textproduct: State College

WHAT HAS CHANGED

* Extreme Heat Warning upgrade for Fulton, Franklin, Perry, and Cumberland Counties

KEY MESSAGES

1) Breakdown of early July heat wave promotes an increased risk of damaging thunderstorm wind gusts and potential flash flooding through Independence Day weekend

DISCUSSION

KEY MESSAGE 1: Breakdown of early July heat wave promotes an increased risk of damaging thunderstorm wind gusts and potential flash flooding through Independence Day weekend

Final day of heat headlines with max heat indices reaching 100-110 degrees to the east of the Allegheny Plateau. The breakdown or ending process of heat waves is often marked by bouts of severe weather - and that will likely hold true through the July 4th holiday weekend.

Clusters of storms are projected to develop through the weekend in a very moist, unstable, modestly sheared environment and will have the potential to produce localized to perhaps widespread damaging wind gusts - especially of they can grow upscale and sustain strong cold pools. A threat for heavy to excessive rainfall will also be in play given high pwats and efficient rainfall/hourly rates.

SPC and WPC outlooks were largely unchanged for this cycle.

AVIATION /08Z SATURDAY THROUGH WEDNESDAY/

Generally VFR conditions are expected through 18Z. Thunderstorm clusters are fcst to develop during the afternoon and last into the late evening with occasional impacts possible at all terminals. Rounds of showers and thunderstorms will be possible through early next week as the pattern transitions from extreme heat back to more seasonal conditions for early July. Density altitude concerns due to the heat this afternoon should become less of an issue next week.

Outlook...

Sun-Wed...Restrictions possible in A.M. fog and P.M. T-storms.

CLIMATE

Williamsport tied their record max 7/3/26 (100F in 1966).

Record maxes for the next few days:

Station/Date...07/04...07/05 MDT.............104.....102 IPT.............100.....100 AOO............. 97......94 JST.............100.....101 BFD..............91......91

CTP WATCHES/WARNINGS/ADVISORIES

Heat Advisory until 8 PM EDT this evening for PAZ019-025>028- 034-045-046-049>053-058. Extreme Heat Warning until 8 PM EDT this evening for PAZ035- 036-056-057-059-063>066.