Two named storms formed on Sunday, Tropical Storm Peter and Tropical Storm Rose, the 16th and 17th named storms of the 2021 Atlantic hurricane season. Both tropical storms are expected to remain weak and not become hurricanes. Rose’s formation marks the second straight year and only the third time in history in which the “R” named storm formed in the month of September.

Early Sunday morning, a long-tracked tropical wave developed into Tropical Storm Peter, the 16th named storm of the 2021 Atlantic hurricane season. As of 5:00 p.m. EDT Sunday, Tropical Storm Peter was centered near 18.4°N 57.8°W, and was moving west-northwestward at about 17 mph. Maximum sustained winds were 40 knots (45 mph), with an estimated minimum pressure of 1007 mb. Although Peter’s low-level circulation was fully exposed earlier, a burst of convection has developed just east of the low-level center. Although Peter is located over warm waters near 29°C (84.2°F), strong wind shear of around 25-30 knots (30-35 mph) is expected to persist for the next five days which will likely prevent the cyclone from strengthening. In fact, it’s likely that Peter will degenerate into a tropical wave in a few days. Peter or its remnants are expected to move west-northwestward through Wednesday, before turning north and eventually northeastward by late week. Since Peter is not expected to bring tropical storm force conditions to the islands and is expected to remain north of them, no watches or warnings are currently in effect to the Lesser Antilles.

Sunday afternoon, Tropical Depression Seventeen over the eastern tropical Atlantic blossomed into Tropical Storm Rose, the 17th named storm of the 2021 Atlantic hurricane season. This is the first usage of the name “Rose” in the Atlantic basin. As of 2:00 p.m. CVT (5:00 p.m. EDT) Sunday, Tropical Storm Rose was centered near 14.3°N 29.9°W, and was moving north-northwestward at about 16 mph. Maximum sustained winds were 35 knots (40 mph), with an estimated minimum pressure of 1005 mb. Rose has a narrow window for intensification with sea surface temperatures warmer than 27°C (80.6°F) while the vertical wind shear is expected to be less than 10 knots. However, 700-500 mb relative humidity values of less than 60 percent will likely slow the intensification rate, and is expected to prevent rapid intensification. In about 36-48 hours, the vertical shear is expected to decrease to greater than 20 knots (25 mph), which will likely cause Rose to weaken. Rose is likely to become a remnant low by late this week, if not sooner. Rose should continue on its current north-northwestward path without posing a threat to land.