Area Forecast Discussion
Issued by NWS State College, PA-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KCTP 251705
Area Forecast Discussion
National Weather Service State College PA
105 PM EDT Tue Oct 25 2016
Weather systems will impact Central Pennsylvania on Thursday and
over the weekend before conditions dry out to end the month. Rain
arriving late Wednesday night may start or mix with snow or sleet
over the northern tier. Temperatures should average near to
slightly below normal with some moderation likely into early
.NEAR TERM /THROUGH TONIGHT/...
As yesterday, the timing of a shortwave has increased/expanded the
cloud cover during the morning instead of the expected diminishing
trend due to mixing and downslope warming.
Residual stratocu with a few lake effect showers over the NW
Alleghenies should give way to decreasing winds and clearing
skies tonight as high pressure moves into the area. Upgraded to
freeze warning tonight which will likely end the growing season.
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
A surge of WAA pcpn ahead of low pressure tracking through the OH
Valley should overspread most of the area early Thursday. Have
increased POPs to near 100 percent based on multi-model consensus
and NMB output. As the WAA pcpn encounters a retreating cold
sector associated with departing high pressure, a period snow or
rain/snow mix may be likely at the onset over northern PA. Confidence
in early-season accumulations is low with the greatest risk over
the highest elevations. Timing would be favorable during the late
night and early morning hours. Despite QPF amounts in the 0.25 to
0.50 inch range, limited gridded snowfall to less than 0.5 inch
given marginal boundary layer profiles and surface temperatures.
Steadier rain should taper to rain/snow showers Thursday night on
the backside of the low. Northwest winds should also increase as
the low deepens into New England.
.LONG TERM /THURSDAY THROUGH TUESDAY/...
-- Changed Discussion --Low pressure center will move across the Lake Erie area thursday
with warm advection across central PA. Mixed precipitation in the
morning in the northeast will change over to rain. The southern
areas will break into the warm sector earlier in the day with
precipitation becoming scattered showers. Associated cold front
will sweep across PA Thursday evening with colder northwest flow
and maybe some lake-effect showers overnight mixing again with
some snow in the higher elevations across the central northern
tier. Flow changes during the day as winds begin to veer already
in advance of the next system approaching the Great Lakes. So
brief high pres ridge across Central PA Friday.
This next system looks to track a bit further north giving us a
warming trend. Northern tier may see some precip as the warm front
pushes northeast. Southern areas will be mild and relatively dry.
Another dry period will likely follow the weekend system with
signs of a warming trend into the first week of November.
-- End Changed Discussion --
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Persistent lake band rolled through the local area and still had
enough punch to make the ground wet, despite dry llvls. It looks
like it is finally drying up as it continues to slip S. Temps
actually a little ahead of fcst curve, but 925/850mb temps should
limit mixing/warming so that sfc temps should not turn out all
that much warmer.
Moisture flowing off of Lk Erie will continue to produce a varying
amount of stratocu across Central PA into this morning with the
most persistent cloudiness and lowest cigs across the higher
terrain from KBFD south to KIPT. Also due to this moisture, MVFR
cigs have developed at BFD as well as scattered rain showers. Both
of those should persist through the morning, before the flow
weakens and shifts by early afternoon.
Today should be similar to Monday, as the flow changes little in
direction but does get a little lighter. Diurnal heating and
resulting mixing within deepening boundary layer will cause cigs
to rise during the day, with widespread VFR conditions through the
Wed...Patchy AM fog possible.
Thu...Rain/low cigs possible.
Fri...AM showers/low cigs possible W Mtns.
Sat...Showers/MVFR CIGS possible NW Mtns.
Freeze Warning from 2 AM to 9 AM EDT Wednesday for PAZ026>028-