textproduct: State College

WHAT HAS CHANGED

* Added slight chance of a thunderstorm Wednesday PM * Added smoke Wednesday

KEY MESSAGES

1) Hot temperatures and high humidity will increase the risk of heat impacts through midweek

DISCUSSION

KEY MESSAGE 1: Hot temperatures and high humidity will increase the risk of heat impacts through midweek

No change to heat headlines for today and Wednesday. Max heat indices peak 100-105 range Wednesday afternoon. BL mixing and noticeable WNW breeze favored lowering dewpoints during the afternoons Tue-Thu. Some daily record high max temps may be challenged Tue-Wed. This hot spell will be shorter and less intense than earlier this month.

Hires model and ensemble guidance supports addition of smoke from upstream wildfires to the fcst with marginal visibility restrictions possible mainly along and to the north of I-80 Wednesday. These data also support a 15-20% chance of a stray thunderstorm Wednesday afternoon/evening.

As the short duration heat pattern breaks down, rounds of showers and thunderstorms are likely to impact CPA this weekend. Temperatures will return to historical averages for mid to late July into next week.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

Aside from some high clouds, not a lot going on before 18Z Wed.

A large area of elevated smoke at the current time from wildfires in Canada. Expect smoke to last into at least Wed. At least for the time being, the smoke at high levels not at ground level.

Borderline for LLWS later tonight for a few sites. Left LLWS out for now.

NGM model has been mainly dry since yesterday with any showers or storms. Any storms would be isolated and late Wednesday into Thursday, as a weak cold front drops southward. Any activity would be after 18Z Wed. The dry trend with the model makes sense, as dewpoints not as high as during the last heatwave. Also 500 mb heights are about as high as one can get, thus expect showers and storms to have a hard time getting thru the elevated mixed layer (EML) cap.

Outlook...

Thu...Mainly VFR, with areas of late night/AM fog. Some reduced visibility possible from smoke.

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

CLIMATE

Daily record high max temperatures July 14-16 _____________________________________________ SITE | 7/14 | 7/15 | 7/16 | --------------------------------------------- MDT | 101/1954 | 99/2024 | 104/1988 | --------------------------------------------- IPT | 102/1936| 103/1995| 103/1988 | --------------------------------------------- AOO | 95/1954 | 98/1995 | 100/1988 | --------------------------------------------- BFD | 89/1979 | 88/2013 | 97/1988 | --------------------------------------------- STCP1 | 93/1988 | 97/1887 | 102/1988 | ---------------------------------------------

CTP WATCHES/WARNINGS/ADVISORIES

Heat Advisory until 8 PM EDT this evening for PAZ004>006- 010>012-018-037-041-042. Heat Advisory until 8 PM EDT Wednesday for PAZ019-026>028-045- 046-049>053-056>059. Heat Advisory from 11 AM to 8 PM EDT Wednesday for PAZ035-036- 063>066.