Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 221558

Area Forecast Discussion
National Weather Service Gray ME
1158 AM EDT Mon May 22 2017

A weak cold front will approach from the west today before
pushing east through the region tonight. Weak high pressure
will build over the area on Tuesday and will hold over the
region through Wednesday. Low pressure will slowly move northeast
out of the Ohio Valley Thursday and pass through southern New
England on Friday. Low pressure will shift east into the
maritimes Friday night. High pressure will build over the area
Saturday through Sunday.



1155 AM...Minor ESTF update to reflect current radar trends,
HRRR output, and the latest mesonet values.

Prev Disc...
910 AM...minor ESTF update to ingest the current mesonet values into
near term grids.

Prev Disc...
640 AM Update...Little change to the going forecast.
Rain/showers continue to move eastward across the region this
morning. The HRRR has been doing a good job with the trends in
PoP so we continued to blend it in heavily through the
afternoon. There should be a break in the rain by late morning
into the early afternoon hours. Otherwise, no changes to the
forecast for today.


A warm frontal boundary will push toward our region today. Cloud
weather is therefore expected, with some rain early on this
morning. Forcing becomes weak later this morning through early
afternoon and therefore we should be dry for several hours
during that period. Thereafter a cold front or occlusion should
approach later in the afternoon with an increase in shower
activity. Today will not be a washout by any means, but clouds
and temperatures in the 50s and perhaps 40s will not make it a
great day. There is also a chance of drizzle, especially on the
coastal plain, this afternoon.


Frontal system moves offshore tonight and allows for any showers
or drizzle to end from west to east, with some clearing
following thereafter. Tuesday should be a much better day than
Monday with high pressure moving overhead helping to boost
temperatures back into the upper 60s to lower 70s.


High pressure will build over the region Tuesday night as a weak
area of low pressure tracks northeast off the New England coast.
Expect high clouds over southern zones during the evening hours
before clearing after midnight. Lows will range from the mid 40s
north to the lower 50s south.

High pressure will gradually weaken over the area on Wednesday
but should provide one more nice day. High temperatures will top
out in the upper 60s to mid 70s away from the coast. An afternoon
sea breeze will cap temperatures in the lower to mid 60s along
the coast.

Vertically stacked area of low pressure over the Ohio Valley will
slowly lift northeast Wednesday night and Thursday. Mostly clear
skies Wednesday evening will give way to high clouds by daybreak
Thursday. Lows overnight will bottom out in the lower to mid 50s.

Low pressure will gradually approach from the southwest on
Thursday. Weak over-running ahead of this system will result in
variable clouds with perhaps a stray shower. Increasing onshore
flow will likely bring ocean stratus into southern zones by late
in the day. Highs will generally range through the 60s.

Vort lobe swinging around upper low will intensify over-running
over the region Thursday night as surface low shifts east into
southern New England. Expect a steady rain to develop over the
region overnight. Lows will be fairly uniform in the lower to
mid 50s.

Low pressure will continue northeast into the Gulf of Maine on
Friday. Steady rain will persist through the morning and will
gradually taper to showers in the afternoon. Highs will range
through the 60s.

Showers will gradually end Friday night as low pressure pulls off
to the northeast. Looking for clearing skies after midnight. Lows
will range from the mid 40s to mid 50s.

Upper level ridging will bring weak high pressure to the region
for the weekend. Looking for a mix of sun and clouds with
seasonable highs.


Short Term...VFR conditions for the most part through mid
morning will deteriorate to MVFR late morning or early afternoon
before becoming IFR later this afternoon and evening. IFR
conditions will improve to VFR early Tuesday morning.

Long Term...VFR Tuesday night through Thursday. IFR/LIFR
ceilings/vsby Thursday night and Friday.


Short Term...A brief period of marginal SCA conditions will be
possible on the ocean waters late this afternoon and evening.
Otherwise relatively tranquil conditions are expected today
through Tuesday.

Long Term...SCA`s May be needed Thursday night and Friday.


Cool and wet conditions are expected today with some drying
likely Tuesday and Wednesday before the next low pressure
system brings rain Thursday and Friday.


High astronomical tides Thursday night (11.8 ft mllw forecast
for Portland), will combine with onshore flow possibly resulting
in minor coastal flooding. Another high tide on Friday night
(12.0 ft mllw forecast) will likely again result in minor
coastal flooding although winds may be offshore by that time.





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