The North Atlantic Tropical Cyclone Season So Far

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Highlight: 2020 Tropical Cyclone Season So Far

Tropical StormsHurricanesIntense HurricanesACE

Index

2020 so far17 (6.2)5 (2.8)1 (1.2)49.1 (48)
CIC forecast23135221
June forecast20104149
April forecast1683128
30-year NML13.87.03.0115
15-Year NML15.57.33.1114

Table 1: The 2020 tropical cyclone activity across the North Atlantic basin so far (compared with normal for this date). The progression in activity amount by CIC seasonal forecasts and the 30-year/15-year normal are also indicated.

Discussion: The tropical cyclone season across the North Atlantic basin (so far) is at a record pace regarding the number of tropical storms (17). However, the activity level is closer to normal with number of hurricanes and accumulated cyclone energy index (Table 1). Currently, Tropical Storm Paulette and Rene are each expected to reach minimal hurricane intensity and a third system moving off the West Africa coast is projected by operational models as a hurricane approaching the Caribbean Sea early next week. Streaks of upper shear across the North Atlantic tropics has suppressed the number of hurricanes so far. However, a lighter shear pattern is projected for a 4-week period from mid-September to mid-October. The CIC seasonal forecast is likely too aggressive with hurricane activity and ACE index. The June forecast may be the best for hurricane/ACE index in 2020 given current trends. Right now the warmest SSTA pattern is across the western North Atlantic basin where most upper ocean heat is located (Fig. 1). Any tropical cyclones moving into the very warm waters will likely intensify dramatically.

Fig. 1: The current sea surface temperature anomalies across the North Atlantic basin identify very warm anomalies for the western basin.