ECM “monthlies” maintain warmer than normal risk into the autumn season but due to El Nino influence begin a wet pattern across Southwest Europe next month likely to expand during autumn to help ease the drought.

A cold front pushing into extreme heat was the catalyst for exceptionally violent severe weather outbreaks extending from the Ohio Valley to New York City on Friday and throughout the Mid-Atlantic region on Saturday. NOAA/SPC tallied 1,602 severe weather events/reports for the 2 days.

In Europe, hot weather is regenerating across Southwest Europe in the 5-day outlook, surging northward in the 6-10-day forecast, and broadening across most of Central and Southern Europe in the 11-15-day projection. The ECM 15-day rainfall forecast emphasizes dryness over France and combined with intense heat drought will worsen dramatically.

The week-3 forecasts are cooler in the East according to most AI models and with weak MJO phase_7 and moderate -NAO there is some support for that projection. HOWEVER, during mid-summer with a vast hot air source region formed during June across the Southwest U.S., the AIFS and ECM Ensembles combine to emphasize the Southwest U.S. high pressure system entering week-3 muting an East Coast trough. CIC is siding with more impactful heat for week-3/week-4 forecasts including the Great Plains week-4.

In Europe, a worse-case scenario is unfolding. The late June heatwave core has shifted across Eastern Europe this week while beginning to regenerate in Southwest Europe/Northwest Africa (Fig. 2). In the medium range, combining GFS and ECM, the Southwest Europe heat expands and intensifies reaching U.K. days 6-10 and continues to expand eastward in the 11-15-day forecast. The hottest weather within this new heatwave expansion is across France.