Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gray ME
1207 PM EDT Thursday Oct 23 2014
a coastal low will bring a prolonged period of rain through the
end of the week. The system will finally drift off into the
Maritimes Friday night. A cold front crosses the region by
Sunday. High pressure builds in for the beginning of next week.
Near term /until 6 PM this evening/...
1202 PM...minor estf update to reflect the current mesonet.
925 am...I made adjustments to 1st period grids to reflect the
current radar trends as well as mesonet. I raised 6 hour quantitative precipitation forecast
amounts along a line from roughly the kpsm - kcon area. The Storm
Warning for the coastal waters was replaced with a Gale Warning
for this update. Tide departure is approaching 1.5 feet ahead of the
11 am high tide at the Portland gage...with 15 foot seas being
observed south of Casco Bay...we will see splashover and some
beach erosion with this high tide along the coast south of
strong low pressure centered south of New England will remain
nearly stationary today. Long conveyor belt of moisture wrapping
around the middle level low will continue to pump rainfall into our
neck of the Woods today.
As of 0730z...the main band of rainfall along with embedded
thunder is located across southern New Hampshire. This band will
gradually lift northward today and affect much of the County Warning Area with a
several hour period of heavy rainfall. Another area of rainfall
off the middle coast of Maine early this morning will wrap back
westward onto the Mainland this morning as well. The heaviest
rainfall looks to be this morning into the early afternoon hours
with the best positive Theta-E advection. Isolated thunder appears
likely across southern and coastal zones as marginal instability
develops as deep Theta-E maximum impinges on the area...mainly this
Thereafter...the precipitation will probably become lighter and
more showery in nature. We expect another 1 to 2 inches of
rainfall today...which combined with the rainfall from the last
couple of days...may cause some localized river flooding issues.
Poor drainage flooding is expected. Therefore...the Flood Watch
remains in effect. However...serious flooding problems are not
foreseen at this time.
It will remain windy today. Current wind speeds and forecast
soundings do not support a Wind Advisory at this time.
However...scattered power outages are likely. Will continue to
monitor the low level jet and mixing heights early this morning
and may decide to issue a Wind Advisory for a portion of the area
if it looks like we will mix better.
Short term /6 PM this evening through 6 PM Friday/...
low pressure will slowly move well east of Cape Cod tonight. It
will remain windy and showery...but the steadiest precipitation
will have ended by evening. Overall...not really a pleasant night
with showers and a raw north wind.
A better day is expected on Friday as low pressure moves further
away. Shower activity should remain only Chancy...but clouds
should continue to be plentiful.
Long term /Friday night through Wednesday/...
Friday night will see upper low pressure transitioning into the Canadian
Maritimes. Shortwave ridging briefly crosses the area early
Sat...allowing for some drying and perhaps partial clearing. This
is short lived though...as a northern stream shortwave trough races out of
central Canada and drives a cold fnt across northern New England. This
will bring a period of showers early sun...before downsloping flow
dries out the coastal plain. Cool...moist...cyclonic flow behind
the departing low will keep the mountains locked in northwest upslope into Monday
however. Expect clouds and showers to linger through sun there...with
snow at higher elevations.
Trough finally begins to lift out Monday...with ridging setting up in
its wake. The region will transition to SW return flow...and see
some seasonably warm temperatures as a result.
Aviation /16z Thursday through Monday/...
short term...Ely low level jet continues to pump significant
moisture into the region this morning. This will gradually lift
across northern New England...with rainfall heavy at times moving S to north
through the terminals along the coast. Farther inland and khie and
kleb rainfall will be lighter...and significant periods of IFR are not
expected. That low level jet will also lead to low level wind shear along the
coast and immediately inland through the middle morning hours. In
addition some northeasterly surface gusts to 40 kts are possible as heavy rain showers
lift northward. As band of precipitation lifts northward this afternoon eventually IFR
will transition to MVFR ceilings.
Long term...should see a general improvement Sat to VFR
conditions...except for the mountains where some lingering MVFR is
possible. Late Sat into sun a low pressure system will drive a cold
fnt through New England. This will bring a round of MVFR with
showers...especially for the mountains upslope flow continues MVFR
ceilings in the mountains through sun. High pressure takes control of the region
Monday...with a return to VFR conditions.
short term...storm warnings for the ocean waters until midday as
low level jet allow for northerly gusts around 50 knots. Gales for
the bays. Winds and seas will slowly wane this afternoon through
Long term...Small Craft Advisory conditions are possible again Sat into sun as a
quick moving low pressure and associated cold fnt cross the waters.
total rainfall amounts of 2 to 4 inches are expected with some
locations in excess of 5 inches. While this rain will not fall
quickly enough to cause flash flooding... the cumulative effect of
this much rain over the last several days may be enough to bring
some streams and smaller rivers into flood. A Flood Watch remains
in effect through Thursday...when the heaviest rain is likely to
occur. We do expect urban and poor drainage flooding today with
the additional 1 to 2 inches that are expected.
pockets of minor coastal flooding and splashover will be possible
today around the time of the midday high tide. Tides are
astronomically low and major problems are not expected.
ME...Flood Watch until midnight EDT tonight for mez007>009-012>014-
Coastal Flood Advisory until 2 PM EDT this afternoon for
New Hampshire...Flood Watch until midnight EDT tonight for nhz004-006-008>010-
Coastal Flood Advisory until 2 PM EDT this afternoon for
Marine...Gale Warning until 6 PM EDT this evening for anz150>154.