Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gray ME
1235 PM EDT Sat Apr 25 2015
upper level low pressure will stay nearly stationary east of Nova
Scotia through the weekend and into early next week. This will
keep cool and unsettled weather over the region. The low pressure
will finally shift east Tuesday as a ridge of high pressure builds
in on Wednesday. A coastal low may develop off the middle Atlantic
coast late next week and could affect our area by Friday...but
current forecast track is well south of New England.
Near term /until 6 PM this evening/...
1230 PM...quick update for the afternoon...which features some
adjusting of probability of precipitation...mainly to change wording to sprinkles or
flurries for this afternoon outside of the mountains in the
Kennebec/Penobscot valley regions. SW ME and southern half of New Hampshire look
950 am...stacked closed low sitting over downeast ME this
morning...and a little pulse of energy is rotating southward around the
west side of it...which is helping to set off a shsn/rain and
sprinkles/flurries this morning. These should shift southward and offshore
by midday...with a bit of a break early to middle afternoon before
another round of scattered rain showers /with just snow in the higher terrain/
moving around 19-21z...mainly in the mountains...which get upslope
enhancement...and the eastern zones closer to the better dynamics.
Probability of precipitation for today followed a blend of the mesoscale models including
rap/hrrr/ncar 3km. Temperatures/sky were adjusted slightly as
well...with more sun in southern New Hampshire and slightly higher maxes there.
Previously...shortwave trough embedded in the upper low over
eastern Maine is rotating through New Hampshire and western Maine
this morning. Some light snow falling mainly in the mountains but
some of this could spill over into the midcoast region. Could see
some afternoon showers developing mainly in the north and East
Part of the area where better instability may exist.
Temperatures today will be a couple degrees warmer than yesterday.
Went below guidance for temperatures in the mountains where
upslope conditions and clouds prevented temperatures from rising
much above freezing yesterday and could cause a similar effect
Short term /6 PM this evening through 6 PM Sunday/...
should see much of the shower activity diminish tonight with the
loss of heating and temperatures fall into the 30s.
While the main upper low slides east by Sunday... a trough will
extend back to the west over northern New England. This trough may
be enough to provide just enough lift and instability for some
afternoon showers again especially over New Hampshire.
Temperatures will be just a few degrees warmer again in the 50s.
Long term /Sunday night through Friday/...
cut off low will remain just to our east for the start of the
forecast period. Models are in good agreement for a short wave to
rotate around upper low and push southwest across the region
Monday afternoon through Tuesday morning. This will bring
widespread rain showers to the area with snow in the mountains.
A ridge of high pressure will build eastward into the region on
Wednesday and finally push the upper level low off to the east.
With the ridge overhead we expect temperatures to climb back to
normal values with daytime highs mostly in the 60s except for the
After Wednesday forecast confidence drops significantly as
another trough digs southward toward the end of next week. Keeping
an eye on how the models trend the next few days with handling a
southern stream system that pushes off the middle Atlantic coast on
Thursday. Could possibly see a coastal low develop that could have
an impact on our weather by next Friday...but for now models are
keeping this feature south of New England.
Aviation /18z Saturday through Thursday/...
short term...VFR conditions expected today except for MVFR
conditions and occasional snow showers at Whitefield. Outside
chance of a shower at Augusta and Rockland as well.
Long term...expect mostly MVFR with with possibly IFR conditions
Monday into Tuesday morning in more widespread rain showers. Ridge
of high pressure starts to build in late Tuesday night with VFR
expected through Wednesday.
short term...weakening pressure gradient will allow winds to
diminish today and Sunday.
Long term...a small craft will be possible on Tuesday as winds
pick up out of the northeast. Other than that the seas should
remain quiet until the end of next week when our next storm may
approach from the southwest.
showery weather continues over most of the area today and for the
next several days. However... southern New Hampshire will be
spared from showers today and will see lower humidity values.