Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 271039
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
639 AM EDT Thu Apr 27 2017

.SYNOPSIS...
A weakening area of low pressure centered over Cape Cod will
continue to drift northeast into the Gulf of Maine today into
tonight. This will prolong the cool damp conditions over all but
far western and northern New Hampshire today into tonight.
A front accompanied by showers will move across the region
Friday morning and will help to sweep out the cool and wet
conditions with warmer temperatures Friday afternoon and into
the weekend. That may be short lived however...as cooler air
tries to slip back in from the north Sunday into Monday while
low pressure approaches from the south.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
635 am update: ESTF update to ingest latest mesonet data. Only
very minor tweaks needed to temps and dewpoints needed at this
time otherwise no other changes.

Previous Discussion:
The weakening of low pressure centered over Cape Cod will
continue to slowly drift to the northeast today into the Gulf of
Maine. This will prolong a cloudy damp and cool air mass over
southern and eastern areas today into tonight. Some partial sun
may occur over far western and northern NH. The low levels will
remain saturated elsewhere since no mechanism is available to
ventilate the low levels. Patchy drizzle and fog may occur
especially along the coast. High temps will be warmest across NH
and the western Maine mountains reaching into the 60s while
over maine portions temps will remain in the 50s with coolest
temps along the coast.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Tonight most areas remain cloudy and damp. Some patchy drizzle
and fog may reform over eastern and southern areas of Maine due
to a very light moist onshore flow. A front approaches from the
west late tonight and moves across the region from west-east
Friday morning. Scattered showers and isolated thunderstorms
will accompany this fast moving front. Also this will be the
much needed mechanism to force mixing and clearing of the
trapped low level moisture during the afternoon allowing a
return to partly to mostly sunny skies and warmer temps across
all areas as winds shift to southwest. Temps will be in the 70s
over all southern and central areas Friday but 60s in the
mountains and even cooler along the midcoast areas where temps
will be in the mid 50s to mid 60s.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Not too much change to the extended forecast this morning as
much of the 00z guidance suite is in agreement with the big
picture over the next week.

A strong short wave trough is expected to move eastward fairly
quickly across southern Canada Friday night and Saturday. This
will act to drive a cold front southward across our CWA on
Saturday. While Saturday looks to get quite warm and potentially
somewhat unstable, the front looks to be pretty moisture
starved and the timing of the short wave trough energy looks a
bit too fast for much in the way of showers and thunderstorms.
Can`t rule out a couple, but the day may very well end up being
dry.

Strong high pressure dives in from the NW Saturday night and
Sunday and will bring with it cool and dry weather. Sunday
should be a winner of a day with strong higher pressure settling
overhead. Light winds should be the theme in the afternoon along
with highs around 60. Some high clouds may move in late.

The high quickly moves off to the east Sunday night allowing for
a WAA pattern to develop. This may mean another couple-day
period of rainy, drizzly, and cool weather for our region Monday
and Tuesday.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
Short Term... Widespread IFR conditions will continue today
into tonight across eastern interior and coastal areas. Over
far western and northern areas conditions will improve during
the day to vfr or MVFR. MVFR conditions in scattered showers and
isolated thunderstorms expected Friday morning over western
areas while eastern areas start out IFR and then slowly improve
to vfr during the afternoon behind the FROPA.

Long Term...A series of warm fronts will try and lift into Nrn
New England thru the weekend. This will most likely lead to
periods of widespread cloud cover. Significant periods of MVFR
CIGs are likely...and areas of IFR could form in the overnights
in onshore flow. Any IFR conditions would be most likely near
the coast...with LEB and HIE being least likely to see
significant impacts.

&&

.MARINE...
Short Term... The persistent light onshore flow will continue
through Friday. So will continue the SCA for Hazardous Seas
through Friday for the outer waters. Seas will remain 5-7 ft
over the outer waters through Friday and only 2-4 ft in the
bays.

Long Term...Marginal SCA seas on the ocean waters will subside
Friday night. A cold front crosses the waters on Saturday. The
CAA regime behind this front could allow for a period of SCA
winds Saturday and Saturday night.

&&

.FIRE WEATHER...
Cool damp conditions with light winds will continue today into
tonight as weakening low pressure moves through the Gulf of
Maine. A front will move through Friday with scattered morning
showers and even an isolated thunderstorm possible with its
passage. Clearing and warmer weather returns Friday afternoon
into Saturday although a few widely scattered mountain showers
will be possible.

&&

.TIDES/COASTAL FLOODING...
A Coastal Flood Advisory is in effect for later this evening
through early Friday morning due to the persistent light
onshore flow combining with the highest astronomical high tides
of this cycle. High tide at Portland is 11.7ft at 12:42am
Friday. Storm surge will run near a half foot at time of high
tide. Some splash over and beach erosion will be possible
through the early morning hours.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Coastal Flood Advisory from midnight tonight to 3 AM EDT
     Friday for MEZ023-024.
NH...Coastal Flood Advisory from midnight tonight to 3 AM EDT
     Friday for NHZ014.
MARINE...Small Craft Advisory for hazardous seas until 8 PM EDT Friday
     for ANZ150-152-154.

&&

$$
NEAR TERM...Marine
SHORT TERM...Marine
LONG TERM...Ekster


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