Preview of NWS' New Version of Forecast
This preview is not operational and should not be used for support decisions.

Area Forecast Discussion (AFD)

Issued by State College, PA (CTP)

                            
000
FXUS61 KCTP 220631
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
231 AM EDT Sat Jun 22 2019

.SYNOPSIS...
A ridge of high pressure over the Great Lakes will build slowly
eastward into Pennsylvania this weekend. This high pressure 
system will bring low humidity levels and plenty of sunshine to 
the Keystone state this weekend. 

A weak cold front will push across the region late Monday night
into Tuesday. Another area of high pressure is likely to build 
into the region by the middle of next week, and a warming trend
is expected.

&&

.NEAR TERM /UNTIL 7 AM THIS MORNING/...
Mostly clear skies, a diminishing breeze and wet ground from
recent rain is allowing patchy valley fog to form early this
morning across the northern mountains of Pa. Based on satellite
imagery and 06Z dewpoint depressions, have expanded mention of 
patchy fog to all areas north of I-80 and also the Laurel
Highlands. 

Readings already down to around 50F in the cooler valleys of the
Alleghenies, where some mid 40s are likely by dawn. Elsewhere,
expect most locations to bottom out in the low to mid 50s.

&&

.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM TODAY/...
High pressure and associated low-pwat air mass will continue to
build southeast from the Great Lakes later today, accompanied 
by fair and cool weather. Model sounding indicate mixing to 
800mb by afternoon, supporting max temps in the 70s with plenty
of sunshine. 

&&

.LONG TERM /TONIGHT THROUGH FRIDAY/...
Surface ridge remains in control on Sunday with moderating 
airmass in return flow. Slightly warmer temperatures and uptick 
in humidity means a slight chance of showers later Sunday night,
with more widespread showers expected on Monday, as a warm 
front pushes into the region. However, the better chance will 
come with a cold front Monday night or Tuesday. 850 temps 
surging to around 17C ahead of the cold front will likely push 
readings well into the 80s Monday. 

Still some model uncertainty with regard to how quickly the 
front clears eastern PA Tuesday, but the trend should be for 
drier/less humid air arriving as the day progresses. Building 
heights trending for midweek across the Mid Atlantic, with a
more summerlike pattern and above normal temps with  and a 
minimal chance of daily convection.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
Band of light showers continues to stream along a boundary
through the eastern half of the CWA. The heaviest of these
showers has brought MVFR vsbys to SEG. MVFR vsbys are possible 
at MDT, LNS and IPT until around 06Z. Due to convective nature,
have just left VCSH in TAFS. Otherwise VFR cigs will continue 
overnight. The latest HREF does produce an area of IFR cigs 
through NW PA. The current gusty winds should decouple shortly
after sunset, so around 01Z. After these winds slacken then the
patchy valley fog/ low stratocu through the NW should begin to
develop. Possible reduction times for BFD could be between 09Z 
to 13Z. 

High pressure and associated low-pwat air mass will build 
southeast from the Great Lakes into Saturday. This will mean 
widespread VFR conditions that will persist into at least 
Sunday night. 

.Outlook...

Sun...No sig wx expected.

Mon...Ceiling restrictions poss in rain showers.

Tue...Scattered showers.

Wed...No sig wx expected.

&&

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

&&

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

&&

$$
SYNOPSIS...Dangelo
NEAR TERM...Fitzgerald
SHORT TERM...Fitzgerald
LONG TERM...DeVoir/Fitzgerald
AVIATION...Ceru/Martin
CLIMATE...