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
000
FXUS61 KGYX 302245
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
645 PM EDT Sun Apr 30 2017

.SYNOPSIS...
A warm front will try to lift north through the region tonight,
but an easterly wind off the Gulf of Maine will keep clouds and
cool temperatures down at ground level. Rain becomes more steady
overnight along the Canadian border and into central Maine in
advance of the warm front. As low pressure tracks east through
southern Canada, a cold front will push from west to east across
northern New England Monday night into Tuesday morning. Some
showers or even a thunderstorm is possible as it does so. This
front will push out the low level maritime air mass and bring a
clearing westerly flow on Tuesday, with temperatures warming
into the 60s and 70s. Another front arrives Tuesday night with
even cooler air moving in behind it for Wednesday. High
pressure builds in from the west Wednesday night before
shifting offshore on Thursday. Low pressure approaches from the
southwest and moves up the east coast for the end of the work
week.

&&

.NEAR TERM /TONIGHT/...
645PM UPDATE...
Have updated the forecast primarily to add a Flood Watch for the
upper Kennebec River basin where water levels remain high from
snow melt and additional rainfall is expected tonight. This is
in coordination with WFO Caribou to our east and fits well with
current expectations along the Kennebec with Skowhegan expected
to rise to near flood stage in the next few days. Otherwise have
also adjusted hourly POPs based on latest radar trends which
show light showers moving out of southern areas and becoming
more steady in the north.

ORIGINAL DISCUSSION...
Clouds have spread across the region this afternoon accompanied
by scattered showers. These clouds are the leading edge of a
broad warm front extending from our area back across New York
and southern Ontario to the Great Lakes ahead of a strong
cyclone in the middle of the CONUS. This front will slowly move
eastwards overnight spreading heavier rain into the northern
portion of our region. Most widespread and heaviest rainfall
will be in the mountains where around an inch of QPF is
expected.

&&

.SHORT TERM /MONDAY AND MONDAY NIGHT/...
Monday the shower activity will decrease in the north with just
a few scattered showers as our region is left in the warm
sector of the cyclone. Sadly it won`t be very warm at the
surface as north to easterly flow off the Gulf of Maine will
keep temperatures in the upper 40s. In the CT valley of NH and
along the Mass border the warmth will creep in with temperatures
reaching the mid 60s. A cold front will approach the region on
Monday night and move through early Tuesday morning with an
additional 0.5" of rain.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
On Tuesday a broad area of upper level low pressure will be
filling and shifting northeast out of the Great Lakes region and
into southern Quebec Province. The system will become negatively
tilted as it weakens to an open wave late Tuesday night. Tuesday
morning a pre-frontal trough will be moving east through Maine
along with a line of showers and some embedded thunderstorms.
Surface low pressure will be nearly vertically aligned with the
upper level system, with most of the surface energy moving
north of us as well. Therefore not expecting any severe weather
but there could be some heavy downpours along the boundary.

Behind the pre-frontal trough but ahead of the actual cold
front (essentially a wind shift to the NW), we will see warming
during the day, with sections of southern NH and interior Maine
reaching the upper 60s to lower 70s.

WSW/near zonal flow will be in place Wednesday through
Thursday. Skies will clear out over the coastal plain first
before clearing occurs elsewhere on Wednesday. Low clouds and
showers will linger over the mountains through late Wednesday
night. Clouds return quickly Thursday night ahead of the next
system. Temperatures for this 2 day period will range from the
50s in the mountains to the 60s south.

Low pressure originating in the southern Plains will eject NE
Thursday and extend a warm front into New England with
precipitation developing by Thursday night in southern NH. Our
area will remain in the warm sector Friday and Saturday, with
additional showers/drizzle in the warm advection regime. Models
have backed off on developing a coastal low as this system
deepens, but a stronger surface reflection will move into
southern Canada by Sunday morning. This will keep northern New
England in onshore flow/somewhat dreary weather for the
remainder of the weekend. A a pre-frontal trough passage is
likely sometime Sunday with some drying occurring.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
Short Term...Conditions will steadily decrease from VFR to MVFR
overnight and into IFR by tomorrow. Rain overnight in the north
may briefly mix with snow or freezing rain at elevation

Long Term...IFR/LIFR ceilings continue Tuesday morning with
improvement to VFR Tuesday. Areas of MVFR ceilings linger in
the mountains Tuesday night through Wednesday. VFR conditions
will prevail Wednesday night through Thursday with deteriorating
conditions Thursday night through Friday with some +SHRA.

&&

.MARINE...
Short Term...
Winds will increase behind the cold front late Monday night
into Tuesday and a Small Craft Advisory will likely be needed.

Long Term...Marginal SCA conditions are possible Tuesday into
Wednesday, mainly in the offshore waters. Stronger SCAs are
possible Friday afternoon into Saturday as a coastal low passes
nearby.

&&

.FIRE WEATHER...
Things moisten up substantially through Monday with low clouds
and drizzle expected. Rainfall of around an inch is possible
across northern NH and the western ME mountains late tonight and
early Monday. Additional rainfall is expected Tuesday as well as the
end of the work week.

&&

.HYDROLOGY...
Have issued a Flood Watch for Somerset County along the upper
Kennebec River basin. The concern is for river flooding on the
Kennebec over the next 48 hours. Most of the rainfall in the
next 24 to 48 hours will focus directly on the upper Kennebec
basins. Moosehead lake is already very full and flows going into
the Kennebec remain high. Downstream flooding is possible
particularly at Skowhegan.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Flood Watch from Monday morning through Tuesday morning for
     MEZ009-014.
NH...None.
MARINE...None.

&&

$$

NEAR TERM...Curtis
SHORT TERM...Curtis
LONG TERM...Hanes



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