textproduct: State College

WHAT HAS CHANGED

*Minor edits to lower dewpoints and bump up wind today *Lower minimum temps tonight

KEY MESSAGES

1) Noticeably cooler/pleasant and rain-free start to the week 2) Warm/humid conditions return mid to late week with best odds for rain Thursday

DISCUSSION

KEY MESSAGE 1: Noticeably cooler/pleasant and rain-free start to the week

Refreshing airmass inbound behind cold front this morning with dewpoints in the 50s across northwest PA. Upslope stratus will dissipate over the Laurel Highlands early this morning with a general decreasing cloud trend and plenty of sunshine expected through the afternoon. Max temps will be 10 to 15 degrees lower/cooler vs. Sunday ranging from the mid 60s in the northern tier mtns to the mid 70s in the southern valleys along the MD line.

Strong radiational cooling pattern tonight into early Tuesday morning with very low pwats beneath area of high pressure migrating over CPA. Min temps with 3-handles are definitely in play in the usual northern tier cold spots with 40-50F lows anticipated elsewhere (4-8F below climo). This setup favors valley fog formation with localized visibility restrictions below 1 mile.

Wide 25-35 degree diurnal range fcst Tuesday with one more pleasant and comfortable afternoon with max temps in the upper 60s to mid 70s.

KEY MESSAGE 2: Warm/humid conditions return mid to late week with best odds for rain Thursday

Return SSW flow on the back side of the high pressure system will pump the dewpoints and moisture/humidity back up from mid to late week. Best rain/QPF signal at this time is on Thursday 9/17 as a weak front sinks southward from the eastern Great Lakes. If the front can push south of the MD line, most of Friday could be dry. Precip odds then steadily increase over the weekend ahead of next frontal system progression from the Great Lakes. Large scale upper level ridging should support a mid to late week warming trend with the largest hi/lo departure from climo Wed-Thu.

AVIATION /12Z MONDAY THROUGH FRIDAY/

Nice day shaping up as the sun is coming up. Low clouds at JST have been breaking up.

More information below.

Some lower clouds and isolated pockets of fog will be over the higher elevations sites like JST and perhaps BFD early this morning.

Lower conditions will give way to VFR conditions by late morning, as a strong cold front moves south and east of the area. Winds will pick up and become gusty about 14Z.

By around 23Z early this evening, winds will drop off with clear skies overnight. Dewpoints fcst to drop into the 40s across much of the area, so fog will be limited.

A dry day expected on Tuesday, as high pressure builds into the area.

Outlook...

Tue-Wed...AM fog possible, otherwise mainly VFR.

Thu-Fri...Increasing SHRA/TSRA chances, mainly on Thu.

CTP WATCHES/WARNINGS/ADVISORIES

None.