500 1000 1500 2000 2500 3000 3500 Figure 1. 30-sec mean topography (m, shaded following scale at...

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Figure 1. 30-sec mean topography (m, shaded following scale at upper left) of the Intermountain West and adjoining regions, with the height of Sierra Nevada crest between points N and S at lower left (position of Lake Tahoe indicated by vertical line). Abbreviations used for Lake Tahoe (LT) and the lower Colorado River Basin (LCRB).

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Figure 2. Synoptic structure of the 25 Mar 2006 cold front at 1200 UTC 25 Mar (left panels) and 0000 UTC 26 Mar 2006 (right panels). Manual surface analyses (top) include conventional frontal symbols, sea level contours (every 2 hPa), and surface wind observations (full and half barb denote 5 and 2.5 m s-1, respectively). NAM 700-hPa analyses (bottom) include temperature contours (every 2°C), wind (full and half barb denote 5 and 2.5 m s-1, respectively), and 800–500-mb mean relative humidity (shaded following scale at lower left). Adapted from Steenburgh et al. (2009).

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Figure 3. WRF topography [m, shaded following scale in (a)] for a subset of the (a) FULLTER and (b) NOSIERRA 12-km nested domain.

Figure 4. WRF-model analyses for 1500 UTC 25 Mar 2006. (a) FULLTER radar reflectivity [dBZ, color shaded according to scale in (a)], cloud-top temperature (°C, grey shaded according to scale in (b)], and 850-hPa geopotential height (solid contours every 10 m). (b) Same as (a) but for NOSIERRA. (c) FULLTER lowest half-η level potential temperature (every 2 K), wind (vector scale at left), and kinematic frontogenesis [K (100 km h)−1, shaded following scale at left]. (d) Same as (c), but for NOSIERRA. (e) Same as (c), but with diabatic frontogenesis. (f) As in (e) but for NOSIERRA.

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Figure 5. FULLTER lowest half-η level potential temperature (every 2 K), FULLTER-NOSIERRA lowest half-η level potential temperature difference [K, shaded according to scale in (a)], and FULLTER-NOSIERRA lowest half-η level vector wind difference [scale in (a)] at (a) 1500 UTC 25 Mar, (b) 1800 UTC 25 Mar, (c) 2100 UTC 25 Mar, and (d) 0000 UTC 26 Mar 2006.

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Figure 6. Three-dimensional 15-h (0000−1500 UTC 25 Mar 2006) trajectories from (a) FULLTER and (b) NOSIERRA. Group X forward trajectories (brown) begin at 850 hPa upstream of the Sierra Nevada. Group Y and Z backwards trajectories (green and light green, respectively) terminate at 850 hPa or the half-η level, whichever is higher. FULLTER-NOSIERRA lowest half-η level potential temperature difference (color filled as in Fig. 5) and terrain difference (0–1000m gray, >1000m black). Trajectory layering based on plotting order and does not indicate relative altitude. Trajectories discussed in text and presented in Fig. 7 labeled to left of start position and right of ending arrow.

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Figure 7. Pressure and potential temperature along (a) trajectories 1 and 2 and (b) trajectories 3 and 4 of Fig. 6.

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Figure 8. Cross sections along line XY (see Fig. 4 and other figures for locations) at 1500 UTC 25 Mar 2006. (a) FULLTER potential temperature (contours every 2K), total cloud water and ice mixing ratio (gray shaded at .0001, .1, and .2 g kg -1 intervals), total diabatic heating rate produced by the explicit moisture scheme and cumulus parameterization (K hr-1, shaded following inset scale), and vectors of along-section wind and pressure vertical velocity (following inset scale). (b) Same as (a) except for NOSIERRA. (c) FULLTER potential temperature [as in (a)] and FULLTER-NOSIERRA potential temperature difference (K, shaded following inset scale). Shading over Sierra Nevada indicates region where differences in the height of the half-η surfaces contribute to the anomaly and introduce a false positive bias.

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Figure 9. Same as Fig. 4 except for 1800 UTC 25 Mar 2006.

c) FULLTER Kinematic (Fw) 1800 UTC d) NOSIERRA Kinematic (Fw) 1800 UTC

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Figure 11. FULLTER lowest half-η level potential temperature (every 2 K) and FULLTER-NOSIERRA surface heat flux difference [W m-2, shaded according to scale in (a)] at (a) 1800 UTC 25 Mar and (b) 2100 UTC 25 Mar 2006.



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Figure 14. FULLTER (red) and NOSIERRA (blue) skew T–log p diagram (temperature and dewpoint) for point A (see Figs. 5c and 12c,d for location) at 2100 UTC 25 Mar 2006.

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Figure 15. Three-dimensional nine-hour trajectories ending at 2100 UTC. (a) FULLTER and (b) NOSIERRA. Trajectory number indicated to right of trajectory ending arrow. FULLTER-NOSIERRA lowest half-η level potential temperature difference (color filled following inset scale) and terrain difference shaded (0–1000m gray, >1000m black).

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Figure 17. Lowest half-η level potential temperature (thin contours every 2 K), potential temperature gradient magnitude [thick contours every 5 K (100 km)-1 beginning with 10 K (100 km)-1], wind [vector scale at upper left of (a)], and kinematic frontogenesis [K (100 km h)−1, shaded following scale in Fig. 4c] from (a) FULLTER, (b) NOSIERRA, (c) FULLTER-FKDRY, and (d) NOSIERRA-FKDRY at 0000 UTC 26 Mar 2006.

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500 1000 1500 2000 2500 3000 3500 Figure 1. 30-sec mean topography (m, shaded following scale at...

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Transcript of 500 1000 1500 2000 2500 3000 3500 Figure 1. 30-sec mean topography (m, shaded following scale at...