Synopsis
A W-O oriented barocliene zone is almost stationary above the northern half of the country. At some altitudes there is strong heat advection due to a complex low pressure area west of the Bay of Biscay. On the north side of this zone there is powerful east to northeast flow that brings cold and dryer air. In the frontal zone there are several fronts, where the dew point is a nice tool. First, to the north of the Wadden, there is an occlusion with to the north the really dryer air (Td < 5°C), above the south of the country a frontal system with the occlusion point current above the southwest. This front marks the dividing line of the (very) soft air in the south of the country (Td > 10°C). The precipitation of this is temporarily somewhat bumpy in character due to the proximity of a short-gold high trench above the southwest of England. A high trench that is located above the Bay of Biscay last night reaches the south of the country on Sunday (in weakened form). As a result, in the frontal system above the south there is a wave with a closed core. During Sunday, this wave moves northeast to Poland and the current becomes north. The occlusion of this wave and the aforementioned occlusion to the north of the Wadden will then move south, the latter leaving the south of Limburg. At that time, another occlusion reaches the north of the country.

Model assessment
Generally few differences between Ha43 and EC and the models are almost identical in terms of timing of the different frontal systems. As far as the cloud base is concerned, above the south of the country EC (with St below 500 vt) is even slightly better on current times than Ha43. As the wave develops during the course of today, the base of both models is mainly in the southeastern half (flow is decreasing) of the country. Ha43 is, as usual, more negative and can be followed. This is particularly true because EC in the southeast St calculates that almost goes down on deck. Furthermore, this evening we see a single discharge at Ha43 at the approaching altitude trench. In view of the progtemp of EHBK this is not entirely excluded above the south of Limburg. For the time being, however, I do not think it is a good idea to include this in the expectations.Attention

Wind
Signal for east 7 Bft along the north coast and 6 Bft elsewhere on the north flank of the frontal zone. This in combination with wind gusts of 65-75 km/h. Slightly lower than calculating models. During the course of today the wind is decreasing with only a small 6 Bft north of the Wadden. Behind the occlusion of Sunday 6 Bft and later 7 Bft. In the event of storms of 75-90 km/h at sea and along the coast.

View
In precipitation near the frontal zone occasionally moderate to poor. Near the ground front in the far south this morning possible mist or mist. The same goes for the (south) east the night to Sunday at passage of the frontal wave.

Temperature
Current large temperature differences with 6°C in the north to 15°C in the south of Limburg. These temperature differences are also seen today during the day, although the cold air is gaining some ground. Only in the course of Sunday does the whole country come in the cold air and in the evening we see temperatures falling inland near freezing point.

Cloud
The northern half (sea area) of the FIR mainly good conditions (Sc-clouding) in dry and cold air. At the frontal zone on an extensive scale St, on the south flank and at the wave base below 500 ft (see model assessment). In the course of the night and especially morning, and again in the night to Sunday, the base probably drops locally to deck (chance of fog). Near the troughs a single shower. Maximum peaks are approx. FL200, where there is still a discharge possible on Saturday evening above Belgium, but probably not within our borders. During Sunday evening of the north from CB's with peaks approx. FL100, but mostly in the ice.

Precipitation
In the northern half of rain from a thick layered package, the last 24 hours have already fallen 30-40 mm in the northwest. In the next 24 hours, 10-20 mm in many places. After passage of the trough gradually decreasing intensity. Then drizzle in many places, but possibly still (especially above sea) an embedded shower. Above land, possibly except South Limburg at the second trough, the instability then decreases strongly and the showers disappear. Sunday evening of the north from a few showers, especially on passage of an occlusion. Grain hail is already a possibility.

Synopsis
During the weekend, the focus area ends up in a northern supply of originally Arctic air from an east current near a saddle area. This brings the focus area next week in another weather regime with chance of frost in the nights and halfway next week also precipitation with a winter character (especially grain hail). Towards the weekend of November 22, we see that low pressure will dominate again north of our country, gradually increasing the flow west and reducing the air flow.

Model assessment and uncertainties
Most of the members support the colder period next week. There are also snow opportunities from Tuesday/Wednesday of about 30%. Looking at the synoptic situations and the freezing levels that will go down to ca. 1500 vt, this is not even completely impossible. However, the main issue is grain hail. As the seawater is still quite warm and the upper air is cold, a focus for next week is that in the colder nights the land may rise with short-term frostbite, especially in places with low soil heat. In terms of uncertainties in the ECMWF cluster scenario, we see an Atlantic Ridge scenario for the period up to 20 November in almost all solutions. During the next period, we gradually see the number of solutions increasing with a zonal flow.

Multi-day Summary
Gradually colder with in the course of next week chance of light frost in the nights. Occasional showers with increasing chance of a winter character.

EPS Period Summary
Occasional weather with temperatures initially below the long-term average and chance of winter rainfall. Gradual transition to a softer weather type with temperatures around or slightly above the long-term average.

Valid from Sunday 16 November to Friday 28 November