Area Forecast Discussion
Issued by NWS Portland, ME
FXUS61 KGYX 191302
Area Forecast Discussion
National Weather Service Gray ME
902 AM EDT Sun Mar 19 2017
Low pressure will develop southeast of Cape Cod today. This low
pressure system will stay on the edge of the Gulf of Maine into
tonight so any snow should be confined to Downeast. Warmer and
dry weather is in store for Monday, with temperatures trying to
get above 40 for the first time in a while in many places.
Warmer air moves in for Tuesday with highs a little warmer than
Monday. A cold front then moves through late Tuesday and
temperatures fall off well below normal again for Wednesday and
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
855 am Update: Quick update to sky grids to give better
representation of sky cover based on latest visible satellte
imagery. Also, input latest mesonet data with minor tweaks to
temps. No other changes needed as we watch the low pres system
well southeast of New England exiting well out to sea.
Update...No major changes to the current forecast. Ocean effect
snow showers are periodically moving onshore across SErn NH and
far SWrn ME. Did not see much reduction in vsbys at PSM and
SFM...so will keep flurry wording for now.
Previous discussion...Baroclinic leaf developing off the Mid
Atlantic coast this morning is marking cyclogenesis as s/wv trof
exits the coast. Low pressure is forecast to develop and track
NE towards the Canadian Maritimes. All of this is forecast to
occur just outside the range of the majority of the forecast
area. Lack of saturation is really going to limit snowfall on
the NWrn fringes of this system...and so I have kept PoP mainly
slight chance with some chance near likely on the far outer
Of note is the deep Ely flow across the Gulf of ME. Given temp
differences greater than 10C...this is promoting cloud
development and some convective echoes are evident on radar this
morning. Given how dry it is across the area...I do not expect
much of this to reach the ground...but I will maintain the
flurry wording in the forecast. These ocean effect clouds and
flurries will gradually dissipate into the early afternoon as
flow becomes more Nly.
Temps will be dependent on how much sun we get today. More sun
and deeper mixing will result in some temps at least near
normal. But thicker cloud cover could limit our mixing and keep
us more in the mid 30s. Played things a little more on the
warmer side...expecting the clouds to mainly be thinning thru
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
Starting tonight s/wv ridging moves into the region from the W.
We will be on the edge of the surface ridge...so not completely
ideal for radiational cooling...but I suspect a few sheltered
valleys will get cold yet again.
Despite shallow mixing Mon...warming temps aloft should result
in fairly widespread temps near 40. This is notable since it has
been roughly 10 days since that last occurred for most locations
except for extreme Srn NH.
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
The models remain in decent agreement on the longwave pattern
into next weekend. We begin the period with a weakening ridge
across the forecast area. The ridge quickly exits the coast as an
upstream shortwave swings across the area on Tuesday driving a
surface cold front across the area accompanied by a few snow
showers and squalls over the higher terrain. A second shortwave
impulse will dive southeast and help reinforce the colder air
as it drives a second cold front southward across the area by
early Wednesday. Upslope snow showers across the higher terrain
late Tuesday and Wednesday will likely produce several inches of
fresh accumulation...ironically as we mark the first full days
of Spring here in northern New England. The upper trough will
lift out during the day on Thursday...with models trending a bit
quicker with its exit over the past day. Rising heights and
surface high pressure building by to our south should allow for
an upward trend in temperatures for Thursday although readings
will still be a good ten degrees below average for the date. By
Friday...a broad upper ridge will be centered across the
southeast CONUS with warm frontal clouds spreading northward
into the region along with an increasing chance for
precipitation. A compromise of the various medium range
solutions suggest the front will get hung up across the region
for much of the weekend...resulting in a prolonged period of
unsettled weather. In the dailies...a weakening ridge of high
pressure will retreat offshore by early Tuesday. Tuesday should
be the mildest day of the work week before a series of cold
frontal passages reintroduce much colder air into the area for
much of the second half of the work week. High pressure will
build east and crest across the region on Thursday before
retreating offshore by Friday. A warm front will move north into
the region late Friday and Saturday then likely
stall...resulting in unsettled weather for much of the upcoming
.AVIATION /13Z SUNDAY THROUGH THURSDAY/...
Short Term...Areas of MVFR CIGs are moving into coastal
terminals this morning. Onshore flow is allowing some ocean
effect clouds to move inland. This will affect mainly
RKD...PWM...PSM...reaching at times as far W at CON and MHT. As
flow becomes more Nly today this will dissipate and VFR
conditions are expected into Mon. A few surface wind gusts near
the coast to 25 kts are possible this afternoon.
Tue - Wed...Sct MVFR in mtn -shsn. NW sfc wind gusting to 25 kt.
Short Term...Winds and seas will increase today as low pressure
passes just outside the Gulf of ME. Gale force wind gusts are
likely on the outer waters...with SCA conditions expected in the
bays. Winds and seas diminish Mon as high pressure moves over
Tue PM - Thu AM...Small Crafts are likely, with winds approaching
Gale at times outside the bays.
MARINE...Small Craft Advisory from 4 PM this afternoon to 8 AM EDT
Monday for ANZ151-153.
Gale Warning from 4 PM this afternoon to 8 AM EDT Monday for