I've been weighing up whether to start a topic devoted to the French heatwave but decided it's probably sufficient to post occasional updates in here, at least until this thread runs out of steam when the temperatures drop. But without doubt it's starting to look like an event to rival the extremes of 2003, 2006, 1983 and 1976. By contrast with those 4 we in Britain have only been on the margins of this one.
I have a particular interest in Macon as I have a holiday home not far from there but nationally it's been quite something too. Especially, for some reason, up the tops of mountains as you'll see below. A few highlights so far, courtesy of Meteociel:
30 June: The heat peaks in the South West, with monthly records set in 18 towns in the region including 40.2C at Cazaux, Gironde, the second highest of this heatwave.
1 July: The first peak of the heat across the central parts of France. 4 all time records beaten and another 10 July records. The highest (and current top for this heatwave) being 40.8C at Chapet just North West of Paris, with a number of readings over 39C in the Paris area and a bonkers 30.9C at the top of Mont Dore in the Massif Central, 1,220m asl.
2 July: Things cool off a tad across the North and West and the heat concentrates in the Centre and East of the country. 2 July records, in high altitude locations in Vosges and Haute Marne, just shy of 36C. (Worth noting that many of these July records are in all time second place to records broken in August 2003).
3 July: The canicule peaks in the Centre and East. 14 July records broken with the top being 39.8C at Issoire in Puy de Dome. One all time record: Alpe D'Huez hitting 27.7C at 1,860m asl. Lucky it wasn't the day of the Tour Stage there.
4 July: An extraordinarily warm night in Eastern France, especially considering the time of year and the fact SSTs are a way off their peak and humidity has been relatively low. All time records for night minima were broken at 11 sites with the warmest of the bunch being a tropical 26.8C at Lons le Saunier in the Jura. Many other monthly records broken too. Note that unlike daily highs, French national records for nightly mins are never going to be set during in inland locations - these are all held (pretty safely for now) at much higher levels by towns on the Mediterranean coast. Likewise this heatwave is unlikely to beat national records for day peaks either, because these tend to be set in the far South West on an axis from Toulouse to Perpignan and are most likely when a Spanish-based heatwave with 25-30C uppers just creeps over the Pyrenees, rather than during a nationwide event.
After the tropics of the night before another very hot day across the centre and East, but with cooler weather well and truly set in along the channel and West coasts. 9 Monthly records and 1 all time record beaten, 3 equalled including the hotspot of the day, Macon with 39.2C. Also notable Briancon in Haute Alpes, at 1,300m asl, manages 33.5C. Meanwhile some channel ports struggle to reach 20C.
5th July: Another very warm night with 4 monthly minimum records beaten, followed by yet another day with heat concentrated across the centre and East. St Etienne takes the prize today with 39C (only rounded values available at this stage). Worth noting that St Etienne sits at over 400m above sea level! Indeed high temperatures at altitude are a feature of this heatwave, probably because the heat is concentrated in areas that happen also to have mountains. Today we saw 5 all-time records beaten in high altitude locations, and 5 monthly records. Pick of the bunch, Alpe D'Huez trouncing its record earlier in the week by registering 28.5C. Also notable is Epinal in Vosges: it has now beaten its previous monthly record of 35C 4 times in 4 days (Thurs 35.6, Fri 36.1, Sat 36.5 and Sun 36.7).
Macon itself has seen temperatures build steadily during the week, typical of towns in the East. From last Saturday: 28, 30, 32, 35, 36, 37, 37, 39, 38.
France has 2 more days of this current heatwave to survive before temperatures return, albeit temporarily, to more typical summer levels. Maxes on Monday are forecast to be around 36-37C in the Centre and also back again in the South West. Tuesday is the final peak: Somewhere like Vichy, Clermont Ferrand or Moulins could hit 41C. Then by Wednesday values crash as a mainly dry cold front comes through - we are back down to mid 20s across almost the whole country.
How long will the respite last, and could things rebuild again? Quite possibly. Today's 12z GFS shows low 30s creeping back into the SW by Thursday, mid-high 30s there on Friday with 30-31C elsewhere, and full on canicule back in central France by Saturday, up again to 35C+ and staying that way for at least 2 further days. Some ensemble members have us exceeding 40C again the week after next, others show a cooler picture.
Drought ("secheresse") is starting to menace large parts of the country especially the centre and Paris basin, after a string of dry months. This is soil moisture (agricultural) drought rather than hydrological drought, as reservoirs and aquifers are very healthy still. My local online paper for Saone et Loire has 3 separate stories today about bush and field fires, and yesterday they were reporting that the Grosne river, one of the more sensitive to drought as it is surface fed, is dropping at such a rate that it's 4-5 days away from the record lows set in August 2003.
At least the French can reassure themselves that by the time I arrive there in holiday in 2 weeks time, in keeping with tradition the heavens will have opened and it will be cold and cloudy.
Originally Posted by: TimS