What a cool time it's been!

The past 18 days have featured extraordinary weather in Annapolis! Temperatures have been below normal since about June 28th - and several days have featured temps much below normal. The culprit has been an anomalous upper-level low parked over the Great Lakes and southern Ontario, which anchored cool Canadian high pressure and northerly lower-tropospheric winds over the eastern 1/3rd of the U.S. since the end of June. See the two figures below: one, the 30-day temperature plot for Baltimore, and two, the mean 500 hPa geopotential height from June 28-July 11. Let's hope the trend continues for the rest of the summer!