textproduct: State College

WHAT HAS CHANGED

* No significant changes to the forecast at this time

KEY MESSAGES

1) A rain-free weekend is on tap

2) Late summer warmth is still slated to end the month of August and start September next week, with severe weather and heavy rain threats also present

DISCUSSION

KEY MESSAGE 1: As a frontal boundary continues to slowly sink southward into the southern Mid-Atlantic this weekend, a ridge of high pressure will become our dominant weather feature. This will mean partly-mostly sunny days and mainly clear nights through Sunday. Given our recent wet stretch of weather and abundant soil moisture in many areas, late night and early morning fog will be common, particularly in the river valleys of northwest and north-central PA.

Temperatures/humidity levels will be seasonable and comfortable through Saturday. On Sunday, as low-level winds begin to switch into a more southerly direction, afternoon temperatures and humidity levels will start to creep upward.

KEY MESSAGE 2: During next week, there is good agreement amongst our various ensemble prediction systems that an expansive summer-time ridge axis at upper levels of the atmosphere will flex its muscle and expand northeastward from the southern states and middle of the CONUS.

There are two primary consequences for the sensible weather across the Commonwealth as a result of the above mentioned scenario. First, very warm and increasingly humid weather will settle in, even as we flip the calendar to September. Second, as a northwest flow aloft develops over much of the Mid-Atlantic and Northeast with embedded disturbances, and overruns the previously mentioned warm, sticky air, episodic showers and thunderstorms are expected. Although fine details are not yet apparent, this overall pattern often favors locally strong- severe thunderstorms and heavy downpours. As we draw closer to next week, we hope to add more clarity with respect to the timing and coverage of showers and storms.

AVIATION /18Z FRIDAY THROUGH WEDNESDAY/

A pleasant afternoon is in store for Central PA, with a light northwesterly breeze of 5-10 kts and partly cloudy skies with CIGs of 3-4 kft.

Under clearing skies and diminishing winds, with abundant soil moisture from recent rains, expect patchy fog to develop again overnight. The highest probability for fog will be across the northern and western valleys.

Once any lingering fog clears, expect another day with widespread VFR conds on Saturday. Winds will generally be light and variable.

Southerly flow will begin on Sunday and continue into early next week, as high pressure pulls off the East Coast. This will be accompanied by warmer temperatures and increasing humidity, which will bring a slight chc of showers and storms each day.

Outlook...

Sat...AM valley fog/restrictions possible, then VFR.

Sun-Tue...Mainly VFR. Isold SHRA/TSRA possible.

Wed...Sct SHRA/TSRA with brief restrictions possible.

CTP WATCHES/WARNINGS/ADVISORIES

None.