Longfellow Mtns where overrunning rain showers will
move through during the afternoon. The coast and foothills will
likely remain in a mostly dry warm sector before the center of
low pres tracks east. Showers will finally move into these
locations Thurs night as the cold front is brought through. The
shortwave amid the longwave pattern is much more amplified over
the Great Lakes vs. when it arrives in New England, thus much
of the precip may consolidate towards the occluded portion. This
may also coincide with orographic lift from the higher terrain
as indicated by WPCs QPF outlook. All in all, it will be the
periods greatest chance for more widespread rain, but fairly
light.

With the cold fronts exit Friday, temps take a turn for more
seasonable conditions. A cooling trend is expected through early
next week as the upper air pattern brings broad low pres aloft
overhead. There will be embedded shortwaves associated with this
pattern, one of which has been producing a sfc low pres system
off the Gulf of Maine in GEM/ECMWF runs fairly consistently. The
positioning of this low and track will be determined by how
quickly the aforementioned cold front escapes the coast. These
solutions keep some semblance of the front near the coastal
waters Saturday, allowing this developing sfc low to strengthen
as a mid level jet rounds the base of the trough. Additional
lift may be in place with an accelerating upper jet across
eastern ME and NB/NS, resulting in a showery precip shield
backing into coastal Maine and NH through the weekend. Alternate
thinking by the GEFS places the passing front outside the
GofME, resulting in a drier solution. Have sided with mentioning
at least some precip across the coastal plain during this time
period.

If the system is allowed to continue strengthening as it exits
to the north and east, an even cooler push of air may be allowed
in across the region into next week. This would result in
possibly the first widespread frost/freeze for the CWA of the
season; very late heading into the last week of October.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
Short Term...Occasional MVFR conditions possible in NW upslope
flow thru this evening. HIE will be the terminal most likely to
experience passing MVFR...especially in any SHRA. Otherwise
widespread VFR with NW wind gusts in excess of 20 kt at times
today. VFR conditions continue into Wed.

Long Term...VFR outside of the NH mountains Wed night, with
ceilings thickening and lowering Thursday. MVFR/IFR will be
possible across northern NH TAFs and KAUG/KRKD. Remaining sites
may remain VFR until a cold front brings down ceilings with
-SHRA Thurs night. Conditions across the area improve to VFR
 Friday, with a trend towards MVFR possible again Saturday.

&&

.MARINE...
Short Term...Marginal SCA conditions are expected to continue
for much of the day. A period of slightly stronger wind
gusts...up to 30 kt...is possible this afternoon with the
passage of another reinforcing front. Winds and seas diminish
Wed.

Long Term...Conditions expected to remain mostly below SCA
criteria through Sat. There will be a period of winds around 25
kt Friday morning as a cold front approaches and passes over
the waters. Wave heights are expected to be 1-2 ft, increasing
to 2-4 ft.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ150-
     152-154.

&&

$$

NEAR TERM...Legro
SHORT TERM...Legro
LONG TERM...Cornwell
AVIATION...Cornwell/Legro
MARINE...Cornwell/Legro


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