Scientific Forecaster Discussion
Area forecast discussion
National Weather Service State College PA
526 PM EDT sun Oct 4 2015
a large area of high pressure over southern Quebec will drift
south over the next several days and slowly weaken. Dry weather
will result for most of the work week...with a mainly dry cold
front in the middle of the week. The next significant chance of
rain will be on the weekend.
Near term /until 6 am Monday morning/...
high pressure exerting it/S influence with strong subsidence and
Clearing is now into Elk/centre/Dauphin counties and continues to
press west/erode from outside in. Made some further cuts to sky
cover grids...but some patchy clouds may try to fill in a bit
before nightfall. Will linger the large patch of the clouds in the
SC mountains longest - not totally clearing them out. Just a little
bit of a gradient wind may linger overnight. Most places north of
the Turnpike should decouple. If the sky stays mainly clear in the
N/E...the temperatures should get into the l40s...and the colder rural
valleys may touch the u30s. Thought for a second about frost
advisory in Tioga Colorado...but the dewpoints are still in the 40s. It
should dry out a little more through the late aftn/evening.
So...will just go with some fog in the valleys. Despite dry
air...the temperatures should drop cold enough to generate River Valley
Short term /6 am Monday morning through 6 PM Monday/...
temperatures should rise quickly on Monday. 800 mb temperatures in the 10-12c range
usually spell slightly milder maxes than we have running...so will
add a degree or two to the going forecast...but halt there since MOS
guidance is cooler and the cold air is rather dense/shallow. 60s
across the board. Sky should be mainly clear. A weak trough and a
few clouds will approach from the northwest by late in the day.
Long term /Monday night through Sunday/...
strong inversion in place this afternoon will have some influence
on the weather the next few days.
With high pressure and light winds expected Monday night...added
some patchy fog in...and lower min temperatures some. Low temperatures
will drop to near or below the forecast dewpoints. Also ground
is wet after recent cool...wet weather. This will aid in fog
Still looking at a nice early fall day on Tuesday...with some sun.
A cold front drops southeast on Wednesday...but should be mainly dry. Lack
of dynamics and moisture.
A high builds across Quebec by early Thursday...but too far north
for frost concerns.
Another cold front for late Friday...with a high building in
for later next weekend. Did cut showers out of the forecast after
Another front to come in after next weekend...but too early to
tell if it will be real strong. Pattern favors cold air that
builds in at low levels...not real deep.
Overall...did not make a lot of large chnages to the package.
Aviation /21z Sunday through Friday/...
early evening visible satellite loop shows a shrinking area of stratus
across the Laurel Highlands/SC mountains dry air advecting in from
the NE should has already brought clearing skies to most of
central PA and linear extrapolation of cloud edge suggests kaoo
will clear between 22z-23z then possibly kjst between 00z-01z.
Focus overnight will shift toward the possibility of late night
radiation fog. Area most susceptible to fog will be the central
mountains...where clearing occurred late in the day...resulting in low
dewpoint depressions going into the evening. Will mention fog in the
late night forecast at kbfd...kunv and kaoo. Fog appears possible
at kjst/kipt and very unlikely at kmdt/klns.
Any early fog should burn off between 13z-14z...then widespread VFR
conds and light winds appear very likely Monday with high pressure
over the region.
Tue-Fri...mainly VFR. Am fog poss.