Estimating Upper Air Pattern in Europe Late August Fig. 1-3: Mega-clusters late August upper air forecast across Europe. Discussion: Estimating the upper air pattern across Europe in late August is based on the latest run of the mega-cluster model averaging various operational models to produce most to least likely scenarios. The most likely pattern in late August is a sprawling ridge pattern common this past summer centered on Western Russia and extending west across much of Europe (Fig. 1). The scenario described implies anomalous warmth and dryness for Central and East Europe. The second-most likely scenario is a stronger more amplified upper ridge pattern which could produce late summer anomalous heat and certainly dryness for Central and North Europe (Fig. 2). The least likely scenario is a warm/dry ridge pattern affecting Northwest Europe only (Fig. 3). The bottom line is the most likely scenario is anomalous warmth and dryness for much of Europe in late August into early September. The dry climate should lead to a new Rhine River minimum at Kaub (Fig. 4). Fig. 4: Rhine River levels the past 30 days at Kaub.  

U.S. Weekly Soil Moisture Change Fig. 1: Rainfall required to end dry-to-drought condition across the U.S. and the weekly change annotated. Discussion: Strong soil moisture deficits remain in-place in the West, Southwest and South-central U.S. (Fig. 1). The largest rainfall deficits are in north-central Oregon and northeast Georgia. In the Great Plains drought extends from Texas to just south of the core of the U.S. Corn Belt. Last week the distinct trend was wetter in parts of the West and Southwest particularly central and north-coastal Texas. Meanwhile the East-central U.S. trended drier most notably in Alabama and also central Illinois. The NOAA/WPC 7-day rainfall forecast indicates 3-6 in. centered on the Mid-South U.S. drought area (Fig. 2). Fig. 2: The NOAA/WPC 7-day rainfall forecast indicates 3-6 in. across the Mid-South drought area.    

Rhine River Levels Continue to Lower Discussion: The summer 2018 drought across Europe most focused on Central Europe has caused river levels to lower toward historic low water levels. The Rhine River has lowered to values 25% of height observed in early summer at Kaub (Fig. 1), to 30% of the early summer level at Cologne (Fig. 2) and 40% of early summer values at Ruhrort (Fig. 3). There is some potentially significant rainfall (several inches) forecast by the GFS OP over the next week just west of the Rhine (Fig. 4). The 8-14 day forecast by the GFS OP is drier (Fig. 5). The GFS OP is the wettest forecast of operational models. Fig. 1: Rhine River level at Kaub has lowered to 75 CM (30 IN) today. Fig. 2: Rhine River level at Cologne has lowered to 120 CM (47 IN) today. Fig. 3: Rhine River level at Ruhrort has lowered to 210 CM (83 IN) today. Fig. 4: GFS OP day 1-7 percent of normal rainfall forecast. Fig. 5: GFS OP day 8-14 percent of normal rainfall forecast.