All-time July National Heat Records Fall on Three Continents

Brutally hot conditions fried portions of three continents during the first three days of July, and four nations have already set all-time July national heat records this month: the Netherlands, the U.K., Thailand, and Colombia. Below is a break-down of the July national heat records set so far this month, courtesy of weather records researcher Maximiliano Herrera.


Figure 1. People cool off in the water fountains at Haarlemmerplein square in Amsterdam, the Netherlands, on Thursday, July 2, 2015. It was the warmest July day since records began in the Netherlands. (AP Photo/Margriet Faber).

Europe
The temperature in Maastricht, the Netherlands, hit 100.8°F (38.2°C) on July 2, setting an all-time July heat record for the nation. According to data from the Royal Netherlands Meteorological Institute, only two other hotter temperatures have been recorded in the nation: 101.5°F (38.6°C), on August 23, 1944 at Warnsveld, and 101.1°F (38.4°C), on June 27, 1947 at Maastricht. Thanks go to wunderground member cRRKampen for this info. According to to weather records researcher Maximiliano Herrera, three stations in the Netherlands set all-time (any-day) highs Thursday:

Volkel (Netherlands), 36.9°C
Twenthe (Netherlands), 36.1°C
Leeuwarden (Netherlands), 34.0°C

Mr. Herrera notes that the Netherlands' all-time hottest temperature in 1944 was surely beaten on July 2, 2015, but all stations in the warmest area were closed many years ago. For example, the city of Maastricht itself, where Thursday's near-record 100.8°F (38.2°C) was recorded at the airport, is slightly warmer in its downtown (perhaps by 1°C) than at the airport station (which is more elevated), but the town station doesn't exist any longer. He also pointed out that Belgium's official all-time hottest temperature is 101.8°F (38.8°C), measured on June 27, 1947. However, according to the Belgian Meteorological Agency, RMI, this value was likely 2.2°C too high, due to improper measurement techniques. If we make this correction, Belgium's all-time hottest temperature was beaten on Thursday, as well as during the 2003 and 2006 heat waves. And in Paris, which measured its 2nd hottest temperature in its history on July 1 (39.7°C), the Paris Observatory had its grass watered (as it should be), but the grass was never watered for the record value of 40.4°C of 1947. This could have been the difference between the two measurements.

London's Heathrow Airport hit 98.1°F (36.7°C) on July 1, setting an all-time July heat record for the UK. Previous record: 97.7°F (36.5°C) in Wisley on July 19, 2006.

Asia
On July 2, the mercury hit 105.8°F (41.0°C) at Kamalasai, Thailand, setting a mark for the hottest July temperature ever recorded in that nation. Previous record: 104.4°F (40.2°C) at Uttaradit on July 12, 1977. Approximately half of all the reporting stations in Thailand set their all-time July monthly heat records on July 1 or July 2 this year. UPDATE: Today (Friday, July 3), Kamalasai, Thailand bested yesterday's July record with a reading of 106°F (41.1°C).

South America
On July 1, Urumitia, Colombia beat that nation's all-time July national heat record, with a 108°F (42.2°C) reading. Urumitia also set Colombia's all-time June heat record last week on June 27, with a 107.6°F (42.0°C) mark.

The heat continued in all these places on Friday. In Europe, the hottest temperatures were over Central France, where Clermont Ferrand hit 104°F (40°C). Meteo France has a color-coded map of current temperatures that show the heat wave in excellent detail. The most intense heat will shift eastwards over Germany and Luxembourg on Saturday and Sunday, into Poland and Southeast Europe on Monday, then over Germany, Switzerland, Austria, and Liechtenstein on Tuesday. High temperatures close to the highest values ever measured can be expected in all these locations. From wunderground's extremes page, we can see that these all-time national heat records may be challenged:

France's all-time hottest temperature is 111.4°F (44.1°C), measured on August 12, 2003 at Conqueyrac and Saint-Christol-Les-Ales Gard Department.

Germany's all-time hottest temperature is 104.5°F (40.3°C), measured on August 8, 2003 at Perl-Nennig, Saarland State.

Switzerland's all-time hottest temperature is 106.7°F (41.5°C), measured on August 11, 2003 at Grono.

Luxembourg's all-time hottest temperature is 104.9°F (40.5°C), measured on August 8, 2003 at Remich.

Poland's all-time hottest temperature is 104.4°F (40.2°C), measured on July 29, 1921 at Proszkow.

Austria's all-time hottest temperature is 104.9°F (40.5°C), measured on August 8, 2013 at Bad Deutsch-Altenburg.

Liechtenstein's all-time hottest temperature is 99.3°F (37.4°C), measured on August 13, 2003 at Ruggel.

Four tropical cyclones in the Pacific
Typhoon Watches continue in the Northern Mariana Islands on Guam and nearby Rota, Saipan, and Tinian islands for Tropical Storm Chan-hom, which is expected to pass through the islands Saturday evening (U.S. EDT time) as an intensifying Category 1 storm. Chan-hom had unexpected troubles on Friday, when it interacted with tropical disturbance 94W to its west. The upper-level outflow from 94W created high wind shear over Chan-hom, which tore away most of the typhoon's heavy thunderstorms and exposed the low-level circulation to view. Dan Lindsey of NOAA/CIRA put together an impressive closeup view of Chan-Hom's evolution on Friday from the Himawari-8 satellite's 0.5 km visible 2.5-min imagery. Here is a link to all the Himawari-8 satellite imagery.

The Philippines are watching Tropical Storm Linfa, which is expected to hit the northern island of Luzon over the weekend at tropical storm strength.

Newly-formed Tropical Depression Eleven is in the Marshall Islands, where it has already caused considerable trouble. According to hurricane scientist Mark Lander of the University of Guam, tropical cyclones in the Marshall Islands occur almost exclusively during El Niño years. So far this year, three tropical cyclones have caused damaging sea inundation in the islands. According to a source of his on Majuro Island:

"We [Majuro] got the weaker side.  Even so, this was the strongest West Wind I have seen here in about 18 years.  And believe it or not, it was not that strong [~25 G40 mph], just steady.  I see 2 fishing boats aground; another one partially sunk already, with a small and large yacht on the beach, and many power boats a mess. The Uliga dock area was a circus all day.  Also add lots of erosion, you can see the Mobil Oil fuel lines exposed. All the mooring failures for boats on the beach so far was due to chafing as we have had happy weather for years and I think few were ready.  If a storm of this nature had hit at King Tides, we would have had a national emergency."

Two areas of disturbed weather in the Central Pacific east-southeast of the Hawaiian Islands, Invest 95E and Invest 96E, are moving west-northwest towards Hawaii. In their 8 am EDT Friday Tropical Weather Outlook, NHC gave 95E and 96E 5-day odds of development of 50% and 70%, respectively. 96E, the disturbance farther from Hawaii, may pose a long-range threat to Hawaii, as the Friday morning runs of the GFS and European models showed the storm coming close to the islands on Friday, July 10.

In the South Pacific, a rare winter tropical cyclone, Raquel, is drenching the Solomon Islands.

Mercifully, the Atlantic remains quiet, with none of the reliable tropical cyclone genesis models showing anything developing over the next five days.

Have a great holiday weekend, everyone! I'll be back by Monday morning at the latest with a new post.

Jeff Masters