FXUS61 KGYX 250158
Area Forecast Discussion
National Weather Service Gray ME
958 PM EDT Tue Apr 24 2018
Low pressure moves north into the area Wednesday and Wednesday
night allowing rain to overspread the area from the southwest
in the morning and work northeast by afternoon. A good soaking
rain is expected for most of the region. This system will slowly
exit the region Thursday. A cold front on Saturday will bring
colder air back into the area, with a freeze possible by Sunday
morning for some of the area.
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
10 PM Update...Little change to the going forecast. Winds have
continued to diminish and clouds continue to increase. Light
rain is expected to begin overspreading southern NH late
tonight. The heaviest rainfall from this system is still
expected to be Wed afternoon and evening.
655 PM Update...Have updated the forecast - mainly for latest
trends in temperatures and sky cover. Clouds continue to
increase this evening with winds diminishing. Dry weather is
expected through much of the night.
Strong upper ridge continues strong subsidence keeping skies
clear across the region into the evening. Mid/high clouds will
spill through the ridge from west-east later tonight ahead of
the approaching low pressure system from the mid atlantic
region. Models similar on timing overall, spreading rain across
NH after midnight and into southwest Maine toward morning. The
increase in cloud cover and developing south to southeast
onshore flow will combine to help keep temps mild tonight with
lows mostly in the 40s.
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Models agree on lifting the upper trof with its associated
surface low northeast across the region Wed and Wed night.
Soaking rains can be expected with QPF in the .75 to 1.5 inches
range. RFC QPF guidance appears reasonable and accepted. With
snowmelt in the mountains combining with the rainfall, some
area river flows may approach flood stage.
Temps will be much cooler Wed due to the rain and onshore flow
with highs only reaching into the upper 40s and lower 50s.
Meanwhile overnight lows Wed will stay in the mid to upper 40s.
.LONG TERM /THURSDAY THROUGH TUESDAY/...
The 500 MB trend across NOAM ans surrounding bodies of water
will trend toward a somewhat less blocky patter, as closed lows
separate from the nrn stream and allow a more zonal flow, with
warmer air moving pole ward toward our latitude. This will not
happen quickly, and will still have to deal with one trough that
cools things down over the weekend, but overall, no major
systems in the area, and perhaps a more significant warming
trend next week.
Thursday will see weakening 500 MB track NE as sfc low tracks
across the CWA in the morning. Showers and some light rain will
be lingering into the morning, but should see showers become
more infrequent and maybe some breaks of sun in the south during
the afternoon. Highs will be in the mid 50s to upper 50s across
most of the cwa, but southern NH could see temps rise into the
low 60s. Some lingering showers will be possible in the
mountains Thu night, but for the most part should see some
clearing everywhere, with lows in the upper 30s N to mid 40s S.
Models agree, in principle, that another sfc wave develops in
response to deepening 500 MB wave to our N, and will bring a
round of showers through NEw England somewhere in the Fri-Sat
nite time period. Chc pops are included for all these periods
for now, and will move up to likely pops once there's a better
signal as to when this system moves thru. Temps will remain
fairly near normal in this time frame with highs in the upper
50s to mid 60s and lows in the mid 30s to mid 40s Friday and
It will turn briefly colder behind this system Sunday into
Monday, with temps running a little below normal, and highs
mainly in the 50s Sunday, and slightly warmer on Monday.
The 12Z Euro keep up with the promise of a big warm ridge
building over the wrn Atlantic and pumping in some very warm
air by the middle of next week, which is supported by the GFS,
although not quite as warm.
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Short Term...VFR conditions thru tonight. Rain spreads from
south to north Wed reducing conditions to IFR.
Long Term...Thu morning will start with IFR or lower, but should
see improvement to MVFR /or VFR in the south/ during the
afternoon. VFR is expected Thu night into FRiday morning, but
may see conds deteriorate to MVFR, or even IFR at times late
Friday into Saturday.
Short Term...Winds and seas will remain below SCA thresholds
tonight after a few gusts around 25 kt this evening. Increasing
onshore flow Wed afternoon will allow winds and seas to build
to SCA thresholds over the outer waters and continue through
Long Term...Seas will remain high through the day Thu despite
weakening winds. The waters should remain quiet Fri and Sat, but
may approach SCA in W flow behind a cold front Sat night into
Basin average rainfall of up to 1.5 inches is expected Wednesday
and Wednesday night. This, along with recent snowmelt in the
north, will allow rivers to rise - especially Wednesday night. A
flood watch may be needed for some mountain and foothill zones.
MARINE...Small Craft Advisory from 5 PM Wednesday to 8 PM EDT Thursday
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