Weather Photos blog

A very powerful and deep cyclone with strong cold front rips through the UK today and continues towards the Denmark and Netherlands later today. Accompanied by intense winds along the leading frontal convergence as seen in radar imagery below. This image shows a very well-defined cyclone with its center just NE of UK on the latest scans. Notice the convective squall-line along the front crossing SE UK, as well as spiral rainbands around the center low to the north.

There have already been reports of very intense and severe gusts from the UK, locally exceeding 100 mph = 160 km/h! Here is the latest report from MetOffice:

Stormy conditions affecting parts of the United Kingdom.
Gusts of 105mph have been reported at Malin Head; 102mph Edinburgh, Blackford Hill and 85mph at Gogarbank; 97mph Islay; 92mph Macrihanish; 92mph Drumalbin; 91mph Glasgow, Bishopton Airport and 84mph Prestwick Airport. Much of the rest of the UK is also experiencing very windy conditions, gusting 78mph at St Bees Head, Cumbria and 69mph at Mumbles in South Wales. Updated 11:05 03/01/2012

Source: Met Office website

The system will rapidly continue towards east when SFC front comes onshore over continental NW Europe. The frontal passage will be characterized with intense/severe winds as well as possible tornado given the impressive wind field/LL shear and helicity in place. More details can be read from ESTOFEX’s outlook for today:

A level 2 was issued for SE-UK, the Netherlands, N-Belgium, N-Germany, Denmark and adjacent offshore areas mainly for severe to damaging wind gusts. An isolated, strong tornado event can’t be ruled out.

… Parts of Ireland, UK, parts of the North Sea, Netherlands, parts of Belgium, N-Germany, Denmark, S-Sweden and the S-Baltic Sea….

The first feature of interest will be the eastward racing cold front, which moves off Ireland during the start of the forecast, then affects UK during the morning hours, Benelux during the afternoon hours and N-Germany thereafter. Of interest is the concurrence between the strong surface front and an IPV streamer, which are both well co-located in past few model runs. Propelled by a stout PVA max, the cold front passage will be pretty active in form of a forced line of convection (LEWP-like) and a solid line of enhanced convection is expected to race eastwards (e.g. over SE-UK, the Netherlands and Belgium, N/NE-Germany, NW Poland and parts of the Baltic Sea). A potent 30-40 m/s 700 hPa jet points into the backside of the cold front with 25-30 m/s at 850 hPa. Forecast soundings hint at a deeply mixed postfrontal air mass and numerous severe to damaging wind gusts are well possible along the cold front. There is not yet an indication that a concentrated swath of damaging wind gusts evolves along the cold front, so the level 2 was cut off onshore pretty fast. Also, with SRH values running off the chart, we can’t exclude embedded, rotating cells with a tornado risk. With expected LL CAPE/shear overlap, even an isolated strong tornado event is possible. The cold front gradually outruns strongest wind fields as the depression over SW-Norway slows down, so the overall risk gradually diminishes further east over the Baltic Sea. However, we decided to expand the level areas far to the east as the weakening phase of forced, convective lines are not well handled in global model fields.
The activity gradually diminishes south of the level 2, as the front drops to the south over France and W-Germany. It becomes aligned more parallel to the background flow and will be left behind strongest forcing to the north, so degree of organization becomes less betimes. Nevertheless, sporadic thunderstorms are possible as far south as CNTRL/E-France and S-Germany with cold front featuring either a more solid LEWP or numerous smaller narrow cold front rainbands. Strong/severe wind gusts will be the primary hazard.

Source: ESTOFEX outlook for Jan 3rd 2012

Stay tuned!

Quite impressive look over the maps and satellites the last two days. Sunny an unusually warm last decade of September continues over large part of Europe as the strong ridge persists. It transformed into a classic omega-block like pattern centered over CNTRL Europe while troughs are located on its left and right edges.

A quick look over the VIS satellite shows an extensive areas of almost no cloudiness over the continent. Surely a remarkable and quite rare event to see such a big area so clear and especially in early autumn, as such pattern would be more likely to occur in summer or mid winter months.

The next couple of days will bring slightly warmer temps into Alpine region when we still expect extremely warm to locally even hot temperatures in the Sat-Mon period.

This pattern will persist for another 5-6 days when it finally collapses with a changing pattern across Europe. Its becoming likely that deep trough from the polar low will expand southwards towards the Alps and bring the summer-killer cold front and end up the summer period completely. This upcoming event will surely be closely monitored, so stay tuned.

There is an Omega-like blocking pattern established over south-central Europe with two upper lows located on its edges. The eastern upper low is slowly moving SW-wards today with a strong NW-SE oriented cold front across the northern Balkans. A well-defined cold front is crossing Slovenia and it just passed my location at around 1420z this afternoon. Upper low and its frontal cloudiness is perfectly visible on the VIS satellite imagery…

It was actually quite interesting passage as we had clear skies through much of the day, then frontal cloudiness arrived from the east and the SFC front came without a single drop. Prior to the front, rather strong sea breeze was blowing up to 20-25km/h. It completely stopped at 4pm and then the cold front blasted in exactly at timeframe 4:20pm. Winds turned to ENE-erlies and already picking up to 60-70km/h now.

Here are a couple of interesting graphs showing the frontal passage at 4:20pm today… temperature and dewpoint drop..

Bora winds picking up to 60-70km/h already… notice the sharp change in wind speed and wind direction…

Bora winds are expected to reach 80-100km/h later this afternoon/evening as a result of strong pressure/temp gradient between Adriatic sea and northern Balkans. A closed low is bringing airmass change, though its not bringing any rain into the coastal area where we are facing serious drough this year. It will continue for at least another week or more…

Stay tuned for the future updates.