I wanted to touch on the setup again and something pretty amazing that’s happening. First, here’s 4 surface maps. July 5th, 21st, 25th, & 30th 2013. We all remember the powerful Bermuda High which brought the longest heat wave to some areas and unprecedented “continous” high dewpoints. Then at one point the flow was East to West… Storms, Satellite, and even an Upper Level low was moving westward. That was amazing to see in itself…
Then around July 20th the first of multiple cold fronts “trys” to push to the coast. I say trys becuase it barely made it and then dissolved fast. (Top right image) At this point the Atlantic Ridge was still strong and just putting up a fight.
Then comes another one pushing eastward and on July 25th it actually pushes off the coast. Enough cold air behind it to produce some record lows here and there. (bottom left image). The Bermuda High now out of the picture and weaker.
Then comes this past one on July 30th. (bottom right image). Again goes off the coast. Refreshing dry mornings and seasonable days. Before this front came through there was a slw moving ULL over the Upper midWest and Great lakes producing numerous Record lows and Record low Max temps. Some areas 20-30 below normal. Should of been in the 80s/90s and barely got out of 60s/70s during the afternoon.
Now here’s a look at the 500mb heights which gives a better idea of how the pattern was. July 8, 21, 25, 29, 2013. I had realized one thing few days ago… the Western Ridge never left. The sole driver of the heat (hottest July for some) in the East was that Bermuda High/Atlantic Ridge. Once that shifted back out to sea we are now entering the pattern we were in with ULLs and troughs moving in the NorthEast.
Notice the top right image (July 21st) the Atlantic ridge finally shifting east.
Bottom left (July 25th) the troughs are starting again
Bottom right (July 29th) the record cold Upper Level low.
A sign of the pattern changing again. While I think the Atlantic ridge will flex its muscles and try to come back, this pattern is more typical of Fall not Summer. Steve has a great discussion on whats driving this pattern. If you’re not a member I definetly recommend it; the discussions, the knowledge and the info is priceless. Could fall be starting a month early? Maybe. Long range shows yet another Upper Level low (impressive one) coming down.
Just keep in mind one thing….All these ULL, fronts and troughs are pushing and keeping away that ridge farther and farther so there might be a chance it doesnt come back in August.
Here’s a look at the Record Cold temps past 7 days. It speaks for itself.
1,122 Record Cold Temps set, 173 Record Warm temps.
Hard to pick and choose a location when so many were like Garden City Kansas where they didnt get past 64° when normal high was 92°F.
Moving forward, I dont think this was a fluke. Models continuing to show another round of reord cold temps possible for Eastern Half of U.S (I think will be confined to Upper MidWest, OV and New England next week) And then maybe another round for around August 9th. (keep an eye on this one)