Area Forecast Discussion
Issued by NWS Portland, ME
FXUS61 KGYX 271412
Area Forecast Discussion
National Weather Service Gray ME
1012 AM EDT Thu Oct 27 2016
A narrow ridge of high pressure will slide off to the east today.
Low pressure will slowly move east through the region tonight and
Friday, bringing rain for most of the region with snow at the
highest elevations. A ridge of high pressure will build in from
the west Friday night and will be quickly followed by a cold front
on Saturday. High pressure will build in from the west Saturday
night through Monday. Low pressure will pass by well to our north
Tuesday and Wednesday.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1005 AM Update...Have adjusted the forecast based on latest trends
in observational data and mesoscale model output. Overall, no
large adjustments. Have slowed the timing of precipitation onset
across our area today as 12z sounding confirms very dry air in
place above the boundary layer. Most snow accums are still
expected to be across the high terrain later today and tonight.
However, we will watch trends in temperature profiles to see if a
slushy inch or so will be possible across lower elevations in
western/southwestern NH late this afternoon due to evaporational
cooling in the column.
High clouds already pushing into the region ahead of low pressure
approaching from the west. Lingering low level moisture in the
form of sc across much of western Maine and portions of New
Hampshire helping to keep temps up early this morning. Snow and
mixed precipitation currently pushing through central New York but
this area is moving into a very deep layer of dry air and will
likely take till mid to late afternoon to get into southern New
Hampshire and the connecticut valley. By then...expect boundary
temps to have warmed above freezing so only looking for a brief
period of wet snow or mixed precip at the onset...mainly over the
higher terrain. High temps today will reach the lower to mid 40s
in most areas.
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Rain will overspread the forecast area from southwest to northeast
through the evening hours with wet snow or sleet in the mountains.
Expect snow or mixed precip to go over to rain in northern New
Hampshire and far northwest Maine after midnight. Snow and mixed
precip will last longest in far northeast zones where 3 to 5
inches may accumulate through noon Friday. Being a late second to
3rd period event...will let the day shift decide on advisories or
any warnings for snowfall. Expect rain to become heavy at times
after midnight and into Friday morning in southern and central
zones as strong low level jet swings in from the west. Highest
rainfall amounts of 1 to 2 inches will fall in favorable upslope
areas along the eastern slopes with a good deal of shadowing to
the northwest of the Whites. Same amounts will accumulate in
southern interior and coastal zones. Low temps will range from the
mid 30s north to the lower 40s south.
Rain will be heavy at times Friday morning and into Friday
afternoon as low pressure pushes into the Gulf of Maine. Snow in
far northeast zones will gradually change to rain or mixed precip
before ending Friday evening. Expect rain to taper off in
southwest zones by mid to late afternoon and will gradually shift
east of the forecast area during the early evening. Highs temps
will top out in the mid 30s to mid 40s north and mid 40s to lower
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Low pressure slowly exits to our east Friday night, moving from
the Gulf of Maine to the Halifax Nova Scotia region. Systems are
currently lined up, embedded in a fast flow aloft. Therefore,
expect only a short period of partial clearing associated with a
very small ridge of high pressure.
On the exiting systems heels will be an approaching cold front on
Saturday which will cross the region Saturday night. Due to its
track, this front will be relatively moisture starved. Moisture of
the precipitation will be in the liquid form as temperatures
modify for the first half of the weekend.
Cooler and drier air will enter much of the region on Sunday.
However, a weak wave passing by south of New England may allow for
additional cloudiness during the day.
Early to midweek next week will feature fairly dry conditions as a
ridge of high pressure parks itself over the region. A strong low
pressure system will exit the Great Lakes region during the
period. However, model consensus suggests its track will take it
well to the north and west of Maine and New Hampshire as it enters
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
Short Term...VFR this morning with MVFR/IFR ceilings developing
late this afternoon and evening. Widespread ifr/lifr ceilings/vsby tonight
Long Term...Some MVFR possible Saturday afternoon and evening with
cold frontal passage. Otherwise expect mainly VFR conditions
through the long term portion of the forecast.
Short Term...Replacing Gale Watch with Gale Warnings 06z Friday
through 00z Saturday.
Long Term...Winds and seas gradually subside Friday night and
MARINE...Gale Warning from 2 AM to 8 PM EDT Friday for ANZ150>154.
NEAR TERM UPDATE...MLE