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801
FXUS61 KGYX 301225
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
825 AM EDT Tue Apr 30 2024

.SYNOPSIS...
Cool winds off the Atlantic will develop for today and
Wednesday with a few showers and temperatures below normal.
Shower chances continue for later this week with temperatures
slowly climbing. An early look at the coming weekend shows a
cool start before another warm up into early next week. A shower
or two is also possible.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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825 AM Update...Latest radar and lightning data shows that some
brief showers that formed over SW NH produced some lightning
with an area of convection holding together as it is now
crossing into the lower CT Valley. Main change was to introduce
isolated thunder to account for these trends and massage PoPs
based on latest Hi Res guidance.

715 AM...Decent WAA aloft, along with some elevated instability
is working to produce some showers across the N and E zones.
This should diminish over the next few hours. Meanwhile another
cluster of convection has developed over NY, and is riding the
ridge into N New England. I expect this system to be similar to
the one that went through overnight, and should weaken as it
rounds the top of the ridge and head into W NH later this
morning.

Previously...Warmer, more humid air to our W, continues to
attempt to make its way into N New England today, but will lose
this battle during several attempts, the first which goes on
through the early morning, as some convection that formed over
NY and QC ride over the top of the 500 MB ridge, but start to
fall apart as they cross into NH on the downstream side of the
ridge. A few light showers may make it through between now and
mid morning in NH. The NE sfc flow will continue to be supported
by the 500 MB into this morning, but eventually the ridging
weakens and shifts far enough E, that flow will turn more E-SE
at the surface and onshore and this along with the clouds will
temps much closer to the Gulf of ME water temps, which are in
the mid to upper 40, so highs today look to be in the 50-55
range. I think even NH gets a break from showers this afternoon
before they return late in the day.
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&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
That 500 MB will have enough waves move into by this evening
that it will flatten toward more zonal flow by tonight. This
still doesnt offer great dynamic forcing, but it should be
enough to bring some SHRA through the CWA overnight. QPF will
remain light on the of a tenth to a quarter of inch, highest in
the CT valley and the NH mtns. Lows will drop into the low 40s
most places, and maybe some upper 30s in the N.

The weak 500 MB trough crosses on Wed, which means mainly cloudy
skies, but it should be dry with very limited forcing. Avery
weak sfc high moves in for the afternoon, which may produce a
few breaks of sun in some places, but don;t expect much. It will
allow onshore flow to continue,so temps may be a few degrees
higher than Tuesday, so well call mostly in the 50s, but may
make to around 60 in the CT and Merrimack valley.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Overview: The 500 mb pattern in this period continues to
suggest ridging building over the northeast, but models continue
to close off an upper low offshore which will try to put the
kibosh on what would otherwise be a warm and dry period.

Impacts:
* No significant weather impacts expected

Details: Brief ridging Wednesday night behind a departing
system will help skies clear ever so slightly, but not enough to
make a difference in low temperatures. Expect another night in
the low to mid 40s across the area with areas along the
International Border maybe a bit cooler as the most clearing
likely occurs there. An interesting piece of energy that looks
to originate from convection in the plains will ride the ridge
into our area during the day Thursday. This is just starting to
get into the window of the 00Z mesoscale model suite which
depicts just enough remnant moisture to develop some light
scattered showers across northern zones and maybe into central
Maine. Otherwise, this system will keep mostly cloudy skies
around and push a warm front into interior New Hampshire where
high temperatures look to climb well into the 60s. Elsewhere,
onshore winds will keep highs capped in the 50s. Clouds likely
won`t budge Thursday night as disturbances rotating around the
upper low graze the region. This results in another night in the
40s area wide.

Skies will be ever so gradually clearing on Friday as a ridge
building just to the west turns upper level flow northwesterly,
advecting drier air into the region. This means that even though
the upper level pattern remains active, Friday looks to stay
dry with temperatures in the low 60s across much of New
Hampshire and upper 50s in Maine where a weak backdoor cold
front may keep things cool. Saturday may be the start of a
warming trend as global models are coming around to the idea of
the ridge axis and surface high pressure building in and the
upper low moving out to sea. However, there is still a lot of
spread in the models for this day in particular and it could end
up quite cool. For now I will stay close the NBM which trends
temperatures down suggesting most areas will struggle to break
out of the 50s with surface winds shifting around back onshore.

Sunday and Monday will certainly be warmer, but will also
reintroduce shower chances as the ridge and surface high
pressure move off to the east. This will turn flow back to
southwesterly, advecting moisture into the northeast from the
Ohio Valley. Surface low pressure dragging a series of fronts
through may result in light showers to begin next week.

&&

.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
Short Term...MVFR should start to developing at S NH terminals
and KLEB late this morning, eventually moving into ME terminals
tonight, with a period of IFR possible overnight into early Wed.
Will likely see a period of MVFR or variable MVFR-VFR on
Wednesday.

Long Term...VFR prevails overnight Wednesday before ceilings
lower during the day Thursday as a weak system will bring light
rain showers to the area. Conditions should improve back to VFR
by Friday morning. The next chance for MVFR ceilings will be
late Saturday night.

&&

.MARINE...
Short Term...NE winds peak this morning, before weakening this
afternoon. Winds/seas are expected to remain below SCA levels
through Wed.

Long Term...Conditions hazardous to small craft are not
expected. Winds shift southerly overnight Wedensday through most
of Thursday. They then shift to northerly overnight Thursday
through the better part of Saturday. They begin to shift back
southerly Saturday evening.

&&

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

&&

$$


NEAR TERM...Cempa/Schroeter
SHORT TERM...Cempa
LONG TERM...Baron