Area Forecast Discussion
Issued by NWS Portland, ME-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KGYX 260509
Area Forecast Discussion
National Weather Service Gray ME
109 AM EDT THU MAY 26 2016
Sunshine and warmer weather will continue this evening ahead of a
cold front. The front will bring clouds and a few showers and
thunderstorms to the area this into early this evening. A ridge
of high pressure will build over the area tonight...then hold
over the region on Thursday as a warm front approaches from the
west. The warm front will stall over the region Thursday night and
Friday and will finally push 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 AM THIS MORNING/...
-- Changed Discussion --109 AM...minor ESTF update to reflect current satellite trends
and current mesonet in near term grids.
1140 PM Update...
Adjusted temperatures for this update with portions of the area
still quite warm...in the 60s and 70s...but most of the area
in the 50s. Otherwise dropped PoPs as showers have moved offshore
and meso models are not indicated anymore precipitation overnight.
750 PM Update...
The forecast has been adjusted to account for less coverage of
showers and to take out mention of thunderstorms. We have not had
any lightning strikes over the past couple of hours and the
convection is on the decline as daytime heating is lost. This
should be it for precipitation except for the odd sprinkle of two
over the highest peaks.
425 PM Update...
Showers are now moving south along both the sea breeze and the
pre-frontal trough. Have updated to expand PoPs for southern
sections. Stronger cells are located over eastern Maine where
lightning activity has increased. Will keep thunder in our
forecast for the time being. Also adjusted temperatures... dew
point temperatures... and winds for this update.
Previous discussion... Showers and thunderstorms will continue
into the evening hours over northern areas. This is the area with
the most instability and best dynamics for the next several hours.
Modest CAPE, steep low/mid level lapse rates and the approaching
trough and surface cold front will trigger the convection. This
instability will be offset by lowering dew points currently
occurring over northwestern sections as the wind shifts to the
Otherwise, expect patchy valley fog to develop overnight. It will
be mild with temperatures mainly in the 50s for overnight lows,
however southernmost NH may hold in the lower 60s.
-- End Changed Discussion --
.SHORT TERM /6 AM THIS MORNING THROUGH 6 AM FRIDAY/...
After patchy morning fog, expect mainly sunny skies on Thursday.
Some high and mid level moisture may spill over the ridge late in
the day as a front south of Maine and New Hampshire remains in
With the sunshine and H8 temperatures around +12C, expect
temperatures to climb into the 80s once again. There will be an
afternoon sea breeze, but even coastal residents will see
temperatures make it into the 70s.
The chance for showers increases Thursday night as the front
begins to track back to the north as a warm front. A very weak
upper level disturbance will assist in triggering the
precipitation. Patchy fog is likely once again in the valley
locations and areas that receive local rainfall.
The best chance for thunder will be over southwestern portions of
the forecast area lake at night. Will keep a chance of
thunderstorms in the forecast for the late night period.
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
An upper ridge axis will continue over New England through the
weekend and into Monday. This ridge will be what we call a "dirty
ridge" as several minor short waves combined with ample moisture
move through the ridge before getting dampened out and setting
off scattered convection at times. Temperatures will be mild and
accepted the blended model guidance. With this scenario timing of
most convection should be in the afternoons and evenings. used the
superblend for pops.
By Tuesday and Wednesday models show a drier cooler canadian air
mass trying to build south across the area. Some instability
showers still can`t be ruled out for now with a cyclonic flow and
cooler temps aloft.
.AVIATION /05Z THURSDAY THROUGH MONDAY/...
Short Term...Sct MVFR across the mtns this PM and evening with
brief lcl ifr psb in -shra/tsra north. Areas of mvfr and lcl ifr
dvlpg btw 08-12z Thu in some valley stratus and fog...bcmg vfr
throughout aft 13z Thu.
Long Term...generally vfr except mvfr in any scattered showers.
Short Term...No flags expected.
Long Term...No flags.
Warm temperatures this evening but with scattered showers and
thunderstorms. Good relative humidity recovery follows for
tonight. Thursday will be one of the only dry days of the week.
Afternoon relative humidity values on Thursday may hover near
30%...but winds will be light. We are forecasting all areas to
receive rainfall this week albeit light.