[1] The seventh named storm of the slightly below average 2009 Atlantic hurricane season, Grace formed from an extratropical cyclone over the Azores on 4 October.

Grace had only minor effects on land, although while it was passing through the Azores, islands close to the storm's center recorded winds of up to 44 mph (71 km/h) and moderate rainfall.

Tropical Storm Grace originated from a large extratropical cyclone that formed along a cold front on 27 September, roughly 470 mi (755 km) east of Cape Race, Newfoundland.

[9] Shower and thunderstorm activity continued to diminish throughout the day on 5 October; however, Grace maintained tropical characteristics, namely a deep, warm core.

In their report, they argued that although the storm presented deep convection, an eye-like feature, and winds above 60 mph (95 km/h), the overall development of Grace was more similar to that of a mid-latitude non-tropical cyclone.

[25] While merging with the frontal system on 6 October, the storm's outer bands produced heavy rains and strong winds over parts of Portugal, resulting in some street flooding.

[31] One ship, the Cap Castillo (call sign A8PI5), recorded sustained winds of 45 mph (72 km/h) on 5 October, while located about 110 mi (180 km) south of the storm's center.

[1] Moisture from the storm's remnants fueled another, more powerful cyclone that caused flooding in parts of Belgium after producing upwards of 2.4 in (61 mm) of rain.

[3][33] However, a post-storm analysis concluded that Grace had actually become a tropical storm 12 hours earlier than initially estimated, placing its location of development further south, at 38.5°N.

[1] This marked the farthest northeast a tropical cyclone formed in the Atlantic basin, breaking the record set by Hurricane Vince in 2005.