Synopsis
An active edge failure (originally a CAD) lies north of the Wadden, where it already moves deep (left exit jetstreak) through the German Curve southeast. With a strong western current, maritime polar air is brought in. On Friday morning, the occlusion (which is preceded by a high trench) travels southeast over the northeastern half of the country. Afterwards a well flowed trekking back followed and at the end of Friday evening the heat front near a layer above the Irish sea approaches the western FIR. This storm layer (Darragh named by Met Office) subsequently travels to the middle of our country in the night to Saturday and Saturday during the day via Humber and the southern North Sea. The corresponding front system passes Saturday in the night and early morning. On the south-east flank a strong windfield first appears, after passage just on the west flank, but this windfield seems to mainly reach the Belgian coast.

Model assessment
On the southwest side of the Friday fault we see a strong wind field with strong gusts. We now assume heavy winds that are also a bit inland. The heavy winds now seem to be coming a bit further south than in the previous runs and the warnings are adapted accordingly. On the basis of a larger 12-hour window, which meets the uncertainty in timing, it cannot be ruled out that the rest of the country will also face heavy winds on Friday. We already see a number of runs that EC and HA43 are now more or less calculating the same Darragh rate. This means that the windfield on the southeast flank reaches the southwest coast for passage, but the windfield at the back mainly the west coast and the far southwest. The heavy winds remain out of port or come on the coast of Belgium. As for St at Darragh, Ha43 has more and lower St than EC on both the (occluding) front and core, we follow Ha43.Issues

Wind
Behind the occlusion we now see west 7-8 occasionally 9 on the North Sea and west 5-6 above land, in accordance with Ha43, EC has too little wind. Friday morning on the northwest coast possibly 9 Bft. Because the wind has then turned to the west-northwest, there will be heavy gusts that can get a little further on the land. Currently code yellow for all provinces and areas north of the large rivers for heavy winds of 75 km/h, North Holland and Friesland probably up to 90 km/h. Seafront breeze to approx. 90-100 km/h, Wadden local 110-120 km/h. Saturday morning on the southwest coast of ZW 7 with heavy winds of 75 km/h. Outdoor probably ZW 8.In the evening the wind decreases strongly due to the passage of Darragh, only the Zeeland coast seems to have NW 6.

Visibility
Actually in polar air good views. In precipitation moderate views, above sea also bad views in precipitation by the hard wind. Tonight/tonight in the north possible mist, there is the most humid air in the back. Saturday evening in/at the core also declining views.

Temperature
No details.

Cloud
In the polar air convective cloud with also Cb's with tops up to ca. FL200. At the recessed occlusion then weather mainly stratiform clouds with Friday morning St north of the Wadden and perhaps just grazing the northeast of the country. Saturday night and morning St on the occluding frontal system and Saturday evening St (under 500 ft) at the core of Darragh above the south of the country.

Precipitation
Actually few showers, in the north also stratiform precipitation at the inverted occlusion. At the thermal front of Friday night above the sea also stratiform precipitation. Saturday behind the occluding front showers with peaks FL120, around the core mainly stratiform precipitation.

Synoptic development
Low pressure area Darragh is above our country on Sunday but soon moves southeast. From 9 December we come under the influence of a high pressure area with the centre above Scotland. This high pulls slowly towards Central Europe but determines us again until the end of next week. From 14/15 Dec there seems to be another southwest current in progress.

Model assessment and uncertainties
Darragh's course now seems consistent in the models. In a previous ensemble there seemed to be still heavy wind blows above the south of the country, the chance of this is now small. The influence of the high is also very clear in the ensemble. At the beginning of next week, the winds are still quite good, so the chance of frost in the night is low. During next week, however, there will be less and less wind because it will be high above our country and therefore the chance of frost in the night will become significant with even an ice day in De Bilt on Saturday 13 December in the undisturbed run. From the weekend of 14/15 December the uncertainty will increase, but most members come with a south-west current which increases the temperature and also the precipitation potential (about 40%). Cold solutions remain, but they are by far in the minority.

Multi-day Summary
Sunday cloudy and occasionally rainy. Then dry, more sun and gradually falling temperatures with light frost in the night from mid-week onwards.

EPS Period Summary
First still quiet and dry with temperatures below the long-term average with light frost at night. Then gradually more wind, rising temperatures to around the long-term average and precipitation opportunities around 40%.

Valid from Sunday 08 December to Friday 20 December