Saturday, August 13, 2022

A Possible Mid-August Coastal Storm


























000
FXUS61 KCAR 140214
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
1014 PM EDT Sat Aug 13 2022

.SYNOPSIS...
Low pressure south of Nova Scotia will track north through the
Maritimes overnight into early Sunday. High pressure will
return Sunday afternoon into Monday. Low pressure will develop
to our south on Tuesday and lift north into the Gulf of Maine on
Wednesday, then into the Maritimes Thursday......

....Sunday: The mid to upper level low will pivot across Aroostook
County during the morning and exit into New Brunswick by the
afternoon. Surface low pressure will deepen along the coast of
Nova Scotia and move northward, remaining well east of the area.
Scattered showers are expected across Aroostook County, with
isolated showers over adjacent areas. Daytime heating should
enhance activity before it diminishes in the evening. Briefly
steeper mid-level lapse rates may lead to an isolated rumble of
thunder, mainly northeast of Caribou. However, if the mid level
low moves even slightly faster, more substantial convection
could be confined to New Brunswick instead. Bangor and the coast
should remain dry with skies becoming partly to mostly sunny.
High temperatures in the 70s are expected, with the warmest
temperatures along coastal Hancock County into the Bangor
region.
&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
High pressure builds quickly Sunday night with clearing skies
and light winds. The high stability will promote a sharp
radiation inversion with the potential for patchy fog,
especially where precip fell on Sunday. Have reintroduced patchy
fog into the forecast in eastern zones. Lows will be in the low
to mid 50s. High pressure centered over James Bay remains in
control on Monday with continued light winds. Highs will recover
to the upper 70s to near 80F. There`s sufficient H850 moisture
for cumulus development and can`t rule out a few sprinkles but
will not include PoPs. The high slowly moves eastward Monday
night, providing another night of clear skies and light winds.
Resultant lows will again be in the 50s. For Tuesday, the high
will north of the state in northern Quebec and induce an
easterly low level flow. Expect more moisture and resulting
cloud cover. There`s just enough lift to mention a slight chance
of showers. High temperatures will be about the same as
Monday`s.
&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
The high to north of the area in Quebec will serve as a block to
a cut off upper low settling over the Mid-Atlantic states on
Tuesday night. A vort max rotating around the low is expected to
result in surface low development off the Mid-Atlantic coast.
The exact timing and positioning remain in question, but the
13/12Z GFS and ECMWF have better general agreement than the
previous runs. Both now show an August Nor`Easter. The low will
quickly deepen and draw deep Atlantic moisture northward. The
pressure gradient between the Quebec high and deepening low will
quickly tighten up with strengthening NE winds Tuesday night
into Wednesday. Precipitation will be increasingly likely to
pivot northward into coastal zones during Wednesday afternoon
and have upgraded to likely PoPs later Wednesday into Thursday
morning. This band of precipitation certainly would have the
potential to produce an inch or two of rain as it moves across
the CWA late Wednesday into Thursday. By Thursday morning,
expect a vertically stacked low slowly filling and meandering
northeastward. PoPs will slowly decrease later Thursday into
Thursday night. The air mass left behind the storm will be warm
and humid. Residual moisture will generate a lot of cloud cover
and hold down Friday`s highs, but next weekend should feature a
return to afternoon highs above 80F......

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