Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 261153
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
753 AM EDT Tue Mar 26 2024

.SYNOPSIS...
Sandwiched between two storm systems moisture will start to
increase over the local area starting this afternoon. Eventually
drizzle is develop. With temperatures across the foothills and
mountains hovering near freezing tonight, some freezing drizzle
is possible. Rain will be light enough that significant icing of
trees is not expected, but slippery travel may result. Gradually
temperatures warm up through Wednesday but the damp weather will
continue. A better chance for steady rain will arrive Thursday,
especially near the coast. Precipitation may try and end as snow
Friday before things become drier and gusty over the weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
745am Update...Some light returns on radar proving fruitful at
the surface. Did observe a few drops of rain here at the office.
However, with the arrival of precip, mixing also increased. This
helped to stir the air and result in a net positive temp change.
The leading edge of these returns has bumped temps up about 3
degrees, limiting potential impact of AM freezing drizzle along
the coast and the interior. Still can`t rule out a light glaze
on elevated untreated surfaces where some of the stronger
returns pass. Additionally, GOES sat derived cloud top temps are
above freezing, so hydrometeors likely lack a supercooled start
to their journey. Overall, pulled mention of freezing drizzle
out of the coastal communities this morning. This could still
fall towards the mountains where sfc temps managed to fall a few
more degrees overnight.

Previous Discussion...
Low clouds will overspread the area today, with drizzle and
freezing drizzle.

CAD should hold firm today as a stout inversion forms off the
surface. This will result in area temperatures near freezing.
Incoming moisture in the low levels will be enough to develop
drizzle for much of the area, particularly this evening and
overnight. During the day, visibility shouldn`t be impacted too
much.

Slick travel conditions are likely this morning into the
interior. Generally a trace of ice is expected, mitigated by the
cloud deck not being too deep. Insolation should prevent much
ice accretion through the day here, but will watch area temps
through the morning hours.

The main icing will take place at higher elevations in the
foothills and mountains this evening and overnight. The cold
termination of the inversion roughly encompasses 1300 to 2500 ft
in depth, and have focused temps/ice amounts here. This is
where ice accumulation could approach three tenths, with lower
amounts below and above. Because the inversion is so sharp,
locations above could be 10 to 15 degrees warmer, particularly
this morning and afternoon.

Primary impacts will be slick travel, particularly for higher
mountain passes, and additional loading on trees or structures
that saw significant snowfall this weekend. Lowered visibility
will also be possible in drizzle/fog tonight.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
Temperatures recover Wednesday, warming into the upper 40s to
lower 50s. Additional showers are possible, crossing the CWA
through the afternoon. Fog may linger to the west, but generally
clear gradually south to north along the coast.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Overview: Slow moving trof will steadily march thru the region by
the start of the weekend. Temps will be fairly seasonable...but the
weather will remain unsettled until the front can clear the area.

Impacts: No significant weather impacts are anticipated at this
time. However 90th percentile QPF is around 3 inches near the coast
and at least in a reasonable worst case scenario those values
could lead to some flooding.

Forecast Details: By Wed night a slow moving cold front should be
moving into western portions of the forecast area. Initially showers
will be possible near the boundary...with drizzle still favored east
of the front where saturation is more likely to be shallow in
nature.

The focus however is really into Thu...as southern stream S/WV trof
drives cyclogenesis along the trailing portion of the boundary off
the Carolina coastline. That wave will propagate north along the
front...just off the New England coast...spreading predominately
rain to the west. There are many factors that will determine how far
west precip makes it...including position of the cold
front...strength of the low pressure...and how quickly it deepens.
It is not surprising that the greatest spread in QPF is across the
interior...along the western edge of the forcing. There is roughly a
1 inch spread between the 90th and 10th percentiles...with that 10th
percentile barely a wetting rain. Confidence is much higher along
the coast that it will rain...and so this is where PoP is
categorical. Using DESI cluster analysis shows the major theme
across ensemble guidance is the amplification of the system. The
flatter and less amplified the flow the drier the QPF. Roughly a
third of the 25.12z ensemble members featured more zonal...drier
solutions. Deeper S/WV trofs and stronger ridging into eastern
Canada...more amplified...produced much larger QPF events. This
was favored by about 20 percent of members...with the rest
falling close to the mean QPF around 1 inch near the coast and
closer to one quarter inch in the mtns. With the large spread
and larger than normal uncertainty...I have stayed close to the
multi model consensus but did bring WPC QPF forecast up closer
to the ensemble mean.

After the trof passage it will get gusty behind the front as CAA
takes over. Flow will stay largely westerly into early next
week. A series of S/WV trofs will approach the area and keep a
threat of showers in the forecast...but limited moisture will
ensure that threat remains scattered more than widespread.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
Short Term...MVFR to IFR/LIFR today and tonight. Lowest ceilings
are expected tonight. Ceilings gradually lower through the day
today, with drizzle and freezing drizzle accompanying. Low
visibility is more likely this evening and overnight as drizzle
thickens. MVFR to IFR ceilings may continue through Wednesday.


Long Term...IFR or lower conditions will persist into
Thu...especially near the coast. Much greater uncertainty
farther northwest...where drier solutions may result in no
reduction of flight category. Early Fri northwest winds will
increase and become gusty...reaching 25 to 30 kt by the
afternoon. Conditions will improve to VFR outside of the
northwest slopes of the mtns including HIE...where MVFR CIGs may
persist in upslope. Gusty winds continue into Sat.

&&

.MARINE...
Short Term...SCA conditions continue as wave heights will remain
7 to 12 feet into Wednesday. NE winds today, with a few gusts
nearing Gale force on the outer waters. Winds lighten Tuesday
night, becoming variable.

Long Term...Despite light winds...seas are forecast to remain
above SCA thresholds outside of the bays into Thu. Northwest
winds begin to increase Fri...with gale force gusts possible by
Fri night. Gusty winds and hazardous seas are expected to
persist thru the weekend.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Winter Weather Advisory from 2 PM this afternoon to 8 AM EDT
     Wednesday for MEZ007>009-012-013.
NH...Winter Weather Advisory from 2 PM this afternoon to 8 AM EDT
     Wednesday for NHZ002>006-008-009-015.
MARINE...Small Craft Advisory until 8 PM EDT Wednesday for ANZ150-
     152>154.

&&

$$


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


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