Every day, KNMI meteorologists analyze and interpret the results of the Hirlam, ECMWF and Harmonie weather models. Below you can read their findings, particularly educational material for those who want to understand more about the weather on the maps and in the graphs.
Please do mind: due to the dynamic nature of this information, we use a machine translation, so please mind the possible translation errors.
Short-term to + 48 hours | Guidance multi-day model review
Synopsis
A high-pressure area over Scandinavia has an extension to above Russia. An altitude above the Channel slowly pulls east. Monday evening and in the night to Tuesday it travels over the Netherlands north-east to north, after which it becomes more or less stationary. Around the height layer on Monday, a peripheral disturbance from Western France to the west of Belgium. On Tuesday morning, this ground floor moves northwest of the Netherlands and becomes stationary above the southern North Sea. Monday evening, an old occlusion of the altitude over the Netherlands draws north. The frontal system (occlusion) of the peripheral disturbance moves northwards in the night to Tuesday across the Netherlands and is stationary just north of the Wadden, the occlusion turns west again on Tuesday. On Wednesday, the layer is filling the Netherlands southeast. In doing so, the precipitation activates the north flank of the layer.
Model assessment
. The position of the ground layer is now almost identical in Harmony and EC and the location and timing of the precipitation is similar. A focus is the type of precipitation. Today mainly rain, possibly some wet snow. The temps are close to (wet) snow. Tonight, the precipitation above the north passes into snow (cooling by falling precipitation), where accumulation is possible. Harmony and EC come with on a large scale 1-3 cm in the northern half, local 3-5 and very local more. Because the models are often on the high side, we start from 1-5 cm to the north. The last runs also come with some snow and accumulation in the west (also due to cooling by falling precipitation). Let's take a look at this. For now, code yellow is enough for the north/northeast. Another focus is the boundary layer cloud. Harmony already calculates ST above the south, we don't see this at present. Tonight and tomorrow with the approach of the layer, the ST chance is clearly increasing. We consider this realistic.Issues
Wind
Especially on Tuesdays there are still differences between Harmony and EC exports. Harmony expects an 8 Bft and EC 7 Bft in the German Curve. It depends on the core pressure (in Harmony output slightly lower than in EC output) of the low how high the wind speed becomes.
Visibility
Monday morning through the polluted air moderate vision. In moderate snow < 1000 m.
Temperature
Today around 3 degrees. Tonight no frost, but in the north in the snow close to zero. Tuesday significant differences: Tmax from 6 °C in the southeast to just above zero in the northeast of Groningen. In the night to Wednesday in a large part of the country probably no frost, only in the area where snow fell in the north just below zero. Wednesday during the day similar large differences: from slightly above zero in the extreme northeast to 7 °C in the southwest.
Cloud
Fields high and high clouds, in the frontal zones mainly layered clouds. Monday and Tuesday in the precipitation zone of the fault layered clouds with ST/NS. For the layer ST < 500 ft.
Precipitation
Precipitation starts like rain, but some wet snow is possible given the temps. A total of 5-10, regional 10-20 mm falls. In the night, the precipitation passes to Tuesday in the northeast in (wet) snow, mainly rain or wet snow. In the north and northeast the snow remains, accumulation several cm. Tuesday during the day it partly melts away. Wednesday in the (outer) north falls again (wet) snow, but additional accumulation seems small. In the last model runs, wet snow is calculated with accumulation in the west on Tuesday morning. Wet snow is not excluded, the risk of accumulation doesn't seem great. Models often exaggerate the accumulation.
Synoptic development
Initially we are dealing with a dipole block above Western Europe with an altitude in the surroundings of the Netherlands. It passes into an omega pattern whose axis is south-north-oriented over Western Europe. The height layer is then initially part of the eastern cyclonal side of the omega. The high ground is first above Scandinavia. It moves to the surroundings of Greenland and Iceland in the second half of the week. It then usually has a south-easterly foothill across Germany to Central Europe. In the long term, the axis of the blockade tends to move east, increasing the likelihood of a south-west current above Western Europe to about 50%.
Model assessment and uncertainties
The output is broadly consistent. (Wednesday: see guide model assessment). From about the middle of the week, uncertainty is growing. Predictability of the orbit of the altitude layer over Western Europe is small and moving. This also ensures low predictability in our environment. The cyclonal influence (from the altitude layer) lasts until Friday, however the precipitation chance is small after Wednesday, but there is a lot of clouds which keep the daily course in the temperature low. The transition to an omega pattern in the second half of the week is evident in the Eps output, but the exact form and location still depends on the behaviour of small-scale contributions such as the altitude layer and therefore there is still uncertainty. The position and shape of the elongator of the high in Greenland creates uncertainty to what extent cold air from Scandinavia can reach the Netherlands. Compared to the exports of the previous 2 runs, the EC0912 Eps output is considerably colder, mainly due to less spread in the position of the back axle. In almost all members it is quite cold and dry until Monday with daytime maximums of several degrees above zero and at night light, during the weekend also moderate frost. At the weekend, the risk of sunshine increases significantly due to the high pressure influence. After Monday, the south-east to south-west current, in a proportion of the members, including oper- The probability of precipitation increases to about 30%.
Multi-day Summary
Large (90%) risk of fairly cold weather with night light, later locally moderate frost. Maximum temperature usually several degrees above zero. Wednesday in the north chance of snow. Then cloudy, during the weekend long sunny periods.
EPS Period Summary
First large (90%) chance of dry, (free) cold weather with sun. The chance of (free) soft and variable weather increases to about 60%.
Valid from Wednesday 12 February to Monday 24 February
Netherlands
Wind forecast nodes
Beaufort wind forecast
Wind forecast + air pressure
Wadden Sea
Wind forecast nodes
Beaufort wind forecast
Wind forecast + air pressure
IJsselmeer and Frisian Lakes
Wind forecast nodes
Beaufort wind forecast
Wind forecast + air pressure
Zeeland
Wind forecast nodes
Beaufort wind forecast
Wind forecast + air pressure