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Kirstie Stramler, Anthony D. Del Genio, and William B. Rossow

temperature anomalies, as stratospheric temperature conditions are primarily of opposite sign to those in the troposphere for the duration of each episode. That these stratospheric warmings and coolings precede their tropospheric counterparts is consistent with the tilt of blocked baroclinic waves with height ( Palmen and Newton 1969 ). The hourly winter NetLW time series at the SHEBA surface site (upper panel, Fig. 2 ) ranges between −65 and 20 W m −2 over the course of the winter 1997/98 season

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Trevor I. Alcott, W. James Steenburgh, and Neil F. Laird

differentiate between GSLE and non-GSLE periods, through the development and analysis of a 13-yr cool-season radar-derived climatology. We will show that GSLE events occur primarily within specific ranges of instability, moisture, and kinematic parameters, whereas considerable overlap exists between the conditions associated with different GSLE morphologies. Furthermore, we identify deficiencies in current forecast techniques and present a new probabilistic approach using lake–air temperature difference

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Robert R. Gillies, Shih-Yu Wang, and Marty R. Booth

soundings (e.g., vertical velocity) at grid points close to KSLC. The NARR was also used for filling in any missing observations in the soundings. Both reanalysis datasets were obtained from the National Oceanic and Atmospheric Administration/Office of Oceanic and Atmospheric Research/Earth System Research Laboratory’s (NOAA/OAR/ESRL) Physical Science Division (information online at ). b. Inversion definition During each winter season, Salt Lake City is subjected to two main

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Stuart A. Browning and Ian D. Goodwin

separately. Table 1. Index phase for the highest-frequency storm seasons (top 15%). All climate indices have been normalized to Z scores (anomaly/ σ ). Negative values (<0.5 σ ) are italicized and positive values (>0.5 σ ) are boldface. 1) ETL Because ETL events are infrequent in late winter (August) we restrict the seasonal investigation to May–June–July. The six highest-frequency ETL seasons (top 15%) were 1984, 1985, 1990, 1996, 1999, and 2008. Seasonal ETL frequency is correlated to cool SST in

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Bunmei Taguchi, Hisashi Nakamura, Masami Nonaka, and Shang-Ping Xie

wind velocities were first averaged into a daily mean, from which the daily wind speeds were evaluated. The daily mean wind speeds from the model and the observations were then averaged in the same manner to produce their monthly means. During the 2003/04 cold season, month-to-month changes in surface winds based on the JRA-25 analysis are characterized by the rapid maturing of the East Asian winter monsoon in December and its subsequent gradual weakening in late winter and early spring ( Fig. 1

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Nyssa Perryman and P. Grady Dixon

UHI environment may act as a lake-enhanced snowfall environment, and possibly enhance urban snowfall downwind of the city center, is presented. Urban temperatures have been shown to exceed rural temperatures in all seasons, including winter ( Gallo and Owen 1999 ; Seeley and Jensen 2006 ). The distribution of the urban temperature through the vertical profile of the atmosphere over the UHI is comparable to that over an unfrozen lake ( Dixon and Mote 2003 ; Tardy 2000 ). When determining the

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Ernesto Muñoz, Antonio J. Busalacchi, Sumant Nigam, and Alfredo Ruiz-Barradas

Reanalysis (NARR). The annual cycle of precipitation in the Caribbean and Central American region has a rainy season in boreal summer ( Giannini et al. 2000 ; Taylor et al. 2002 ) that extends from May through October. During boreal summer the intertropical convergence zone (ITCZ) shifts northward, leading to intense precipitation over the tropical North Atlantic, Central America, and the tropical northeastern Pacific. However, over the Caribbean Sea the precipitation is not as intense as it is over

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Justin E. Jones and Judah Cohen

1. Introduction Strong polar anticyclones are a prominent climatological feature across the high-latitude continental landmasses of the Northern Hemisphere during the cool season and are often associated with intense equatorward cold surges that can in turn have an adverse impact on the human population. These anticyclones are known to develop in response to a number of thermodynamical and dynamical factors. Early research has suggested that thermodynamic arguments (e.g., radiational cooling

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R. K. Yadav, J. H. Yoo, F. Kucharski, and M. A. Abid

southwest monsoon season (June–September) contributes about 75% to the annual rainfall, winter precipitation from December to March (DJFM) contributes 15%–20% to the annual rainfall over this region. The northwest (NW) India winter precipitation (NWIWP) is very important for winter crops, particularly for wheat, as it supplements the crops with irrigation–moisture and maintains low temperature for the development of the crops. Moreover, precipitation in the form of snow over the hilly regions of NW

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B. Timbal, R. Kounkou, and G. A. Mills

during the winter months from May to September, and are known locally as cool-season tornadoes (CSTs). Although associated with large thunderstorms or deep convective clouds, Hanstrum et al. (2002) showed that CSTs occurred in a large-scale environment, which differs from that for summer tornadoes; they form in a combination of less (but still) positively buoyant and high low-level vertical wind shear environments. While individual events remain nearly impossible to forecast at any scale outside

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