Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Gray ME
649 PM EST sun Nov 29 2015
high pressure will build over northern New England tonight
through Monday. The high will slide offshore Monday night and
allow a storm system to approach from the west on Tuesday. A
mainly rain event is expected to begin late Tuesday afternoon or
night and move out early Wednesday. A few colder spots over
northern locations may experience some sleet or freezing rain.
High pressure then builds over the region for the end of the week
and into the weekend.
Near term /until 6 am Monday morning/...
Northerly flow is pushing some of the northern stratocumulus deck
south...especially through the CT River Valley. Elsewhere the
clouds are hanging tough in the valleys. As the middle and upper
levels dry out there will some cloud dissipation overnight but
wouldn't be surprised if some of the low level moisture is caught
underneath the forming subsidence inversion and therefore stays
through early morning. In any case the available moisture doesn't
appear to be enough for snow to reach the ground and therefore
removed probability of precipitation except for kmwn. Will watch temperatures closely
with this in mind. In addition winds will be non zero...
interrupting radiational cooling processes.
a secondary cold front is pushing through the region this
afternoon and evening. This front has little in the way of
moisture and forcing but orographic lift as it crosses the
mountains has spawned snow showers in the favorable upslope
regions in the north. The snow showers and clouds will remain
confined to the north and mountains and southern areas will remain
mostly clear through the night. Clouds will start to diminish
later tonight as the front pushes offshore. A reinforcing shot of
cold air behind the front along with radiational cooling will make
for a cold night across the region...with coldest spots falling to
the single digits above zero.
Short term /6 am Monday morning through Monday night/...
high pressure will be overhead tomorrow and will provide the basis
for a cool but sunny day. Temperatures will be 5 - 10 degrees
below normal. However...the high slides off shore tomorrow
afternoon and a weak return flow will help keep US a bit warmer
tomorrow night. Nonetheless...clear skies will still provide for
efficient radiational cooling with lows dropping slightly below
normal by Tuesday morning.
Long term /Tuesday through Sunday/...
high pressure will be anchored over northern New England early
Tuesday...keeping cool...dry Canadian air over the region. This
surface ridge will exit out to sea late Tuesday.
A broad scale upper level low pressure system will be approaching
the Great Lakes region Tuesday night. Well in advance of this
system...a relatively weak area low pressure will develop along
the Middle Atlantic States and travel northeast along the coast. This
track will allow for winds to gradually back with time Tuesday
night to the northeast...bringing a halt to any warm air advection
at the surface. The atmosphere will be sufficiently dry and cool
enough well into the interior...including the mountains and
foothills of Maine as well as northern New Hampshire to allow for
areas of light freezing rain.
Boundary layer temperatures will gradually be on the rise on
Wednesday morning to change the precipitation back to all rain...
even in the mountainous regions as the surface low crosses
through the Gulf of Maine.
The upper level low pressure system will remain to our west on
Thursday...triggering the development of another low pressure
system in the Gulf of Maine. This will allow for more scattered
rain and snow showers...mainly in the north.
Surface high pressure will build over the region late in the
week and into the weekend as a gradual warming trend ensues.
Aviation /00z Monday through Friday/...
short term...most areas will be VFR through Monday...but hie will
likely see some MVFR ceilings and possibly a snow shower through
this evening as a weak cold front passes. High pressure and mostly
clear skies will persist tomorrow into Tuesday morning.
Long term...VFR and Tuesday..then conditions lowering to IFR Tuesday
night and Wednesday.
short term...a weak cold front will cross the waters later this
evening and winds will likely gust to small craft criteria through
tomorrow morning. High pressure moves overhead tomorrow and no
other flags are expected through Tuesday morning.
Long term...conditions to remain below Small Craft Advisory levels Tuesday through Tuesday
night. On late Tuesday night and Wednesday a southeast onshore flow will
allow seas to possibly reach 5 feet over the outer waters. A strong
northwest flow will allow for Small Craft Advisory winds on Thursday.
Marine...Small Craft Advisory until 8 am EST Monday for anz150-152-154.