Formation of the North Atlantic warm hole (NAWH), the strongest since 2018 fuels an upper air pattern promoting hot and potentially dry high pressure ridge areas across the East U.S. and much of Europe for mid-summer. Dangerously hot weather is developing and the risk of continuation during July has increased significantly.

Earlier this week, Climate Impact Company updated the month 1-4 ahead outlook. Indicated was a wetter trend in the East/Southeast and drier/hotter trend in the West. Today's NOAA/CPC matches that sentiment. The East/Southeast should be prepared for flooding rains and increased risk of coastal tropical cyclone risk while the Northwest/West U.S. is hot and dry and headed for a hostile fire season later this summer.

The Nino34 SSTA is exactly normal (again) as meteorological summer arrives in the northern hemisphere. The APR/MAY 2025 multivariate ENSO index (MEI) was steady at -0.4. While oceanic ENSO is exactly neutral, atmospheric ENSO is borderline La Nina. In the subsurface, there is no change in the upper ocean heat anomalies which are slightly warm during recent weeks. A collection of operational Nino34 SSTA forecasts reveal a tendency toward weak La Nina for later this year.

-GLAAM has been common since the middle of last February. -GLAAM is present when mid-latitude jet stream flow is slower than normal increasing the risk of longwave trough presence and attendant storminess. Interestingly, the persistent -GLAAM produced widespread wet soil moisture changes around the northern hemisphere during meteorological spring.