Tropical Storm Julio (2008)

Map plotting the storm's track and intensity, according to the Saffir–Simpson scale

Map key

Saffir–Simpson scale

  Tropical depression (≤38 mph, ≤62 km/h)
  Tropical storm (39–73 mph, 63–118 km/h)
  Category 1 (74–95 mph, 119–153 km/h)
  Category 2 (96–110 mph, 154–177 km/h)
  Category 3 (111–129 mph, 178–208 km/h)
  Category 4 (130–156 mph, 209–251 km/h)
  Category 5 (≥157 mph, ≥252 km/h)
  Unknown

Storm type

Tropical cyclone

Subtropical cyclone

Extratropical cyclone, remnant low, tropical disturbance, or monsoon depression

On August 20, a tropical wave became discernible about 800 miles (1300 km) off the coast of Mexico,[2] which in the next day developed a large area of convection, or thunderstorms. Initially, conditions were unfavorable for development, due to strong upper-level wind shear.[3] Tracking northwestward parallel to the Mexican coast, the system became better organized on August 22,[4] though later that day its structure deteriorated.[5] On August 23, a strong area of convection developed and persisted near a circulation center, despite strong wind shear. With banding features becoming more prominent, the National Hurricane Center (NHC) classified the system as Tropical Depression Eleven-E about 345 miles (555 km) south-southeast of the southern tip of the Baja California Peninsula.[6]

The tropical depression initially moved northwestward around the southwestern periphery of a ridge over Mexico.[6] Convection continued to develop to the west of the center,[7] and late on August 23, a ship report confirmed the depression intensified Tropical Storm Julio.[8] Initially, the persistent shear left the center partially exposed from the thunderstorm activity, though upper level conditions gradually became more favorable for strengthening.[9] On August 24, Tropical Storm Julio attained peak winds of 50 mph (85 km/h) as intense convection developed near the center.[10] Shortly thereafter, the center became difficult to locate,[11] and late on August 24 the storm moved ashore along the southwestern coast of the Baja California Peninsula.[12]

Tropical Storm Julio quickly weakened over land, although it initially maintained strong convection near its center.[13] By early on August 26, however, the low-level and upper-level circulations separated, with the upper-circulation continuing quickly northeastward into mainland Mexico; the low-level circulation slowed as it entered the Gulf of California, after having been separated from its deep convection.[14] Later in the day, the NHC discontinued advisories after the storm failed to maintain enough organized convection to be considered a tropical cyclone.[15] The remnants of Julio were absorbed by a thermal low over the Mojave Desert on August 27.

Tropical Storm Julio over Baja California Peninsula on August 25.

Shortly before it was named, the government of Mexico issued a tropical storm watch in the state of Baja California Sur, from Santa Fe on the Pacific coast around the peninsula to Buenavista along the Gulf of California.[16] About 24 hours prior to landfall, the watch was replaced with a warning from Santa Fe to San Evaristo, and the tropical storm watch was extended along both sides of the peninsula.[17] Prior to it making landfall, more than 2,500 families in susceptible areas left their homes. Officials opened several shelters in the area where the storm struck.[18]

As Julio made landfall, it produced lightning and locally heavy rainfall,[18] which left more than a dozen communities isolated due to flooding. The flooding damaged several houses and killed two people.[19][20] Winds were generally light,[18] although strong enough to damage a few electrical poles and small buildings.[21] In nearby Sinaloa, rainfall from the storm led to an emergency evacuation of 500 residents.[20]

Moisture from Julio developed thunderstorms across Arizona, including one near Chandler which produced winds of 75 mph (120 km/h); the storm damaged ten small planes at Chandler Municipal Airport, as well as a hangar.[22] The damages at the airport were estimated at $1 million (USD).[23] The storms also dropped heavy rainfall, reaching over 1 inch (25 mm) in Gilbert, which caused flooding on Interstate 17.[22]

On August 25, 2008, moisture from the remnants of Julio caused minor flooding in parts of the south-western region of the United States.

• List of Pacific hurricanes
• Other tropical cyclones named Julio
• Timeline of the 2008 Pacific hurricane season