| Description |
For over a dozen years the Oklahoma Mesonet network has provided surface observations at over 100 stations. These observations are used to analyze mass flux estimates from surface divergence, frontal passages, and cold pools, the latter defined herein as active regions where precipitation processes are creating near-surface cold air masses. Case studies are detailed and a 15-yr climatology of frontal passages and cold pools was computed in this research. Convergence, divergence, and precipitation are most strongly correlated in the summer months and least correlated in the winter months. Wet spring and summer days had the highest average convergence and divergence values while dry summer and fall days had the lowest average convergence and divergence. Frontal passages and cold pools are tracked throughout the Mesonet in various case studies, four of which are covered herein. The methodology is able to represent front location and cold pool areas quite well despite the low resolution of the Mesonet grid. The climatology of front and cold pool data yielded many similarities. Winter has the largest magnitude changes in AT, AP, and Ah/cp while spring and fall had the largest magnitude change in Aq^. Summer has the lowest with the exception of spring AT. Correlations between these variables are lowest in the more convectively active summer season. Convergence is roughly equal ahead of fronts from spring through fall; however, divergence is present in summer frontal passages earlier and stronger compared to the other seasons. Fronts and cold pools are most likely to occur in summer and spring with summer having the highest percentage of fronts which lead to cold pools. Fronts and cold pools are substantially more likely to occur during the late afternoon and early evening in the summer; other seasons had a slighter nocturnal increase in frequency. Western Oklahoma had higher frequencies of frontal passages and cold pools than Eastern Oklahoma with frontal passages having the stronger signal. These findings help identify seasonal, diurnal, and geographic distributions of fronts and cold pools and can be used in modeling studies to better the understanding of cold pool processes and parameterizations. |
