Cold Fronts with and without Prefrontal Wind Shifts in the Central United States

Schultz, David M.
August 2004
Monthly Weather Review;Aug2004, Vol. 132 Issue 8, p2040
Academic Journal
Time series of cold fronts from stations in the central United States possess incredible variety. For example, time series of some cold fronts exhibit a sharp temperature decrease coincident with a pressure trough and a distinct wind shift. Other time series exhibit a prefrontal trough and wind shift that precedes the temperature decrease associated with the front by several hours. In early March 2003, two cold fronts passed through Oklahoma City, Oklahoma (OKC), representing each of the above scenarios. The cold front on 4 March was characterized by a coincident sharp wind shift, pressure trough, and a strong temperature decrease of 10°C in 2 min. On the other hand, the cold-frontal passage on 8 March was characterized by a prefrontal wind shift occurring over a 7-h period before the temperature decrease of 10°C in 2 h. Twelve hours before frontal passage at OKC, both fronts had the same magnitude of the horizontal potential temperature gradient and Petterssen frontogenesis. By the time of frontal passage at OKC, the magnitude of the horizontal potential temperature gradient for the 4 March front was double that of the 8 March front, and the frontogenesis was nearly four times as great. The simultaneity of the surface horizontal potential temperature gradient and deformation and convergence maxima (coincident with the wind shift) was primarily responsible for the greater strength of the cold front in OKC on 4 March compared to that on 8 March. Whether a prefrontal wind shift occurred was determined by the timing and location of cyclogenesis in the central United States. On 4 March, a cyclone was adjacent to the slope of the Rocky Mountains and developed on the cold front as it moved through Oklahoma, permitting greater frontogenesis and resulting in a cold-frontal passage at OKC with a simultaneous temperature decrease and wind shift. On 8 March, the cyclone moved eastward through Oklahoma before the arrival of the cold front, resulting in a prefrontal wind shift associated with the northerlies behind the cyclone, followed by the frontal passage. A 2-yr climatology of cold-frontal passages at OKC supports the results from the two cases above, indicating that the timing and location of cyclogenesis was responsible for these two different cold-frontal structures. These results imply that, for situations resembling those of this study, the prefrontal trough is not directly associated with the cold front, but is caused by external processes related to the lee troughing.


Related Articles

  • Adjustment of Near-Equatorial Wind Stress with Four-Dimensional Variational Data Assimilation in a Model of the Pacific Ocean. Vossepoel, Femke C.; Weaver, Anthony T.; Vialard, Jér&ocaron;me; Delecluse, Pascale // Monthly Weather Review;Aug2004, Vol. 132 Issue 8, p2070 

    A four-dimensional variational scheme is described in which ocean observations are assimilated into an ocean general circulation model using wind stress forcing fields as control variables. Idealized (“twin”) experiments are performed to evaluate the possibility of reconstructing...

  • A Study on the Effect of Nudging on Long-Term Boundary Layer Profiles of Wind and Weibull Distribution Parameters in a Rural Coastal Area. Gryning, S.-E.; Batchvarova, E.; Floors, R. // Journal of Applied Meteorology & Climatology;May2013, Vol. 52 Issue 5, p1201 

    By use of 1 yr of measurements performed with a wind lidar up to 600-m height, in combination with a tall meteorological tower, the impact of nudging on the simulated wind profile at a flat coastal site (Høvsøre) in western Denmark using the Advanced Research version of the Weather...

  • Using the MIUU Model for Prediction of Mean Wind Speed At Low Height. Olauson, Jon; Samuelsson, Jonatan; Bergström, Hans; Bergkvist, Mikael // Wind Engineering;Oct2015, Vol. 39 Issue 5, p507 

    This paper presents an evaluation of using the MIUU mesoscale model to predict mean wind speed at 10 meters above ground. This was done by comparing the model output to 128 meteorological measurements in Sweden. Although some terrain-dependent bias was seen, the model worked surprisingly well....

  • Turbulent Velocity-Variance Profiles in the Stable Boundary Layer Generated by a Nocturnal Low-Level Jet. Banta, Robert M.; Pichugina, Yelena L.; Brewer, W. Alan // Journal of the Atmospheric Sciences;Nov2006, Vol. 63 Issue 11, p2700 

    Profiles of mean winds and turbulence were measured by the High Resolution Doppler lidar in the strong-wind stable boundary layer (SBL) with continuous turbulence. The turbulence quantity measured was the variance of the streamwise wind velocity component σ2u. This variance is a component of...

  • The Ways of WIND. Schleichert, Elizabeth // Ranger Rick;Mar2006, Vol. 40 Issue 3, p12 

    The article presents information on wind power.

  • Influence of wind speed gusts on power generation. Tomson, Telan; Hansen, Maire // Proceedings of the Estonian Academy of Sciences, Engineering;Dec2002, Vol. 8 Issue 4, p276 

    Based on the analysis of the Estonian offshore and onshore wind database, the boundaries of the probability of wind speed gusts and lulls, which lead to disturbances in the electrical grid, are assessed. These boundaries are assigned to the probability distribution function (pdf) of wind...

  • New energy in search for future wind.  // Biomedical Market Newsletter;9/30/2011, Vol. 21, p430 

    The article reports on the efforts of several scientists in improving their research on wind speed changes for further development of the wind energy industry.

  • Well, Blow Me Down.  // Harrowsmith Country Life (11908416);Jun2006, Vol. 30 Issue 188, p48 

    Discusses ways of evaluating if there is enough wind and the best condition of generating wind power. Required wind speed to generate wind power; Use of an anemometer in measuring wind speed; Other factors to consider.

  • Hybrid Wind Speed Prediction Based on a Self-Adaptive ARIMAX Model with an Exogenous WRF Simulation. Erdong Zhao; Jing Zhao; Liwei Liu; Zhongyue Su; Ning An // Energies (19961073);2016, Vol. 9 Issue 1, p7 

    Wind speed forecasting is difficult not only because of the influence of atmospheric dynamics but also for the impossibility of providing an accurate prediction with traditional statistical forecasting models that work by discovering an inner relationship within historical records. This paper...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics