The full paper can be accessed at http://journals.ametsoc.org/doi/abs/10.1175/JAS-D-13-0153.1.
The paper can be accessed at http://journals.ametsoc.org/doi/abs/10.1175/JTECH-D-13-00006.1.
The 2013 Atlantic hurricane season officially ends on Saturday, November 30. The season was very inactive, having the fewest hurricanes since 1982, and ranks as the sixth-least-active Atlantic hurricane season since 1950. Despite this, HRD had a very active year in gathering data for research and assimilation into numerical models to improve forecasts.
Tail Doppler Radar and dropwindsonde composite at 3-km altitude from the G-IV flight into the system that eventually became Tropical Storm Gabrielle (left) and from Hurricane Ingrid (right).
Flights during our annual Hurricane Field Program Intensity Forecasting Experiment (IFEx) were conducted in Tropical Storms Gabrielle and Karen, and Hurricane Ingrid. A total of 367 dropwindsondes and 136 airborne expendable bathythermographs were released from the aircraft to obtain profiles of important variables in the atmosphere and ocean. The NOAA G-IV successfully gathered data, especially with its new Tail Doppler Radar, during 9 flights, and the two NOAA P3s flew 17 times during the season, all using a total of 150 flight hours. Many of the flights were coordinated with the NASA Hurricane Severe Storm Sentinel (HS3) flights conducted during the summer with two Global Hawk aircraft. You can find more information on the data collected from the debrief presentation for each storm (Gabrielle, Ingrid, and Karen). One of the highlights of the season is that, for the first time, Tail Doppler Radar data were transmitted from the aircraft to NOAA Central Operations and successfully assimilated into the operational HWRF model.
Initial total precipitable water (left) and mean sea-level pressure (right) for a basin-scale HWRF run. Tropical Storm Karen is seen in the central Gulf of Mexico.
On the modeling and data assimilation side, HRD provided near-realtime runs of the Hurricane Weather and Research Forecast (HWRF) model initialized with the Hurricane Ensemble Data Assimilation System (HEDAS), a testbed for improving the assimilation of data into the operational HWRF model. For the first time, high-resolution cloud-motion vectors as well as some satellite retrievals were ingested into a research version of HWRF. The model forecasts showed that the assimilation of these data with a sophisticated data assimilation system can provide better forecasts of track and intensity than the current operational system. A new basin-wide version of HWRF developed at HRD was also run in realtime during the season, allowing for multiple storms to be forecast concurrently for the first time. And HRD’s HWind group successfully made 33 surface-wind analyses in six storms in the Atlantic basin this year.
East-west cross section of wind speed and relative humidity through the center of Hurricane Ingrid (left) and average wind speed around the center of Ingrid at the same time (right), from HEDAS analyses.
Left: Hwind analysis of the surface winds in Tropical Storm Fernand just before landfall on the Gulf coast of Mexico. Right: Eric Uhlhorn, Robert Rogers, and Jun Zhang just before a P3 flight into Tropical Storm Gabrielle.
HRD is thankful that we were able to successfully complete the season having achieved some major milestones, all without having a hurricane make landfall in the United States, and with only minimal loss of life and property to the public due to tropical systems.
On November 29, 1988 a severe tropical cyclone struck Bangladesh with approximately 125 mph winds and a 5-10 foot storm surge. With an estimated 2000 people killed, it was the worst tempest to ravage this storm-plagued area since the 1970 Bhola cyclone. During its early stages, it brought heavy rains to Indonesia, Malaysia, and Thailand creating thousands more injured and dead. In addition it rendered over $9 billion in damages to the agriculture in the area.
On November 19, 1912, Robert Homer Simpson was born in Corpus Christi, Texas. A pioneer in the field of hurricane science, Bob Simpson carried out research missions “piggybacked” on Air Force reconnaissance flights in the late 1940s and early 1950s. He wrote the plan establishing the National Hurricane Research Project in 1955 and became its first director. He was later the Weather Bureau’s Deputy Director of Research for Severe Storms and the inaugural director for Project STORMFURY, the U. S. Government’s twenty-year long experiment testing the hypothesis that seeding tropical cyclones with silver iodide would reduce their maximum wind speeds.
In 1968, he was named director of the National Hurricane Center. He reorganized the Center so that it was separate from the Miami National Weather Service Office, he established its small research section, and expanded its satellite analysis branch. He ensured the Center remained current in computer and technological advances and was critical in raising the warnings about the severity of Hurricane Camille. He also worked with his friend Herb Saffir in formulating a five-level scale for ranking hurricanes that became known as the Saffir-Simpson Wind Scale.
He retired from Government service in 1974 and took a faculty position at the University of Virginia. He and his wife Joanne established Simpson Weather Associates, a private consulting firm. Bob now lives in Washington, D.C. and is eagerly awaiting the publication of his autobiography sometime next year.
Sometimes a tropical cyclone doesn’t have to make landfall in order to cause destruction. On Nov. 15, 1993 a Very Severe Cyclone in the Arabian Sea approached the coast of Pakistan, but dissipated before coming ashore. Nevertheless, its rains brought heavy flooding to Karachi and the Thatta and Badin districts. The floods killed over 600 people and left another 200,000 homeless.
The northern Indian Ocean has a bimodal distribution to its tropical cyclone season. This means there are two peaks in activity, one in early spring the other in late fall. Thus this storm was not unusual, forming during the later period.
The paper can be accessed at http://journals.ametsoc.org/doi/abs/10.1175/WAF-D-12-00130.1.
On November 2, 1743 a severe storm struck the American colonies from Virginia northward. The storm might have been a late-season hurricane or strong midlatitude cyclone. It provided some essential insights into the way the weather works.
Harvard Science Department
For example, Harvard Professor Jonathan Winthrop recorded the dip in pressure as the storm passed over Boston, making this the first such storm in which barometric observations were made. He also noted the rise in sea level and winds during the storm’s passage.
National Portrait Gallery
The storm became know as the ‘Eclipse Hurricane’ because it struck on the night of a lunar eclipse. Benjamin Franklin was residing in Philadelphia and was set to make observations of the predicted eclipse, but the clouds from the storm interfered. Franklin observed that the winds accompanying the storm were from the northeast and assumed the storm had come from that direction and so had also interfered with lunar observations made by his brother back in Boston. He was surprised to later find that the eclipse had been visible in Boston and that the storm had struck there hours afterward. Franklin concluded the storm had moved contrary to surface winds. His observations were confirmed by another hurricane which traveled up the east coast of the Colonies in October of 1749, which Franklin was able to trace by using newspaper accounts from various cities along the storm course.
Because of this storm, scientists became aware that storms, rather than being driven by the surface wind, had wind circulations independent of the storm motion. By the early 19th Century, New England scientists began theorizing that storms were, in fact, giant whirlwinds that traveled over the Earth’s surface.
The full article can be accessed at http://journals.ametsoc.org/doi/pdf/10.1175/MWR-D-12-00335.1.
The full text can be found at http://journals.ametsoc.org/doi/abs/10.1175/MWR-D-13-00076.1.