The marginal oceanic/atmospheric conditions they refer to are mainly anomalous:
1) Warmth in equatorial E. Pacific (ENSO 1.2 region)
2) Coolness in E. Tropical Atlantic (E of 60W)
3) High wind shear in MDR including Caribbean
4) Low Relative Vorticity in E. Tropical Atlantic

— Yaakov Cantor (@yconsor) May 4, 2023