June is typically a quiet month in the tropics, although activity this time of year is certainly not out of the ordinary. Tropical Storm Arlene whirled up rather quickly on Tuesday evening, after hurricane hunter aircraft found a closed circulation at the surface and sustained winds in excess of 40 miles per hour.
Arlene is a relatively weak tropical storm, but it's in an area that is very conducive for tropical development. The upper-level winds aren't very strong, which helps the showers and storms grow taller and taller into the atmosphere without being "ripped apart." This allows the overall storm to continue strengthening. It's also currently over some very warm waters in the Bay of Campeche near the coastline of Mexico. Arlene won't be over water for much longer as a landfall could occur as soon as Thursday morning along the coast of central Mexico. After landfall, the winds will begin to decrease, but this storm will pose a significant threat for flash flooding and mudslides over portions of Mexico. At this point, it doesn't look like this system will have any direct impact on the United States, even though parts of the desert southwest could desperately use some of the rainfall.
Elsewhere in the tropics, the weather is fairly quiet. It's also important to note that the peak of hurricane season doesn't usually occur until late August and early September. This season is still predicted to be an above average season with 12 to 18 named storms, according to NOAA scientists.