Weather WorldUpper Ste. Clair High School, PA Weather Forecast
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Upper Ste. Clair High School Weather Forecast
| OVERNIGHT | TODAY | TONIGHT | WEDNESDAY | WEDNESDAY NIGHT | THURSDAY | THURSDAY NIGHT | FRIDAY | FRIDAY NIGHT | SATURDAY | SATURDAY NIGHT | SUNDAY |
 |  | |  |  | |  |  |  |  |  | |
| Mostly Cloudy | Patchy Fog | Patchy Fog | Chance of T-Storm | Showers | Chance of T-Storm | Chance of T-Storm | Mostly Sunny | Clear | Chance of Showers | Chance of Showers | Chance of T-Storm |
| Lo: 65°FLo: 18°C | Hi: 80°FHi: 27°C | Lo: 61°FLo: 16°C | Hi: 80°FHi: 27°C | Lo: 61°FLo: 16°C | Hi: 79°FHi: 26°C | Lo: 59°FLo: 15°C | Hi: 79°FHi: 26°C | Lo: 61°FLo: 16°C | Hi: 80°FHi: 27°C | Lo: 61°FLo: 16°C | Hi: 75°FHi: 24°C |
| POP: 50% | POP: 70% | POP: 50% | POP: 40% | POP: 50% | POP: 50% | POP: 50% |
POP = Probability of Precipitation.
Weather Outlook Updated: 202 AM EDT Tue Aug 18 2026 
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Upper Ste. Clair High School Forecast Discussion
Issued: 1256 AM EDT Tue Aug 18 2026
Key Messages
1) Showers and lower probability thunderstorms return Wednesday into Thursday, featuring limited flood concerns.
2) Periodic rain chances and a seasonably cool pattern is favored for the late week to weekend period.
Discussion
... KEY MESSAGE 1... Surface ridging and drier zonal flow aloft today will be shunted southeast as a weak shortwave trough and associated surface cold front drop southeast Wednesday. Due to weak forcing at surface/aloft, models genera...