Area Forecast Discussion
Issued by NWS Portland, ME

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
490
FXUS61 KGYX 262344
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
744 PM EDT Wed Jul 26 2017

.SYNOPSIS...
High pressure will move offshore tonight. A cold front moves
across the area on Thursday bringing scattered showers and
thunderstorms. High pressure will attempt to build into the
region Friday and into the weekend as low pressure moves south
of the area. This high will remain established over the
Northeast through early next week.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
700 PM  Update...
Clouds continue to advance from the west early this evening and
will quickly overspread the region through midnight. Area radar
composite showing precipitation moving into northern New York
ahead of cold front back over the Great Lakes. Looking for
showers to edge into far northwest zones after midnight and will
gradually drop southeast through the remainder of the forecast
area through daybreak. HRRR seems to be doing a good job on
timing and extent and current pops looking good. Have made minor
adjustments to temps/tds but no major changes planned to
current forecast attm. Next update will be around 1000 pm.

Previous discussion...
Clouds will advance eastward during the night. This will limit
the patchy fog as compared to last night. Nevertheless, there
will be some fog, especially before midnight.

Showers will work their way east ahead of an approaching cold
front. This front will reach the Saint Lawrence River Valley by
daybreak.

With the cloud cover and light southerly gradient, temperatures
will stay in the upper 50s to lower 60s for overnight lows.
There will be a couple readings in the mid 50s over far northern
areas.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
As the surface cold front approaches the region Thursday,
scattered showers and thunderstorms will break out across the
region. Dependent on the amount of morning sunshine, the
atmosphere will destabilize through the morning and early
afternoon, yielding CAPE values of over a 1000 J/KG. The threat
will primarily be in areas away from the immediate shoreline
where conditions will be more stable. A few of the storms may be
sufficiently strong to produce damaging wind gusts. Hail is
less of a threat on Thursday.

Increasing surface dew points and precipitable water values will
allow for locally heavy rainfall. The slow moving nature to the
front may allow for training of storms over any particular
region.

As the precipitation ends Thursday night, patchy fog may form
over areas that receive heavy rainfall during the day.

Scattered convection expected to continue until sunset at the
slow moving front remains over central and northern areas.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
The front drops south of the area on Friday with low pressure
forming and moving eastward along that front south of New
England Friday night into Saturday. It is looking like the rain
from this system will stay to our south, with our area remaining
under high pressure with seasonable temperature and low
humidity this weekend.

The center of high pressure shifts east across the area on
Monday, with a westerly flow developing aloft which will
transport warmer, slightly more humid air from the center of
the continent eastward into New England. There are no
significant rain chances in the forecast through midweek as we
will broadly be under the influence of high pressure.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
Short Term...Mainly VFR conditions will yield to lowering
ceilings and visibilities in showers and storms on Thursday.
Locally, IFR and LIFR conditions expected in any of those storms
which will last into Thursday evening. Patchy fog develops
thereafter.

Long Term...VFR conditions are expected with fog possible each
morning in the usual locations, Lebanon and Whitefield.

&&

.MARINE...
Short Term...Winds and seas will remain below Small Craft
Advisory levels.

Long Term...Expect light winds and low seas through the weekend
and into next week as high pressure builds through the area.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.

&&

$$



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.