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Area forecast discussion
National Weather Service Gray ME
329 am EDT Wed Jun 28 2017

Synopsis...
a trough of low pressure will move offshore this afternoon with
a few showers possible across the interior and mid coast. A
warm front will approach on Thursday and bring increasing
chances of rain during the afternoon and and especially the
nighttime hours. Another low pressure system may affect the
region on Saturday and possibly Sunday with more showers and
thunderstorms.

&&

Near term /until 6 PM this evening/...
an upper level trough will gradually move east today with
heights beginning to rise. Even still, the air aloft will be
anomalously cold which will aid in some surface based
instability. A few showers and isolated thunderstorms should
develop around or after midday - mainly across western/northern
New Hampshire and the mid coast of Maine. Severe weather is not expected
today and thunderstorm coverage is expected to be much less than
yesterday. Most locations in the forecast area will likely
remain dry. The best chance may very well be in Coos County New Hampshire
and portions of the western ME mountains between 21z and 00z as
a subtle short wave trough approaches in the mean northwest flow
aloft.

In the meantime, some early morning patchy dense fog in spots
is expected to burn off after sunrise.

&&

Short term /6 PM this evening through 6 PM Thursday/...
any lingering showers/isold storms should dissipate quickly
around 00z. Otherwise, we expect a pleasant night with
temperatures dropping into the 50s - with some 40s at the better
radiators well inland.

A cold front will sharpen up and approach from the southwest on
Thursday. Clouds will increase during the morning hours with
light rain likely developing across western New Hampshire around midday or
a bit later. This will spread eastward to adjacent western ME by
early evening. Southernmost New Hampshire may remain dry for the entire day
as the forcing for ascent remains just north of Cheshire and
Hillsborough counties.

&&

Long term /Thursday night through Tuesday/...
the forecast period begins with a fairly zonal upper level flow
with a series of weak short waves helping to touch off showers.
By Saturday a deeper trough has developed over the Great Lakes.
This trough and accompanying surface cold front will move
through the area on Sunday making way for high pressure to start
next week.

Friday will see a warm front draped across the forecast area.
It will be hot a muggy with dew points in the mid 60s and high
temperatures reaching the upper 80s across the southern portion
of the area. Showers and thunderstorms will continue through the
day. Expect there to be an east west oriented axis of heavier
precipitation however still quite a bit of uncertainty of the
exact placement within the region so have just gone with a
generally equal pop.

The warm front begins to pull to the north on Friday night
leaving our area firmly in the warm sector for Saturday. With
temperatures in the 90s and dewpoints approaching 70 in the
south the heat index will approach 95 in southern New Hampshire.
This stifling heat and humidity will be perfect for
thunderstorms and expect widespread storms in the afternoon as
cape climbs. While there will be lots of instability there will
not be as much shear for severe storms. 40kts or so at the
tropopause will support thunderstorms but the larger concern
will be heavy rain. Precipitable water values will also reach
near maximum values for the date and storms would be slow to
move without any fast jet or major forcing over head.

Sunday a cold front will cross the region setting off yet
another round of thunderstorms. Here the storms will be more
focused along the front and a few severe winds gusts are
possible.

Monday and Tuesday high pressure builds back into the region
with clearing skies and decreasing humidity. Highs will be near
80 for the 4th of July. Water temperatures offshore remain in
the low to mid 50s and with the popular Holiday weekend a beach
hazard statement may need to be considered with the hypothermia
risk continuing.

&&

Aviation /07z Wednesday through Sunday/...
short term...patchy valley fog will burn off most locations by
13z this morning. Otherwise we expect VFR conditions today with
some more patchy valley fog later tonight. A few hit or miss
showers are expected this afternoon, but coverage is expected to
be minimal.

Long term...
showers and thunderstorms will continue through the weekend.
Brief periods of heavy rain and thunder will impact all
terminals. Friday in the north will see more widespread MVFR
ceilings while Saturday expect scattered convection to influence
all locations.

&&

Marine...
short term...small craft conditions are not expected today
through Thursday.

Long term...
building seas with wind gusts to near 25kts in south westerly
flow will likely necessitate a Small Craft Advisory for Friday
into Saturday. Seas will subside for the end of the weekend and
start of next week.

&&

Gyx watches/warnings/advisories...
ME...none.
New Hampshire...none.
Marine...none.

&&

$$

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