During neutral ENSO, the Madden Julian oscillation (MJO) is normally active. During northern hemisphere summer, influence of the convection phase of the MJO causes an increase in wet monsoon moisture and tropical cyclone risk in neighboring longitudes. The ECMWF 14-day MJO forecast indicates anomalous convection in the tropical West Pacific (now) shifts eastward and across the tropical North Atlantic in 8-14 days.

Potentially due to the slow-down of the Atlantic Meridional Overturning Circulation (AMOC) and the natural variability of the Atlantic multi-decadal oscillation (AMO) and North Atlantic oscillation (NAO) the North Atlantic “cold blob” also known as the North Atlantic warm hole (NAWH) shifted east toward Europe in May and is responsible for an unusually cold and wet May Europe climate. The NAWH became more enhanced in 2013 and has been semi-permanent south-southeast of Greenland since that time.

The North Atlantic SSTA analysis reveals a developing cooler trend. The cool changes are in the Gulf of Mexico and the Bahamas. In the Gulf of Mexico, the unusually warm SSTA of earlier this spring causing increased low-level atmospheric moisture was used by passing low-pressure areas to unload historic rains on Louisiana into Texas the past 3-6 weeks. The energy provided by the anomalous warm SSTA is easing as the two-week SSTA trend is much cooler.

The semi-permanent upper ridge over a vast area of warm SSTA north and northeast of Hawaii and known as the “warm blob” present since 2013 has the usual attendant upper-level high-pressure ridge in-place. The compensating cool pool of SSTA south-southeast of Greenland has an attendant semi-permanent upper trough widening influence in May. Downstream from the Northeast Pacific ridge a subtropical low in the upper atmosphere persists over the Southwest U.S. inducing a moist inflow of moisture off the Gulf of Mexico to cause the Texas rains.