textproduct: State College

WHAT HAS CHANGED

* The threat for thunderstorms today has ended. * The heat advisory has expired.

KEY MESSAGES

1) Wildfire smoke from Ontario and northern Minnesota will trigger code red and orange air quality alerts Thursday and Friday

2) Thunderstorms with potential for locally heavy rainfall to start the weekend followed by cooling trend next week

DISCUSSION

KEY MESSAGE 1: Wildfire smoke from Ontario and northern Minnesota will trigger code red and orange air quality alerts Thursday and Friday

The smoke will continue to overspread the Commonwealth tonight into tomorrow. As of 8 PM, lowest air quality index (AQI) in PA was over the northeast corner, on the north side of a cold front that pushed through earlier this evening. The HRRR model shows this area of smoke pushing due south and impacting places east of I-99 through sunrise. However, the more dense smoke is still located over the Great Lakes. This batch of smoke is progged to arrive in the northwest mountains around sunrise and push southeastward across the rest of central PA during the day on Thursday.

The PA Department of Environmental Protection (DEP) has issued statewide Code Red Air Quality Alert for Thursday and Code Orange Air Quality Alert for Friday. These alerts are based on predicted 24 hour averages. Individual hours may see worse air quality.

KEY MESSAGE 2: Thunderstorms with potential for locally heavy rainfall to start the weekend followed by cooling trend next week

Thunderstorms are expected Saturday and could produce locally heavy rainfall and isolated flash flooding. PW values are forecast to reach the 1.5-2.0" range which suggests intense rain rates will be possible. A drying trend is expected Sunday. Additional bouts of rain/t-storms are possible into the workweek. Temperatures will trend near to below historical averages through late week with some noticeable cooler nights possible.

AVIATION /00Z THURSDAY THROUGH MONDAY/

Smoke from fires up in Canada and northern Minnesota will be across the area through Thursday. For western airfields (BFD/JST/AOO), smoke will transition from mostly elevated at 00z Thu to more sfc level through the day on Thursday as smoke comes in from the northwest. For eastern airfields (IPT/UNV/MDT/LNS), sfc level smoke already moved into IPT behind a cold front that pushed through earlier Wed evening. This smoke is expected to move south into at least LNS by 4z. MDT and UNV will be on the western periphery of this batch of smoke, but likely will also see vsby drop later tonight. The eastern airfields will see a reinforcing shot of sfc level smoke come in from the west in the late afternoon or early evening on Thursday. Aside from smoke, there may also be some valley fog late tonight into Thursday morning mainly in the north.

With a cold front across the southern tier of PA by 18z Thu, can't rule out a few popup showers or thundershowers (10 pct chc at JST, MDT, LNS) otherwise dry through the TAF period.

Outlook...

Fri AM...Mainly VFR, with areas of late night/AM fog. Some reduced visibility possible from smoke, with an isolated late- day SHRA/TSRA possible.

Fri PM-Sun...Chance of showers and t-storms, mainly during the afternoon hours on Saturday into early Sunday aft.

Mon...Mainly VFR.

CLIMATE

No daily records were tied or broken today (Jul 15).

Daily record high max temperatures for July 15th _______________________ SITE | RECORD/YEAR | ----------------------- MDT | 99/2024 | ----------------------- IPT | 103/1995 | ----------------------- AOO | 98/1995 | ----------------------- BFD | 88/2013 | ----------------------- STCP1 | 97/1887 | -----------------------

CTP WATCHES/WARNINGS/ADVISORIES

Air Quality Alert from midnight tonight to midnight EDT Thursday night for PAZ004>006-010>012-017>019-024>028-033>037- 041-042-045-046-049>053-056>059-063>066.