Roger Smith

Just looking at the 00z 500 mb chart, it shows 597 dm high right over my location. I for one welcome our alien visitors. There's a slug of 594-97 thickness shown over south central OR and the 588 dm thickness is basically overlapping the 594 dm height oval (except in the southern portion where it continues south into CA). The GEG sounding has a -4C temp at 500 mb. The 850 mb chart has readings in the mid 30s but you have to keep in mind most of southern BC except for valley floors is land up to and even above the 850 mb elevation, where I live is probably around 900 mb. So my 42 C air temp would be a 900 mb temp I suppose. The nearby ski hill is probably within shouting distance of 850 mb and up there it is probably around 35-37 C. Took some pictures during the heat to illustrate this thread (a picture is worth a hundred words in my case).

Looks like that all-time Canadian record lasted one day, it's edging up to 47 C at Lytton BC now. Probably the most remarkable temperature on the list is 40 C in downtown Victoria BC. YVR maintains a sea breeze and is stalled at 31 C, however, as I said that reflects almost nothing about what two million people in greater Vancouver have outside their homes, the range for 90% of the urban area is probably 36 to 41 C at present. A few lucky seafront areas are in the 20s. Another traditional hotspot, Osoyoos, is up to near 43C and Warfield near my location is 42.2 C. Have to say I am acclimatizing to this, if you take a very cold bath about twice a day and don't exert yourself, it feels comfortable enough inside, we don't have a thermostat because there's no heating system to control here but it feels like it's about 32 C (90F) inside. Somebody called to ask if I was okay being an old person, so I said sure thing, this is nothing compared to 1936 in North Dakota, had to take off the t-shirt for that one.

I was not aware of any predictions of 112 for SEA unless they were humidex predictions (which verified near that level). I watch local SEA and GEG t.v. news and weather segments and the general range of predictions was accurate in all regions (same in BC). We knew this was coming a week ago and it has been on the news cycle in terms of get ready for about a week. All of these coastal urban areas have very large variations from one part of town to another, so the airport high is just part of a greater complexity. YVR is more marine-modified than most of the urban area it represents and a better idea of conditions for most of the two million residents of greater Vancouver can be gained from the Pitt Meadows station which is inland (Abbotsford even more so). For Seattle and Tacoma, SEA is also somewhat more exposed to sea breezes than large parts of those two cities but at the same time a few neighborhoods of Seattle are probably more exposed than SEA to sea breezes. Here again, in some heat waves you'll get a better representative temperature from McChord Air Force Base which is situated between the two cities and inland several miles. The bottom line is, it is dangerously hot in a coastal region that does not get a lot of severe heat waves even in peak season. Our climate is a bit different from the east coast, we don't just glide into summer through June, quite often there's a long delay of full summer heat and drought (which is normal there for about 6-8 weeks) until the second half of July. Even in the hotter interior regions, June is usually quite temperate and the main heat arrives in mid to late July and persists through most of August. That's the main story here, a full on midsummer heat wave in June is considered odd here, I wouldn't imagine it would seem that odd in NYC or DC (although mean temps are still rising in late June and so are daily records, the differential is larger out here at least by the coast).

I disagree to some extent that this is just a bell curve shifter, it's a singularity and there was nothing in the June climate records within 5-6 deg of this on a regional scale, so the shift is more to do with a longer season than a former climate moved over to the right, in my opinion anyway. I am right under the H today, very close to the station "Warfield" in the Trail area listed in Don's report above. Just in from a morning walk and would say it is well over 95 F at 1100h local time, feels oppressively hot out of the shade. Thank goodness we have very little humidity this far inland, the situation is probably quite a bit worse in the large cities near the coast because they are getting moderately high dew points in the 60s, here it's more like 50F. Some were commenting on the amount by which daily records had fallen yesterday. Part of that is simply that June 27 didn't produce any real heat in past years although I see Warfield was only slightly over a 2015 record. Other dates a little later into the summer would have had narrower margins for these records. The same will happen today. Also just because it gets hot in this region is no guarantee that coastal locations will set records, in some heat waves they hold on to sea breeze or marine layer conditions, as shown in coastal Oregon where the southern half of the coast stayed quite moderate while Astoria got up to 101 with a land breeze. In this heat wave the severity is overwhelming the sea breeze protection, the Straits of Juan de Fuca and Georgia are turning into the Sea of Cortez del Norte with coastal 40 C and over water 25 C readings. The outer coast of Vancouver Island still has some locations in cooler marine layers and probably dense fog as water temps out there are only in the 50s to low 60s F. Will not be surprised if our new national record lasts only one day and gets replaced today. Warfield is not quite as rocky a location as the three traditional record setting spots (Lytton, Lillooet and Osoyoos north of Omak WA), but it does heat up with a southeast exposure and keep in mind this thermometer is 400 feet above the Columbia River where Trail, BC is located; I often notice on car thermometers that it is 1-2 C warmer in Trail than in Warfield, it is very rocky around Trail partly because the smelters there killed off the first growth of the forest cover and what they have since improvements were made resembles a Utah open woodland setting without large trees. Working on part three of that study of mean temps, we'll see if it overlaps the maxima or the minima better.

That aspect was covered in the previous post to the minima. The point is that mean temperatures are an average of ,max and min, so I am interested in understanding how record high mean temperatures will be affected by differential changes over time in max and min. The study of mean temps has not been posted yet.

Without going into quite as much detail, the rank order of highest seven-day average minimum values at NYC is as follows: 1. 2013 __ 79.29 _______t25 1876 __ 75.71 2. 1896 __ 79.14 _______t25 2018 __ 75.71 3. 1988 __ 78.14 _______t27 1972 __ 75.43 4. 2011 __ 77.86 _______t27 2020 __ 75.43 5. 1908 __ 77.71 _______t29 1892 __ 75.29 6. 1999 __ 77.43 _______t29 1911 __ 75.29 7. 2006 __ 77.29 _______t29 1917 __ 75.29 t8 1905 __ 77.14 _______t29 1948 __ 75.29 t8 1906 __ 77.14 _______t29 1955 __ 75.29 10. 1980 __77.00 _______t29 1961 __ 75.29 t11 1993 __76.86 ______ t29 1982 __ 75.29 t11 2016 __76.86 ______ t29 2005 __ 75.29 t13 1898 __76.71 ______ t37 1884 __ 75.14 t13 1981 __76.71 ______ t37 1944 __ 75.14 15. 1995 __76.57 ______ t37 1973 __ 75.14 t16 1885 __76.43 ______ t40 1890 __ 75.00 t16 1952 __76.43 ______ t40 2015 __ 75.00 t16 1953 __76.43 ______ t42 1887 __ 74.86 t16 2010 __76.43 ______ t42 1983 __ 74.86 t20 1977 __76.29 ______t42 1984 __ 74.86 t20 2002 __76.29 ______ 45. 1870 __ 74.71 t22 1909 __76.14 ______t46 1901 __ 74.57 t22 1979 __76.14 ______t46 1907 __ 74.57 24. 2001 __75.86 ______t46 1938 __ 74.57 ____________________________________________________ Most of the years with the top average maxima are in this list, but quite a few rather average cases (for daytime max) are sprinkled in with them, indicating that some cloudier or more humid spells were included where average max may have been closer to 90F. The frequency distribution is somewhat skewed towards two intervals, the decade of 1901-10, and the recent past. As to the decade of 1901-10, it is possible that site interference was playing a role as the station was moved into Central Park from a more urban setting around 1919-20 (or so I am told). So with that in mind, here's the distribution of these top 48 years for average minimum in summer heat. The following chart shows the ranks of the distributed cases: 1869-1900 __ 2, t13, t16, t25, t29, t37, t40, t42, 45 1901-30 _____5, t8, t8, t22, t29, t29, t46, t46 1931-60 ____ t16, t16, t29, t29, t37, t46 1961-90 ____ 3, 10, t13, t20, t22, t27, t29, t29, t37, t42, t42 1991-2020 __ 1, 4, 6, 7, t11, t11, 15, t16, t20, 24, t25, t27, t29, t40 ________________________________ So unlike the average maxima, these warmer summer nights are increasing in frequency and severity (note the depth of high ranked cases as well as the frequency). The average for this statistic is 73.34. In the intervals above, the means are 73.4, 72.7, 72.7, 73.2, and 74.4 which is fairly consistent with urban heat island growth combined with site alterations to reduce direct effects. So this suggests that the warmer summer overnight spells are contrasting with recent cases of cooler summers at other times, such as 1992, 2000, 2003, 2004, 2007, 2009 and 2014. After some rest and reflection I will tackle the question of how overall means for these summer heat waves compare. I think it will be a blend of the two different patterns seen. Some further analysis possible now that I have created a similar list of 48 hottest years for weekly averages (not quite the same as 48 top heat waves, 1988 for example had two in the range, and there are two cases in my list that could be taken as two separate heat waves, but as we are studying the frequency of events, a yearly count seems appropriate). Of the above list of top 48 warm overnight low averages, the following ranks do not match a high max top 48, and from inspection I could say that when a year produces both, they are usually in the same heat wave if not exactly the same seven days. So I have listed the 15 of 48 that do not overlap with the mean maximum peak for that year. 5th 1908 _ 89.00 t8 1905 __ 90.43 t8 1906 __ 88.29 t13 1898 __ 91.43 t22 1909 __ 89.71 t22 1979 __ 89.86 t25 2018 __ 91.57 t27 2020 __ 90.14 t29 1982 __ 92.00 t37 1884 __ 89.57 t40 1890 __ 88.14 t42 1887 __ 89.29 45 1870 __ 89.71 t46 1907 __ 87.71 t46 1938 __ 90.86 __________________________________________ These include all five summers in the period 1905-09, and two recent ones (2018, 2020). The somewhat reduced heat of the daytime components may have been due to either cloudiness holding highs down, or the flow pattern favoring sea breezes that would limit the peak warming on at least some days. This means of course that 15 of the 48 hot daytime contenders did not make the list of warmest minimum averages. Those include 1933, 1936, and 1966. Clear skies during those heat waves probably allowed for just enough cooling at night, and this observation is supported by the lack of daily records set, it wasn't a case where several nights were very oppressive and one or two brought the average down, more that the base level of overnight lows was set in the mid rather than high 70s. Another top heat wave (1944) did qualify here but was well down the list from its daytime rank. _______________________ the final segment will be posted by July 2nd, as I compare the top 48 mean seven-day peaks with these two lists. By mathematics you would expect about a 40-8 outcome in each case but we'll see how that develops.

This may illustrate the point I was making about daytime and overnight temperatures ... Top 91 NYC warm weeks 94.0 avg or higher (and top 48 ranked years for high 7d avg max) _ equates to top 25 NYC warm spell years (since many entries have 3-5 consecutive warm 7d intervals overlapping) _ (any qualifying value is highest of a number of consecutive values, those which belong in top 30 are added to entry, the entry is given the dates of the highest qualifier so the dates of the other entries can be determined by counting back or forward from that as needed -- all weeks that exceeded the indicated 30th place value or a higher ranked value with ties through 30th place are in the table. ... this table cuts off at 94.0 F) late June into July 1966 could be considered two separate hot spells but it was probably experienced as one uninterrupted month-long hot spell that was more about duration than extreme values. A few notes are added about Toronto heat wave comparisons, in the 1953 heat wave below, not much space so will add here that averages around 95F were noted for Aug 27-Sep 2 and Aug 28-Sep 3. There were heat waves in late July, August 1916 and 1918 that made top ten for Toronto that failed to reach this level for NYC despite one or two notably hot days individually. But otherwise the Toronto list would not be very much different from this NYC list. Heat waves in 1955, 1966 and 2002 could be divided into two apiece but with little cooling between them, they are shown as unified entries. A second heat wave for 1953 has the rank "2b" to keep the ranking oriented to years and not to specific heat waves. ranks of hottest mean daily max (with consecutive 94+) __ ranks of all noted weekly intervals (consecutive) 1. July 15-21 1977 _ (96.86) (96.71) 98.43 (97.29) (95.71)(94.71) _ t10 t12 1 t5 t22 t50 ___ 12 days covered by 6 intervals 2. Aug 27*-Sep 2* 1953 _ (94.57)(95.86)(96.71) 98.29 98.29 (97.14)(95.29) _ t53 21 t12 t2 t2 7 t31___ 13 days covered by 7 intervals 3. July 7-13, 1993 __(96.29)(96.57)(97.00) 98.00 (97.00)(95.57)(94.00) ___19 t14 t8 4 t8 28 t83____ 13 days covered by 7 intervals 4. July 17-23, 1991 _ (94.71) (96.57) (96.43) 97.29 (96.43) __ t50 t14 t17 t5 t17 _____ 11 days covered by 5 intervals 5. Aug 10-16 1944 _ (94.29) (95.71) 96.86 (96.57) (94.14) __t66 t22 t10 t14 t78 __ 11 days covered by 5 intervals 6. July 17-23 and Aug 1-7 1955 __ (94.00) 95.43 ... ... (95.00) 96.14 (94.00) ___ two hot spells with only slight cooling between them ___________________________________ t83 t29 _____________t37, 20, t83 _________ 8d 2int, 13d separated then 9 d covered by 3 intervals t7. June 27 - July 3 1966 _ 95.71 (95.29) (94.57) (94.43) (94.29) (94.86) _ t22^ t31 t53 t59 t67 t47 __ 4d 91-93 then July 7-9 ... ___ July 8-14 (94.29) 94.57 (94.14) ___ t67 t53 t78 ___w4 more d 90-93 _ 18 or 22 days covered by 9 intervals and 7 nearly as hot ____ ____ _____ _____ ______ _______ _____ _____ ____ ____ ___ ___ also six days before the first interval 91-92F avg (total 28d) t7. Aug 28 - Sep 3 1973 __ (94.57) 95.71 (95.00) ______ t53 t22* t37 ________ 9 days covered by 3 intervals (93.86 values at each end) t7. July 17/18-23/24 2011 (94.29) 95.71 95.71 ________t67 t22* t22* _______ 9 days covered by 3 intervals 10. June 27 - July 3 1901 _ (95.00) 95.43 _____________ t37 t29^^ ___________ see note (extended but not as intense) t11. Aug 9-15 1988 _(94.00) 95.29 (94.29) ____________ t83, t31, t67 __ an earlier hot spell peaked at 93.57 July 5-11 t11. Aug 4-10 2001 ________95.29 (94.14) _____________t31 t78 _____________ 8 days covered by 2 intervals t13. Aug 5-11 1896 _ (94.29) 95.14 (95.00) (94.71) ____t67 t35 t37 t50 _____10 days covered by 4 intervals t13. July 3-9 2010 __ (94.00) 95.14 (94.29) (94.00) _____t83 t35 t67 t83 _____10 days covered by 4 intervals t15. June 1-7 1925 ______ 95.00 _______________________t37** _______________ see note t15. July 28 - Aug 3 1933 _(94.43) 95.00 ______________ t60 t37 _________________8 days covered by 2 intervals t15. Aug 24-30 1948 _____(94.43) 95.00 (94.57) _______t60 t37 t53 _____________ 9 days covered by 3 intervals ___ ____ _____ ______ ________ _________ _____________ ________ ______ ____ ____ __ Toronto avg 95 F (Aug 23-29) t15. July 12-18 1983 _____ 95.00 (94.00) ______________ t37 t83 ________________ 8 days covered by 2 intervals t15. July 23/24-29/30 1999 __ 95.00 95.00 (94.00) (94.14) _ t37 t37 t83 t78 ___ 10 days covered by 4 intervals t20. July 8-14 1936 _(94.29) (94.43) 94.86 ____________t67 t60 t47 _____________ this was Toronto's hottest week (99.29) t20. July 16-22, 1980 _ (94.43) 94.86 _________________ t60 t47 ___ (a second hot spell averaged 93.57 Aug 3-9). t22. July 29 - Aug 4, Aug 12-18 2002 _ (94.43) ... (94.29) 94.57 (94.29) _ t60 ... t67 t53 t67 __ entered as one (slight inter- cooling) 23. July 14-20 2013 _______ 94.57 (94.43) _____________t53 t60 __ note this is the most recent entry before 30th 2b July 15-21 1953 _______ 94.43 ____________________ t60 ______ separate event from late Aug-Sept 1953, which ranked 2. 24. July 7-13 1981 ________ 94.14 _____________________t78 25. July 1-7 1911 _________ 94.00 _____________________ t83 ________________ Toronto avg 98 July 1-6 (after this point in the list, I have added years ranked 26 to 48 to provide a similar data base to the minimum temperature analysis posted later in the thread ... these are not entirely heat waves 24 to 48 in rank order because as noted above, a few years produced two or even three non-qualifying separate heat waves that would insert themselves into this list. But the maximum values above can be read in the same way as the rank ordered (1-25) highest seven-day average minima.) The numerous ties are created by the math of dividing whole number totals by seven, there can only be seven rounded two-decimal outcomes (.00, .14, .29, .43, .57, .71, .86). This list shows the second heat waves in 1988 and 1980 noted above but does not include them in the rank numbering system (if you wanted to convert to a list of heat waves then add one to each rank number below a second heat wave note). xx. __ 93.86 ___ (none) t26. __ 93.71 ___ 1940, 1949 ___ also 2nd 1988 heat wave July 5-11 (heat wave 30) __ 93.57 ___ (none) ____ also 2nd 1980 heat wave Aug 3-9 (add 3 to ranks if counting heat waves and not years, the additional ones include 1953 "2b" and 1988, 1980 above) 28. __ 93.43 ___ 1937 t29. __ 93.29 ___ 1943, 1995 t31. __ 93.14 ___ 1872, 1892, 1917, 1952, 1964, 2016 xx. __ 93.00 ___ none t37. __ 92.86 ___ 1957, 2008 t39. __ 92.71 ___ 1885, 1984 t41. __ 92.57 ___ 1954, 1963, 2012 xx. __ 92.43 ___ none t44. __ 92.29 ___ 1923, 1924, 1941, 1961, 2005 (also in top 50 ...) t49. __ 92.14 ___ 1876, 1919, 1997, 2006 ... note that in Aug 1918, seven days in a 10d span Aug 5-14 averaged 95, but a 71F max midway through left this two-part heat wave (with the all-time Aug record of 104F) on the sidelines. ... ... ... the warmest week 2017 to 2021 so far is 91.57 June 29-July 5, 2018. ... ... ... the average for all years 1869 to 2020 is 90.8. For 1869-1900 it was 89.3, for 1901-60 it was also 90.8, and for 1961-90, 1991-2020 both halves had identical 91.6 averages. (for clarity, this is the average of the warmest 7d interval of each year). (note the coldest weeks have warmed up more, the same stats for that are 1869-2020 27.15, 1869-1900 24.2, 1901-60 28.0, 1961-90 26.7 1991-2020 29.2) Just as a basis for discussion, these stats are consistent with an urban heat island increasing by 1 F deg in summer to the 1930s and another 1 F to present day assuming a levelling off after 1980. If you think that estimate of the u.h.i. for NYC is too large then the amount by which you estimate the u.h.i. leaves a trace of some other process at work (some combination of natural warming and AGW). The winter or coldest week stats are consistent with an urban heat island increase about twice as large with evidence of a colder turn around the 1960s to 1980s and signs of a further warming recently that would more likely be from some factor unconnected to the heat island. _____________________________________________________________ * same value Aug 28 - Sep 3 1953 ... Aug 28 to Sep 3 1973 average was 95.71 ranked t22. ^ This heat wave took top spot for all weeks from the one indicated to July 2-8, but values were lower than 20th (near 95 F). ^^ The 1901 value shown was second highest for that weekly interval but took top spots for the two previous intervals which were 92.57 and 95.00. ** The 1925 early June heat wave took top spots for weeks ending June 5 to 10, the other values were all in the range of 90 to 93. ====================================================== ANALYSIS _ There were 25 qualifying heat waves with at least one seven day average of 94.0 F. That provided a total of 91 intervals with the average therefore being about 3.6 intervals, meaning that a nine- to ten-day span of three or four consecutive seven-day intervals was the core of the average heat wave. The more intense ones also had longer durations in the range of 10-15 days mostly, with the 1966 case extended with two separate qualifying peaks. Late July and early to mid August 2002 had two rather separate heat waves but they are grouped together since the study will concentrate on years rather than individual heat waves. Of the 25 heat waves that qualified, one was in the interval 1869-1900, three were 1901-30, six were 1931-60, seven were 1961-90 and eight were 1991-2020. When the list was expanded to 48, this produced totals of 4, 6, 14, 11 and 13. The frequency has levelled off since around 1931. To give some idea of the degree of warming, for the 1869-1900 interval to provide six would require the minimum qualification to drop to 92 F, and for 1901-30 to double its total to six would require that we add these three near misses ... 93.14 in 1917 (late July early Aug), and 92.3 in 1923, 1924. ... Summer of 1930 was hot but only managed a peak weekly average of 91.86. One could postulate that NYC summer heat waves have remained steady state under an assumption of a 3F total increase in urban heat island that reduced to 2F by 1931 and rapidly decreased below 1F after 1940. That seems a bit contrived, 2F with a steady decrease is probably more accurate. So some of this change in frequency appears to be natural variability at work. There are only faint signs of any role of AGW in NYC heat wave daily high temperatures. I will add material in a separate post overnight (hopefully) to show that for overnight lows, a different conclusion can be drawn. Then we'll see how that blends together for daily mean temperatures. Some mention should be made of outliers, heat waves that were far enough from the peak of solar warming that they were at a disadvantage in reaching these criteria. The most prominent early outliers were five day heat waves in late May 1880 (91.6 May 24-28) and late May-early June 1895 (94.6 avg May 30-June 3, 93.17 May 29-June 3). These had high enough temperatures but could not sustain a seven-day average to qualify. Sept 20-23 1895 averaged 94.0, but seven-day averages were in the high 80s. In mid-September 1931 there was a mean of 91.0 for the week of Sept 9-15. The average for Sept 20-26 1895 was 89.3 F. Hot spells of about four days in April 1976 and 2002 are even greater outliers. These both averaged around 92 F for four days and had weekly averages near 86F. A second post will give a comparative account of the top 48 years for high seven day averages of summer minimum temperatures.

Here are some hourlies from one of the hottest locations, PSC ( Pasco Tri-Cities airport in se WA) 2 pm PDT __ 109 F 3 pm PDT __ 110 F 4 pm PDT __ 113 F 5 pm PDT __ 114 F 6 pm PDT __ 112 F (max reported as 115 F) This looks to be a fairly normal sequence for this abnormal heat.

One of the big news stories here is that the raspberry crop, which usually matures in early July for a leisurely picking by thousands of ordinary citizens who pay for the privilege, has instantly appeared and is now baking to worthless quality on the plants. Next stop, blueberries, they are usually ready to pick in August. Have been seeing bears on a regular basis around town here, they are clearly distressed by the extreme heat which is probably throwing off their feeding habits too.

Yes but only 107F where I live, thinking of getting the parka out.

It's going over the top anyway Don, looking at the full range of reports I feel sure one of the official stations will top both the BC and national record values. I am going to post something I was working on but won't be able to finish parts two and three right away, for your general interest. This will be a list of the top 30 NYC weekly averages (max only in this post, will add min and mean later). That should be up shortly. The local station (Warfield) has been up to 41 C already and will likely top off at 42 C, it feels about that outside although I am up the hill 2 miles and 500 feet higher. However I was in Las Vegas in Aug 2011 when it was 46 C and that was noticeably hotter although the sky looks very similar.

you missed my living room 3 F

On this question of the role of AGW in the appearance of such events, I agree with previous comments about the difficulty of disentangling the signal from the processes. Logically speaking, if we at least agree that AGW must be warming the atmosphere by some amount (1 C deg on average but closer to 2 C in subarctic regions, and also from some studies stronger in the n.h. than the s.h.), then we have a number of possible interactive scenarios: (a) the atmosphere is doing what it would have done without the signal, but all components are warming up; (b) the atmosphere is being forced to develop warm outcome patterns more frequently than it would do without the human input; (c) some number of incompletely understood feedback loops are interacting with only partially predictable consequences. These are not necessarily completely independent or mutually exclusive outcomes. For example, I noticed that the singularity of the Nov-Dec 2015 warm signal across N America into Europe followed the northward track of remnants of Hurricane Patricia in late October 2015. Without that exceptional hurricane and its ability to move large amounts of tropical air north, would the full extent of that warm signal have developed? On the other side of the coin, certain statistical profiles argue for a general blanding of climate in some regions, with less extreme cold a certain factor, but also less frequent daytime heat as the increases seem to be falling mostly into the overnight low category. I have done an extensive study of Toronto and New York City temperature records. Both have an urban heat island factor to remove from the data but that should create more frequent warmth at all times of day, so even without addressing that factor, here's an interesting finding -- the frequency of hot days is not increasing in statistical terms since a peak around the 1944 to 1955 era. The frequency of warm nights is increasing. The main periods of stress on daytime high records is either end of winter, i.e., late Nov-Dec, and late Feb-early March. In those time windows, more than the expected number of record high maxima occur, at other times of year, the distribution is either random or it favors earlier decades. Both temperature series showed a natural warming signal around the 1890s with a relapse in the 1904-07 interval and further natural warming around 1911-22. The 1920s turned somewhat colder again. The 1930s are of course well known for hot summers but also had a number of very mild winters (and one very cold one, 1933-34, with 1935-36 known for its cold further west). Anyone who wants to take a deep dive into these stats can find links to my files (which are posted on the UK site net-weather, mainly because they have a larger download limit than here) -- the links are through a portal in the NYC subforum. The files are continuously updated. Right now I am working on warmest and coldest weeks at NYC. This is not completed but I can already see that the frequency of warm weeks by daytime highs is fairly well distributed and the frequency of warm weeks by overnight lows is dominated by more recent years. Since mean temperature is the average of both, the frequency of warm weeks by mean temp is skewed a bit towards the recent past but so far the impact of the higher mins is not that substantial as to overturn many of the earlier contenders which survive so far. December 2015 was quite a singularity in our recent climate. Britain for example had a mean temperature 1.6 C higher than previous monthly records (set in 1934, 1974). NYC and Toronto had means even more separated from second place. December has shown a much more robust recent warming than most months. We had 1982 which set new records, followed by a few more in Dec 1984, then 1990 and 1998 broke some of them and 2013 or 2015 broke most of the rest. I got far enough into the compilation of record warm weeks to find that Dec 2015 holds almost all the high values after mid-month. Even with the recent warming, some of the most impressive warm spells (even before adjusting for urban heat island) fall way back into the past. July 1868 was a very hot month at Toronto. Late May of 1880, late September of 1881, and two periods in 1895 (late May-early June, and mid-Sept) still hold on to records that are sustained over several days to a week. It's a mixed bag of signals in general in these historical climate records, and the details of modern or AGW warming are perhaps more subtle than many might imagine. When I look back on these historical warm spells, and even ones that as an older weather enthusiast I can remember (like the mid-April 1976 heat) I wonder if they would play out the same way (perhaps 1 deg warmer or so), or if they would evolve differently and hit further north than they did back then. The same thing applies to U.K. climate records. It remains true that the warmest May (by over 1 C deg) was in 1833, and the warmest June was in 1846. Until broken in 2006, the warmest September was 1729. Some months in the U.K. records have showed a greater tendency to modern warming than others. The process is not just some blanket warming of 1-2 degrees. Driving warmer air into the arctic is going to cause arctic air masses to try to flow out behind disturbances. Some think that in recent years, the climate of the Canadian prairies has become subject to more extremes with unusual out of season snowfalls and frosts like the snowstorm in Calgary in early September of 2014 (and the more recent Denver snowstorm and freeze in Sept). Without the luxury of a "control earth" that we could study for differences, the field is wide open to speculation, which in a way is causing a lot of unhelpful confusion since relatively low-information onlookers are quite free to take any climate occurrence and concoct an "explanation" for it that falls entirely into climate change, for example, the recent rather cold April they had in Europe was "explained" as a consequence of AGW, which of course begged the question, why were most of the years that had similar means back in the Maunder minimum or the coldest parts of the 19th century? And why is every April not now like this? (most are quite warm in recent years). The answer is probably that the cold April was just "one of those things" and cannot realistically be explained by greenhouse gases, in fact one could argue that it was even less likely to occur than it might have been otherwise. I do believe that the frequency of warm weather events of all kinds is bound to increase if we warm the atmosphere by 1-2 deg but it has to be said that the increase must be demonstrated to fall in a higher range than you could expect by relaxing criteria by 1-2 deg from past frequencies, in order to demonstrate a change in process, otherwise all you are left with is a realization of the shifting range of the bell curves.

Some highlights of the 12z 500 mb analysis (from EC) ... 598 dm high over s central BC. 586 dm thickness max near Salem OR where sounding gives -2 C at 500 mb. ============================== Just a wait and see now, we got some relief overnight with most places dropping to the low 70s briefly.

In terms of return periods of a heat wave this intense in this region, we have not yet gone past two consecutive readings of 44.4 C (112 F) at the same locations mentioned in B.C., and a check of the weather maps for those two days (July 16-17, 1941) shows something very similar, a localized 500 mb heat dome around 598 dm. Here's a link to the historical weather chart for July 17, 1941. https://www.wetterzentrale.de/reanalysis.php?uur=1800&var=1&nmaps=24&map=2&model=noaa&jaar=1941&maand=07&dag=17 So I went into the historical data archives for EC to check the longevity of the 1941 heat wave, finding the following (I have converted the data back to the F deg that it was originally measured in as each of the C equivalents has an uncertainty of about 0.2. The hottest period was July 12-18. date ____ max Lytton BC ___ max Lillooet BC Jul 12 ___ 96 __________ 98 Jul 13 __ 100 _________ 101 Jul 14 __ 105 _________ 106 Jul 15 __ 109 _________ 109 Jul 16 __ 112 _________ 112 Jul 17 __ 112 _________ 112 Jul 18 ___ 96 __________ 92 __________________________________ Both locations had very few hot days during the summer before this heat wave set in, and returned to modified versions in mid-August with about a week in the high 90s (normal at these locations in the high 80s F). There was a small amount of rain at Lytton on the 16th and about a quarter inch at both locations on the 18th with the passage of weak cold fronts. This indicates to me that the 1941 heat wave produced localized nearly dry thunderstorms that were probably a forest fire hazard at the time. In terms of where the current heat wave is in its evolution, I would say around day 2 or 3 of the above, except that in the current case, it was somewhat warmer for about four days before this intense heat set in than was the case in 1941, highs for the past six days at Lytton (before Saturday) were 32.5 C (20th), 35.5 C (21st), 33.9 C (22nd), 31.6 C (23rd), 31.3 C (24th), 39.2 C (25th). Converted to F deg those would be 91, 96, 93, 89, 88, 103 (and around 110 today). We'll see what the seven-day average is this time around, in 1941 it was 104.3 at both locations. Assuming three or four more days near 110 this time, we could be looking at an average of 106 and that could climb a bit if the exit from the heat is warmer than the 89, 88 above. I would say that as a climate "singularity" this is so far about equal to the 1941 event. Weather buffs will probably recognize 1941 as the year when NYC had record heat in early October (94 F the highest Oct temp on record there). The summer of 1941 was generally a hot one in eastern North America and set a few daily records although it is not in the first tier of hot summers. Some of those records were in late July with a lag of about ten days indicated from the western heat wave. It was mid to high 90s sort of heat rather than 100+ at least for the locations I could check (Toronto, NYC). Another parameter worth comparing is the highest minima in these BC heat waves, only about 73 F for the 1941 version. Overnight lows in the high 70s or low 80s seldom occur in this climate (r.h. too low generally, high probability of clear skies at night). The 1941 heat wave seemed to end with a spell of cloudy and warm weather as the highs dropped more than the lows, and there were thunderstorms around. I may check the 2003 heat wave that led to serious fire hazards around the Okanagan valley in late July and early August. From memory it was not quite this hot but more sustained for two or three weeks, and there were a few episodes of dry lightning from storm cells that fired up over the Cascades in WA and moved north into BC overnight. Those started the worst of the fires near Kelowna and Salmon Arm BC. Salmon don't really have arms by the way, that's a feature of Shuswap Lake.

Predict the temperature anomalies (F deg rel to 1991-2020 averages) for DCA _ NYC _ BOS __ ORD _ ATL _ IAH ___ DEN _ PHX _ SEA on-time deadline for entries is 06z Thursday July 1st.

Just watching local newscasts from both sides of the border, a few fires to report, nothing too serious yet, but with so many people out camping this weekend, and doing yard work, there are opportunities for fires to start and the forests are starting to dry out. Vehicle fires from overheating have been a problem. Lillooet BC apparently hit 43.0 C That would be 109.4 F in old money, so within 2.6 F of the all-time record there. (Just saw Don's post about Lytton at 43.3 C). We had a week of less extreme heat before this started so everyone is partially acclimatized, I would imagine this might be the Dec 2015 of Junes in terms of annihilating previous records (inland, the anomalies were not very large at SEA or YVR before this hot spell began, Spokane is close to +5 F and will end up +6 to +7). I looked up data for June 1958 which was one of the warmer ones, nothing like this sustained, just one day around 37 C, although the first half of that month was probably about equal to this year. This is not our first June heat wave either, it was very hot here on the first three days of June, hitting 36 C several days in a row.

Sorry I didn't notice that last entry around the deadline, I'm going to assume it was close enough that nobody will protest if I include it, so I am putting it into the table now. Nothing much going on with this for a while, I would imagine. All the heat is out west here, I am first to 100 degrees apparently (101 F outside here as I type). But it's a dry heat yada yada. The contest consensus (derived from means of 26 forecasts) is 101_101_102_102 I think BWI was marginally below RIC and IAD marginally below DCA but rounded off these two pairs are equal.

Just FYI, Victoria airport is a long way north of the city and the southern part of the city is currently getting a fairly nice sea breeze cooling to about 25 or 26 C, but just a few miles inland it's 35 C at U-Vic. Same happening around Vancouver, one or two of the lighthouse stations have 25 C while in the valley it's 37-40 C. The one good thing here is that we don't have as high a dew point locally, the dews are 18-20 C in coastal areas and just 10 C here, so it's just scorching hot without any humidity. The sky is quite an intense shade of blue like you see in the desert southwest in heat waves, with really tiny cumulus fractus on the horizon mostly. I would not be that surprised if a roadrunner appeared outside my window.

Well anyway it's now 101 F at SEA, case closed (ended up 102). (104 Sunday all time SEA record) (105 hourly 3 pm Monday, could be 106 for the max?) 108 where I live, probably also all-time record or close to it.

101F at Sea-Tac at 4 pm PDT .. is that all-time for SEA? I can remember it hitting maybe 99 or 100 a few years ago. 104F at PDX and 109F at The Dalles (which is a heat trap but still ... ) also 104F at YKA (Kamloops) which is not often within 1-2 of the heat trap locations. (to be fair, you couldn't design a better heat trap than the Fraser canyon, it points due south, it has bare rocky surfaces and the weather stations are at airports on south-facing benches, nobody in their right mind would live right there anyway). The full effects are not quite into the normal hot spots of southeast WA and eastern OR which are in the low 100s, sometimes those places like Walla Walla, Pasco and Pendleton can get into the low 110s. Probably will tomorrow.

This early onset is certainly the main feature, Don, we often count on a cloudy and unsettled June to keep the wildfire situation under control and in most years the weather gradually dries out and warms up through July in this northern extension of the interior west, so breaking all-time June records will be child's play for this late July heat wave. It ,may end up breaking the July records too. The Fraser valley region east of Vancouver has 38-39 C readings and the dew points are oppressive for this climate, around 18 or 19 C, adding some discomfort to the humidex values. That is a heavily populated region so it's not just 100 and something in a desert with tumbleweed and a couple of houses beside a dried out lake, we're talking about millions of people between greater Vancouver and Sea-Tac taking on this 100-degree heat without much a/c and generally not all that used to it (although it does seem to happen every other year now). Also you would think there's a lot of places to go to cool off at a beach, but in a lot of places beach access is very limited around these regions, the shoreline tends to be either lined with cottages or swamp where you can't swim. And inland lakes are very small and fill up with day users very quickly. The current temperature at YVR (Vancouver Int'l A) is only 30 C (86 F) but it's probably closer to 35 C in most of the urban areas around Vancouver, the airport is very close to the sea and almost always has a seabreeze during heat waves. The all-time record there from late July 2009 is only 35 C.

Posted this in the other discussion not realizing this thread had been opened up, so the info is more relevant here than there ... We are under the heat dome big-time now, in southern BC as well as the Pac NW region. For BC, the all-time record highs are 44.4 C (recorded as 112 F) in July 1941 at locations in the Fraser canyon region about 150 miles northeast of Vancouver. Numerous other inland locations have recorded extremes between 42 C and that value, a few of them since we converted from F to C in the late 1970s. Canada's all-time high is just one F deg higher (113F which is 45.0 C) and that was in July 1937 in towns southeast of Regina SK. In both the 1936 and 1937 heat waves, numerous 42-44 C readings were registered and the all-time warmest top thirty (available on wikipedia) is dominated by these three events (1936, 1937, 1941) despite the warming trends recently. For whatever reason Canada has not seen any new extremes, a couple of times around 2003 and 2009 there were 42C readings. Toronto has about a dozen days with 100+ readings, the hottest were in 1936 (three at 105F) and almost all the rest between 1911 and 1953. Only 2011 contributed one to this list after 1953. There has been an increase in mean temperature at Toronto but almost all of it is with overnight lows, not daytime highs (compared to the mid-20th century, obviously all parameters increased from late 19th to early-mid 20th). This current heat wave appears capable of approaching those all-time record highs, will report back on the results. We are right under the heart of this 500 mb heat dome (shown at 599 dm) in south-central BC this weekend. I live about halfway up the west side of the Columbia valley where the base elevation is about 400m asl and the local peaks in the Monashee range are around 2000-2500m. My local elevation is about 1050m. The nearest reporting station (Warfield BC) is at about 700m. It can be one of the province's hottest reporting sites, Osoyoos near the US border in the Okanagan and Lytton or Lillooet in the Fraser canyon are more frequently tops. We weren't quite under the full effect of this on Friday but already it was 36 C (97 F) at Warfield. Expecting closer to 40 C today and the peak likely around Monday-Tuesday. (since I typed that two hours ago it has hit 41 C at Lytton BC, I also see 107F at The Dalles east of Portland OR, and numerous low 100s in WA state. About 38C or 100F at my place. This heat wave looks like it might more or less match the July 1941 event but this one has appeared earlier, one has to wonder if there could be a more severe event later in the summer). A/C is not all that common in our part of the world despite the fact that almost every summer there are a few sweltering days. It does tend to cool off fairly well at night here, I was out at midnight admiring the rising moon near Saturn, and it was quite comfortable, probably about 65F. If you have clear skies where you live tonight, have a look between midnight and 0200h local time, you'll see the Moon very close to Saturn and then Jupiter off to the left rising a bit later. The Moon will then be close to Jupiter on Sunday night.

<<<<<< ============ - - - - Annual Scoring for 2021 (Jan-June) - - - - ============ >>>>>>>> High scores for nine locations shown in red, high scores for regions in bold. June provisional scores are used and adjustments will be made here to reflect changes there. New feature _ change in rank is shown after forecaster name. No entry there means same position as last month. One forecaster passed Normal but not any other forecaster, so their change is shown as zero, Normal is shown down 1. Tom was ahead of consensus in May but his "down 1" refers only to the forecasters, Consensus is up one relative to the forecasters. FORECASTER _________________DCA_NYC_BOS__east_ ORD_ATL_IAH__cent __c/e ___DEN_PHX_SEA__west___TOTALS DonSutherland1 ______________ 428 _474 _336 _ 1238 __397 _446 _390 _1233__2471 __248 _452 _384 _ 1084___ 3555 BKViking (up 2) _______________416 _494 _374 _ 1284 __308 _420 _346 _ 1074__2358 __280 _402 _422 _ 1104___ 3462 wxdude64 (down 1) ___________453 _481 _378 _ 1312 __289 _360 _343 __ 992 __2304 __333 _429 _365 _ 1127___ 3431 ___ Consensus (up 1) _________ 448 _492 _358 _ 1298 __296 _396 _362 _ 1054 __2352 __266 _406 _384 _ 1056___3408 Tom (down 1) _________________436 _505 _396 _ 1337 __258 _341 _394 __ 993 __2330 __314 _405 _332 _ 1051___ 3381 hudsonvalley21 _______________ 426 _454 _382 _ 1262 __287 _440 _336 _ 1063 __2325 __212 _380 _406 __ 998___ 3323 wxallannj ______________________366 _450 _342 _ 1158 __264 _366 _400 _ 1030 __2188 __350 _386 _396 _ 1132___ 3320 RodneyS ______________________ 392 _446 _301 _ 1139 __271 _412 _336 _ 1019 __2158 __300 _416 _402 _ 1118___ 3276 so_whats_happening (up 1) ____453 _447 _286 _ 1186 __348 _450 _285 _ 1083 __2269 __218 _413 _357 __ 988___ 3257 Scotty Lightning (down 1) ______416 _432 _279 _ 1127 __192 _390 _374 __ 956 __2083 __298 _412 _372 _ 1082___ 3165 RJay __________________________ 372 _426 _394 _ 1192 __326 _350 _316 __ 992 __2184 __224 _332 _302 __ 858___ 3042 ___ Normal (down 1) ___________ 400 _378 _244 _ 1022 __154 _ 384 _388 __926 __1948 __348 _372 _350 _ 1070___ 3018 Roger Smith ___________________ 356 _322 _155 __ 833 __309 _314 _398 _ 1021 __ 1854 __264 _370 _380 _ 1014___ 2868 Best scores for the locations and regions FORECASTER _______________ DCA _ NYC _ BOS __ east __ ORD _ ATL _ IAH __ cent __ c/e ___ DEN _ PHX _ SEA __ west ___ Totals DonSutherland1 ______________ 2 ____ 0 ____ 0 _____ 2 ______ 2 ____ 0 ____ 1 ____ 3 ____ 3 _____ 0 ____ 3 ____ 1 _____ 0 _____ 1 __ Jan wxdude64 ____________________ 1 ____ 1 ____ 0 _____ 1 ______ 0 ____ 0 ____ 0 ____ 0 ____ 0 _____ 2 ____ 1 ____ 0 _____ 2 _____ 1 __ Mar (t) BKViking _____________________ 0 ____ 1 ____ 1 _____ 1 ______ 0 ____ 0 ____ 1 ____ 0 ____ 0 _____ 0 ____ 0 ____ 2 _____ 0 _____ 1 __ Apr ___ Consensus _______________ 0 ____ 0 ____ 0 _____ 0 ______ 0 ____ 1 ____ 1 ____ 0 ____ 0 _____ 0 ____ 0 ____ 1 _____ 0 _____ 0 __ Tom __________________________ 1 ____ 1 ____ 1 _____ 1 ______ 0 ____ 0 ____ 1 ____ 0 ____ 1 _____ 0 ____ 0 ____ 1 _____ 1 _____ 1 __ May hudsonvalley21 _______________ 0 ____ 0 ____ 0 _____ 1 ______ 0 ____ 0 ____ 0 ____ 0 ____ 0 _____ 0 ____ 0 ____ 2 _____ 0 _____ 0 __ wxallannj _____________________ 0 ____ 1 ____ 1 _____ 0 ______ 1 ____ 1 ____ 2 ____ 1 ____ 0 _____ 2 ____ 1 ____ 1 _____ 1 _____ 0 __ RodneyS _____________________ 1 ____ 1 ____ 0 _____ 0 ______ 0 ____ 1 ____ 0 ____ 1 ____ 0 _____ 0 ____ 0 ____ 0 _____ 1 _____ 1 __ Feb so_whats_happening _________ 2 ____ 0 ____ 0 _____ 0 ______ 1 ____ 2 ____ 0 ____ 1 ____ 1 _____ 0 ____ 0 ____ 0 _____ 0 _____ 1 __ Mar (t) Scotty Lightning ______________ 1 ____ 0 ____ 0 _____ 0 ______ 1 ____ 1 ____ 1 ____ 0 ____ 0 _____ 0 ____ 0 ____ 0 _____ 0 _____ 0 __ RJay _________________________ 0 ____ 1 ____ 4 _____ 1 ______ 1 ____ 0 ____ 1 ____ 0 ____ 1 _____ 0 ____ 0 ____ 0 _____ 0 _____ 0 __ ___ Normal ___________________ 1 ____ 0 ____ 0 _____ 0 ______ 0 ____ 0 ____ 0 ____ 0 ____ 0 _____ 1 ____ 1 ____ 0 _____ 1 _____ 0 __ May Roger Smith __________________ 0 ____ 0 ____ 0 _____ 0 ______ 1 ____ 1 ____ 2 ____ 1 ____ 0 _____ 2 ____ 1 ____ 1 _____ 1 _____ 1 __Jun ---------------------------------------------------------------------------------------------- EXTREME FORECAST STANDINGS High score must go to either the extreme warm or cold forecast, or second most extreme, for a station to qualify. So far this year, 38 locations out of 54 have qualified, 4 in Jan, 5 in Feb, 7 in March, 6 in April, 8 in May and 8 in June. Of those, 22 were awarded to warmest forecasts, 16 to coldest. A loss in the standings represents a case where second most extreme forecast had the high score and the win for that month. Normal can only win along with a forecaster. There have been six shared wins (one by three) accounting for the 46 total wins (excl Normal). FORECASTER _________ Jan __ Feb __ Mar _ Apr _ May _ Jun ___ TOTAL to date wxallannj ______________ ---- __ ----- __ ----- __ 3-0 __ 2-0 __ 3-0 __ 8-0 DonSutherland1 _______ 2-0 __ 1-0 __ 2-0 __ 0-1 __ 2-0 __ 1-0 __ 8-1 Roger Smith ___________ 2-1 __ 2-0 __ ---- __ 1-0 __ 1-0 __ 2-0 __ 8-1 RJay ___________________ ---- __ ---- __ 2-0 __ 2-0 __ 1-0 __ 1-0 __ 6-0 so_whats_happening ___---- __ 1-0 __ 2-0 __ ----- __ ----- __ 1-0 __ 4-0 wxdude64 _____________ ---- __ 1-0 __ 2-0 __ ----- __ ----- __ ----- __ 3-0 RodneyS ______________ ----- __ ----- __ ----- __ ----- __ 2-1 __ 1-0 __ 3-1 Normal _________________---- __ ---- __ 2-0 __ ----- __ 1-0 __ ----- __ 3-0 BKViking ______________ ----- __ ----- __ ----- __ ----- __ 1-0 __ 1-0 __ 2-0 Tom __________________ ----- __ ----- __ ----- __ ----- __ 1-0 __ 1-0 __ 2-0 Scotty Lightning ______ ----- __ ----- __ ----- __ ----- __ ----- __ 1-1 __ 1-1 __________________________________________

We are under the heat dome big-time now, in southern BC as well as the Pac NW region. For BC, the all-time record highs are 44.4 C (recorded as 112 F) in July 1941 at locations in the Fraser canyon region about 150 miles northeast of Vancouver. Numerous other inland locations have recorded extremes between 42 C and that value, a few of them since we converted from F to C in the late 1970s. Canada's all-time high is just one F deg higher (113F which is 45.0 C) and that was in July 1937 in towns southeast of Regina SK. In both the 1936 and 1937 heat waves, numerous 42-44 C readings were registered and the all-time warmest top thirty (available on wikipedia) is dominated by these three events (1936, 1937, 1941) despite the warming trends recently. For whatever reason Canada has not seen any new extremes, a couple of times around 2003 and 2009 there were 42C readings. Toronto has about a dozen days with 100+ readings, the hottest were in 1936 (three at 105F) and almost all the rest between 1911 and 1953. Only 2011 contributed one to this list after 1953. There has been an increase in mean temperature at Toronto but almost all of it is with overnight lows, not daytime highs (compared to the mid-20th century, obviously all parameters increased from late 19th to early-mid 20th). This current heat wave appears capable of approaching those all-time record highs, will report back on the results. We are right under the heart of this 500 mb heat dome (shown at 599 dm) in south-central BC this weekend. I live about halfway up the west side of the Columbia valley where the base elevation is about 400m asl and the local peaks in the Monashee range are around 2000-2500m. My local elevation is about 1050m. The nearest reporting station (Warfield BC) is at about 700m. It can be one of the province's hottest reporting sites, Osoyoos near the US border in the Okanagan and Lytton or Lillooet in the Fraser canyon are more frequently tops. We weren't quite under the full effect of this on Friday but already it was 36 C (97 F) at Warfield. Expecting closer to 40 C today and the peak likely around Monday-Tuesday. A/C is not all that common in our part of the world despite the fact that almost every summer there are a few sweltering days. It does tend to cool off fairly well at night here, I was out at midnight admiring the rising moon near Saturn, and it was quite comfortable, probably about 65F. If you have clear skies where you live tonight, have a look between midnight and 0200h local time, you'll see the Moon very close to Saturn and then Jupiter off to the left rising a bit later. The Moon will then be close to Jupiter on Sunday night.