Scientific Forecaster Discussion
fxus61 kgyx 221906
Area forecast discussion
National Weather Service Gray ME
306 PM EDT sun Sep 22 2019
high pressure sliding offshore will bring deep southwest flow
over the region through Monday. That will mean a continuation of
very warm temperatures for late September. Gradually a cold
front will approach Monday, bringing showers to the area into
Tuesday. Cooler, but still seasonable temperatures will follow
the front Tuesday and Wednesday. Another cold front will cross
the region Thursday, followed by high pressure on Friday.
Near term /until 6 am Monday morning/...
an increasing low level gradient from the southwest will allow
for above normal temperatures for this time of the year tonight
with mild lows in the 60s. Plenty of low level moisture will
continue as well with dew points in the lower 60s across much of
the region. This ample moisture will allow for fog to form,
mostly in the northern and western sheltered valleys. However,
fog formation should not be as widespread as last night due to
the persistent southwesterly gradient.
There will be partly to mostly cloudy conditions in the north
with the outside chance for a stray shower right along and near
the Canadian border. This is in the closest proximity to a cold
front over Quebec province.
Short term /6 am Monday morning through Monday night/...
clouds will increase, thicken and lower on Monday as a cold
front approaches from the west. There will be a chance for
showers, mainly over northern sections and mainly later in the
day. Widespread 80s can be expected for daytime highs despite
the cloud cover with 70s in the north and mountains as well as
portions of the coastline.
Showers are possible in all areas Monday night as the front
crosses through the region. Sufficient instability Monday
afternoon through Monday night to allow for a few thunderstorms
Rainfall totals for the month of September have only reached .16
inches for Portland. Another .16 inches of rain is possible with
the Monday into Tuesday precipitation, keeping the Forest City
well below normal for the month of September. The driest
September ever recorded in Portland was .30 inches which fell
during this month in 1948.
Long term /Tuesday through Sunday/...
500 mb pattern across noam will continue to favor ridging over
the ventral and srn Continental U.S. As troughing persists along the West
Coast. One issue, however, is the weak troughing that will
linger over the Canadian Maritimes as ridging develops over
Greenland, this will likely allow some cooler spells across New
England at times, although these would be drops from above
normal to near normal. There will be some rounds of precip
associated with the frontal passage, buit nothing that could be
called significant attm.
Although cold front crosses the County Warning Area Mon night, upper lvl low
will drift across nrn New England on Tuesday, and this will
provide a chc for showers and T-storms, mainly in the north.
West winds and p/sunny skies in the south will allow for highs
in the low to mid 70s there, and generally upper 60s in the
mtns. Tue night should be dry with skies clearing out in the
south, but with lingering upslope clouds in the mtns and lows
mid 40s to mid 50s.
Wed should be mainly sunny as ridging moves across the County Warning Area and
temps a little cooler, but still abv normal in the mid 60s to
A fast moving trough passes across the far nrn zones late Thu
into early Friday, and will bring another round of showers
mainly centered around Thu night. The cooler air only builds in
briefly on Friday, before the ridge starts building up again
with warmer air moving back in for next weekend.
Aviation /19z Sunday through Friday/...
short term...localized IFR conditions in developing late night
fog in the sheltered valleys tonight, mainly over northern and
western portions of the forecast area. Localized MVFR conditions
developing later Monday afternoon into Monday evening in showers
and isolated thunderstorms.
Long term...some spotty flight restrictions in rain showers on Tuesday,
mainly in the mountains. Mainly VFR Tue night through Thu
morning, with another chance of rain showers late Thu and Thu night.
Also, valley fog expected Tue and Wed night.
short term...have issued scas for both winds and seas for Monday
into Monday night with the approach and passage of the cold
Long term...winds/seas generally stay below Small Craft Advisory levels Tue
Marine...Small Craft Advisory from 6 am to 6 PM EDT Monday for anz153.
Small Craft Advisory from 11 PM this evening to 6 am EDT
Tuesday for anz150>152-154.