On the Formation of the Low-Level Jet over Texas

Djurić, Dušan; Damiani, Michel S.

doi:10.1175/1520-0493(1980)108<1854:otfotl>2.0.co;2

Cited by 21 publications

(10 citation statements)

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“…However, owing to the complex physical geography of the North American continent and its impacts on the development of synoptic-scale weather systems (e.g., Hobbs et al 1996), the synoptic-scale flow configurations and processes associated with central U.S. ARs likely differ from those associated with ''classic'' precold-frontal ARs over open-ocean basins. Specifically, in the spring and early summer, southerly LLJs that support water vapor transport into the central United States commonly develop in connection with a strong low-level pressure (or geopotential height) gradient between a developing terrain-induced lee trough or extratropical cyclone to the east of the Rocky Mountains and a subtropical ridge over the southeastern United States and may not involve a well-defined surface cold front (e.g., Djurić and Damiani 1980;Uccellini 1980;Augustine and Howard 1991;Martin et al 1995;Mo et al 1995).…”

Section: B Linkage Between Tropical Water Vapor and Heavy Precipitatmentioning

confidence: 99%

Physical Processes Associated with Heavy Flooding Rainfall in Nashville, Tennessee, and Vicinity during 1–2 May 2010: The Role of an Atmospheric River and Mesoscale Convective Systems

et al. 2012

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A multiscale analysis is conducted in order to examine the physical processes that resulted in prolonged heavy rainfall and devastating flash flooding across western and central Tennessee and Kentucky on 1-2 May 2010, during which Nashville, Tennessee, received 344.7 mm of rainfall and incurred 11 flood-related fatalities. On the synoptic scale, heavy rainfall was supported by a persistent corridor of strong water vapor transport rooted in the tropics that was manifested as an atmospheric river (AR). This AR developed as water vapor was extracted from the eastern tropical Pacific and the Caribbean Sea and transported into the central Mississippi Valley by a strong southerly low-level jet (LLJ) positioned between a stationary lee trough along the eastern Mexico coast and a broad, stationary subtropical ridge positioned over the southeastern United States and the subtropical Atlantic. The AR, associated with substantial water vapor content and moderate convective available potential energy, supported the successive development of two quasi-stationary mesoscale convective systems (MCSs) on 1 and 2 May, respectively. These MCSs were both linearly organized and exhibited back-building and echo-training, processes that afforded the repeated movement of convective cells over the same area of western and central Tennessee and Kentucky, resulting in a narrow band of rainfall totals of 200-400 mm. Mesoscale analyses reveal that the MCSs developed on the warm side of a slow-moving cold front and that the interaction between the southerly LLJ and convectively generated outflow boundaries was fundamental for generating convection.

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Section: B Linkage Between Tropical Water Vapor and Heavy Precipitatmentioning

confidence: 99%

Physical Processes Associated with Heavy Flooding Rainfall in Nashville, Tennessee, and Vicinity during 1–2 May 2010: The Role of an Atmospheric River and Mesoscale Convective Systems

et al. 2012

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“…Under both kinds of flow conditions, the afternoon sea breeze, or bay breeze, which occurs almost daily in Houston, typically progresses into a nocturnal low‐level jet in what Nielsen‐Gammon [2006] refers to as the “sea breeze low‐level jet.” This jet is similar to the summertime Great Plains LLJ [ Parish et al , 1988; Holton , 1967; McNider and Pielke , 1981] in the sense that both are a result of topographically driven baroclinity. However, the close relationship with the sea breeze makes the LLJs in Houston physically distinct from the Great Plains LLJs or the synoptically forced LLJs over Texas and the western Gulf of Mexico [ Uccellini and Johnson , 1979; Djurić and Damiani , 1980; Igau and Nielsen‐Gammon , 1998]. Some of the weaker Houston sea breeze LLJs observed during TexAQS 2006 occurred only locally, independent of these other LLJs, such that they were not observable with profilers located further inland or further out to sea.…”

Section: Introductionmentioning

confidence: 99%

Relationships of coastal nocturnal boundary layer winds and turbulence to Houston ozone concentrations during TexAQS 2006

et al. 2010

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[1] Measurements made with a ship-based Doppler wind lidar during the summertime 2006 Texas Air Quality Study are used to study the relationship between lowertropospheric vertical structure and winds and ozone (O 3 ) concentrations in Houston, Texas, under two different flow regimes. We observed that strong southerly flow regimes, dominated by the subtropical anticyclone (Bermuda high) off the Atlantic coast of the United States, resulted in strong (i.e., high wind speed) onshore nocturnal low-level jets (LLJ) and low O 3 and oxidant O x (where O x = O 3 + NO 2 ) concentrations at night and the following afternoon. In contrast, periods dominated by northerly or easterly flow resulted in relatively weak (low wind speed), but still onshore, nocturnal LLJs associated with higher concurrent and next-day concentrations of O 3 and O x . We present lidar data from 24 h example periods for each of these conditions and demonstrate how each type of flow regime is related to in situ ship-based ozone measurements. We expanded the study to include all days during the study when the ship was near Houston, to demonstrate how the strength of the meridional winds aloft show a better relationship to concurrent shipmeasured O x concentrations than the winds near the surface do. We found a strong relationship between a parameterization of the observed nocturnal jets, which reflect the synoptic conditions, to peak hourly O 3 measured the next day at the ship and averaged throughout the Houston/Galveston/Brazoria continuous ambient monitoring stations monitoring network, indicating potential applications for planning air quality.

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“…Djuric and Ladwig (1 983) found that during the 1977 winter season only very weak and short-lived lows in the south-western Great Basin were not associated with southerly LLJs. During the advanced stage of the cyclone, the LLJ is typically located in the cyclone's warm sector (Djuric and Damiani, 1980). Cyclogenesis in Alberta, a recognized although less-active springtime site (Whittaker and Horn, 1981), could also account for the enhanced southerly 1000 hPa wind component in Saskatchewan and Manitoba, particularly if such activity was also accompanied by high pressure located in the vicinity of Hudson Bay, as previously discussed.…”

Section: Discussionmentioning

confidence: 76%

Climatological Characteristics of Springtime Lower Tropospheric Airflow Over Central and Eastern North America

WINKLER¹,

HARMAN²,

WALLER³

et al. 1996

Int. J. Climatol.

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A climatology of springtime lower tropospheric airflow, as represented by 850 hPa observed winds and 1000 hPa geostrophic winds, is presented for central and eastern North America. The climatology is based on twice-daily grid-point values for 1969-1989 from the operational analyses for the Northern Hemisphere prepared by the USA National Weather Service's National Meteorological Centre. Sixteen-point wind roses are used to show the spatial and temporal distributions by direction category of wind frequency, average speed, and wind run. These analyses are supplemented by resultant wind vector and streamline maps for each month. Evident in the climatological distributions is the declining strength of the circulation from March to May, the northward migration and strengthing of the North Atlantic subtropical anticyclone in late spring, and the nocturnal strengthening and veering of southerly airflow over the southern Great Plains. Additionally, areas of cyclonic and/or anticyclonic resultant flow correspond well with earlier identified centres of cyclogenesis and anticyclogenesis. The results presented here may provide a useful climatological baseline for future studies involving lower tropospheric airfiow.

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On the Formation of the Low-Level Jet over Texas

Cited by 21 publications

References 0 publications

Physical Processes Associated with Heavy Flooding Rainfall in Nashville, Tennessee, and Vicinity during 1–2 May 2010: The Role of an Atmospheric River and Mesoscale Convective Systems

Physical Processes Associated with Heavy Flooding Rainfall in Nashville, Tennessee, and Vicinity during 1–2 May 2010: The Role of an Atmospheric River and Mesoscale Convective Systems

Relationships of coastal nocturnal boundary layer winds and turbulence to Houston ozone concentrations during TexAQS 2006

Climatological Characteristics of Springtime Lower Tropospheric Airflow Over Central and Eastern North America

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