Complex sentence: In 1944, four B-25Ds were converted for weather reconnaissance by the 53d Weather Reconnaissance Squadron, originally called the Army Hurricane Reconnaissance Unit, now called the "Hurricane Hunters".
Split into simpler sentences: In 1944, four B-25Ds were converted for weather reconnaissance. One later user was the 53d Weather Reconnaissance Squadron, originally called the Army Hurricane Reconnaissance Unit, now called the "Hurricane Hunters".