TheClimateChanger

Yeah, this drought has been crazy. Looks like the Mississippi River will be seeing extremely low levels for a fourth consecutive fall: The Mississippi River is Set to Fall to Severe Levels for the Fourth Year in a Row I know the gauge at Memphis had three of its 4 lowest gauge readings in the last 3 years. Last year reached at least -10.41 feet in early November, but this chart was never updated. Crazy to just be blowing out the 1988 & 2012 droughts ever single year with hardly a peep? I'm sure dredging/channel deepening is aiding these very low gauge heights (i.e., the same volume of water may pass with a lower river level) but still..

Yeah, no end in sight either. Only another 0.10" so far in September, with little precipitation expected over the next two weeks. Only "abnormally dry" though according to NOAA.

Can definitely see that immediate, incredible impacts of that sensor change at FFC, which occurred on July 31, 2024. Based on this data, some locations may have cooled as much as 3.5 or 4F with the new sensors, but perhaps the aspiration was broken at the FFC site. They also changed (or are in the process of changing) the aspiration and solar radiation shields. Still even low temperatures dropped precipitously compared to ATL. June 2024 FFC: 92.9/68.2 ATL: 91.1/71.8 July 2024 FFC: 92.4F/73.0 ATL: 90.7/74.0 August 2024 FFC: 90.2/67.3 ATL: 92.0/72.3 Wow! ATL was 2.0F above 1991-2020 in August 2024, while FFC was 1.1F below 1991-2020.

What is so funny about this comment? It's a legitimate question/concern. Others have noticed this change as well on other weather forums: New ASOS Temperature/Dewpoint System This user noted that FFC, one of the original test sites, went from running warmer than ATL to colder: This user noted that Valentine (NE) Airport went from quite a bit warmer than his readings to about the same, if not cooler. He also notes the sudden proliferation of 100% humidity which was pretty much non-existent on the traditional sensors.

Looks like its going to vary widely from site to site. DTW has only cooled about 0.1F relative to its divisional mean, while CLE has cooled about 0.6-0.7F relative to its divisional mean compared to 2024.

Looking at the observations from Pittsburgh (PIT), it appears to be about a 1F cooling offset. But YMMV by location - definitely something to keep an eye out for. In June 2024, PIT was 72.8F, which was 3.9F above the Pennsylvania Southwest Plateau mean of 68.9F. In June 2025, PIT was 73.1F, which was 2.9F above the Pennsylvania Southwest Plateau mean of 70.2F. In July 2024, PIT was 76.5F, which was 3.3F above the Pennsylvania Southwest Plateau mean of 73.2F. In July 2025, PIT was 77.0F, which was 2.3F above the Pennsylvania Southwest Plateau mean of 74.7F. So it looks like relative to the Climate Division in which it is located, the new sensor shaved off 1F. Of course, the WBAN sites make up a decent proportion of the total stations in nClimDiv such that the offset may bias the divisional means unless it's been corrected by the pairwise homogenization algorithm. But if there is a residual bias in the divisional data, then the actual cooling offset may be a bit more than 1F. This is a big reason why state and divisional rankings were higher this summer than the cities, as the cooperative sites [and other stations] had no change in equipment and thus had more continuity of record. This is a reversal of recent years/decades in which cities tended to rank higher than the corresponding state and divisional data.

Do you think the new sensors are playing a role in the explosion of record lows? It's been wild to see these airports go from way warmer than everywhere to colder. 100% humidity observations went from basically non-existent to now I'm seeing some of these rural airports having eight hours a night at 100% with no weather (fog, precipitation).

Not really convinced these temperatures are accurate, but 30F was observed at Zelienople Municipal Airport.

28F at the Water Treatment Plant in Wauseon yesterday.

Yes, they haven't updated the spreadsheet since July 1, so I suspect they've swapped out most by this point. Just wondering if there's been any cool bias? I would argue, yes, but I'm wondering if anyone else has noticed this. It looks like the stations that were running on legacy sensors did much better for heat early on this summer versus the stations that had swapped in the new sensors. I wonder if we are going to have to temper our expectations for heat. Might be difficult to beat some of these 90s-2020s records if the sensors were reading hot. We've grown accustomed to breaking 100-150 year old records left and right. May not be the case moving forward. It look decades of climate warming before the ASOS HO-1088 hygrothermometer was regularly beating out the extremely warm biased HO-83. Even to this day, many summer records still date to that short era from about 1986-1995 (summer has substantially less natural variability, so biases have an outsized impact on the rankings). Might be a similar story for these new Vaisala sensors.

Lots of brown/gray dirty stuff showing up aloft on satellite across the Ohio and Tennessee Valleys. I guess this is smoke from somewhere?

What are you guys seeing with the new ASOS Vaisala 155E temperature and dewpoint sensors? They seem to read lower for max temperatures than the HO-1088, no? Also many more 100% humidity observations than previously? They rolled these out in most areas, but I haven't seen any sort of analysis to see how they compare to the older readings. When ASOS was rolled out, there was a lot of comparative analyses.

What are you guys seeing with these new temp/dewpoint sensors? I haven't seen much discussion on this, but they seem significantly cooler than the legacy sensors. And MUCH higher on humidity, at least in the overnight/mornings. All of a sudden, it's 100% humidity all the time at night around here. Never used to see ASOS throw up a 100% humidity before. Current Events

These new temperature sensors seem to be helping a lot with the colder lows: Current Events I was wondering why PIT went from being several degrees warmer for lows than me to about the same. Would never see all these 100% humidity observations with the legacy sensors.

Starting to see some drought showing up finally. I've only received about 1/2 of an inch since late July. Needless to say, lawns are quite brown and dormant, with some premature leaf droppage.

I think people need to temper their expectations a bit. It's not supposed to be nonstop 80s and 90s all summer long. I was reading P. Vanderbilt Spader's weather record for New Brunswick, New Jersey. He installed self-registering max/min thermometers on February 1, 1857, with periodic records back to 1847. And it looks very similar to those old Newark records you shared earlier this summer. I'm not sure what's going on here, but the summer temperature and precipitation regime looks more like New Brunswick, Canada than New Brunswick, New Jersey. Looks cold and wet. Very weird. Weather Record for New Brunswick, New Jersey, 1847-1890 - Google Books

Thanks for the update, Don. Akron, Ohio saw its driest month on record. Not just driest August, but driest of any month. Looking over the numbers, it looks like Ohio had either its driest or second driest August on record. Pennsylvania looks like a top 5 driest August as well. I didn't look at any other states, but it looks like dryness prevailed from Missouri to Maine.

Nice graphic. Just curious - Is this data from NCEI? What is the source for the last 30 days? I just took a look at precipitation data from all CoCoRAHS, Coops, and WBAN sites, and I think August will be among the Top 5 driest for Pennsylvania. It looks like it was either the driest or 2nd driest for the State of Ohio. The official NCEI values are scheduled for release next Tuesday, I believe. Average of 269 well-separated stations with no missing data is 1.94 inches. Average of 417 stations with not more than 5 missing days is 1.90 inches. This actually gives a pretty good estimate of what the official tally will be, so it looks like the statewide average will come in under 2" for the month, although gridding could make it close. There are only 4 Augusts with a statewide mean under 2" (1930, 1957, 1995, and 1951).

Rankings are also misleading these days too, because of so many recent years being anomalously warm. I suspect the CONUS finishes in 12th place for summertime mean. However, if it does so, it would be warmer than EVERY summer before 2006, except for the dust bowl juggernauts of 1936 & 1934. For those of us who were around in the 1990s, those seemed like insurmountable numbers. Not even scorching summers like 1995 and 1988 could surpass those. And so the 12th place finish really seems to undersell just how hot this summer was. In the 1990s or early 2000s, if someone came out and said this summer the CONUS would be hotter than every year except 1934 & 1936, everybody would recognize that is a VERY hot summer with massive cooling demands, etc. The media would be running constant stories about the heat and ramping up hysteria about climate change and a new dust bowl. That doesn't happen anymore. With that said, 1936 still holds the #1 slot (now tied with 2021). I think it's only a matter of time before we see a summer (or summers) that far surpass anything previously observed when you look at how many recent summers are in the top 10 nationally. It won't take much more warming to get us to that point.

If August comes in exactly at the 1991-2020 mean, summer would finish up around 73.22F. If August comes in at +0.2F, then the final summer tally would be 73.29F. If August comes in at +0.5F, the final summer value would be 73.39F. All of these are 12th warmest between 2018 (73.48F) and 2002 (73.16F). So I doubt it will finish in the top 11. Likely range 12th-15th, with 12th being most probable IMO. To put it another way, August can finish anywhere between 0.2F below and 0.7F above the 1991-2020 mean, and we'd still probably wind up in 12th place.

Should finish around 12th place IMO. The last PRISM update had us at +.22F for the month of August compared to 1991-2020 mean. Even if NCEI comes it at -0.3F below the 1991-2020 mean, we'd still have a summer mean of 73.12 (13th place). To drop to 15th place, August would need to come in around -0.5F below the 1991-2020 mean, which would give a summer mean of 73.06F. I don't think PRISM would be off that significantly, especially with the sign of the departure.

I haven't looked at any other states, but I suspect this will go in the books as the second driest August for the state of Ohio with a chance for #1. Precipitation is a bit more difficult to track as a statewide average, but it was very dry.

While summer is coming to an end on a bit of a disappointing note with very chilly temperatures to close out August, it will still go in the books as a fairly hot summer overall. Provisionally for August statewide means, I have the following: Michigan: 67.3, 42nd warmest Ohio: 70.8, 58th coldest Indiana: 71.9, 52nd coldest West Virginia: 70.1, 56th coldest Kentucky: 75.1, 59th warmest For meteorological summer, I calculate the following provisional statewide means: Michigan: 68.1, 19th warmest Ohio: 73.3, 10th warmest Indiana: 74.4, 22nd warmest West Virginia: 72.6, 6th warmest Kentucky: 76.6, 13th warmest

Down to 32 at Zelienople Municipal AP AWOS: https://forecast.weather.gov/data/obhistory/KPJC.html