Scientific Forecaster Discussion
Area forecast discussion...corrected
National Weather Service Gray ME
320 PM EST Wednesday Mar 4 2015
high pressure will gradually build in from the west tonight
through Thursday and will crest over the region on Friday. A cold
front will approach from the west Friday night and will cross the
area on Saturday. Weak low pressure will move in from the west
Saturday night and will push east through the region on Sunday.
High pressure will build south of the region Monday and will shift
offshore south of New England on Tuesday.
Near term /through tonight/...
high pressure continues to nose towards the forecast area this
afternoon. For the time being the real cold push remains back
across Canada...and will wait to push through until the overnight. As
such have blended 2 M temperature guidance in with the mav/met for
overnight lows. Cold air advection will keep at least marginal mixing in the
lowest levels...and I Don/T expect radiational cooling to be much
of an issue. With the push of cold/dry air upslope shsn and clouds
will come to an end overnight as well.
Short term /Thursday through Thursday night/...
a series of waves will ripple along the slowly advancing cold
front through Thursday night. The first of which...currently over the middle
MS River Valley...arrives early Thursday. Have maintained some schc pop
in southern New Hampshire along the Massachusetts border. I really Don/T expect much more
than shsn along the border if precipitation does fall. The second wave
arrives late Thursday evening...and should be even farther S than the
High pressure begins to assert more control over the region...and
skies will quickly clear from north to S. With surface ridge axis
aligned overhead...expect boundary layer to decouple and the
typical cold spots to fall well below zero. Sided with the colder
Long term /Friday through Wednesday/...
pretty quiet extended forecast through early next week....
high pressure will crest over the region on Friday before
shifting offshore. Despite a fair amount of sunshine
temperatures will continue to average well below normal
with highs in the middle teens north and lower to middle 20s south.
Cold front will approach from the west Friday night bringing
increasing clouds and a chance of snow showers in in northern
zones after midnight. Front will take all day Saturday to push
through the region. Will likely include low chance probability of precipitation for most
of the forecast area but expect any snow shower activity to be light
and spotty with this moisture starved system. Highs on Saturday will
reach the middle 20s to middle 30s.
Skies clear briefly Saturday evening as the front pushes offshore...
but clouds will again be on the increase after midnight as weak
clipper approaches from the west. Will see a chance of snow
showers toward daybreak in southern New Hampshire but once again
expect any amounts to be light and spotty. Entire forecast area
will see the chance of occasional light snow on Sunday as low
pressure moves into southern Maine by late in the day. Quantitative precipitation forecast
forecast to be light with this system with most areas seeing only
an inch or two of snow through Sunday evening.
Expect light snow to wind down Sunday evening as low pressure
shifts east into the Maritimes. Variable cloudiness will linger
through the night and into Monday as low pressure trough lingers
over the area. High pressure building in from the west will
gradually clear skies downwind of the mountains Monday afternoon.
High pressure builds south of New England Monday night and Tuesday.
Warm front passing through southern Quebec will brush northern
zones with clouds Monday night but the majority of associated
precipitation will remain north of the forecast area. Net affect will be
a moderation in temperatures with much of the area seeing highs at or
above normal with middle 30s north to lower 40s south.
Warm air will stick around on Wednesday as weak low pressure
passes south of New England.
Aviation /19z Wednesday through Monday/...
short term...VFR conditions expected to prevail through Friday morning.
Local MVFR conditions are possible in scattered shsn across the northern
mountains late this afternoon...before upslope flow weakens.
Long term...VFR Friday through Saturday. Areas MVFR/IFR
ceilings/visibility Sunday. VFR Monday.
short term...marginal Small Craft Advisory conditions continue through Thursday night.
Winds gust 20 to 25 knots at times...with seas remaining right
around 5 feet. A period of moderate freezing spray is possible late
Long term...sca's may be needed Saturday.
Marine...Small Craft Advisory until 7 am EST Thursday for anz150>154.