Netherlands sees first official summer weather day, but storm warning issued

The Netherlands recorded its first official summer weather day of the year on Thursday. Official weather observations for the country are measured in De Bilt, Utrecht, where the meteorological institute KNMI is based. The institute cautioned that the sunny weather will become stormy for most of the country in the afternoon, and issued a Code Yellow weather warning for wind, hail and heavy rain.

The temperature in De Bilt surpassed the summer-weather mark of 25 degrees at 2 p.m., according to weather website Weeronline. The measurement of 25.1 degrees took place two weeks earlier than the long-term average. The first summer day is normally recorded on May 16, though last year it took place on June 9.

The earliest first annual summer weather day in the Netherlands took place on April 14, 2007, when the temperature soared to 27.6 degrees. The record for the latest date was set on July 18, 1906, when the mercury rose to 25.6 degrees.

Locally, the first 25-degree day this year was recorded on April 6 in several cities in the south and east of the country. It was also warmer in some of those areas on Thursday, as the mercury rose above 26.0 degrees in Eindhoven.

However, thunderstorms were already beginning to move across part of the country by the late afternoon, with local storms forming around Tilburg, and another between Amersfoort and Hilversum. A bigger storm cell was approaching from western Germany and eastern Belgium that was set to blanket the Dutch provinces of Limburg and Noord-Brabant by about 5:30 p.m. It was likely to expand further across Gelderland and Utrecht by about 7 p.m., then Flevoland, Noord-Holland, Zuid-Holland and Zeeland by the end of the evening.

"Tonight, there will be rain and thunderstorms, especially in the center and south, possibly with hail, gusts of wind and locally heavy rain," the KNMI wrote on Thursday. "This may cause disruption to traffic and outdoor activities. Local flooding may also occur."

The wind will gust up to 70 kilometers per hour, and could be accompanied by hail about the size of small marbles. Rainfall could range from 20-40 millimeters in an hour, and possibly topping 50 millimeters within a six-hour period.

Gelderland, Limburg, Noord-Brabant and Utrecht were all put under a Code Yellow warning from 3 p.m., and it was expected to last for about eight hours. Both Zeeland and Zuid-Holland were under a shorter storm warning from 8 p.m., ending around 1 a.m. on Friday.

Scattered showers and thunderstorms were also predicted for the overnight hours, with the temperature dipping to 12 degrees. The wind could remain strong along the western coast into the morning. A much cooler Friday was predicted to remain around 13 or 14 degrees everywhere in the country, with only a few breaks for sunshine in Noord-Holland, Friesland, and Groningen in the afternoon.

The weather was expected to clear up by Friday evening, and should remain dry, the KNMI said.