Weather Photos blog

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.

Looks like a TLC (=tropical like cyclone) will form in southern Mediterranean later this week. On the eastern flank of a strenghtening upper ridge over W-CNTRL Europe, a weakly cooled mid levels remain in place under the upper cold core low. This disturbance will be gradually shifting southwards during the next 72 hours and especially a WRF model shows a developing intense small scale cyclone starting on Wed morning. Characterized by strong pressure gradient, strenghtening wind field and well-defined inner core, it seems that a tropical like system formation will take place.

A look over the 6hrs precipitation map shows this well-defined inner core, with precipitation in the circle around the center. It surely will be interesting to monitor this rare event so early in the autumn period as such TLC formations are usually more likely to form later towards the winter months. In that time, usually polar trough transform into polar lows and occasionally result in TLC formation over still warm waters on southern Mediterranean sea. This time it seems that unusually very warm SSTs of Mediterranean are enough to support such formation.

An aforementioned gradually strenghtening ridge into W-CNTRL Europe will continue to support unusually warm and sunny period for much of Europe for at least another 7-10 days. When it peaks across central Europe over the weekend, its likely that near record values for month of October will be recorded over these areas. Both ECMWF and GFS have the ridge axis right over the Alps which looks ideal for extreme warmth/heat for southern Alpine region.

Stay tuned for future updates!

Unusually stable and warm pattern persisted over much of Europe during the last weeks, with much above average temperatures and much below average precipitation. This is slowly becoming a serious threat for the agricultures as drought is just around the corner if we don’t receive some rain soon. This year’s water balance (the difference between total rainfall and total evapotranspiration – pETO) across Slovenia and southern Alpine region is already between -50 and -100mm and it is just getting worse with expected sunny/warm conditions in the next two weeks. Such sunny/windy days like this week have daily pETO around 5mm, so one can imagine how fast this is worsening.

With persisting ridging over Europe there is also a lack of convective activity this year where no serious activity have been seen this season yet. However, there were only two cold frontal activities where the last front about a week ago was quite interesting. Please refer to the previous blog post for some photos or click here to see images in my gallery: First lightning strikes of the season (Prosecco, Italy) – 12/04/2011.

As mentioned earlier, stable weather is on schedule for the following week as a large omega-like block pattern persists over S-CNTRL Europe. However, there is some activity expected in SW corner of Europe where an upper low is wobbling west of Iberia. Here is the forecast for today I made at ESTOFEX…

At ESTOFEX, a level 1 was issued for mostly Alpine region, read more details below:

Storm Forecast
Valid: Tue 19 Apr 2011 06:00 to Wed 20 Apr 2011 06:00 UTC
Issued: Mon 18 Apr 2011 19:56
Forecaster: KOROSEC
No threat levels have been issued.

SYNOPSIS / DISCUSSION

The dominant feature on Tuesday is the moderate ridging over much of south central Europe. On its edges, two upper lows will be the focus for convective activity. One remaining quasi stationary over eastern Aegean sea / western Turkey where only marginal diurnal activity is expected in non-sheared environment.

Another developing potent upper low NW of Iberia and moving southwards will be the main focus for convection over Iberian peninsula. A surface cold front will set west of peninsula. SW flow ahead of the this cold front will continue advecting warm airmass northwards across the peninsula, resulting in unstable airmass. Several hundreds of MLCAPE will result but given the rather limited deep layer shear, severe storms are unlikely. A lack of large scale ascent will also limit the activity. But however, the complex topography should trigger convection over parts of Spain and Portugal as a result of strong daytime heating. Slightly better shear is located over southern Iberia where the strongest cells could become briefly organized with threat for some marginally large hail but not reaching severe criteria. Activity will be mostly diurnal driven and should diminish after sunset.

Source: ESTOFEX outlook from April 19th 06z until April 20th 06z 2011

Stay tuned for future updates!