The atmospheric conditions that lead to strong offshore surface winds in Southern California, commonly referred to as Santa Ana winds, are investigated using the North American Regional Reanalysis and a 12-year, 6-km resolution regional climate simulation of Southern California. We first construct an index to characterize Santa Ana events based on offshore wind strength. This index is then used...

Climatological studies of blocking in the Southern Hemisphere (SH) demonstrate that blocking events are less common (e.g. Lejenas, 1984; Renwick 1998), and are weaker (e.g. Wiedenmann, et al., 2002; hereafter WLMT02) throughout the SH when compared to their NH counterparts. WLMT02 implied that the relative roles in the interaction between planetary-scale and synoptic-scale waves may partially e...

First, it cannot explain the differences among the writers—unless it is assumed that verbal differences indicate different events. In that case, one would have to say that Jesus was tempted by the devil twice, that the Lord’s Supper was offered twice, and that Peter denied the Lord six to nine times! In fact, one might have to say that Christ was raised from the dead more than once if this were...

Analyses of more than 40 years of climatic data reveal intriguing spatial variations in climatic patterns for Beringia (North-eastern Siberia and Alaska), aiding the understanding of the hierarchy of climatic controls that operate at different spatial scales within the Arctic. A synoptic climatology, using a subjective classification methodology on January and July sea level pressure, and July ...

In this study, we investigate the interaction between the tropical Intraseasonal Oscillation (ISO) and midlatitude atmospheric low-frequency variability, using observational data and numerical models, with a special emphasis on the role of the synoptic eddy feedback. A statistical closure for the synoptic eddy-to-low frequency flow feedback is constructed, based on a singular value decompositio...

The role of scale interactions in the maintenance of eddy kinetic energy (EKE) during the extreme phases of the intraseasonal oscillation (ISO) is examined through the construction of a new eddy energetics diagnostic tool that separates the effects of ISO and a low-frequency background state (LFBS; with periods longer than 90 days). The LFBS always contributes positively toward the EKE in the b...

The climatology of northern hemisphere blocking events is presented assessing the relative contributions of the planetary and synoptic scales to 500 hPa heights in order to determine the proportion of blocks dominated by a single-scale. The heights were averaged over a region encompassing the block, and then compared with corresponding monthly mean values. If planetaryscale or synoptic-scale he...

The daily weather at a particular place is largely influenced by the synoptic circulation and thermodynamic profile of the atmosphere. Heavy rainfall occurs from a particular subset of synoptic and thermodynamic states. Baseline climatologies provide objective information on heavy rainfall-producing circulation patterns and thermodynamic variables. This is how climatologically large or extreme ...