Area Forecast Discussion Issued by NWS Portland, ME
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000
FXUS61 KGYX 081425
AFDGYX
Area Forecast Discussion
National Weather Service Gray ME
1025 AM EDT Thu Jun 8 2023
.SYNOPSIS...
Persistent upper-level low will keep conditions cool with
chances of showers through Saturday along with a few
thunderstorms on Friday and Saturday. The low will finally begin
to get nudged out by a ridge Sunday and Monday, allowing for
mostly dry conditions and warmer temperatures. Another low
pressure and cold front will increase rain chances again Monday
night through Wednesday of next week.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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1025 AM Update...Have made some tweaks to PoPs and T/Tds based
on observations and incoming near term guidance. This did not
result in any significant changes to the going forecast for
today.
725 AM...Adjusted POPs to cover the band of showers across N NH
and central ME this morning, which seems to correlate with some
convergence close to the center of the stacked low. Models
suggesting this spreads out thru the morning as showers rotate
around this center through today.
Previously...The 500 MB closed low continues to sit over N New
England and surround areas of Canada /and will do so through
Friday/. It will gradually fill starting today, and the trend
will be for more diurnal influences to produce showers, so
expect the threat of showers to ramp up later this morning and
through the afternoon. The showers will be more cellular and
convective today, but thunder is unlikely. Best chance for
shower swill be in the mtns down to the Capital region of ME.
But, they are possible anywhere this afternoon. Given the
stacked low over the CWA, flow will be light today, and mixing
will be limited but expecting highs similar to the last few
days, with highs 55-60 in the mtns to the low to mid 60s in the
S. Once again, expect best chc of any sun in the morning and
late in the day.-- End Changed Discussion --
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
The threat of showers decreases this evening and overnight
mostly due to loss of heating. Still could see a few around
overnight, especially in the mtns. Mostly cloudy conditions
persist, but winds should be very light, so some rad cooling is
possible, and low range from the mid 40s to around 50. Given the
light winds, will likely see patchy fog tonight, especially in
areas where it rains this afternoon.
Friday looks similar to Thursday, although showers look more
convective and cellular as stagnant flow allows for better low
level moisture beneath cold pool aloft, so TSRA is possible,
especially over NH. There may be a little more sun as well /but
still mostly cloudy/. Highs will be a few degrees warmer than
Thursday, mainly inland areas, as onshore flow will keep the
coast from rising as much and highs will run 60-65 or so.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Can`t rule out a few showers Friday night with 500-mb low still
on top of us, but for the most part shower activity is expected
to dwindle through Friday evening with the loss of daytime
heating/instability. Given the high shower coverage we`re
forecasting on Friday, I think there is pretty good potential
for low stratus, fog, and or/drizzle Friday night into early
Saturday with light winds and sufficient low-level moisture.
This is supported well with SREF probabilities, and some of the
fog could be locally dense.
The upper low will start to open into a wave as it finally
begins to move slowly to the east on Saturday. However, plenty
of remaining PVA aloft and moisture will support another round
of scattered to numerous showers during the daytime hours.
Forecast soundings do show steepening lapse rates and a few
hundred J/kg of CAPE, which also supports a slight chance of
thunderstorms in the forecast. There could be some gusty winds
with the steep low-level lapse rates, but the overall potential
for strong storms looks low with little to no shear to work
with. Convective coverage will diminish Saturday evening with
the loss of heating once again, but we could see patchy fog
again Saturday night, especially for those that see rain on
Saturday as winds will again be light.
Temperatures warm up for Sunday and Monday with upper-ridging
briefly building into the region, giving high temperatures
mostly in the 70s. This will also provide mostly dry conditions,
but a couple of showers may occur on Sunday and generally
confined to the upslope regions.
After that, we`ll lose the ridge as another upper low moves
slowly across the Great Lakes sending a round of precipitation
and a cold front our way. This is still toward the end of the
forecast period, but the global models have started to agree on
a slower eastward progression with this system, resulting in a
lowering of PoPs for Monday and an increase PoPs for Monday
night and Tuesday. An additional round of showers is possible
Wednesday as the upper low moves across the region.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
Short Term...Tricky day today, as will likely see variable cigs
from VFR-MVFR at times at all but KMHT/KCON. Scattered showers
could reduce vis as well. Will have to watch for low stratus
developing tonight, especially at coastal terminals and KAUG,
which brings a chance for IFR overnight into Friday. Friday will
likely be similar to Thursday, with showers and variable cigs
between MVFR and VFR.
Long Term...The potential for low ceilings and/or fog and drizzle
has increased during the Friday night into early Saturday morning
timeframe, which could produce IFR to even LIFR restrictions. After
that, most should return to MVFR or VFR by late Saturday morning,
but showers and possibly a couple of thunderstorms could bring back
some restrictions during the day on Saturday. High pressure will
bring mainly VFR Saturday night through Monday before an area of low
pressure increases chances for precipitation and flight restrictions
Monday night through Wednesday of next week.
&&
.MARINE...
Short Term...Low pressure from the surface stacked through the
atmosphere will keep winds light and seas low, well below SCA
through Friday.
Long Term...Light flow will keep conditions below SCA levels this
weekend and into Monday. After that, southerly flow will increase
Monday night into Tuesday ahead of a low pressure and cold front,
possibly resulting in SCA conditions over portions of the
waters.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
&&
$$
UPDATE...Schroeter
NEAR TERM...Cempa
SHORT TERM...Cempa
LONG TERM...Combs