Area Forecast Discussion
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FXUS61 KGYX 261032
Area Forecast Discussion
National Weather Service Gray ME
632 AM EDT THU MAY 26 2016
A ridge of high pressure will crest across the area this morning
before sliding offshore this afternoon. Summer like temperatures
will be tempered a bit near the coast as light winds turn onshore
by afternoon. A warm front will stall over the region tonight and
Friday before finally pushing east of the region on Saturday. A
cold front will cross the region Saturday night then stall just to
our south on Sunday. The front will return north as a warm front
on Memorial Day.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --628 AM...minor ESTF update to reflect the current mesonet in near
At 06z...a 1009 millibar low was over Eastern New Brunswick
province with a trailing cold front through the gulf of Maine.
A ridge of high pressure extended southward into Western New
England. Goes infrared imagery showed clear skies across the
forecast area under the building ridge. The light winds and clear
skies were allowing patchy valley stratus and fog to form across
the area. For today...early morning stratus and fog should burn
off quickly with sunshine under the cresting ridge pushing
temperatures into the 80s in many locations...but turning cooler
by afternoon ear the coast as the light synoptic flow turns
onshore. Clouds will increase over southern and Western sections
late today ahead of approaching warm front with a late day rain
shower possible over southwest New Hampshire.
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.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
For tonight...warm air advection clouds will spread north and east
across the remainder of the area. Onshore flow should also introduce
some late night drizzle and fog to the coastal plain.
otherwise...expect a few showers and thunderstorms to precede the
warm front overnight. Lows tonight should be mainly in the 50s.
Friday will be a tale of two regimes with summer time heat developing
across much of New Hampshire into the Maine mountains and
International border area while further east clouds should hang
tough with an onshore breeze as the surface warm front makes
little if any progress against the cool...damp...stable marine
layer. Expect we`ll see drizzle and fog linger into the afternoon
at the coast...especially north and east of Casco Bay. We`ll see
scattered convection continue across the forecast area as well
with the best chance for thunder from the Connecticut valley
northward along the International border area. Highs will range
from the 80s across the Connecticut valley and International
border to the upper 50s in mid coast Maine.
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Overall pattern in the extended remains consistent with seasonably
strong ridging building in from the Wrn Atlantic. With mean ridge
axis more or less overhead...the forecast area will be in the
battle ground between summer-like warmth and spring-like chill.
One common theme is dry wx...with ECMWF EPS producing less than
0.75 inches QPF across the forecast area thru day 10. While any
individual shower or storm could drop more than that...it does
point towards an an overall lack of robust forcing.
More specifically...model guidance shows mid level temps warming
into Sat. GEFS forecasts of greater than 2 SD anomalies would
suggest deterministic guidance may be biased a bit too cool.
Outside of the sea breeze...winds will be favorable for interior
warmth...and so I went above guidance by a couple of
degrees...especially the Srn NH traditional warm spots. One note
about Sat regarding precip chances. While scattered showers and
storms are possible just due to the hot and increasingly humid air
mass...some organized convective wx is not out of the question.
The region will reside on the Srn edge of strong Wly flow aloft.
We lack a strong trigger to focus convection...but some
solutions...like the 26.00z GFS show a sub 400 mb PV anomaly
crossing the Maritimes Sat afternoon. If that forcing could extend
a little farther SW...a stronger storm or two is possible.
By Sun that PV anomaly will help leave behind a boundary which the
pres gradient will likely push Wwd. The Ern half of the forecast
area looks to be much cooler Sun...though farther W parts of the
CT River Valley might remain very warm. Beyond the weekend we look
to remain with warmer than normal temps. Precip chances are much
less confident...with weak forcing and possible moisture
influences due to Invest 91 in the Wrn Atlantic forecast to move
towards the Carolinas this weekend and early next week.
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
Short Term /through Friday/...sct mvfr and lcl ifr through 12z in
valley stratus and fog...otw vfr throughout. Areas of mvfr dvlpg
tonight in -shra/-tsta with lcl ifr vcnty of the coast in drizzle
and fog. Areas of mvfr continue Fri in sct -shra/tsra with lcl ifr
lingering vcnty of the coast in drizzle and fog.
Long Term...Ridging looks to dominate the pattern for the
extended...which will favor drier conditions and more VFR than
not. With warmer air masses and moisture increasing in the
area...the risk for afternoon SHRA and TSRA will remain. MVFR or
lower will be possible in any heavier precip. In addition...front
moving swwd thru the area Sun may bring some marine low clouds to
Short Term /through Friday/...Quiet on the waters with winds and
seas remaining below Small Craft threshold.
Long Term...Winds and seas look to remain below SCA thresholds
with ridging in control of the region. Post front on Mon there is
possibility of seas nearing 5 ft outside of the bays...but
confidence is low at this time.
Today will be one of the only dry days this week. Afternoon
relative humidity values may hover near 30 percent...but winds
will be light. Moderate to high humidity levels return for tonight
through the start of the holiday weekend. We are forecasting all
areas to receive rainfall for the end of the week into the upcoming
weekend...although amounts should be relatively light.