Several days ago when I was looking at the GFS and especially the EURO models in the medium range, they were going record to all-time record heat across a good part of the nation by today. Serious records, like well above 100 F, some areas breaking 110 F. It looked epic and convincing. While the Euro and the GFS are good at long-range predictions, they are not perfect, and today, it’s time to admit they were wrong about this heatwave. Even up until Monday morning, they were still holding on, but already backing off, a degree or two each day. So what happened?
Two things happened: 1) The big cooldown in the Northeast was WAY MORE INTENSE than predicted. This kept the northerly flow going much longer than predicted. It was initially supposed to only be 1-2 days, with Sunday being the last day. Yesterday, Tuesday, we still had influence here in South Carolina as it dropped into the high 50s for overnight lows. For South Carolina, that’s chilly for late June. The lower dew points last a lot longer and also helped to cool the atmosphere just enough. 2) The actual strength of the ridge was a lot stronger last week than this week. They were about equal several days ago, but the upper-level heat dome was just not as strong. If the heat dome is not as strong up above, it won’t be as hot down below near the surface. When the trend started this weekend I should have latched onto it, but Monday morning I was still holding on. Now, it’s not going to happen. Bad on me.
But it’s still going to be hot. Make no mistake about it. Even taking 4-8 degrees off of the models, it’s still going to be searing hot today across the Carolinas and Tennessee. Records are still in jeopardy. It’s still going to be around 100 F. Just not well into the 100s. The heatwave rotates south and west tomorrow and by Friday is in the lower Mississippi Valley and into Texas. This weekend it rolls from Texas back into the Mississippi Valley before the heatwave ends. Still lots of 90s and 100s. Still a good heatwave. Just not epic.
Looking ahead to next week, the last week of June, it’s looking closer to NORMAL across a good part of the nation. If anything, maybe a touch below normal from the Great Lakes to the Plains and the southern Rockies. That’s a relief, especially in the Great Plains where the heat has been reminiscent of 1988, the brutally hot and devastating summer which outside of the 1930s dust bowl, is the standard by which all other hot summers are judged. In terms of severe weather, there really isn’t a whole lot of it. If things do pop up, we’ll let you know.