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Area Forecast Discussion (AFD)

Issued by State College, PA (CTP)

                            
000
FXUS61 KCTP 262235
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
635 PM EDT Tue Mar 26 2019

.SYNOPSIS...
Dry weather expected through midweek, followed by an increasing
chance for rain showers Thursday into the weekend. Temperatures
will trend warmer through late week, with highs reaching the 
60-70 degree range by Saturday. A cool-down is expected early 
next week, as the calendar switches to April.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Sprawling high pressure will provide a clear and chilly
overnight. Went a little lower than guidance on dewpoints and 
min temps. Expect lows in the teens across northern PA by
daybreak on Wednesday, and possibly in some of the normally 
chillier spots across the south as well.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
High pressure will begin to drift east of the area on 
Wednesday, with a light southerly flow developing by afternoon. 
Combined with plentiful sunshine, this should ensure a pleasant
afternoon after a chilly beginning to the day.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Increasingly mild south to southwest flow ahead of a cold front
pushing through the Great Lakes will support a warming trend 
right through Saturday, with afternoon max temps reaching the 
mid- upper 50s on Thursday. 

The initial frontal boundary will have limited southern movement 
in response to a relatively flat and fast-moving upper trough 
that will swing across SERN Canada. The boundary will sag south 
into Northern PA (perhaps as far south as Central PA) Friday and
Friday night before lifting back to the north as a warm front 
on Saturday. 

Showers associated with this wavering boundary should stay very
near, if not mainly north of it, as heights aloft stay steady
state or build slightly. 850 mb temp anomalies will likely stay
within 1 sigma of normal across PA (and points north and west)
Thursday and Friday, thanks to the uncertainty of the exact 
position of the initial cold, then warm frontal boundary, and 
potential for showers. 

Temps aloft do warm to plus 1-2 sigma or 6-8C on Saturday, when
max temps will peak - around 60F across the NW mtns, and upper 
60s to around 70F in the southern valleys (which is a solid, 
15-20 deg F above normal). 

An amplifying and slightly neg tilt northern stream trough will
move east from the Glakes through the NE States Sunday and 
could slow the front enough to change the rain to a brief period
of wet snow/snow showers at the tail/western end Sunday into 
Sunday evening (especially if enough dynamic lift occurs to 
develop a weak wave along the frontal boundary). 

12Z GEFS plumes have a very low percentage of members with a 
light to moderate amounts of wet snow across Laurel Highlands NE
to the Endless Mtns of Ncent PA, though the most likely outcome
is for the front to push steadily through the region with just 
some scattered rain/snow showers across the Northern and Western
Mtns following Cfront, as the sharp upper trough swings 
through.

Temps will trend down to a moderate degree Sunday into Monday 
(at least to 5-10 Deg F below normal), with some scattered 
mountain snow showers and isolated rain/wet snow showers 
possible in the Central Valleys.

Temps will then bounce back several to 10 deg F Tuesday with 
dry weather thanks to southwesterly flow in the LLVLS, as a 
result of high pressure drifts east from the Southern 
Appalachians and becomes located off the Carolina Coast.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
For the late afternoon TAF update and the 00Z TAF set, no big
changes.

Massive area of high pressure will be overhead tonight and 
Wednesday, with very dry air.

VFR conditions should hold through Friday. 

.Outlook...

Wed...No sig wx.

Thu...Mainly VFR, but SCT SHRA poss NW along WFRONT.

Fri...SHRA N, mainly VFR elsewhere.

Sat...Mainly VFR, but SCT SHRA poss NW as CFRONT nears.

Sun...A wide range of conditions with a chance of showers.

&&

.FIRE WEATHER...
Dewpoints will be low for the rest of the day with the 
inversion forming by mid evening. Dewpoints through northern PA 
today and tomorrow will be in the single digits this afternoon 
and the low teens tomorrow. Expect RH/s today and tomorrow to be
in the 20s with the possibility of dropping to the teens 
through the afternoon hours. 

Dewpoints will be slightly higher through southern PA with 
readings in the low teens today and the mid to upper teens 
tomorrow. Expect RH/s to again drop to the 20s by late tomorrow 
morning and continuing through the afternoon hours. 
  
Winds will be 5 to 10 mph with gusts in the 15-25mph range. Gusts will 
cease early evening. Winds tomorrow will be lighter with no gusts expected
at this time. 

Southwesterly winds ahead of a cold front on Thursday should
bring an increase in dewpoints and humidity. The front should move through
Thursday night into Friday which will bring a chance 
of rain showers. 
MinRH will trend higher and range between 40-70 percent through
late week.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$
SYNOPSIS...Steinbugl/Evanego
NEAR TERM...Ceru/Evanego
SHORT TERM...Ceru/Evanego
LONG TERM...Lambert/Steinbugl
AVIATION...Ceru/Martin
FIRE WEATHER...Lambert/Ceru