After 4 record highs in 6 days I decided to look back at National Blend (NBM) guidance to see how it performed. In short, not great. Many of the high temps were outside the 95th percentile forecast.

Some of that is to be expected. If you blend a lot of model guidance together it will tend to smooth out extremes. This is an extreme pattern, so forecasters must dive into the details to decide when to deviate from the NBM.

Ensemble sit. awareness table provided clues with several days of ~+3 SD anomalies in the region, here centered just north of the GYX CWA. Add that mean 850 mb T was ~ 12C (typically translates to highs in the upper 70s), and there was a strong signal to go well above guidance.