The Low-Level Jet as Related to Nocturnal Thunderstorms over Midwest United States

Pitchford, Kenneth L.; London, Julius

doi:10.1175/1520-0450(1962)001<0043:tlljar>2.0.co;2

Cited by 99 publications

(61 citation statements)

References 4 publications

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“…While most of the United States experiences peak convective storm activity in the late afternoon, coinciding with maximum surface heating, the Midwest is often affected by storms during the overnight hours. Researchers have suggested links between the nocturnal GPLLJ and the nighttime maximum in storm formation in that region (Pitchford and London 1962;Rasmusson 1967;Maddox 1983;Astling et al 1985;Zhong et al 1996;Pu and Dickinson 2014).…”

Section: Introductionmentioning

confidence: 99%

Observing and Simulating the Summertime Low-Level Jet in Central Iowa

Vanderwende

Lundquist

Rhodes

et al. 2015

Monthly Weather Review

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In the U.S. state of Iowa, the increase in wind power production has motivated interest into the impacts of low-level jets on turbine performance. In this study, two commercial lidar systems were used to sample wind profiles in August 2013. Jets were systematically detected and assigned an intensity rating from 0 (weak) to 3 (strong). Many similarities were found between observed jets and the well-studied Great Plains low-level jet in summer, including average jet heights between 300 and 500 m above ground level, a preference for southerly wind directions, and a nighttime bias for stronger jets. Strong vertical wind shear and veer were observed, as well as veering over time associated with the LLJs. Speed, shear, and veer increases extended into the turbine-rotor layer during intense jets. Ramp events, in which winds rapidly increase or decrease in the rotor layer, were also commonly observed during jet formation periods. The lidar data were also used to evaluate various configurations of the Weather Research and Forecasting Model. Jet occurrence exhibited a stronger dependence on the choice of initial and boundary condition data, while reproduction of the strongest jets was influenced more strongly by the choice of planetary boundary layer scheme. A decomposition of mean model winds suggested that the main forcing mechanism for observed jets was the inertial oscillation. These results have implications for wind energy forecasting and site assessment in the Midwest.

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Section: Introductionmentioning

confidence: 99%

Observing and Simulating the Summertime Low-Level Jet in Central Iowa

Vanderwende

Lundquist

Rhodes

et al. 2015

Monthly Weather Review

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“…An additional key factor for nocturnal MCS development and maintenance is the supply of potentially buoyant air associated with the southerly LLJ (e.g., Pitchford and London 1962;Pu and Dickinson 2014). This nocturnal jet is common in the central Great Plains in late spring and summer (Fig.…”

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confidence: 99%

The 2015 Plains Elevated Convection at Night Field Project

Geerts

Parsons

Ziegler

et al. 2017

Bulletin of the American Meteorological Society

223

198

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“…If an anemometer is located near an obstruction, it may register a wind speed and direction that are very different from the general movement of the nearby atmosphere. Exposure problems are especially likely (a) This was discussed as early as the 1960s in a paper by Pitchford and London (1962).…”

Section: Need For Good-quality Measurementsmentioning

confidence: 99%