TheClimateChanger

It is sure looking like we are going to see our hottest temperatures of the season in September. It seems like the first half of September every year features temperatures rivaling or exceeding the summertime maxima these days.

Now this is an actual cold summer. On this date 41 years ago, the temperature dropped to 38 at Washington-Dulles Airport. Widespread frost, and even areas of freezing conditions, throughout the eastern US. https://www.washingtonpost.com/archive/local/1982/08/30/a-cold-snap-replaces-usual-august-steambath/8ae62318-f533-4734-8ef0-2f9d4a99edc5/

On this date in 1982, record low of 38 at Dulles. Frost and even freezing conditions at many places in the eastern U.S. https://www.washingtonpost.com/archive/local/1982/08/30/a-cold-snap-replaces-usual-august-steambath/8ae62318-f533-4734-8ef0-2f9d4a99edc5/

Looks like the Houston record may be short-lived.

Not be to be argumentative, we are on the same side here. But also keep in mind changes in observation time and site location. That chart is based on raw data from a threaded record. Observations moved to the airport in 1953, which is right around the time that graph shows a huge dropoff in 95+ days at Cedar Rapids. More importantly, the airport data is likely midnight to midnight. The min & max thermometers from the co-op data were likely reset in the late afternoon or early evening, as was common practice at the time. This is colloquially known as the TOBS error, or time of observation bias. It can significantly impact analyses of maximum temperatures, especially when looking at days above a certain threshold. Due to the time of observation, an extra hot day appears in the records after each hot period. Because if the high was 97F, the temperature at 5 or 6 pm would probably still be 93-95F, and then that's what the max thermometer is reset to read. The high the next day might only be 87F, but the high would be recorded as 95F. This can add a not insignificant number of hot days to the record, if left uncorrected. I'm not saying the number of very hot days isn't down somewhat, but I believe that graphic is exaggerated for these reasons.

@bluewave I bet dewpoint and apparent temperatures are rising though. Here are three plots for Des Moines (1936-present). Starting in the hottest month on record also probably effects this trend. Take particular notice of the trend in dew points. Surprisingly, despite the major heat, 1936 had the lowest mean dewpoint of record for any year from 1936 to the present. Thus, despite the temperature that month being 1.5F warmer than the second warmest year on record (2012), both 2012 & 2011 had higher mean apparent temperatures. There's two recent summers that "felt" hotter than 1936, even if the official numbers say they were cooler. Not enough emphasis is placed on the increased humidity that has also occurred. Just in the past 13 years, there have been two Julys that have presented Iowans with a more brutal combination of heat & humidity than July 1936, but you won't hear about it because the only thing ever reported is the dry bulb temperature. Actually, 2011 (which is only 5th warmest on record by mean temperature) has the highest mean apparent temperature of record. No data for 1901 or 1934, although given the drought conditions would expect them to have mean apparent temperatures that don't deviate significantly from the actual temperature. Temperature [+1.18F/century] Dew Point [+3.18F/century] Heat Index [+2.07F/century]

Yes, that can be done. I just did the analysis using the Iowa Environmental Mesonet site. Here is a link that should generate the plot below: Automated Data Plotter (iastate.edu) September dewpoints have risen substantially over that time frame at PIT, but not 5F. The chart below estimates a slope of +8.4F/century. Note that this data computes average dew point and average temperature by averaging the numbers observed at every hourly observation. You can also download the raw data to an Excel spreadsheet, which I did. For 1990-1999, the average September temperature was 63.9F, and the average dewpoint was 55.2F. For 2013-2022, the average September temperature was 66.5F, and the average dewpoint was 57.7F. An increase of 2.6F and 2.5F, respectively.

This is absolutely incredible. Since the ASOS was installed in 1997 at Bradford (McKean County) Regional Airport, the mean summertime maximum temperature is increasing at an astounding 13.8F/century and the mean summertime minimum temperature at an even more astounding 14.7F/century. May be too short of a period to draw any conclusions, but still surprising.

Lost a tree in the storms overnight. Sounds like there were a lot of downed trees areawide.

Much of northeast Ohio now covered with tornado warnings.

Mesoscale Discussion 2042 NWS Storm Prediction Center Norman OK 0833 PM CDT Thu Aug 24 2023 Areas affected...Northern Indiana...Northern Ohio...western Pennsylvania...western New York Concerning...Severe potential...Severe Thunderstorm Watch likely Valid 250133Z - 250300Z Probability of Watch Issuance...80 percent SUMMARY...A Severe Thunderstorm Watch downstream of WW656 is likely shortly. DISCUSSION...A broken line of severe storms continues to move southward out of Michigan and across Lake Erie. Consensus within hi-res guidance is for this line to continue to track southward into portions of northern Indiana, northern Ohio, western Pennsylvania, western New York within the next couple of hours. Downstream of this line, there is a gradient of MLCAPE around 1500-3500 J/kg and deep layer shear 35-45 kts. The environment will continue to be supportive of severe storms and risk of damaging winds along with isolated embedded circulations and a tornado or two. A downstream watch will be needed shortly. ..Thornton/Hart.. 08/25/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BUF...CTP...PBZ...CLE...ILN...DTX...IWX... LAT...LON 41518508 41958507 42108334 42718217 43268107 43227964 43187928 42957884 42657845 42047859 41647892 41267957 40838018 40478091 40358120 40378168 40478235 40658301 40868378 41138471 41518508

Mesoscale Discussion 2042 NWS Storm Prediction Center Norman OK 0833 PM CDT Thu Aug 24 2023 Areas affected...Northern Indiana...Northern Ohio...western Pennsylvania...western New York Concerning...Severe potential...Severe Thunderstorm Watch likely Valid 250133Z - 250300Z Probability of Watch Issuance...80 percent SUMMARY...A Severe Thunderstorm Watch downstream of WW656 is likely shortly. DISCUSSION...A broken line of severe storms continues to move southward out of Michigan and across Lake Erie. Consensus within hi-res guidance is for this line to continue to track southward into portions of northern Indiana, northern Ohio, western Pennsylvania, western New York within the next couple of hours. Downstream of this line, there is a gradient of MLCAPE around 1500-3500 J/kg and deep layer shear 35-45 kts. The environment will continue to be supportive of severe storms and risk of damaging winds along with isolated embedded circulations and a tornado or two. A downstream watch will be needed shortly. ..Thornton/Hart.. 08/25/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BUF...CTP...PBZ...CLE...ILN...DTX...IWX... LAT...LON 41518508 41958507 42108334 42718217 43268107 43227964 43187928 42957884 42657845 42047859 41647892 41267957 40838018 40478091 40358120 40378168 40478235 40658301 40868378 41138471 41518508

Nice. Also looks like there have only been 4 days [in 3 years] with 100+ readings later in the calendar year. It was 101 on September 1 & 2, 1953, and 100 on September 7, 1939 & September 7, 1960. For the record, it was also 100 on this date in 1947.

Looks like there is a chance next Wednesday could stay below 70F. I'm a little doubtful at this point, but it would be the first in over two months (6/27) should it occur.

Me? I was just asking a relevant question about the current weather conditions. I was curious as to whether there was any validity to my observation, and if so, what the causes might be.

Minor earthquake near Cleveland this morning: Earthquake recorded this morning near Madison (cleveland19.com)

Just by way of example, here is the July 1995 heat wave. There was a much more pronounced heat island effect at O'Hare, and especially Midway, relative to Rockford than in recent heat waves (including the current one). RFD ORD MDW

Are low temperatures becoming more uniform between urban areas and suburban/rural areas? I feel like in the past, it was common for their to be a 5-10+ degree difference in low temperatures during heat waves between the big urban airports and surrounding sites. And now it looks like most places are within a couple degrees of each other. O'Hare and Midway were 81, while suburban Kenosha was 82 and Waukegan was 83. Rockford was 79. Janesville and Madison, in Wisconsin, both 81. Admittedly, the typical cool spots (Aurora) were still somewhat cooler at 76, but most places were right around 80. Has anyone else noticed this change, or am I misremembering?

Many gusts over 40 knots over the lake. Huron Harbor Lighthouse had a peak gust of 56 knots, and a C-MAN station on South Bass Island observed a peak gust of 51 knots. A 56 knot gust was observed earlier at the buoy north of Lorain.

Severe Weather Statement National Weather Service Cleveland OH 1121 PM EDT Wed Aug 23 2023 OHC043-077-240345- /O.CON.KCLE.TO.W.0026.000000T0000Z-230824T0345Z/ Huron OH-Erie OH- 1121 PM EDT Wed Aug 23 2023 ...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1145 PM EDT FOR NORTHWESTERN HURON AND ERIE COUNTIES... At 1120 PM EDT, a severe thunderstorm capable of producing a tornado was located between Bellevue and Kimball, or 9 miles northwest of Norwalk, moving south at 15 mph. HAZARD...Tornado and quarter size hail. SOURCE...Radar indicated rotation. IMPACT...Flying debris will be dangerous to those caught without shelter. Mobile homes will be damaged or destroyed. Damage to roofs, windows, and vehicles will occur. Tree damage is likely. This dangerous storm will be near... Bellevue around 1130 PM EDT. Other locations impacted by this tornadic thunderstorm include Monroeville. PRECAUTIONARY/PREPAREDNESS ACTIONS... TAKE COVER NOW! Move to a basement or an interior room on the lowest floor of a sturdy building. Avoid windows. If you are outdoors, in a mobile home, or in a vehicle, move to the closest substantial shelter and protect yourself from flying debris. Torrential rainfall is occurring with this storm, and may lead to flash flooding. Do not drive your vehicle through flooded roadways. && LAT...LON 4132 8281 4132 8271 4123 8270 4123 8284 4129 8284 TIME...MOT...LOC 0320Z 014DEG 12KT 4130 8277 TORNADO...RADAR INDICATED MAX HAIL SIZE...1.00 IN $$ Sullivan

At 10:35, a 60 mph wind gust was observed at Port Clinton Keller Field.

Severe Weather Statement National Weather Service Cleveland OH 1055 PM EDT Wed Aug 23 2023 OHC043-077-093-123-143-240315- /O.CON.KCLE.SV.W.0154.000000T0000Z-230824T0315Z/ Huron OH-Ottawa OH-Erie OH-Sandusky OH-Lorain OH- 1055 PM EDT Wed Aug 23 2023 ...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1115 PM EDT FOR NORTHERN HURON...OTTAWA...ERIE...NORTHEASTERN SANDUSKY AND SOUTHWESTERN LORAIN COUNTIES... At 1054 PM EDT, severe thunderstorms were located along a line extending from Sandusky to near Wakeman, moving southwest at 20 mph. HAZARD...70 mph wind gusts and quarter size hail. SOURCE...Emergency management. There have been several reports of tree damage in Sandusky. IMPACT...Minor damage to vehicles is possible. Expect considerable tree damage. Wind damage is also likely to mobile homes, roofs, and outbuildings. Locations impacted include... Sandusky, Norwalk, Western Vermilion, Vermilion, Port Clinton, Kelleys Island, Put-In-Bay, Bellevue, Wellington, Northern Milan, Milan, Wakeman, Castalia, Oberlin, Catawba Island, Pittsfield, Monroeville, Marblehead, Berlin Heights and Bay View. PRECAUTIONARY/PREPAREDNESS ACTIONS... For your protection move to an interior room on the lowest floor of a building. Torrential rainfall is occurring with these storms, and may lead to flash flooding. Do not drive your vehicle through flooded roadways. && LAT...LON 4159 8262 4155 8265 4153 8265 4142 8249 4147 8238 4118 8211 4111 8220 4110 8240 4133 8297 4148 8298 4155 8288 4165 8283 TIME...MOT...LOC 0254Z 032DEG 16KT 4144 8270 4119 8247 THUNDERSTORM DAMAGE THREAT...CONSIDERABLE HAIL THREAT...RADAR INDICATED MAX HAIL SIZE...1.00 IN WIND THREAT...OBSERVED MAX WIND GUST...70 MPH $$ Sullivan

High water rescues on I-90 in Lakewood, as slow moving thunderstorms have dumped up to 4 inches of rain.

Maybe I'm confused about criterias over there. The forecast for Allen County, Indiana calls for heat index values up to 106, even though there are no alerts in effect. For clarification, alerts currently in effect. There is an excessive heat warning for tomorrow.