Observations show that soil moisture at the start of the period is considerably lower than average over much of central and northern Europe. This is consistent with the recent drier than average weather and suggests that natural water stores generally are depleted in these regions. At this time of year, hydrological forecasts for central Europe are sensitive to these initial conditions.

Sea surface temperatures in the North Atlantic Ocean are generally cooler than average; a trend which is predicted to persist through the three-month period. This tends to favour drier than average conditions over northern and central Europe. An emerging El Nino would also favour drier than normal weather in in northern Europe according to ERA Interim teleconnections.

There is a moderate signal for higher than usual sea-level pressure over northern Europe, which is associated with an overall tendency for drier and warmer-than-average conditions. Skill for meteorological predictions over Europe is generally low in summer, but the level of agreement between the different prediction systems is higher than usual, giving us more confidence in the forecasts.

The hydrological forecasts show lower than average streamflow over northern and central Europe, which is consistent with the initial hydrological state and the forecast tendency for drier conditions. This is particularly true in some of the source regions of the river Rhine. Indeed, streamflow outlooks for the Rhine in Germany highlight increased risks of low flow developing within this period.