As the disturbance traveled around the gyre (Fig. The definition used by Lander (1994) and Holland (1995) is largely subjective, with no clear delineation between when a large subtropical low is or is not a gyre. [16] Convection persisted around the increasingly well-defined LLCC, and the disturbance continued to consolidate under favourable diffluence. This case study examines the complex history of a tropical storm that formed southeast of a large subtropical gyre. • Realign JTWC; singular focus on tropical forecasts and warnings • Implement “Decision Support” capability .
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Table 2 examines the maximum wind speeds in the storms, the ambient 850–200-hPa vertical wind shear direction and magnitude, the mean SST within 1° latitude and longitude of the storm center, and the mean wind at 1000–200 hPa. What is the shaded area around the forecast track on your warning graphic? Cheers, Patrick Hoareau Wu et al. Wu et al.
10 (136 / 2550)", http://severe.worldweather.wmo.int/tcc/document/review/Thailand.doc, "Depression turns into cyclonic storm: Port operation stopped", "NASA Earth Observatory: Tropical Cyclone Gonu", "Significant Tropical Weather Advisory for the Indian Ocean 191800Z-201800Z", "Significant Tropical Weather Advisory for the Indian Ocean 191800Z-201800ZJUN2007", "Depression over Bay of Bengal (BOB 03/2007/01)", "Deep Depression over Bay of Bengal (BOB 03/2007/03)", https://www.webcitation.org/5PlTDy9FR?url=http://metocph.nmci.navy.mil/jtwc/warnings/io032007web.txt, "Deep Depression over Bay of Bengal (BOB 03/2007/06)", "Depression over Marathawada (BOB 03/2007/09)", "UPDATE: Weather Advisory No.6 for Sindh / Balochistan. While its presence is not unusual, there is no established nomenclature to describe the feature. As a result, there is still some evidence at this time of two vorticity maxima. [32] According to the PMD, the centre of the system reached within 90 km (55 mi) of Karachi. At the time, the official WMO body responsible for tropical cyclones in the, Timeline of the 2007 North Indian Ocean cyclone season, North Indian Ocean tropical cyclone seasons, Regional Specialized Meteorological Centre, "IMD Cyclone Warning Services: Tropical Cyclones", "Tropical depression in the Gulf of Thailand No. The tropical cyclone scale for this basin is detailed on the right. [72][73] Kavali in Andhra Pradesh received 550 mm of rainfall in 48 hours between 29 & 30 October. The origins of the Joint Typhoon Warning Center (JTWC) can be traced back to June 1945, when the Fleet Weather Center/Typhoon Tracking Center was established on the island of Guam, after multiple typhoons, including Typhoon Cobra of December 1944 and Typhoon Connie in June 1945, had caused a significant loss of men and ships. Following the formation of a low pressure area and circulation centre, the India Meteorological Department (IMD) initiated advisories, declaring it a depression, as it was located about 150 km (90 mi) southeast of Kolkata, West Bengal, in India, along the Bangladeshi coast. 1j, located within clouds associated with the fishhook north of the gyre.
Uppercase letters refer to individual vorticity maxima. In 1962 the original structure that housed JTWC was destroyed and operations were moved to COMNAVMAR where they remained until the 1990’s. Gyre-based TCs peaked in frequency during August and September. 781 0 obj <>/Filter/FlateDecode/ID[<0CDC81B5F94BA842B7CB228F0E449298>]/Index[766 38]/Info 765 0 R/Length 93/Prev 1350444/Root 767 0 R/Size 804/Type/XRef/W[1 3 1]>>stream It made landfall on the coast near the Bangladesh–Myanmar border early on May 15, and weakened quickly inland. This motion closely fits the sudden track changes of western North Pacific storms described by Carr and Elsberry (1995). Only time periods where the TC reached tropical storm intensity or greater are used in this work. 2007; online at www.ecmwf.int/products/data) interpolated to 1.125° latitude–longitude resolution and available 4 times daily were used to obtain values for the wind, height, temperature, relative humidity, and vorticity fields. TCFAs indicate the likelihood that a TC formation will occur within 24 h. Six-hourly evolution in TS Ken–Lola of maximum wind speed (kt; from JTWC postseason analysis); ambient vertical wind shear direction and magnitude (m s−1), calculated following Corbosiero and Molinari (2003); underlying SST; and mean 1000–200-hPa wind in a 500-km radius around the storm. In addition, the clear region at the center of the gyre coincided with midlevel cold advection and thus dynamically induced subsidence. Table 1 gives a brief chronology of major events and warnings issued by JTWC regarding the formation and decay of Ken and Lola in real time. 8c) lay farther northwest of the tropical storm. Joint Typhoon Warning Center (JTWC) TC track and intensity data were obtained from the National Oceanic and Atmospheric Administration’s (NOAA) International Best Track Archive for Climate Stewardship (IBTrACS) database (http://www.ncdc.noaa.gov/oa/ibtracs/index.php?name=ibtracs-data).
1k), TS Lola had an asymmetric cloud structure, but a well-defined circulation with high clouds rotating to the south of the center. Mean flow had turned to the northeast, vertical shear remained moderate, and SST continued to rise as the storm turned toward the southwest. The case examined in this paper took place before the characteristics of subtropical gyres were recognized (Lander 1994). (2007), and Wu et al. [50] The JTWC then issued its last advisory later that day, as the system moved inland. [51] Early on June 30, with the system centred over Madhya Pradesh and Chhattisgarh, the IMD downgraded the system to a depression,[52] and discontinued advisories 6 hours later. Amravati district, northeast of Mumbai, was also severely affected by floods. The storm attained a maximum wind speed of 30 knots (56 km/h) and a minimum pressure of 1006 hPa.[7][8]. TCs tend to propagate along the inner edge of clouds and thus are always close to the dry air. In this paper we have identified several additional characteristics of gyres that create a complex background flow for TCs. [26] The Pakistan Meteorological Department (PMD) had warned of heavy rains and wind from the system as early as Friday June 22.[27]. This resulted in a mean flow from the southeast that accelerated the storm poleward after the nearly stationary period (see mean flow evolution in Table 2).
It formed on May 10, and continued to intensify gradually. The scope of this article is limited to the Indian Ocean in the Northern Hemisphere, east of the Horn of Africa and west of the Malay Peninsula.
How often are warnings updated by JTWC? If warnings are due out, those too would be prepared with the TDA’s primary responsibility at that time being to make sure all PLA’s (Plain Language Addresses) are present and correct so that proper dissemination is attained.