Tropical storm (SSHWS/NWS) | |
![]() Tropical Storm Alpha making landfall near Barahona in the Dominican Republic | |
Formed | October 22, 2005 |
---|---|
Dissipated | October 24, 2005 |
Highest winds | 1-minute sustained: 50 mph (85 km/h) |
Lowest pressure | 998 mbar (hPa); 29.47 inHg |
Fatalities | 26 direct, 17 indirect |
Areas affected | Haiti, Dominican Republic |
Part of the 2005 Atlantic hurricane season |
Tropical Storm Alpha was the 23rd name storm of the 2005 Atlantic Hurricane Season. The cyclone developed from a tropical wave that passed through the Windward Islands on October 19. A weak low pressure area formed in the wave, and organized enough to become a tropical depression on October 22, 180 mi (290 km) southwest of San Juan, Puerto Rico. It turned to the northwest and strengthened into a tropical storm prior to landfall near Barahona, Dominican Republic the next day. The passage over the island weakened the system, and it was downgraded to tropical depression status before moving northward off the coast of Hispaniola. Alpha remained in this diminished state while moving north before being absorbed by the powerful circulation of Hurricane Wilma on October 24 north of the Bahamas.
Alpha brought several inches of rain and 50 mph winds to Haiti and the Dominican Republic. Flooding and mudslides damaged infrastructure, including utilities and hundreds of homes. Twenty-six people died, and several hundred families were left homeless.
Storm History
editTropical 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
Alpha's origins were from a tropical wave that developed near the Windward Islands on October 20.[1] Satellite images indicated that a low pressure center associated with the tropical wave formed near Barbados and moved west-northwest with increasing convective activity. In an area of light wind shear, the convection increased and doppler weather radar data from Puerto Rico detected a well-defined cyclonic circulation.[1] On October 22, the area of low pressure organized into Tropical Depression 25, southeast of Hispaniola.[2] Shortly thereafter, satellite imagery indicated that a closed circulation had developed, and the associated convection had started banding.[3] Later that same day, the depression had organized enough to be upgraded to Tropical Storm Alpha; this was the first time the National Hurricane Center had to use a Greek name for an Atlantic hurricane.[4]
When Alpha came within the Doppler weather radar range of Puerto Rico, the radar suggested that an eyewall-like feature had developed.[5] Alpha was tracking along the southwest edge of a subtropical ridge.[5] With nearby Hurricane Wilma's large circulation, Alpha was experiencing strong southerly flow from Wilma.[5] Alpha, with it's small circulation, was then faced with the mountainous terrain of Hispaniola, which led forecasters to believe Alpha was soon to dissipate.[6] Shortly after Alpha reached its peak intensity on October 23 its wind decreased. While convection remained in bands, the low level circulation was disrupted by land, thus, leaving a very ill-defined center, which made locating the center difficult.[7]
Late on October 23, Alpha made landfall in Hispaniola, quickly decreasing in intensity as it did so.[8] After making landfall, the storm had weakened, leaving it just between tropical storm and tropical depression status.[8] Because of the weakening, and the strong southerly flow from nearby Hurricane Wilma, it was hard to determine weather a low-level circulation was present.[8] However, satellite imagery suggested that a new center had developed over open waters to the north of Hispaniola.[8] It was downgraded to a tropical depression early the next day, now re-emerging over open waters.[9]
The storm soon developed an elongated center of circulation which indicated that the system was weakening.[10] On October 24, a low-level center was not present any longer, and only a small area of convective activity persisted, thus, the system dissipated, and was a remnant low pressure system when the National Hurricane Center issued their last advisories of Alpha.[11] Shortly after, the remnant low was absorbed into the circulation of Hurricane Wilma on October 25.[1]
References
edit- ^ a b c Avila (2005). "Tropical Storm Alpha Tropical Cyclone Report" (PDF). National Hurricane Center. Retrieved 2008-01-25.
- ^ Roberts/Knabb (2005). "Tropical Depression 25 Public Advisory #1". National Hurricane Center. Retrieved 2008-01-25.
- ^ Roberst/Knabb (2005). "Tropical Depression 25 Discussion #1". National Hurricane Center. Retrieved 2008-01-25.
- ^ Mainelli/Knabb (2005). "Tropical Storm Alpha Public Advisory #3". National Hurricane Center. Retrieved 2008-01-25.
- ^ a b c Franklin (2005). "Tropical Storm Alpha Discussion #3". National Hurricane Center. Retrieved 2008-01-25.
- ^ Franklin (2005). "Tropical Storm Alpha Discussion #4". National Hurricane Center. Retrieved 2008-01-25.
- ^ Avila (2005). "Tropical Storm Alpha Discussion #5". National Hurricane Senter. Retrieved 2008-01-25.
- ^ a b c d Avila (2005). "Tropical Storm Alpha Discussion #6". National Hurricane Center. Retrieved 2008-01-25.
- ^ Rhome/Stewart (2005). "Trpical Depression Alpha Discussion #7". National Hurricane Center. Retrieved 2008-01-25.
- ^ Stewart (2005). "Tropical Storm Alpha Discussion #8". National Hurricane center. Retrieved 2008-01-25.
- ^ Beven (2005). "Tropical Depression Alpha Discussion #9". National Hurricane Center. Retrieved 2008-01-25.