On July 11, an area of low pressure formed east-northeast of Bermuda. The system moved slowly eastward over the next few days and deepened a bit, though the Atlantic waters at that latitude were only lukewarm and atmospheric conditions weren't ideal for development. At first, thunderstorm activity was disorganized and displaced southeast of the vorticity center, but a curved banding structure emerged by July 13, wrapping more tightly around the low-pressure center. The storm began to produce gale force winds as well. At that point, the low was still elongated and extratropical in apperance. On July 14, however, it became better defined and the system was classified Subtropical Storm Don. The subtropical classification was due to the broad and diffuse convective structure and its interaction with an upper-level trough nearby.
Don was named with 50 mph winds and actually weakened slightly during the following day. The center was meandering a great deal, but the storm generally moved northward through July 15. There was a ridge of high pressure steering Don from the west, and the storm began a slow clockwise loop around it as the ridge pressed eastward over the following days. Ocean temperatures under the system became yet colder and could not be totally offset by colder-than-usual upper-atmospheric temperatures. As a result, Don weakened to a subtropical depression on July 16. On July 17, the storm was reclassified as a tropical depression after separating from the upper-level trough.
Don strengthened into a tropical storm overnight but still looked unimpressive on satellite imagery. Around midday on the 18th, Don was halfway through its large loop and was moving south, which returned it to a more conducive environment with warmer seas and lower shear. Soon after that, the storm finally developed some consistent deep convection over the center. This allowed it to begin some modest intensification. It turned west, then northwest over the next couple of days. Around July 20, Don developed an eyelike feature at the center of its very small central dense overcast. The storm was so small that it struggled to mix the dry air out of the very compact circulation. However, it got a boost on July 22 from passing over the slightly warmer waters of the Gulf Stream and vaulted to hurricane strength, becoming the first hurricane of the 2023 Atlantic hurricane season.
Hurricane Don peaked with winds of 75 mph and a minimum pressure of 988 mb late on the 22nd. Overnight, the storm moved north of the Gulf Stream and sea surface temperatures underneath it began to plunge. The system was recurved toward the northeast and soon weakened to a tropical storm. It lost the last of its deep convection by early on July 24 and became post-tropical shortly after that. The remnants dissipated another day or so later.
The above image shows Don as a hurricane on July 22. The cyclone had an impressive but small core, and became a hurricane at a fairly high latitude.
Don was a long-lived storm by July standards; it lingered around the subtropical Atlantic over 10 days and became at the time the fifth longest-lasting July storm (including time both as a tropical and a subtropical cyclone). Subtropical points are squares in the above track, while tropical points are circles. Triangles denote points where the system was not yet named or post-tropical, and are not counted toward its longevity. Despite its long life, Don never affected any land areas.
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