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Area Forecast Discussion (AFD)

Issued by State College, PA (CTP)

FXUS61 KCTP 180041

Area Forecast Discussion
National Weather Service State College PA
841 PM EDT Mon Jun 17 2019

An unsettled and stormy weather pattern is expected across 
central Pennsylvania this week thanks to the close proximity 
of a slowly meandering stationary front over Pennsylvania. 
There will be multiple rounds of heavy downpours with the 
potential for flooding and isolated severe storms. After a cool 
day today, temperatures will get back closer to normal highs for
the rest of the week, but remain milder than normal at night.


Active night coming up with convection to the west headed
towards central PA. HRRR very consistent with some locally 
heavy rain with these storms in predawn hours. One hour FFG is 
generally 1.5-2" across the area, PWAT is running 1-2 STDs above
normal for June, and dewpoint 65-70F over the srn third+ of the
CWA. With multiple rounds of showers/storms expected, and the 
high moisture of the atmosphere right now, will continue with 
FFW even though nothing is immediately expected.

Min temps will vary from the upper 50s across the north, to 
upper 60s in the south.


The threat of flash flooding continues Tuesday into Tuesday
night, despite the possibility of a few to several hour lull in
storms late Tuesday morning and early Tuesday afternoon.

The Flash Flood Watch runs into Tue night as additional storms 
will ride along on the train later Tues afternoon/evening. The 
ground will only be getting wetter, and streams swelling. 

Temps may warm a little for the daytime on Tues, but that all
depends on the timing of the minor troughs aloft and how long we
can spend in between the rounds of rain/storms. Have kept the
forecast high in continuity, but could see things being a 
little cooler on Tuesday if the storms don't exit stage right in
the morning, and we get some breaks of sun.


Wet pattern with repeat rounds of rain along nearly stationary
frontal zone will continue to bring an increased flood risk to 
south central PA through midweek. 

A strong low pressure system for June will track across the area
on Thursday, and could bring a significant threat of severe
storms and flash flooding. 

Breezy and drier conditions will arrive into Friday as the
system continues to deepen as it moves away from the area. 

The latest guidance favors a dry start to the weekend before
more showers and storms return to the forecast on Sunday. 

Persistent cloud cover suggests highs running a bit below 
average through midweek while higher dewpoints favor muggy
nights/above avg lows. Near normal temps are forecast through
the weekend.


Abundant low level moisture and light wind in vicinity of a
stalled frontal boundary will lead to developing low cigs and
fog across central Pa overnight, along with the chance of
showers. Latest SREF probability charts indicate IFR conditions
will become likely late tonight over the high terrain of the 
Alleghenies from KBFD south through KJST. Further east,
thickening cloud cover could limit the extent of fog formation,
but can't rule out patchy IFR vsbys. 

Diurnal heating and resulting mixing of drier air aloft will
yield improving cigs/vsbys Tuesday, with predominantly VFR
conditions by mid to late afternoon. However, a brief reduction
will remain possible from scattered showers/thunderstorms. 


Wed...AM rain/low cigs possible.

Thu...AM rain/low cigs possible. Scattered PM tsra impacts

Fri...AM low cigs possible W Mtns.


Astronomical summer (solstice) begins Friday, June 21st at
1154AM EDT (1554 UTC).


Flash Flood Watch through late Tuesday night for PAZ017>019-


NEAR TERM...Ross/Lambert
SHORT TERM...Lambert/Evanego
LONG TERM...Steinbugl