1 1 United States Mexico 2 3 4 Figure 1. Geographical area of northwestern Mexico with topographic contours (shaded, m) given in the 5 vertical bar. Specific locations mentioned throughout the text are the states of Nayarit (NAY), Sinaloa 6 (SIN), Sonora (SON), Baja California (BC), and Baja California Sur (BCS). Circled letters are the five 7 largest communities in BCS and SIN, shown in Table 1. Dots represent landfall positions from tropical 8 cyclones during the period 1969–2006. The dashed box outlines the area shown in Figs. 12 and 15. 9 1 2 11 Figure 2. Tracks of tropical cyclones that, during the seasons 1969–2006, made first landfall over the (a) Baja California Peninsula and (b) Mainland Mexico. Thick lines are tropical cyclones from 2006. Temporal frequency (percentage) of landfall strikes is shown in upper-right inserts. The lower-left lists provide the five strongest hurricanes at landfall: name, year, and maximum winds in m s-1 (Saffir-Simpson scale category). Small dots are initial locations with corresponding labels (first letter name and two-digit 2 year). The large dot represents Isla Socorro. 3 13 15 Figure 3. Mean streamlines at the 500-hPa level from the NCEP-NCAR reanalysis for selected cases from Fig. 2. Tropical cyclones at time of landfall over the (a) Baja California peninsula and (b) the mainland are considered. Dashed line is the 10 m s-1 wind speed contour at 500-hPa. The black dots indicate corresponding mean position of TCs from the best track, plus signs are 12 and 24 hours before and after lnadfall. Shading represents the 850-200 hPa wind shear with light, intermediate and dark tones indicating -1 values above 10, 20 and 30 m s respectively. 3 4 16 Figure 4. Tracks of tropical cyclones John (28 August– 4 September), Lane (13-17 September), and Paul (21-26 October) in 2006. Positions are marked every 6 hours, numbers are dates of fixes at 00:00 UTC with final positions given by lower-case initials. Location of maximum intensity (MAX) and recurvature initiation (REC) are indicated. Inserts show sustained wind speed (m s-1), maximum intensity, and time of landfall (vertical line). Dashed lines are the tropical storm (17 m s-1) and hurricane (33 m s-1) intensity thresholds. 4 5 18 20 Figure 5. Rainfall accumulations from TRMM during selected periods and during the development of tropical cyclones in 2006. The vertical bar indicates the amount of accumulations (mm). Best-track positions are indicated by circles (John), plus signs (Lane), and crosses (Paul) at 6-hour intervals. 5 6 22 24 Figure 6. GOES-11 infrared and water vapor imagery at landfall. Infrared images are from (a) Hurricane John, (b) Hurricane Lane, and (c) Tropical Depression Paul in 2006. Landfall positions are symbols as in Fig. 4 and the vertical bar indicates a calibrated scale of cloud top temperature (°C). Simultaneous water vapor imagery is at the right column with precipitable water (mm) from upper-air soundings. Crosses represent missing soundings. 6 7 25 Figure 7. North American Regional Reanalysis fields at 00:00 UTC from (a-c) 31 August–2 September, (d-f) 15–18 September, and (g-i) 24–26 October 2006. Streamlines are at the 500-hPa level. Shading represents the 850–200 hPa horizontal wind shear with light, intermediate and dark tones representing values above 10, 20, and 30 m s-1, respectively. Dashed lines are wind speeds at 20 and 30 m s-1. Thick lines are the locations of the vertical cross sections shown in Fig. 11. Black dots are the corresponding tropical cyclone positions at 00:00 UTC as well as 12 hours before and after. Colored dots are corresponding positions from tropical cyclones Kristy (blue) and Miriam (red). 7 8 26 Figure. 8. Reflectivity (dBZ) from the Cabo San Lucas, Baja California Sur, radar at (a) 05:53 UTC 1, September, (b) 18:42 UTC, 1 September, and (c) 02:03 UTC 2 September. Rain rate (mm h-1) image from the Guasave, Sinaloa, radar at (d) 12:15 UTC 2 September. Radar stations are located at the white dots. 8 9 1 Figure 9. Total rainfall (mm) in Baja California Sur from the period 31 August–4 September 2006. 27 Top ten reports are circled and shown in Table 2. Best-track positions (large dots) and intensities (Hurricane=HR, Tropical Storm=TS, and Tropical Depression=TD) are indicated. Terrain elevations (shaded) are at 300-m intervals. Asterisk is the landfall site for John and triangles are the four strongest hurricanes (name initial and year) from Fig. 2a. 9 10 37 Figure 10. Radar images of (a) reflectivity (dBZ) from Cabo San Lucas, Baja California Sur, at 12:03UTC 16 September and (b) rain rate (mm h-1) from Guasave, Sinaloa, at 19:17 UTC 16 September 2006. The radars are located at the white dots. (c) GOES-11 visible image at 19:15 UTC 16 Sep. 10 a 11 b c 38 Figure 11. Cross section from the NARR at (a) 00:00 UTC 15 September, (b) 00:00 UTC 16 September and (c) 00:00 UTC 18 September 2006. Vertical axis is pressure from 100-1000 hPa. Shading is mixing ratio (g kg-1) with contour interval given in the bar. Isotachs (contour interval 5 m s-1) of zonal wind component given by the thick (positive) and dashed (negative) lines. Geographical location of cross sections is indicated in Figs. 7d-f. 11 12 45 47 Figure 12. Total rainfall (mm) in Sinaloa from the period 14–16 September 2006. Top -ten reports are circled and shown in Table 3. Best-track positions (large dots) and intensities (Hurricane=HR, Tropical Storm=TS, and Tropical Depression=TD) are indicated. Terrain elevations (shaded) are at 600-m intervals. Asterisk is the landfall site for Lane and triangles (name initial and year) are three strongest hurricanes from Fig. 2b. 12 a 13 49 51 b Figure 13. GOES-11 visible imagery at (a) 20:45 UTC 24 October and (b) 14:45 UTC 25 October 2006. The circles represent the low-level circulation associated with Tropical Storm Paul. 13 14 53 Figure 14. Time series of winds and mixing ratio from upper-air soundings for the period 00:0055 UTC 22 October through 00:00 UTC 29 October 2006. Full wind barbs indicate 5.0 m s-1 and half barbs 2.5 m s-1. Mixing ratio (g kg-1) is shaded and contour intervals are given in the bar. Vertical axis represents pressure levels from 1000 to 100 hPa. 14 15 57 59 Figure 15. Total rainfall (mm) in Sinaloa from the period 24–26 October 2006. Top -ten reports are circled and shown in Table 4. Best-track positions (large dots) and intensities (Tropical Storm=TS, and Tropical Depression=TD) are indicated. Terrain elevations (shaded) are at 600-m intervals. Asterisk is the landfall site for Paul. 15 16 61 63 Figure 16. Best-track and official forecast positions for John, Lane, and Paul. Initial dates of forecasts are given in the lower-left inserts (symbol, day, and month). Forecasts are valid at 12, 24, 36, 48, 72, 96, and 120 hours. Thick and thin (with dots) lines represents best tracks. Black dots are locations of upper- air stations in Mexico. Numbers indicate released soundings at 00:00 UTC (left from slash) and 12:00 UTC (right from slash) during the three days covered by each case. Insert table indicates track errors (km) at valid times the bold number representing maximum error per time. 16 17 64 -1 65 Figure 17. Mean track (aa, km) and intensity (bb, m sP )P errors from official forecasts for tropical 66 cyclones John, Lane, and Paul. Mean errors from all tropical cyclones from the eastern North 67 Pacific basin, during the season of 2006, are indicated (thick line). Data sources is the are forecast 68 verification reportstatistics byfrom Franklin (2007, Table 13). 17 18 69 Figure 18. Global Forecast System forecast (FCST) and analysis (ANL) fields at 00:00 UTC (a, d) 2 September, (b-e) 18:00 UTC 16 September, and (c-f) 00:00 UTC 26 October, 2006. Streamlines are at the 500- hPa level. Shading represents 850–200 hPa wind shear with light, intermediate, and dark tones representing values above 10, 20, and 30 m s-1, respectively. Thick arrows are an estimate of the steering flow. Black dots are tropical cyclone positions from the best track. Circles and dots are positions from Kristy (blue) and Miriam (red). 18 19 Figure 19. Best-track and official forecast positions from tropical cyclones making landfall in Baja California (top panels) and mainland Mexico (bottom panels) during the period 1998-2005. Forecasts are valid at 12, 24, 36, 48, 72, 96, and 120 hours. Forecasts were issued, approximately, 72- (plus signs), 48- (circles), and 24- (crosses) hours prior to landfall. Thick line represents the best track and black dots are locations of available upper-air observations. 19 20 70 71 Table 1. Population (inhabitants) from the five largest cities in the states of Baja California Sur and 72 Sinaloa, Mexico. Source of data INEGI (2005). The city identification (CI) is used to show the 73 corresponding geographical location in Fig. 1. 74 ____________________________________________________________ 75 CI Baja California Sur CI Sinaloa. 76 ____________________________________________________________ 77 Baja California Sur (512,170) Sinaloa (2,608,442) 78 79 A La Paz (189,176) A Culiacán (605,304) 80 B Cabo San Lucas (56,811) B Mazatlán (352,471) 81 C San José del Cabo (48,518) C Los Mochis (231,977) 82 D Ciudad Constitución (37,221) D Guasave (66,793) 83 E Loreto (10,283) E Guamúchil (61,862) 84 ____________________________________________________________ 85 86 Number of inhabitants is indicated in parenthesis.