The Summer Feedback LoopAdded : Tuesday at 9:29 Take a quick look at this chart :-
This is the Haines Index forecast. Not the most exciting of charts granted. But this shows the soil moisture level across Europe and you can see the dry soil up well across much of Western Europe.
This is important, as when soil is much drier or wetter than normal it aids in producing a feedback loop, especially seasonal ones. When the soil is wetter than average it tends to promote and allow cooler and wetter weather patterns to develop, especially during the Summer when the sun heats the land, evaporates the moisture from the soil which produces showers which falls as rain and continues to keep the ground moist. But when it's dry then the opposite happens. Lack of moisture means less showers and therefore less rain which results in drier soils.
One thing which we tend to look for at this time of year is the start of the European monsoon. This is where the European plateau heats up and the cooler, wetter air comes in from the Atlantic. It's a pretty regular event and happens most years in three distinct waves. The GFS ► seems to be picking up on this developing towards the very end of the latest run :-
But of course this is T+372 and should never be taken too seriously by any forecasters. That said, if we revert back to a more mobile weather pattern during the first week or two of June then that shouldn't come as a shock as it's simply the first wave of the monsoon (please ignore any ridiculous media concepts of the monsoon, it's not endless rain, but just a transitional period where nature balances out the temperature variations).
June tends to be the month where we see this happen (think Glastonbury and Wimbledon), but the intensity and length of this period will be important in determining how much moisture can be delivered to soils across Western Europe.
If drier than average, then the feedback mechanism will continue across Summer and this could result in some issues with lack of rain for some areas this Summer, especially across Western Europe.
METEOROLOGIST : MARSH |