textproduct: State College

WHAT HAS CHANGED

* Expanded fog/mid morning stratus cloud cover in the Valleys of Central and Northern PA

KEY MESSAGES

1) One more day of comfortably cool/pleasant and rain-free conditions today

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

DISCUSSION

KEY MESSAGE 1: One more day of comfortably cool/pleasant and rain-free conditions today

Clear skies, light/variable wind and very cool temps in the upper 30s to upper 40s will lead a fairly extensive valley fog as a result of air/water delta Ts easily exceeding 20 deg F.

The fog will dissipate between 12-1330Z as temps bump up a few deg F and a light SE to southerly wind develops.

Otherwise, A ridge of high pressure stretched from the Upper Saint Lawrence River Valley south into Pennsylvania this morning. This weather feature will bring the region another pleasant late Summer day with a mix of sunshine and mid and high clouds, along with a light southeast to southerly breeze and comfortably low humidity. A wide 25-35 degree diurnal range is fcst for today with afternoon high temps ranging from the upper 60s North to mid and upper 70s in the Southern Valleys.

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

Fair and cool weather will continue for tonight, before humidity and temperatures steadily climb Wednesday and peak on Thursday.

There will be a high probability of showers and scattered thunderstorms late Wednesday into early Thursday across the Northwest Mountains and mainly during the daylight hours Thursday across Central PA and the Susquehanna Valley, 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 for the second half of 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 /18Z TUESDAY THROUGH SUNDAY/

Clear skies with some high cirrus will prevail through the rest of the afternoon. A few gusts in the 15-20kt range are possible at BFD and JST but will likely grow more infrequent through the rest of the afternoon. Calm conditions the first half of tonight with mostly clear skies at most terminals, although BFD may see some scattered showers in the late night/early morning. Reflected latest timing thinking in its TAF. Some models show showers lingering later into the morning there so updates on timing may be needed.

Model signal is once again relatively mute on early morning restrictions, however the possibility of some early morning low cloud formation is possible at IPT akin to this morning. Confidence isn't high enough (<30%) to include it in TAFs but more near term guidance may pick up on a cloudier signal. Should conditions get moist enough, some mist may also impact AOO and UNV in the 10-13Z range. Likewise, confidence in occurrence at this time is <30%, will reassess at further TAF packages.

Outlook...

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

Thu-Sun...Increasing SHRA/TSRA chances, mainly on Thu, restrictions possible.

CTP WATCHES/WARNINGS/ADVISORIES

None.