Does another heat wave follow the current episode for next weekend? ECMWF says yes and forecasts a stronger event than currently taking place. The GFS is not nearly as hot. The question is whether the hot air source region in the Central U.S. pulses eastward (or not). GFS says no while ECM is (vigorously) yes! The precedent is set as last week’s Midwest heat wave has shifted into the East now. A second event is likely and given peak summer heat the next event could be hotter.

The Pacific tropical basin has observed no significant tropical cyclone activity since early June including no category-3 systems, the first time in the satellite measuring era (since 1966) according to the Australia Bureau of Meteorology. Using accumulated cyclone energy (ACE) index the seasonal activity (so far) for the Pacific basin is 20% of normal.

In 2020 the likelihood of at least 10 hurricanes given the very warm TNA pattern and no suppressing El Nino is expected!

The subsurface equatorial Pacific to the east of the Dateline is losing a moderate-strength cool signature which developed in May and signaled La Nina ahead. In recent weeks the cool anomaly has nearly disappeared. Subsurface support for La Nina evolution will need to rebuild.