Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 290750
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
350 AM EDT SUN MAY 29 2016

.SYNOPSIS...
While Saturday may have felt like the dog days of summer...today
will feel distinctly spring-like behind a southwest moving cold
front. Temperatures are going to struggle to climb much higher
than morning readings for much of the area. The best chance for a
nicer day will be areas well inland...like the Connecticut River
Valley. Tonight moisture associated with Bonnie begins to stream
north...and the chances for rain will increase with it. Rain may
even be heavy at times into Memorial Day...especially across
southern New Hampshire and coastal Maine.

&&

.NEAR TERM /TODAY/...
What a difference a day makes. High pres building into the
Maritimes has pushed a cold front back to the SW across New
England. Behind it stratus and patchy fog continues to spread
across the forecast area. The result will be temps some 20 or more
degrees colder than yesterday. The air mass to our W remains quite
warm...and winds aloft remain SWly to Wly advecting that over the
top of the low level marine layer. This will strengthen our
inversion today...and make it all the more difficult to break
thru. High temps across much of the area will be near current
readings if stratus can fill in all the way. Farther W across the
CT River Valley may escape the marine influence...and temps should
be able to climb well into the 70s. Along this differential
heating boundary however a few showers or storms may be possible
this afternoon. Again with the lack of a strong upper level
forcing mechanism...any convection will be widely scattered.

&&

.SHORT TERM /TONIGHT THROUGH 6 PM MONDAY/...
Tonight attention turns towards Bonnie. WV satellite imagery
already shows moisture from her streaming into parts of Wrn PA and
NY. This will continue into New England...first with an increase
in clouds...followed by an increase in precip chances. Model
forecasts depict PWAT values climbing to near 2 inches by early
Mon. Those high PWATs coupled with light steering flow will create
a recipe for heavy rnfl. However the threat looks more localized
than widespread at this time...so I will be holding off on any
sort of flood watch headline. ECWMF EPS favors that threat holding
off until Mon...and mainly for Srn zones at that. This is
supported by the SREF as well. Looking at individual EPS members
shows that only a handful drop heavy rnfl over parts of the
forecast area...with the rest mainly light to moderate QPF
amounts. All the more reason to keep heavy rnfl wording localized
at this point.

Another thing to keep an eye on will be if trends continue to keep
most of the precip across Srn areas Mon. Thru the mtns could clear
out and heat a fairly moist air mass. A strong jet streak is
forecast move over the region during the afternoon. This could
provide the forcing for ascent and shear necessary for a few
organized storms. Have added gusty wind wording to the mtn zones
for the afternoon...trying to keep it close the SPC marginal risk
forecast.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
A broad ridge of high pressure will remain in place over the
forecast area for the week. The high strengthens through Thursday
and then shifts eastward allowing a 500mb short wave to push
towards our region at the end of the week. The high remains in
place and the shortwave will rotate to our north through Quebec.

A generally warm and sunny week is in store for Northern New
England. On Tuesday highs will get into the 80s as temperatures
climb to +11C at 850mb. Northwesterly flow in the wake of Monday
nights frontal passage will keep the sea breeze at bay allowing
the warmth to extend for all but the immediate coastline.

On wednesday the temps aloft cool slightly as the high crests
overhead. The weak pressure gradient will allow for a sea breeze to
push well inland in the afternoon. With water temperatures still
in the 50s this will keep temperatures down in the low 70s for all
of the coastal plain of Maine and Rockingham county NH. Further
inland Keene and the CT river valley will soar to the 80s under
sunny skies.

Thursday will remain sunny as dry conditions continue under the
surface high. Aloft a wedge of colder air pushes southwestwards
out of the Canadian maritimes. 850mb temps drop to +5C with
surface high temperatures dropping back into the 70s region wide.

Friday the ridge starts to break down as a trough moves into the
great lakes. A cold front moves through touching off showers and
thunderstorms in the afternoon.

&&

.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
Short Term...Marine fog and stratus continues to develop this
morning behind backdoor cold front. Hi-res model guidance has had
a good handle on trends this morning...with development over Srn
NH first...and expanding NEwd from there. Coastal terminals will
see IFR CIGS this morning...lifting but remaining MVFR today. Will
have to keep an eye on SHRA/TSRA this afternoon on the periphery
of the cloud deck...but confidence is too low to include in any
TAFs at this time. Clouds are then expected to increase everywhere
tonight...as moisture from Bonnie begins to lift Nwd. Heavy rnfl
is possible across Srn NH and coastal ME Mon...with IFR or lower
conditions in the heavy precip.

Long Term...VFR conditions expected through the week under high
pressure. Thunderstorms are possible Friday afternoon.

&&

.MARINE...
Short Term...Initial surge from backdoor cold front will bring a
few gusts near 25 kts this morning. Otherwise winds and seas are
expected to remain below SCA thresholds. Some patchy fog will also
be possible on the outer waters today.

Long Term... High pressure will keep wind and waves calm through
the week.

&&

.FIRE WEATHER...
Cool...onshore flow will dominate most of the area today. Relative
humidity values will remain moderate to high region-wide. On Mon
tropical moisture associated with Bonnie will stream into the
area. Showers are likely...with some possibly heavy at times. A
wetting rain looks most likely across southern areas.

&&

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

&&

$$

NEAR TERM...Legro
SHORT TERM...Legro
LONG TERM...Curtis
AVIATION...Curtis/Legro
MARINE...Curtis/Legro
FIRE WEATHER...Legro



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