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454
FXUS61 KGYX 211228
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
828 AM EDT Fri Jun 21 2024

.SYNOPSIS...
A cold front will stall over Southern New England today through
Sunday as waves of low pressure ride along it. This will result
in near seasonable temperatures and rounds of scattered showers
and thunderstorms. Another front will then cross on Monday with
additional unsettled weather before high pressure builds
towards the middle of next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

-- Changed Discussion --
8:25am Update... A quick update to increase POPs for this
morning for the scattered showery activity developing with the
passing cold front. An isolated thunderstorm is also possible
near the ME/NH border over the next few hours.

645 AM Update... A few isolated showers have developed within
the Portland Metro and therefore adjusted PoPs to account for
these. Latest CAM guidance indicates a somewhat growing
potential for some modest destabilization to occur later today
over southern NH and there is a decent amount of bulk shear
present and therefore while the threat for a severe storm is
low, cannot rule out one or two gusty storms this afternoon...
especially in southwestern part of the state.

Previously...
Satellite imagery this morning shows an area of mid-level clouds
streaming from northwest to southeast over the region and radar
shows an area of showers dropping southeastward over interior
western ME. Patchy fog and low ceilings have developed across
portions of the region, especially over valley sites and this
will continue to be possible through 7am or so. Current
temperatures are primarily into the upper 60s and lower 70s with
another degree or two of cooling possible through daybreak. It
will otherwise continue to be a warm and humid start to the day.

The cold front that was responsible for yesterday`s severe
weather is progged to become stationary over southern New
England today, putting our area into the cool sector. This will
result in significantly cooler high temperatures compared to the
last few days with readings topping out into the upper 70s to
lower 80s for most areas. Skies will be partly sunny across much
of western ME and partly to mostly cloudy over NH. A weak wave
of energy will ride along this boundary through the day, which
will result in scattered showers and perhaps rumbles of thunder
over NH while much of western ME remains dry under light
northeasterly sfc flow.

Scattered showers will become more likely areawide tonight,
especially after midnight as a vorticity maximum crosses the
area... providing some extra lift. Rainfall amounts are
expected to be light with generally between 0.10-0.25". Low
temperatures will range from the middle 50s across the north to
lower and middle 60s south. Patchy fog may develop as well given
the light flow and abundant LL moisture.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
The stationary front will slowly begin to retreat northward on
Saturday as another wave of low pressure rides along it from the
west. Skies will be partly to mostly cloudy with scattered
showers and isolated thunderstorms areawide. An additional
0.10-0.25" of rainfall can be expected in most locations.
Locally higher amounts will be possible though, especially over
the mountains. High temperatures will be cool given the cloud
cover and onshore flow with readings along the coast only into
the 60s and then lower to perhaps middle 70s over the interior.
The warmest area will likely be southwestern NH which could
approach the 80 degree mark.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Overview:  Relatively progressive flow after the NE CONUS ridge
becomes suppressed with a more active polar jet stream and Canadian
troughs moving across New England. Shortwave ridging is expected
between the troughs bringing a see-saw weather pattern over the next
week.  This will bring periods of active weather with thunderstorms
and temperature swings from near normal to above normal.

Impacts: There is the potential for localized flash flooding on
Sunday across the mountains. In addition, severe weather can`t
be ruled out Sunday at this time across most of the forecast
area.

Forecast Details: By Sunday the stationary boundary becomes a
warm front and surges north of the area bringing the region back
into the warm sector. Threat for severe weather will increase
as a robust mid-level shortwave and associated cold front pushes
through the area sometime late Sunday into Monday morning.
There is some model spread on the order of 12 hours or so on
timing of FROPA at this time. Monday the shortwave trough swings
through with the potential for much cooler weather and showers,
but this depends on the timing of the trough. Tuesday looks to
have the highest potential for being the driest day of the week
as a shortwave ridge moves over the area with a rebound in the
temperatures. Wednesday could be warm once again as a return to
southwest flow is possible ahead of the next approaching trough.
A period of storms is possible in the Wednesday night into
Thursday timeframe as the next cold front swings through the
area.

&&

.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
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Short Term...Mainly VFR conditions can be expected today with
scattered -SHRA at times, mainly across NH TAF sites. More
widespread -SHRA arrives tonight along with low ceilings/FG
which will likely result in IFR to LIFR restrictions at times.
Conditions slowly improve on Saturday but MVFR CIGS could linger
through much of the day. Winds will be light out of the NE
today then ESE on Saturday. No LLWS is expected.

Long Term...Showers and thunderstorms could bring temporary MVFR to
IFR conditions on Sunday as the threat for afternoon
thunderstorms increases along with gusty southwest winds. Storm
coverage should trend downward by the beginning of next week.
-- End Changed Discussion --

&&

.MARINE...
Short Term...Onshore winds and seas to remain below SCA
thresholds through the period as a front stalls south of the
waters.

Long Term... By Sunday strong SW winds could develop leading to
marginal SCA conditions by the afternoon and evening hours
ahead of an approaching cold front. Cold front pushes through on
Monday with a return to offshore flow and possible SCA
conditions.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.

&&

$$


NEAR TERM...Clair
SHORT TERM...Tubbs
LONG TERM...Dumont