Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 122325 AAA
AFDGYX

Area Forecast Discussion...UPDATED
National Weather Service Gray ME
725 PM EDT Fri Apr 12 2024

.SYNOPSIS...
More showers are expected into this evening as a cold front
pushes through the area, and although a brief downpour is
possible, overall additional rainfall amounts will be limited.
Showers will linger into Friday, ahead of another front. Drier
and warmer conditions return for Sunday. High pressure gradually
builds in early next week with partly to mostly sunny skies and a
warming trend. Cooler conditions with mainly rain expected late
next week as low pressure develops to our south.

&&

.NEAR TERM /UNTIL 7 AM SATURDAY MORNING/...
Update...Minor changes to reflect the latest observational
trends. Will mostly be monitoring area rivers tonight...as
routed flow is now entering the larger basins.

Previous discussion... Impacts:
*Convective showers associated with a cold front may aggravate
 ongoing snowmelt flooding in the White Mountains early this
 evening, but are not expected to significantly add to totals.

Widespread rain has moved out of our forecast area, but
scattered showers continue in it is wake as the area remains
under broad cyclonic flow. Therefore, the Flood Watch has been
cancelled, but runoff and snowmelt continue and so small stream
and river rises will as well. For this reason, areal Flood
Warnings and Advisories remain in effect across the north.
Confidence is increasing in some convective
showers/thunderstorms moving up the Connecticut River Valley
around 5-6 PM ahead of a cold front. Latest HRRR runs suggest
available surface based CAPE is only around 300 J/kg so wouldn`t
expect anything rising to the level of severe, but these
showers could contain some graupel or small hail as well as
brief heavy rain. Should these storms pass over the White
Mountains they may aggravate the flooding situation there, but
would not add any significant totals. Elsewhere instability is
limited by the onshore flow, so any storms should be confined to
western New Hampshire.

Patchy fog remains in the forecast through tonight as dewpoints
remain elevated subsidence behind the cold front may lock in
some boundary layer moisture, however the front may also scour
out a lot of that low level moisture, and give us a clearer
night. Either way, low temperatures look to bottom out in the
40s area wide.

&&

.SHORT TERM /7 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
Chances for rain showers will continue Saturday as the area
remains under broad cyclonic flow and a secondary cold front
sweeps through. Skies will remain mostly cloudy with highs in
the low to mid 50s across much of the area. The aforementioned
front will work to clear things out south of the mountains, but
upslope snow showers look to continue across the higher terrain
through the overnight hours with light accumulations possible. A
period of breezy winds, 20-25 mph, is also likely in the wake
of the front and as low pressure makes its final departure to
the north. Low temperatures Saturday night look to be pretty
uniform as cold air advection cools northern zones into the
lower 30s and mostly clear skies help areas to the south cool
into the low 40s.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Current 500 MB double omega block across NOAM mid latitudes and
surrounding oceans, does start to weaken and flatten a bit a
bit later this weekend, but troughing stays nearby through the
week, although, we will be under W-NW zonal flow early next week
which should allow for 2 or 3 mostly dry days in the period.
For the most part temps run near to a little above normal
through the period. Late next week the chance for a steadier
rain returns as 500 MB troughing shifts in from the west.

Sunday will feature a bit of a break with partly sunny skies as
a weak ridge move across the area in the morning. Clouds are
likely to increase in the afternoon, with some showers possible
late in the day, especially across NH. It will be mild with
highs around 50 in the mtns to 55-60 in the S. The best chance
for showers across the region will be Sunday evening, as a weak,
and fast moving 500 MB wave moves through. Showers will be
light, and most of the CWA should see at least some clearing by
daybreak. Lows range from the mid 30s to the 40s, N to S.

As we transition to more zonal flow at 500 MB on Monday, warmer
air will move in but still will see some clouds as we shift
away from cyclonic flow aloft. So, partly sunny covers it, but
it will be a bit warmer with highs mid 50s in the mtns to low
60s in the S. It’ll be a little breezy as well with W wind gusts
to 20-25 mph. As the sfc high builds to the W Monday night, it
will clear out, but should enough flow to prevent widespread rad
cooling, but the sheltered mtn valleys will likely decouple,
and mins range from the low 30s in the mtns to the upper 30s in
the S. Tuesday looks mostly sunny and even warmer, as sfc high
crosses into the region with highs mid 50s in the N to mid to
upper 60s in the S. WE could still eek out a decent Wed, with
clouds moving in during the afternoon, although will see more
onshore flow developing, especially near the coast, so while
highs may climb into the low to mid 60s in the srn half of NH,
they will be limited to the 50s obs the coast and in in the
mtns.

As the ridge moves out Wed night into Thu, upper level trough
will stretch across the NE from W to E, and this bring the
potential for mainly rain across the region, potential in
several rounds Thu into Fri.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
Short Term...Low ceilings continue into tonight with some
clearing likely along the coast as low pressure continues to
move northward out of the area. However, patchy fog may develop
in these areas as dew points remain elevated. Ceilings lower
again as another cold front sweeps through Saturday afternoon.
This front will help to improve conditions back to VFR overnight
Saturday, but will also keep Saturday night on the breezy side
with westerly gusts to 20 kts.

Long Term...Some tempo MVFR conds are possible in SHRA late
Sunday into Sunday evening, but should see VFR for the most part
Mon-Wed.

&&

.MARINE...
Short Term...Southerly gale force wind gusts continue through
this evening before diminishing overnight. Conditions will stay
hazardous to small craft through early Saturday morning, but
winds will be diminishing throughout the day. A cold front
crosses the waters Saturday night shifting winds westerly. This
will also help to diminish seas, but they will remain in the 5-8
ft range through the overnight hours Saturday.

Long Term....SCA’s will likely need to be
continued Sunday into Monday, with seas staying in the 4-6 ft
range outside the bays, and borderline 25 kt gusts. Conditions
eventually subside to sub-SCA criteria Tue into Wed.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Gale Warning until 11 PM EDT this evening for ANZ150>154.

&&

$$

NEAR TERM...Legro


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