Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gray ME
325 am EDT sun Jul 5 2015
weak low pressure will cross just north of the area today accompanied
by scattered showers or storms. High pressure brings dry weather
and gradually warming conditions Monday into Tuesday. Another
passing trough and cold front will bring a chance of showers and
thunderstorms midweek. High pressure follows for late Thursday
Near term /until 6 PM this evening/...
the valley fog will lift early this morning with the
sunrise...leaving US with more sun than not today. A weak trough
will swing through early this afternoon...mainly brushing northern and eastern
zones. The Pocket of colder temperatures that comes with it aloft will
help increase cloud cover with daytime heating. Across interior
western ME...expect that eventually this results in isolated to scattered
thunderstorms. It appears though enough ice will exist in the clouds that
straight thunder mention seemed appropriate for the afternoon
forecast. Flow is fairly weak...so shear is rather modest as well.
Do not foresee much organization to the afternoon
convection...though steepening low level lapse rates may bring
about some gusty outflow from any storm that does develop.
Convection allowing models also show a fairly small window for
thunderstorms...with early afternoon initiation and clearing the coast
Short term /tonight through Monday/...
this period looks to be mainly dominated by ridging aloft.
Dewpoints creeping back up in returning flow should keep things
milder than tonight. With ridge axis aligned surface and aloft
Monday...weak flow will prevail. This should be ideal for sea breezes
to develop along the coast and dictate afternoon temperatures for those
areas. Inland it looks like a very warm day...with 800 mb temperatures
climbing to near 15c. Mixing that down...which looks
achievable...yields middle to upper 80s for the favored warm spots of
southern New Hampshire into the sfm area.
Long term /Monday night through Saturday/...
the models are in general agreement on the long wave pattern
through late in the upcoming work week. However...timing of
individual shortwave energy becomes difficult after day five in
the nearly zonal flow. We begin the period with an upper ridge
that quickly exits into the Canadian Maritimes. Return flow behind
the departing ridge will transport increasingly humid air into
the area ahead of an approaching upstream trough and associated
surface cold front. Scattered convection could arrive as early as
Tuesday afternoon ahead of this system...with activity continuing
through early Thursday before the front finally clears the coast.
It should be noted that models differ on exactly how fast and far
the front sinks to our south and east on Thursday before stalling.
High pressure will eventually build in on Thursday then remain in
control into Saturday. The next shortwave impulse and associated
surface reflection should arrive in time for the second half of
Aviation /07z Sunday through Thursday/...
short term...patchy IFR or lower visibilities in valley fog will continue
through sunrise. Conditions quickly improve to VFR during the day.
Isolated to scattered thunderstorms and rain are possible this afternoon...but chances
are not high enough to include in the tafs for Aug and rkd at this
time. Expecting sea breezes to develop along the coast Monday.
Tuesday PM - Thursday am...scattered MVFR in showers and thunderstorms.
short term...winds and seas expected to remain below Small Craft Advisory
thresholds. A brisk SW wind ahead of the front today may help
increase seas to 3 or 4 feet near Matinicus this afternoon.
Tuesday - Wednesday...small craft winds and seas are possible.