Arlene formed into a tropical storm on the evening of 28 June 2011 in the Bay of Campeche in the southwestern Gulf of Mexico from an area of low pressure that had formed the day before just west of the Yucatan Peninsula. Arlene did not have time to fully develop and came ashore as a strong tropical storm two days later on the morning of 30 June near Cabo Rojo along Mexico's east coast with sustained winds reported at 65 mph. Although wind damage from the storm was relatively minor, Arlene brings the threat of heavy rains and flash flooding to the region as it continues to move inland. The

The National Hurricane Center (NHC) named Tropical Storm Arlene the first tropical storm of the 2011 Atlantic hurricane season on 29 June 2011 at 0000 UTC (7 PM CDT). The TRMM satellite had a good look at Arlene when it passed above on 29 June 2011 at 0502 UTC (0:02 AM CDT). At that time Arlene's winds were estimated to be about 34 knots (~39 mph) indicating that it was barely a tropical storm. TRMM's Microwave Imager (TMI) and Precipitation Radar (PR) data were used in the analysis on the upper left and show that Arlene was getting better organized and contained scattered heavy thunderstorms

The TRMM satellite again flew over tropical storm Arlene on 30 June 2011 at 0408 UTC before the first tropical storm of the Atlantic hurricane season came ashore in Mexico. Arlene had become a strong tropical storm with sustained winds of about 55 kts (~63 mph). The rainfall analysis above is from TRMM's Microwave Imager (TMI) and Precipitation Radar (PR). It shows that Arlene contained areas of very heavy rainfall. A few rain showers from Arlene were starting to reach Mexico and extreme southern Texas but at that time the most intense storms were still located in the Gulf Of Mexico east of