Based On ACE Index, 2023 About 33% More Active Than Normal So Far

U.S. JUN/JUL 2023 Verification Using Constructed Analog Forecasts
08/22/2023, 10:12 am EDT
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Highlight: All activity out of the deep tropics right now, ALERT posted for TC development early next week eastern tropics, so far 2023 about 33% more active than normal.

Fig. 1: Climate Impact Company tropical scorecard identifying satellite features across the North Atlantic basin including T.S. Idalia and Hurricane Franklin, the axis of upper shear, and an ALERT posted for the easter tropics for early next week. The 2023 season so far data is also provided.

Discussion: Tropical Storm Idalia rumbled through the Southeast U.S. yesterday and overnight and has quickly exited the Carolina Coast this morning. Idalia is forecast to move east and southeast during the next 2-3 days and then northeastward across Bermuda early next week with sustained tropical storm intensity. One (of 8) tropical cyclone model returns Idalia to hurricane strength near Bermuda. Hurricane Franklin will continue to accelerate northeastward and weaken to an extra-tropical storm by later weekend. Tropical Storm Jose will last another couple days while drifting northward and dissipating. An impressive Tropical Disturbance is located across the western Cape Verde Islands although an upper shear zone is likely to prevent much development as the system drifts northwestward. ECM indicates potential for tropical cyclone development near 30W in the deep tropics later this weekend. ECM suggests this system could become a hurricane although turning northwestward and likely staying out-to-sea mid-to-late next week. The remainder of the tropics is ALL CLEAR. The latest seasonal totals so far assembled by Colorado State University (CSU) indicates 11 tropical storms have formed with 3 reaching hurricane strength including 2 major hurricanes. The accumulated cyclone energy (ACE) index is 48.6 compared to the normal value for this date of 36.3. Using the ACE index, the 2023 season so far is judged about 33% more intense than normal.