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Area Forecast Discussion (AFD)

Issued by State College, PA (CTP)

FXUS61 KCTP 211957

Area Forecast Discussion
National Weather Service State College PA
357 PM EDT Sun Apr 21 2019

An upper low overhead will slide south and east tonight. A 
ridge of high pressure will then build in and provide us with 
fair, dry weather for much of Monday and Tuesday. A cold front 
will bring a few showers or a thunderstorm late Tuesday and 
Tuesday night. Wednesday and Thursday should feature mainly dry 
conditions once again under the influence of another area of 
high pressure.


Diurnal heating and cool air aloft have combined to make
numerous weak SHRA over the central counties. Most concentrated
area of wetness is over the NC mtns attm. The upper low/shear 
axis seems to be over KLHV. Models slink it southward thru the 
evening. Loss of heating should dwindle the showers as the 
evening begins. Not much should be left on the radar by 9 PM. 
The western highlands should remain dry, but mainly cloudy. The 
clouds over the NErn mtns and Alleghenies should last much of 
the night, but clouds will be thinning over the SE and SC 
counties. Mins should range from u30s NW to 50F in the SErn 
cities as the wind gets lighter out of the NW, but not die off 


Clouds should decrease nicely in the morning, with only the
smallest chc of a SHRA in the aftn over the extreme eastern
towns. This will be due to the old upper low spinning back to
the north up/off the East Coast. Maxes should be 10F higher than
Sunday as 8H temps rise from 3-4C to about 6-8C through the day.
The wind will pick up to 5-10MPH out of the NW, strongest in the


There is decent model agreement in the next cold frontal system
moving through the area during the midweek period. Ahead of the
front on Tuesday, increasing clouds and mild as temps peak in
the 70s. Showers and sct tstms impact mainly NW areas Tue 
night, with diminishing showers surviving into the SE through 
early Wed, followed by a breezy and cooler day.

Beyond Wednesday, the weak frontal boundary washes out as it
gets nudged further south, keeping dry weather in place through
Thu. Thu will start of chilly, with dry air in place and light 
winds, lows likely dip into the upper 30s in the valleys of the
northern mountains.

Models then focus on a digging trough shifting eastward
across the GLakes for late week, with a transition to SW flow 
ahead of it as a weak surface low lifts up the Appalachians. 
Combined with a potent shortwave progged in on Friday, this  
will bring the next shot for showers/tstms followed by another
shot of cooler air and breezy conditions to start the weekend
with temps recovering back to normal by Sunday.


Upper low is right overhead and has helped SHRA form over the 
airspace between KIPT-KBFD-KUNV. These should expand a bit for
the next few hours to the space between KAOO and KMDT. Showers 
should end this evening, as the upper low slides south and east
of the area and we lose the heat of the day. Expect that the
only flight trouble overnight will be the possibility of low
clouds and a little fog over KBFD and KJST. But, the dry air and
plenty of drying time from this morning's rain until nighttime
stratification argues against it. Will include the first hints
of IFR for a few hours late tonight/early Mon. But, won't hit it
too hard.

Monday looks like widespread VFR as high pressure builds in 
despite the old upper low circling back north along/off the 
East Coast. Any light showers Mon should remain to the east of 


Tue...Mainly VFR. Scattered SHRA/TSRA possible far NW late.

Tue PM...Cold frontal passage, with accompanying SHRA/TSRA.

Wed-Thurs...No sig wx.

Thurs PM-Fri...SHRA/TSRA. Restrictions probable.




NEAR TERM...Dangelo/Lambert
SHORT TERM...Lambert