Synopsis
A southwest current feeds damp air. A cold front is above the east. A wave in this cold front, currently (00 UTC) above the middle, is moving north. The wave and the front soon leave the (north) east this morning. Monday afternoon passes from the west from the large altitude trench. Tuesday we come under the influence of the front system of a low northwest of Scotland. The front system passes Tuesday afternoon and evening in (almost) geo-occluded form The Netherlands.

Model assessment
The position of the wave in the front is currently in the observations a bit further northwest than in the export. EC exports are still best on this. The main focus is on the visibility and cloud base in the boundary layer. We see a highly variable image with mist, in clearances temporary mist, and local St, sometimes with very low (<500 vt) base. The Ha43 eps gives low odds, but its position is too east, because the frontal wave in most members of the eps is too east. We do see that the chance of St in this Eps increases during the night (at the frontal wave, because of little wind and precipitation). Monday morning there is (except the far southwest) chance of turbulence stratus, chance in the Ha43 Eps is 50-80%. The Opers of Ha43 and EC also give a strong indication of this. Furthermore, this morning in the Ha43 export we see an expanding fog area above the north of the FIR. This is usually exaggerated, but it is a focus given the damp air and the still quite cool seawater. To the east of the FIR we are also currently seeing low clouds/mist in the satellite observations. Monday's convection is fairly consistent in the various outputs (height trench, daily corridor). In the night to Tuesday in the northeast a clear signal for (possibly dense) fog. Further southwest, fog is not excluded, but depending on the increase of wind and clouds in the approaching frontal system. In this system we see the usual difference in cloud base between the Ha43 and EC exports where EC exports are much too dry and Harmony exports are realistic.Attention

Wind
Monday and in the night to Tuesday, there is very little wind. Outliers in showers (see Ha43 export indicative), 25-30 kn. Tuesday during the day, the south wind is increasing strongly, outside port is 6 Bft probably.

View
Tonight there is local mist, if it clears up there is a chance of missing (see model assessment). In the north of the FIR this morning chance of fog (see model assessment). In precipitation further moderate visibility, during a strong shower poor visibility. On the night of Monday on Tuesday in the northeast a large (50-80%) chance of fog. The Ha43 eps can be used as a guide for the location, depending on the timing of the approaching frontal system (see model assessment).

Temperature
In clearances there is not enough daily activity. In the northeast it can be local 1°C in the night to Tuesday and Tuesday by day 18°C.

Cloud
At the cold front and especially at the wave mainly stratiform clouds. Also here and there (flards) St. We are following the current situation and the evolution of the wave from the Ha43 eps, with the remark that the wave is currently a bit more northwesterly. Both exports and the Ha43 eps give a realistic picture of where turbulence St can occur this morning. Above the north of the FIR, Ha43 shows an expanding fog area this morning, taking into account that this can happen (see model assessment). In the showers Cb with tops just above FL250. At the frontal system of Tuesday stratiform clouds where the risk of stratus above the North Sea and in the west of the country increases sharply in the afternoon and evening.

Precipitation
The precipitation at the wave has a predominantly stratiform character. Near the trough above the sea some showers, in the northwest of the FIR tonight and this morning possible with thunderstorm (CAPE 500-700 J/kg). Monday afternoon showers above land, CAPE between 500-1000 J/kg and up to about 20 kn effective shear. In the absence of linear forcing mainly single cells and multicells with a low level of organization. Thunderstorm probability is great, also based on both the "graupel" proxie in the Ha43 output and the EC lighting flash density output. Given the relatively high instability and low zero-degree levels (small) hail is possible. At the frontal system of Tuesday again stratiform precipitation.

Synopsis
A low west of Ireland creates a southwest current above our environment. This gradually brings warmer and damp air. An associated front passes in the course of Tuesday and an altitude trench on Wednesday making it variable. On Wednesdays and Thursdays the large-scale trough with the steering layer will lie a little further southwest of Ireland, making a high development above France. This high pulls north to our area. Our country will remain under the influence of this (blocking) high until Pentecost weekend, with the core first (just) to the east and later to the north of our country. The large-scale trough will then gradually lie further and further above the ocean, creating a high-pressure bond from the Azores to Scandinavia. During the week of May 25th a high pressure core develops in the southwest part of this band, which then moves north west of the British Isles (Atlantic Ridge). The current becomes north because of this.

Model assessment and uncertainties
Low pressure areas west of Ireland bring warmer and humid air with a southwest current. On Tuesday there is a back just east of our country, so there is little current. This gives the output a small chance of (close) fog. A frontal system passes in the course of Tuesday, on Wednesday followed by a high trench. So we are dealing with a rather variable weather with daily high precipitation opportunities. Due to the stormy weather type, the quantities will vary greatly from place to place. From Thursday we come under the influence of a high pressure area above our environment. The daily probability of precipitation decreases to around 10%. The temperature rises from around or below the long-term average to (clear) above it. After the Whitsun weekend, the temperature forecast is gradually uncertain, in most members there is a large-scale back from the Azores to Scandinavia, with the axis just northwest of our country. In a small part of the members (over 20%) this band already splits towards the end of the Whitsun weekend and we come under influence of an altitude layer, and later a low pressure area from the ocean. During the week of May 25th we see the cyclonity increase over Scandinavia, where we remain mainly under the influence of a high above the British Isles (largest part of the members, 60-70%). This creates a northern flow with a cooler and fairly dry weather type. In a minority of the ensemble (30-40%) low pressure areas from the southwest or west are approaching, but even then the flow pattern is strongly blocked and high pressure areas usually remain close. This creates a warmer, sometimes somewhat unstable weather type.

Multi-day Summary
Different with few showers, gradually dry and sunny from Thursday. Initially temperatures below the long-term average that rise from Thursday to above.

EPS Period Summary
Periods with sun, quite warm and mainly dry. During the week of May 25th, uncertainty in the temperature forecast is increasing, but the probability of precipitation remains relatively low.

Valid from Tuesday 19 May to Sunday 31 May