04/13/2023, 11:55 am EDT

Daily Tropical Feuture: Colorado State University 2023 Seasonal Tropical Cyclone Forecast

Colorado State University 2023 North Atlantic tropical cyclone forecast indicates 13 storms, 6 hurricanes, and 2 intense hurricanes with an ACE index of 100. The forecast is very close to the Climate Impact Company forecast issued in late March (12/7/3/92). CSU Hurricane Seasonal Forecasting ( The forecasts are slightly below long-term averages held back by El Nino risk although a warmer than normal North Atlantic supports over-achieving strength of the storms that do form. The CSU risk of a major hurricane striking the Gulf Coast is near average (28%). Risk of an East Coast strike is 21% (also near average). Significant increase in confidence of supporting forecast factors is expected with the early June update. For now, CSU, CIC, and TSR/U.K. are all in very close agreement.
04/06/2023, 9:45 am EDT

Tropical Feature: Tropical Storm Risk U.K. North Atlantic 2023 TC Outlook

Tropical Storm Risk/U.K. issues their 2023 North Atlantic tropical cyclone outlook… 12 tropical storms; 6 hurricanes; 2 intense hurricanes. 82 ACE index. CIC forecast was 12/7/3/92. TSR risk report… Tropical Storm Risk (TSR) for long-range forecasts of hurricane, typhoon and cyclone worldwide The TSR lower than normal amount forecast is based primarily on stronger than normal trade winds across the North Atlantic tropics and suppressed heat of North Atlantic SSTA in the tropics between the Caribbean Sea and Northwest Africa coast. Climate Impact Company does not whole-heartedly agree with that outlook. Dynamic models are forecasting a warm North Atlantic basin and are discounting risk of the North Atlantic warm hole (NAWH) south-southeast of Greenland common in the 10-year climatology. If so, the thermal gradient in North Atlantic SSTA is reduced resulting in below normal trade winds. Additionally, all dynamic models are forecasting warm SSTA in the North Atlantic tropics east of the Caribbean Sea. The dynamic models may be too warm, but likely warm enough to allow at least normal trade winds and  marginally warm SSTA in the outer tropics. ENSO is “uncertain” based on the TSR forecast while Climate Impact Company is forecasting at least a weak El Nino.  Presence of weak El Nino has a suppressing influence on seasonal TC activity in the North Atlantic. However, the warm SSTA in the tropics should keep seasonal activity fairly close to normal although ACE index is moderately below normal. Bottom line: Seasonal activity in 2023 is below the active period of the past 7 years. However, at least 1 or 2 hurricanes could threaten the Gulf and/or Southeast U.S. Coast. There is disagreement on the ENSO and North Atlantic SST environment. This sentiment is likely stated by CSU in their Apr. 13 outlook. Implied is below average forecast confidence. Expect substantial increase in confidence with early June updates by CIC, TSR and CSU. The NOAA outlook is issued in late May.