WeatherBlog 14 2019/20 | Daily greetings from the west

Sabine was followed by Victoria

Last week, we looked at low Sabine in this post. Sabine felt much more present in the media than Victoria and also caused more widespread gale-force winds (at the UK Met Office, Victoria is called Dennis this time). From a meteorological point of view, however, Victoria also had a lot to offer. Like Sabine, it originated from the strong westerly flow over the Atlantic. Victoria reached an impressively low core pressure of around 920hPa on its way towards northern Europe, making it one of the top 5 "deepest lows" in the North Atlantic. It underwent a bombogenesis (the WeatherBlog is happy every time it has the opportunity to use this beautiful word). This means that the core pressure drops by at least 1hPa per hour for at least 24 hours - in other words, the low intensifies extremely quickly.

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Victoria aka Dennis from a satellite perspective.

severe-weather.eu

In addition, Victoria was briefly accompanied by low Uta and they joined forces for a little dance. In the so-called Fujiwhara effect, two lows initially circle each other and rotate around a common center before they join together. This is observed more frequently with tropical cyclones, but rather rarely with extratropical depressions. The DWD has an animation of Victoria and Uta at the Fujiwhara Waltz.

Instead of wind records, Victoria brought one or two temperature records on Sunday thanks to warm air masses from the south. At 3106m, 3.9°C was measured at Sonnblick - the highest temperature ever recorded there in February.

Current situation and outlook

Since the passage of a cold front on Tuesday night, it is no longer quite so "hot", but still very mild and generally spring-like throughout the Alps. After the influence of intermediate highs yesterday (Tuesday), the next frontal system will touch us today and the day will be cloudy, especially north of the main ridge. It will also snow a little, but not very heavily. The Valais-Bernese Alps area will tend to get the best weather, but here, too, the alerts are unlikely to run out.

Gray and very warm last Sunday in the Tyrolean lowlands. — Grey and very warm last Sunday in the Tyrolean lowlands
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LH

Thursday will be almost completely sunny again and Friday should also offer good touring weather, albeit with a little more cloud. It will be very mild again at the weekend - even milder than it already is. The frontal zone will move a little to the north and we will be on the anticyclonic side and in the area of influence of very warm air masses in the south. As already mentioned, the strong westerly basic current will remain with us for the time being. While it will be mainly warm in the Alpine region, the series of strong storms will continue uninterrupted in northern Europe.

The AO index, a measure of the strength of the polar vortex, recently reached a new record value and the related NAO index is also clearly positive. All in all, and with minor reservations, the signs point to west, west, west well into the crystal ball range.