30
Day

After a mild past weekend across the Great Lakes and Northeast low-mid 90°  heat has spread back into the regions from the more persistent hot airmass entrenched farther south that has yet to peak in intensity. Some areas between the central and southern Plains and interior Southeast are forecast to reach the hottest temperatures yet this year midweek (low-mid 100s in Dallas) before all models abruptly end the most widespread and prolonged excessive heat of summer east of the Rockies by the end of this workweek (Aug 1). Latest model forecasts valid during the 6-10 day period are the coolest yet across the Midwest, South, and East including several consecutive days of well below average temperatures (70s-low 80s) deep into the Southeast. Longer range forecasts are less aligned in rate of gradual warming but relatively mild (seasonably cool) conditions are likely to linger across the Great Lakes and Northeast into the end of the 11-15 day period (Aug 10-11). An opposite scenario unfolding across the West this week is certain to replace recent widespread below average temperatures (both daytime highs and overnight lows) with above average heat, with exception of portions of the Southwest moderated by daily monsoon rainfall.  Model trends re-establishing above average Southwestern monsoon rainfall during the latter half of this coming week are associated with  more sustained Western focus of greatest U.S. heat ridging, which typically limits magnitude of warmth able to return to the Midwest and East mid-late August. That does not preclude a relatively warm end to summer skewed by greater magnitude overnight minimum temperatures across the Midwest and East associated with high atmospheric moisture (humidity) similar to that observed in June and July, but additional Northeastern heatwaves are considered unlikely.