Tropical Storm Olga (2007)

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Tropical Storm Olga
Tropical storm (SSHWS/NWS)
Tropical Storm Olga (2007).PNG
Tropical Storm Olga near Dominican Republic landfall.
FormedDecember 11, 2007
DissipatedDecember 13, 2007
Highest winds1-minute sustained: 60 mph (95 km/h)
Lowest pressure1003 mbar (hPa); 29.62 inHg
Areas affectedPuerto Rico, Hispaniola
Part of the 2007 Atlantic hurricane season

Tropical Storm Olga was the fifteenth named storm of the 2007 Atlantic hurricane season. In the second week of December, after the official end of the hurricane season, a low formed east of the northernmost Lesser Antilles. It slowly gained tropical characteristics, and late on December 10, the NHC declared it Subtropical Storm Olga while just north of Puerto Rico. It is the first post-season storm since Tropical Storm Zeta in the 2005 season, making this season one of the few with activity both before and after the official bounds of the hurricane season. The storm made landfall on December 11 on the eastern tip of the Dominican Republic. Later that evening, Olga transitioned into a tropical storm just after making landfall. Olga tracked over Hispaniola and emerged in the Caribbean Sea. Strong wind shear and dry air caused Olga to weaken into a remnant low early on December 13.

The storm impacted many areas affected by Tropical Storm Noel a month earlier. In Puerto Rico, moderate rainfall caused one death. 37 fatalities were confirmed in the Dominican Republic, including twenty deaths due to the release of floodgates at a dam in Santiago Province. Two deaths were also reported in Haiti.

Storm history[change | change source]

Storm path

In the first week of December, a westward-moving upper-level low led to the formation of a broad surface trough well to the east of the northern Lesser Antilles.[1][2] With a strong ridge to its northeast, the trough tracked slowly westward, creating scattered convection and some cyclonic turning.[2] On December 8 convection began to persist in association with the trough and an upper-level low.[3] Early on December 9, officials at the Tropical Prediction Center began classifying the system using the Hebert-Poteat technique,[4] and several tropical cyclone forecast models expected its development of tropical characteristics.[5] The system, which included of a sharp trough with an area of gale force winds to its north, continued westward through an area of moderately warm sea surface temperatures.[6] On December 10 a low-level circulation developed within the system, though its convection had become disorganized and well-removed from the center.[7] Southerly wind shear left the structure asymmetric,[8] and convection steadily increased closer to the center. With an upper-level low situated just south of the center, the National Hurricane Center classified it as Subtropical Storm Olga at 0300 UTC on December 11 while located about 55 miles (85 km) east of San Juan, Puerto Rico.[9]

After being classified as a subtropical cyclone, Olga kept an organized outflow, and located to the southeast of a strong ridge over the western Atlantic Ocean, the cyclone moved west-southwestward.[9] The storm strengthened a little bit while moving right along the north coast of Puerto Rico,[10] and after an increase in convection near the center, Olga made landfall near Punta Cana, Dominican Republic at 1800 UTC on December 11.[11] A Hurricane Hunters flight into the storm reported a tighter wind gradient and peak winds of 60 mph (95 km/h), and at 0000 UTC on December 12 the National Hurricane Center reclassified Olga as a tropical cyclone while it was still inland.[12] Convection quickly weakened as the storm crossed central Hispaniola, and after reaching the Caribbean Sea the system lacked the convection required for the classification of a tropical cyclone; rainbands well to its northeast had stronger winds, though the center became very disorganized with dry air and strong wind shear.[13] Late on December 12, convection increased a little bit over the center, though by that time the cyclone weakened to tropical depression status.[13] As a certain amount of convection failed to exist, the National Hurricane Center discontinued advisories on Olga earlier on December 13 while located about 80 miles (130 km) northwest of Kingston, Jamaica.[14] Its remnants continued west-northwestward with a clear low-level circulation, creating scattered thunderstorms over Cuba and the Cayman Islands with its moisture extending northward into southern Florida.[15]

Preparations[change | change source]

On December 10, the Tropical Prediction Center gave out a gale warning for waters north of the Lesser Antilles, Puerto Rico, and the Dominican Republic, in association with the disturbance that would later become Olga.[8] Right after it being classified as a subtropical cyclone, the government of the Dominican Republic gave out a tropical storm warning from Cabo Engaño along the north coast to its border with Haiti; a tropical storm watch was also issued along the southern coastline to near Santo Domingo.[16] Because winds were well to the north of its center, a tropical storm warning was not issued for Puerto Rico.[9] Just before the storm moved ashore, the government of Haiti issued a tropical storm warning for its northern coastline,[17] and later a tropical storm warning was issued for the Turks and Caicos Islands, as well as the southeastern Bahamas.[18]

The San Juan National Weather Service office issued a flood watch for all of Puerto Rico, including the islands of Culebra and Vieques. Continued periods of heavy rainfall also resulted in flash flood warnings for areas across the island.[19] Ferry service between Fajardo and the islands of Culebra and Vieques was temporarily stopped during the passage of the storm.[20] In the Dominican Republic, officials opened shelters in 15 provinces, with citizens in low-lying areas recommended to stay elsewhere during the passage of the storm;[21] citizens in 22 communities were evacuated.[22]

Impact[change | change source]

Olga's rainfall in Puerto Rico.

The cyclone dropped light to moderate precipitation across Puerto Rico, with the maximum rainfall amount at 9.54 inches (242 mm) in Villalba.[1] The rainfall increased levels along several rivers across the island, including the Arecibo Big River which was reported at several feet above flood stage.[19] Its passage left about 79,000 people without power and 144,000 without water.[22] In the northern portion of the island, the rainfall caused a mudslide that buried an automobile, which killed its driver.[23]

Heavy rainfall fell across the Dominican Republic, with isolated totals of 10 inches (250 mm) expected.[12] The rainfall caused flooding along the River Yaque del Norte, and at first there appeared to be a threat that the Tavera Dam along the river would fail, potentially killing thousands in Santiago Province. Officials instead chose to open all six floodgates at 0400 UTC on December 12, which released about 1.6 million gallons (6.1 million liters) of water into the river every second. It formed a 66 foot (20 m) wave of water is a result that caught many off guard due to the time of night and only about 15 minutes to prepare, according to eyewitnesses who criticized the decision; the flooding killed at least 20 people[24] and left homes seven towns flooded.[25] Two other deaths were reported elsewhere in the country, and more than 34,000 people fled their homes due to the storm; more than 7,500 houses were damaged. In neighboring Haiti, two deaths were reported in the northern portion of the country.[24]

On December 11, a station in the Turks and Caicos Islands recorded sustained winds of 36 mph (58 km/h).[11]

Related pages[change | change source]

References[change | change source]

  1. 1.0 1.1 David Roth (2007). "Rainfall Summary for Tropical Storm Olga". Hydrometeorological Prediction Center. Retrieved 2007-12-13.
  2. 2.0 2.1 Gladys Rubio (2007). "December 7 Tropical Weather Discussion". National Hurricane Center. Retrieved 2007-12-11.
  3. Patricia Wallace (2007). "December 8 Tropical Weather Discussion". National Hurricane Center. Retrieved 2007-12-11.
  4. Mike Tichacek (2007). "December 9 Tropical Weather Discussion". National Hurricane Center. Retrieved 2007-12-11.
  5. Mike Formosa (2007). "December 9 Tropical Weather Discussion". National Hurricane Center. Retrieved 2007-12-11.
  6. James Franklin (2007). "December 9 Special Tropical Disturbance Statement". National Hurricane Center. Retrieved 2007-12-11.
  7. James Franklin (2007). "December 10 Special Tropical Disturbance Statement". National Hurricane Center. Retrieved 2007-12-12.
  8. 8.0 8.1 John Cangialosi (2007). "December 10 Tropical Weather Discussion". National Hurricane Center. Retrieved 2007-12-12.
  9. 9.0 9.1 9.2 Beven (2007). "Subtropical Storm Olga Discussion One". National Hurricane Center. Retrieved 2007-12-12.
  10. Knabb & Mainelli (2007). "Subtropical Storm Olga Discussion Two". National Hurricane Center. Retrieved 2007-12-12.
  11. 11.0 11.1 Franklin (2007). "Subtropical Storm Olga Discussion Four". National Hurricane Center. Retrieved 2007-12-12.
  12. 12.0 12.1 Avila (2007). "Tropical Storm Olga Public Advisory Four-A". National Hurricane Center. Retrieved 2007-12-12.
  13. 13.0 13.1 Franklin & Mainelli (2007). "Tropical Storm Olga Discussion Seven". National Hurricane Center. Retrieved 2007-12-12. Cite error: Invalid <ref> tag; name "disc7" defined multiple times with different content
  14. Avila (2007). "Tropical Depression Olga Discussion Nine". National Hurricane Center. Retrieved 2007-12-13.
  15. Gladys Rubio (2007). "December 13 Tropical Weather Discussion". National Hurricane Center. Retrieved 2007-12-13.
  16. Beven (2007). "Subtropical Storm Olga Public Advisory One". Retrieved 2007-12-12.
  17. Franklin & Brown (2007). "Subtropical Storm Olga Public Advisory Three". Retrieved 2007-12-12.
  18. Franklin & Brown (2007). "Subtropical Storm Olga Public Advisory Four". Retrieved 2007-12-12.
  19. 19.0 19.1 Puerto Rico National Weather Service (2007). "Watches, Warnings, and Advisories for Tropical Storm Olga in Puerto Rico". Retrieved 2007-12-13.
  20. Associated Press (2007-12-11). "Domestic News by State/Province". |access-date= requires |url= (help)
  21. Michael Melia (2007-12-11). "Subtropical Storm Olga spreads heavy rains across Puerto Rico". Associated Press. |access-date= requires |url= (help)
  22. 22.0 22.1 Ramon Almanzar (2007-12-11). "Subtropical Storm Olga forces evacuations in Dominican Republic". Associated Press. |access-date= requires |url= (help)
  23. Ramon Almanzar (2007-12-12). "Tropical Storm Olga forces evacuations in Dominican Republic; one killed in Puerto Rico". Associated Press. |access-date= requires |url= (help)
  24. 24.0 24.1 Ramon Espinosa (2007-12-14). "Flood survivors blast Dominican officials for lack of warning about opening dam during Olga". Associated Press. |access-date= requires |url= (help)
  25. Los Angeles Times (2007-12-13). "Tropical storm leaves 14 dead". |access-date= requires |url= (help)

Other websites[change | change source]

Tropical cyclones of the 2007 Atlantic hurricane season

Saffir–Simpson Hurricane Scale
TD TS C1 C2 C3 C4 C5