Central PA Summer 2026 Discussion/Obs Thread

[Yardstickgozinya]

@TheDreamTraveler I was reading back over posts from the other day and noticed that I made a typo. Shortly after you posted about setting a record low, I posted a comment that said "New records are broken here and not very impressive ". I use a voice app that doesn't always copy my voice properly and sometimes I miss my mistakes.. What I wanted to say was "No new records we're broken here and not very impressive". I was actually referring to the comet thatI made about stretching and making fun of myself.., however I now realize it may not have came across as such. 

[mahantango#1]

Hazardous Weather Outlook
National Weather Service State College PA
312 AM EDT Sun Jul 26 2026

PAZ028-036-050-052-056-057-059-063-270715-
Juniata-Franklin-Snyder-Northumberland-Perry-Dauphin-Lebanon-
Cumberland-
312 AM EDT Sun Jul 26 2026

This Hazardous Weather Outlook is for central Pennsylvania.

.DAY ONE...Today and tonight.

Scattered strong to severe thunderstorms with gusty winds and
isolated instances of hail are possible this afternoon and evening.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

Scattered strong to potentially severe thunderstorms with localized
damaging wind gusts, hail and heavy rain will move into the Central
and Eastern Pennsylvania on Tuesday.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report significant hazardous weather.

Hazardous Weather Outlook
National Weather Service State College PA
312 AM EDT Sun Jul 26 2026

PAZ064>066-270715-
Adams-York-Lancaster-
312 AM EDT Sun Jul 26 2026

This Hazardous Weather Outlook is for central Pennsylvania.

.DAY ONE...Today and tonight.

Scattered strong to severe thunderstorms with gusty winds and
isolated instances of hail are possible this afternoon and evening.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

Scattered strong to potentially severe thunderstorms with localized
damaging wind gusts, hail and heavy rain will move into the Central
and Eastern Pennsylvania on Tuesday.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report significant hazardous weather.

[canderson]

Had a little rain shower early this am

[Mount Joy Snowman]

Low of 62. Boat day. 

[Voyager]

My forecast for today...sunny

My reality at this time...cloudy 

[ChescoWx]

One last great weather day before we turned unsettled and wet for a good part of the upcoming work week. Hopefully, most of us see some rain as many spots, especially across Northern Chester County missed the rains last week. Below normal temperatures look to continue all week but with increasing humidity with the rain. The sun looks to it will return by Friday. Note: below on the climate records there is an errant snow report in the data set that is being corrected.

[Jns2183]

Six Windows, Four Products, One Rainfall Puzzle in the Lower Susquehanna

The clearest finding is that the Lower Susquehanna’s apparent wetness depends heavily on the time window being examined. Lancaster and Cumberland looked dry during the most recent seven and fourteen days, but abruptly became wet when the period expanded to twenty-one days. That reversal occurred because the twenty-one-day window captured a substantial rainfall episode around July fourth through July tenth, while the shorter windows missed much of it. By thirty days, both areas were closer to normal, while the sixty- and ninety-day periods still reflected broader background dryness. Schuylkill experienced a weaker early-July wet surge and remained comparatively drier over the longer periods. There was therefore no single honest answer to whether the region was wet or dry without first stating the dates involved.

MRMS, PRISM, Stage IV, and IEM Reanalysis generally agreed on the broad placement of wetter and drier areas, particularly over the seven-day period and again by ninety days. Their seven-day accumulation estimates were fairly close, and their ninety-day totals converged to roughly ten and a half to eleven inches across the three forecast-zone domains. The most conspicuous disagreement occurred in Cumberland during the fourteen-day period. MRMS estimated about zero point eight nine inches of precipitation, while IEM Reanalysis estimated about one point two six inches, PRISM about one point two eight inches, and Stage IV about one point three six inches. MRMS was therefore describing a materially drier two-week period, not merely displaying the same rainfall through a different map resolution.

The products disagreed more strongly about percent of average than they did about actual rainfall accumulation. PRISM frequently appeared wetter relative to normal even when its estimated rainfall total was similar to the other products. Over seven days, for example, PRISM showed Lancaster near ninety-eight percent of average, Cumberland near one hundred one percent, and Schuylkill near one hundred thirteen percent. IEM Reanalysis showed those same areas near seventy-one, sixty-eight, and eighty-three percent. This demonstrates that some disagreement comes from the climatological normal used by each product rather than from the estimated rainfall itself. Accumulation describes how much precipitation a product believes fell, while percent of average combines that estimate with the product’s own definition of normal. Examining only the anomaly maps would therefore hide whether the argument concerns the rainfall numerator, the climatological denominator, or both.

The PACLIMATE station archive provides the observational context needed to determine which product was most accurate, but the station records must also be treated carefully. Stations such as Middletown-Harrisburg, Reading, Harrisburg Airport, Reading Airport, Cashtown, Newport, Mahanoy City, Lebanon, and Harrisburg Eight South-Southwest had little or no estimated precipitation during the recent one-year period and are the strongest starting points for validation. Other series contained many estimated days, including Landisville and the Lower Susquehanna Climate Division, where all three hundred sixty-five recent days were estimated. Those records remain useful for understanding and reproducing PACLIMATE behavior, but they are not equally independent gauge truth. The next analytical step is to mask the grids to the exact forecast-zone boundaries, extract each product at the reliable station locations, and calculate bias, mean absolute error, and root-mean-square error for every time period.

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[Jns2183]

I plan to do a whole series of posts in the next week but if anyone wants a little preview I did a big study of Schuylkill County climate and I plan to do the same one for each of the counties around here here is a link to the PDF.

https://drive.google.com/file/d/1MHxIs3rJgobWYai4cVpQR4d_XyRf-hFQ/view?usp=drivesdk

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