Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gray ME
255 am EST Thursday Nov 26 2015
high pressure will remained anchored to our east today and the
southwesterly flow around it will warm things up for Thanksgiving
day. However...there will be more clouds than sun. A cold front
will approach the region on Friday and cross our area Friday night
into early Saturday morning. It will bring a few
showers...especially across northern portions of the forecast
area. High pressure will build in behind the front on Saturday
with cooler conditions. Our next chance of
precipitation...probably in the form of rain for most areas...will
be Tuesday and Wednesday.
Near term /through today/...
around a plus 3 Standard deviation...strong high pressure is slowly
sliding eastward S of the Canadian Maritimes this morning. As we become
increasingly part of the western edge of the surface ridge axis...return
flow and warm air advection will in turn increase. Temperatures for the most part have
leveled off this morning...and they will remain that way to tick
upwards through daybreak.
The increasing SW flow is also bringing moisture northward. Gentle
upslope from the warm air advection and interaction with terrain is allowing
areas of stratus to form S of the mountains down through southern New England.
This trend will continue this morning...and lingering into the
afternoon. Some break are possible...but overall trend is mostly
cloudy. This may hold temperatures down some outside of the southern
zones...but still an above normal Thanksgiving day temperatures.
Short term /tonight through 6 PM Friday/...
not much change tonight into Friday. High pressure remains off the
northeast coast...with deep layer southwesterly flow dominating the region.
Temperatures will fall a little with the loss of daytime heating...but
overall expect steady readings overnight...and much above normal
low temperatures. This will give the forecast area a good launching pad
for above normal daytime temperatures Friday too. Expect some lower 60s
across far southern zones...with widespread 50s elsewhere.
The strength of high pressure to the east and lack of a strong shortwave trough
diving southeast I feel limits the push of frontal boundary into the
region. Have held off any pop until very late in the period
Friday...and only in the mountains at that.
Long term /Friday night through Wednesday/...
a cold front will drop through Maine and New Hampshire Friday
night. Forcing for ascent and moisture availability will wane with
time Friday night...so highest probability of precipitation for rain showers will be
across northern New Hampshire and the western Maine mountains.
Further south...went with only chance probability of precipitation to even slight chance
down near the New Hampshire/Massachusetts border. Perhaps a lingering showers early
Saturday morning...but high pressure will provide for fair and
cooler weather for the bulk of the day. The high will hold
overhead on Sunday with a secondary cold front passing through
with little fanfare late Sunday or Sunday night. High pressure
will once again move in for Monday. The high quickly moves off to
the east on Monday as a low pressure system approaches from the
west. This low looks to move across the area Tuesday and Wednesday
and will represent the best chance of substantial precipitation
through the next 7 days. Right now...it looks like a mainly rain
event as there really is no mechanism in the pattern to hold cold
air in. However...will keep watch for any changes.
Aviation /07z Thursday through Monday/...
short term...increasing moisture...waa...and upslope enhancement
of lift is leading to the development of stratus as expected this
morning. So far ceilings remain VFR...but patches of MVFR will be
possible especially prior to dawn. Eventually heating of the day
should help lift the ceilings and keep them VFR today. MVFR conditions
become a little more likely tonight across a more widespread area.
Long term...MVFR conditions will be possible Friday night with
showers associated with the passing of a cold front. The best
chance of MVFR or perhaps even brief IFR conditions will be
across the northern mountains. Thereafter high pressure builds in
overhead and VFR conditions should persist through Monday.
short term...winds and seas will gradually increase in response to
return flow building through the day...as high pressure slides eastward. Small Craft Advisory
is in effect for all waters.
Long term...small craft conditions should be present Friday night
through Saturday...mainly on the ocean waters.
Thereafter...subsiding conditions are expected into early next
astronomical tides will be near the peak for the month over the
next few days. On Friday the high tide in Portland around 1130 am
is 11.5 feet. At this time though it is not looking likely that we
will see any flooding as winds will be from the southwest and
parallel with the coast...limiting the surge potential along most
coastal areas. However...along the Maine midcoast the southwest
winds have a slight onshore component...but any impacts in these
areas should still be very minor.
Marine...Small Craft Advisory from 7 am this morning to 7 am EST
Saturday for anz150>154.