Scientific Forecaster Discussion
Area forecast discussion
National Weather Service State College PA
244 PM EST Thursday Nov 20 2014
Arctic air will continue to move into the region on a gusty west
wind. High pressure will bring more tranquil conditions Saturday
before an approaching storm system brings a chance of rain showers
Sunday into the first part of Tuesday.
Near term /through tonight/...
Temperatures over the lower susq valley have managed to recover into the
middle 40s...but colder air is moving in and will continue over the
next 12-24 hours.
Other than some scattered flurries over western and even central
areas...any sig precipitation will hold off until later today and
overnight and will eventually become focused over Our Lake effect
snow belt areas of the northwest and parts of The Laurels.
Mean wind from the west will gradually veer to the west-northwest this
evening in the wake of a weak trough passage...pushing the snow
band gradually south and more inland. Latest hrrr shows the snow
slipping into Warren-McKean counties by around 00z and continuing
into the evening. Snow intensities later tonight will likely
become less impressive as the over-lake trajectories
shorten...but forecast soundings show well aligned winds-little
wind shear continuing into at least middle day Friday.
Haven't changed the configuration of the headlines or the
expected snow amounts significantly since overall thinking has not
Overnight lows in the teens to around 20 will be well below
normal. Wind chills will range from around zero over the
north...to around 10-15 above over the southeast.
Short term /Friday/...
Friday will see the lake effect snows gradually wind down as high
pressure builds into the region bringing lowering inversion
heights. Flurries and even the possibility of isolated/narrow
bands of les blowing well inland on an approx 310 degree axis may
affect the Central Ridge and valley region and communities along
the West Branch of the susq river...but this threat will wane as
well as the high approaches.
High temperatures Friday will be very similar...if not a few degrees colder
Long term /Friday night through Thursday/...
high pressure builds NE from the Ohio Valley late Friday into
Saturday bringing clearing skies and diminishing wind.
More in the way of sunshine and a warming trend will occur on
Saturday...as the high becomes centered over the middle Atlantic
A warm front and limited moisture return arriving from the Ohio
Valley will bring thickening clouds and a chance of wet snow and
rain for late Sat and Saturday night.
Milder temperatures are in store for the later part of the
weekend into early next week...but some chance of showers into
Did up temperatures some...given rather strong warm advection.
Also did up probability of precipitation some for Sunday night into Monday...given
type of airmass being advected northward.
Cooler again by middle week...but not as cold as what we have
Aviation /19z Thursday through Tuesday/...
A gusty west wind of 15-25kt today will diminish somewhat to
All sites are VFR as of early afternoon...and should continue into
the evening but for the possibility of an isolated snow shower
bringing briefly reduced conditions.
By later today into tonight the pattern will settle into a more
familiar one where most of the region is VFR while the higher
western and northern elevations have the best chance for MVFR
with occasional IFR in scattered snow showers. Bradford stands the
highest chance of significant reductions as lake effect snow bands
settle into the northwestern part of the state overnight into Friday.
Snow showers will gradually wind down as high pressure builds into
the area. Bradford will likely hold onto reduced conditions the
longest as flow off the lake continues to drag moisture and snow
showers into the northwest mountains...but even there improvement
is likely during the afternoon.
Sun...mainly VFR with a chance of rain showers.
Monday...MVFR with rain showers.
Tuesday...MVFR with snow showers over western high terrain. VFR
lake effect Snow Advisory from 5 PM this afternoon to 3 PM EST
Friday for paz005.
Lake effect snow warning from 5 PM this afternoon to 3 PM EST
Friday for paz004.
near term...la corte
short term...la corte