Area Forecast Discussion
Issued by NWS State College, PA-- Remove Highlighting --
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FXUS61 KCTP 211657
Area Forecast Discussion
National Weather Service State College PA
1257 PM EDT Fri Oct 21 2016
A wavy cold front will move east of the area this evening,
followed by windy and showery conditions for tonight through
Saturday night. The first bout of lake effect and upslope rain
and snow showers are possible over some of the higher ridge tops.
.NEAR TERM /THROUGH TONIGHT/...
The low and cold front just passed through Williamsport with a
wind shift and quick gust to 33kt. The rain is continuing in the
colder air west of the front but it is also becoming more spotty.
The HRRR keeps the off an on rain going even into the overnight
before finally beginning to wind down for the second half of the
overnight. Existing flooding issues are reportedly beginning to
improve so most of the flood watch has been canceled.
Something to consider for later tonight into early Saturday will
be the potential for the season`s first accumulating snows over
the RIDGETOPS of the Laurels and Northern Mountains. The guidance
has been persistent in bringing the coldest 850mb temps of the
season to date in behind our deep upper low. The potential for a
light slushy inch over the ridges is shown in the HRRR and NCAR
ensemble. The deterministic NAM and GFS are showing chances for
light accums over larger more general areas of the west and north,
this seems too generous given surface temps will be relatively
warm. Am thinking we will try to emphasize a light slushy accum
over the higher elevations only.
.SHORT TERM /SATURDAY/...
A cool and unsettled day is in store Saturday as persistent
northwest flow and progressively cooler boundary layer air is
forced into the region. In fact 850 mb temps remain below 0
throughout the day throughout central PA...and we`ll certainly be
looking at a few flurries mixing in with any shower spritzes in
the afternoon and evening over the higher terrain of the northwest
and northern mountains.
Maxes will range from the lower 40s northwest to the lower to
middle 50s southeast.
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Anomalous upper level trough will close off and take on a
negative tilt early in the period, with a deepening coastal
surface low tracking from southern New England north and west into
eastern Quebec. A seasonably cold and brisk northwest flow will
grip the area early this weekend with lake effect and orographic
rain and snow showers likely over the Northwest Mtns and Laurel
Highlands into Saturday night. There is still a low risk for
coating into Saturday night with accums very hard to come by
during the daylight hours this early in the season. 25-35 mph wind
gusts will add an additional blustery chill to below normal temps.
GFS/EC/CMC all show a fast-moving low diving through the Great
Lakes and Northeast into early next week. There is better
agreement with this system embedded in the WNW flow aloft passing
to the north of the area with max POPs over the far northern
tier. This feature will reinforce the cold air aloft at least into
Tuesday before strong warm advection commences through midweek.
The models show a low near the Great Lakes by the end of the
period with some hints a at a cold air damming pattern at low
levels with high pressure retreating into New England. Overall
not much pcpn expected Mon-Wed.
Temperatures will be noticeably colder by the weekend with highs
in the low 40s to mid 50s on Saturday. Expect some moderation on
Sunday followed by a steady to cooling trend with readings
averaging near to below normal through next Wednesday.
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
Widespread IFR/MVFR will continue behind the front today and even
overnight as a slow moving cold front slides east across the
flying area. The wind will turn the NW behind and become gusty in
the 10-20kt range today.
Sat...Scattered showers with restrictions NW. Brisk NW wind.
Sun...No sig wx.
Mon...Mainly VFR. MVFR with rain showers possible NW.
Tue...No Sig Wx.
Flash Flood Watch until 4 PM EDT this afternoon for PAZ037-041-
NEAR TERM...La Corte
SHORT TERM...La Corte