Monday, July 20, 2009

2009 PHS

The 2009 Pacific hurricane season is an ongoing event in the annual cycle of tropical cyclone formation. The season officially started on May 15 in the eastern Pacific, and on June 1 for the central Pacific, and will end on November 30, 2009. For the first time in ten years, no tropical depressions formed during the month of May. This inactivity continued into the early part of June and was the least active since 1994.[1] The first named storm of the season did not develop until June 21, marking the second latest start to a Pacific hurricane season since reliable records began.
Tropical Depression One-E

An area of disturbed weather persisted off the southwest Mexican coast on June 15.[5] It moved slowly west-northwestward, developing an area of low pressure as it became better organized.[6] The system continued to organize, and on June 17 the National Hurricane Center (NHC) noted the likelihood for tropical cyclogenesis, although at the time the circulation was not well-defined.[7] Subsequently it organized further,[8] and early on June 18, the NHC initiated advisories on the first tropical depression of the 2009 season about 370 miles (595 km) south-southwest of Mazatlán, Mexico.[9] Deep convection persisted near the southern portion of the depression; however, the northern portion of the depression was partially devoid of convective activity. A mid to upper-level trough situated over the Baja California Peninsula led to a northward movement of the depression.[8] The system remained disorganized most of its lifetime due to shear. One-E dissipated as it made landfall early on June 20.[10]

On June 19, 2.44 in (62 mm) of rain fell in Mazatlán, near where the remnants of the depression moved ashore.[11] High winds in Mazatlán knocked down several trees, cutting power to numerous residents. Heavy rains also triggered street flooding throughout the city.[12] Landslides along major roadways caused several accidents, one involving a bus that was damaged by rocks.[13]

Hurricane Andres

Andres originated from a broad area of disturbed weather associated with remnant of tropical depression One-E persisted off the southern coast of Mexico after Tropical Depression One-E formed, which generated shower and thunderstorm activity. At this time, the National Hurricane Center remarked upon the possibility for tropical cyclone formation.[14] On June 20, associated convective activity began to organize.[15] The system continued to develop, though by early on June 21, the low-level center had not yet become well-defined.[16] Later that day, the NHC declared that Tropical Depression Two-E had developed near the southern coast of Mexico.[17] Early the next day, the depression strengthened to the first tropical storm of the 2009 season and was named Andres. Andres strengthened in a steady stage eventually becoming a hurricane around 2 p.m. PDT on June 23, although it was possible that Andres became a hurricane earlier that day. [18] It also brought gale force winds to the Mexican coast. The system then weakened back to a tropical storm shortly after. High shear and dry air weakened Andres rapidly to a depression on the 24th, with the NHC issuing their last advisory that day.

Rough seas produced by the storm led to the drowning of a fisherman off the coast of Mexico. Flooding caused by Andres resulted in the evacuation of 200 people and 14 shelters were opened to accommodate the evacuees.[19]

Tropical Storm Blanca

On July 6, an area of disturbed weather situated approximately 420 mi (675 km) south-southwest of Baja California, Mexico was designated as Tropical Storm Blanca by the NHC, skipping tropical depression status.[1] The newly upgraded storm featured deep convection and a possible eye-feature around the center of circulation. Favorable conditions allowed the storm to intensify later that day.[2] Large convective banding features developed around the central dense overcast during the morning of July 6, as winds around the center of the storm increased to 45 mph (75 km/h). All forecast models agreed on further intensification of the storm; however, some models indicated rapid intensification before the storm moved into a less favorable environment.[3] However, this did not happen, and the system moved into colder waters, weakening to a tropical depression on the 8th, before finally becoming a remnant low on the 9th. The remnants began moving northwestward, and they dissipated early on July 10, a thousand miles or more west-northwest of Baja California. The remnants of the storm brought unseasonable rainfall, although negligible, to parts of southern and central California on July 11.[4] The moisture reached the region after being pulled northward by an upper-level low off the coast of Oregon.[5] The storm produced usually heavy rainfall, exceeding 2 in/h (50 mm/h) at times.[6]

Hurricnae Carlos

On July 9, showers and thunderstorms associated with an area of disturbed weather located about 900 miles south of the southern tip of Baja California became more concentrated around a developing low level centre. In the early hours of July 10th, the system was designated as Tropical Depression Four-E, and the NHC commenced advisories. Around 2:00 p.m. PDT, the system strengthened into Tropical Storm Carlos. On July 11, Tropical Storm Carlos strengthened into a minimal Category 1 hurricane. It also developed a small eye feature, based on satellite presentation. However, by morning of July 12, the National Hurricane Center noted that the small eye-like feature had disappeared. Overnight on July 11 through the morning of July 12, the structure of Carlos became disorganized for unknown reasons. Deep convection contracted to a small region around the center of circulation and the overall size of the storm diminished. In the early afternoon hours, the continued degeneration of the system led to its downgrade to tropical storm status. Throughout the rest of the 12th and until mid-day on the 13th, Carlos continued to weaken, but the weakening trend slightly abated, enough for Carlos to reintensify slightly, from 50 mph to 65 mph. A statement from the NHC that day predicted Carlos to either stay at 65 mph for the next three days or so, or to constantly fluctuate in intensity. However, by July 14, a new eye wall developed and Carlos was given hurricane status again. It rapidly intensified to a peak of 90 knots, or 105 mph (at 0900 UTC on July 15), and the NHC noted the distinct "pinhole eye feature" in their TWD. By the end of July 14th, the eye had started to get less defined, and on the 15th, the system began a weakening trend. On July 16, Carlos degenerated into a remnant low, and the final advisory was issued. [1]

Tropical Storm Dolores

On July 14 a sprawling area of disturbed weather to the south of Baja California showed signs of tropical organization, and advisories on Tropical Depression Five-E were initiated that day. The depression soon strengthened into a tropical storm, being named Dolores during the morning of July 15, and later that day began developing good banding features as well as good convection. Dolores strengthened to peak winds of 50 mph early on July 16. But, later that day, the deep convection associated with Dolores began to weaken, and the storm began a slow, but sure weakening trend. Dolores weakened to a tropical depression late on the 16th, and by early the next day, all deep convection had been lost, and the NHC issued their last advisory on the weakened Tropical Depression Dolores, as it quickly dissipated over cooler waters and under adverse shear.

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