List of Figures
Fig. 1.1. Areas where coastal front activity is most commonly observed, including: (a)
the southern New England coast, (b) the Carolina coast, and (c) the Texas coast (Bosart
et al. 1972).
Fig. 1.2. Mean sea level pressure for the onset of 57 coastal frontogenesis cases, showing
the relative position of a northern New England high-pressure system and a developing
short wave along the mid-Atlantic coast (Bosart 1975).
Fig. 1.3. A physical model of coastal frontogenesis dominated by the focusing of
isotherms in association with northerly inland flow and easterly onshore flow (Bosart
1975).
Fig. 1.4. Coastal front normal and front-relative horizontal wind speed (m s-1) for cases
analyzed by Nielsen and Neilley (1990), clearly identify cold air trapped east of the
terrain and a sloping inversion caused by ascent of warm, easterly flow.
Fig. 1.5. Conceptual model for a cold-air damming situation. Note the low-level wind
maximum (LLWM) within the cold dome and the easterly flow ascending the sloping
inversion at the top of the cold dome (Bell and Bosart 1988).
Fig. 1.6. (a) Ageostrophic flow and upper-level divergence for a straight jet streak. (b)
Direct and indirect circulations associated with jet entrance (A–A’) and exit (B–B’)
regions. (c) Vorticity distributions and vorticity advections associated with a straight jet
streak (Uccellini and Kocin 1987).
Fig. 1.7. Interacting transverse circulations coinciding with the entrance and exit regions
of a coupled jet structure, resulting in a broad area of upward vertical motion (shaded
region) (Uccellini and Kocin 1987).
Fig. 1.8. Widely varying terrain in the Northeast United States further complicates
precipitation forecasts during landfalling and transitioning tropical cyclone events.
Fig. 1.9. Three step conceptual model of the transformation stage of extratropical
transition (Klein et al. 2000).
Fig. 1.10. Cyclone phase-space diagram for Hurricane Floyd (Evans and Hart 2003),
showing the phase of transition based upon storm symmetry and cyclone strength.
Fig. 1.11. Two regions of possible heavy precipitation during tropical cyclone events,
with region A investigated by Bosart and Carr (1978), and region B investigated by
Bosart and Dean (1991).
xii
Fig. 1.12. A coastal front analyzed by Bosart and Dean (1991) during the passage of
Tropical Storm Agnes across the Washington, D.C. area revealed a pronounced
boundary produced by the intersection of northerly continental air and easterly tropical
flow.
Fig. 3.1. Storm track relative to precipitation (mm) for Hurricane Bob, 19–20 August
1991, with the position of the system plotted every 6 h and the white squares denoting
the daily storm position at 1200 UTC.
Fig. 3.2. Daily precipitation (in) and topography (m) for the 24-h period (1200–1200
UTC) ending on (a) 19 August and (b) 20 August 1991.
Fig. 3.3. A fine-resolution analysis of storm total precipitation (in) for Hurricane Bob
(1991) (Horwood 2003).
Fig. 3.4. Plots of 200 hPa geopotential height (dam), wind speed (shaded every 5 m s-1),
and divergence (contoured in red, 10-5 s-1), with the approximate center of circulation
denoted by a gray “B” for: (a) 1800 UTC 18 August, (b) 0600 UTC 19 August, (c) 1200
UTC 19 August, and (d) 1800 UTC 19 August 1991.
Fig. 3.5. Plots of 500 hPa geopotential height (dam) and absolute vorticity (10-5 s-1), with
the approximate center of circulation denoted by a black “B” for: (a) 0600 UTC 19
August, (b) 1200 UTC 19 August, and (c) 1800 UTC 19 August 1991.
Fig. 3.6. Plots of 850 hPa geopotential height (dam), potential temperature (shaded every
3 K), and wind (barbs in units of knots), with the approximate center of circulation
denoted by a black “B” for: (a) 0600 UTC 19 August, (b) 1200 UTC 19 August, (c) 1800
UTC 19 August, and (d) 0000 UTC 20 August 1991.
Fig. 3.7. Plots of 925 hPa geopotential height (dam), equivalent potential temperature
(shaded every 5 K), and wind (barbs in units of knots), with the approximate center of
circulation denoted by a black “B” for: (a) 0600 UTC 19 August, (b) 1200 UTC 19
August, (c) 1800 UTC 19 August, and (d) 0000 UTC 20 August 1991.
Fig. 3.8. Surface plots containing temperature (oC), dewpoint (oC), wind (knots), and the
approximate position of the coastal front at 1600 UTC 19 August 1991.
Fig. 3.9. Surface plots for 1600 UTC 19 August of: (a) wind (knots), potential
temperature (K), and potential temperature gradient (shaded every 10-4 K (100 km)-1),
and (b) wind (knots), equivalent potential temperature (K), and equivalent potential
temperature gradient (shaded every 2x10-4 K (100 km)-1).
Fig. 3.10. Same as Fig. 3.8 except for 1700 UTC 19 August.
Fig. 3.11. Same as Fig. 3.9 except for 1700 UTC 19 August.
xiii
Fig. 3.12. Same as Fig. 3.9 except for 1800 UTC 19 August.
Fig. 3.13. Same as Fig. 3.8 except for 1800 UTC 19 August.
Fig. 3.14. Same as Fig. 3.1 except for Hurricane Gloria, 26–28 September 1985.
Fig. 3.15. Same as Fig. 3.2 except for (a) 26 September, (b) 27 September, and (c) 28
September 1985.
Fig. 3.16. Same as Fig. 3.3 except for Hurricane Gloria (1985).
Fig. 3.17. Same as Fig. 3.4 except for the approximate center of circulation denoted by a
gray “G” for: (a) 1800 UTC 26 September, (b) 0000 UTC 27 September, (c) 0600 UTC
27 September, and (d) 1200 UTC 27 September 1985.
Fig. 3.18. Same as Fig. 3.5 except for the approximate center of circulation denoted by a
black “G” for: (a) 0000 UTC 27 September, (b) 0600 UTC 27 September, (c) 1200 UTC
27 September, and (d) 1800 UTC 27 September 1985.
Fig. 3.19. Same as Fig. 3.6 except for the approximate center of circulation denoted by a
black “G” for: (a) 0000 UTC 27 September, (b) 0600 UTC 27 September, (c) 1200 UTC
27 September, and (d) 1800 UTC 27 September 1985.
Fig. 3.20. Same as Fig. 3.7 except for the approximate center of circulation denoted by a
black “G” for: (a) 0000 UTC 27 September, (b) 0600 UTC 27 September, (c) 1200 UTC
27 September, and (d) 1800 UTC 27 September 1985.
Fig. 3.21. Same as Fig. 3.8 except for Hurricane Gloria at 0600 UTC 27 September
1985.
Fig. 3.22. Same as Fig. 3.9 except for Hurricane Gloria at 0600 UTC 27 September
1985.
Fig. 3.23. Same as Fig. 3.8 except for Hurricane Gloria at 0900 UTC 27 September
1985.
Fig. 3.24. Same as Fig. 3.9 except for Hurricane Gloria at 0900 UTC 27 September
1985.
Fig. 3.25. Same as Fig. 3.8 except for Hurricane Gloria at 1200 UTC 27 September
1985.
Fig. 3.26. Same as Fig. 3.8 except for Hurricane Gloria at 1500 UTC 27 September
1985.
xiv
Fig. 3.27. Same as Fig. 3.9 except for Hurricane Gloria at 1200 UTC 27 September
1985.
Fig. 3.28. Same as Fig. 3.9 except for Hurricane Gloria at 1500 UTC 27 September
1985.
Fig. 3.29. Same as Fig. 3.1 except for Hurricane Belle, 9–11 August 1976.
Fig. 3.30. Same as Fig. 3.2 except for (a) 9 August, (b) 10 August, and (c) 11 August
1976.
Fig. 3.31. Same as Fig. 3.3 except for Hurricane Belle (1976).
Fig. 3.32. Same as Fig. 3.4 except for the approximate center of circulation denoted by a
gray “B” for: (a) 0600 UTC 9 August, (b) 1200 UTC 9 August, (c) 1800 UTC 9 August,
and (d) 0000 UTC 10 August 1976.
Fig. 3.33. Same as Fig. 3.5 except for the approximate center of circulation denoted by a
black “B” for: (a) 0600 UTC 9 August, (b) 1200 UTC 9 August, (c) 1800 UTC 9
August, and (d) 0000 UTC 10 August 1976.
Fig. 3.34. Same as Fig. 3.7 except for the approximate center of circulation denoted by a
black “B” for: (a) 0600 UTC 9 August, (b) 1200 UTC 9 August, (c) 1800 UTC 9
August, and (d) 0000 UTC 10 August 1976.
Fig. 3.35. Same as Fig. 3.8 except for isotherms (dashed lines every 1oC) for Hurricane
Belle at 0600 UTC 10 August 1976.
Fig. 3.36. Surface plot containing temperature (oC), dewpoint (oC), and wind (knots) at
0800 UTC 10 August 1976.
Fig. 3.37. Same as Fig. 3.36 except for 1100 UTC 10 August 1976.
Fig. 3.38. Same as Fig. 3.36 except for 1300 UTC 10 August 1976.
Fig. 3.39. Same as Fig. 3.1 except for Hurricane Connie, 12–14 August 1955.
Fig. 3.40. Finer-resolution precipitation analysis for Hurricane Connie with approximate
coastal front locations (black lines) plotted every 3 h beginning at 0330 UTC (A) and
ending at 1230 UTC (D) 13 August 1955 (Horwood 2003).
Fig. 3.41. Same as Fig. 3.5 except for the approximate center of circulation denoted by a
black “C” for (a) 1800 UTC 12 August and (b) 0600 UTC 13 August 1955.
Fig. 3.42. Same as Fig. 3.4 except for the approximate center of circulation denoted by a
gray “C” for (a) 1800 UTC 12 August and (b) 0600 UTC 13 August 1955.
xv
Fig. 3.43. Same as Fig. 3.6 except for the approximate center of circulation denoted by a
black “C” for (a) 1800 UTC 12 August and (b) 0600 UTC 13 August 1955.
Fig. 3.44. Same as Fig. 3.7 except for the approximate center of circulation denoted by a
black “C” for (a) 1800 UTC 12 August and (b) 0600 UTC 13 August 1955.
Fig. 3.45. Surface plots for 13 August 1955 with temperature (oF), wind (knots) and
pressure (hPa) for (a) 0330 UTC, (b) 0630 UTC, (c) 0930 UTC, and (d) 1230 UTC
(Kocin 1995).
Fig. 3.46. Same as Fig. 3.1 except for Hurricane Diane, 17–20 August 1955.
Fig. 3.47. Same as Fig. 3.40 except for Hurricane Diane, beginning at 0630 UTC (A) and
ending at 1530 UTC (D) 19 August 1955 (Horwood 2003).
Fig. 3.48. Same as Fig. 3.5 except for the approximate center of circulation denoted by a
black “D” for (a) 1200 UTC 18 August and (b) 0000 UTC 19 August 1955.
Fig. 3.49. Same as Fig. 3.4 except for the approximate center of circulation denoted by a
gray “D” for (a) 1200 UTC 18 August and (b) 0000 UTC 19 August 1955.
Fig. 3.50. Same as Fig. 3.7 except for the approximate center of circulation denoted by a
black “D” for (a) 1200 UTC 18 August and (b) 0000 UTC 19 August 1955.
Fig. 3.51. Same as Fig. 3.45 except for 19 August 1955 at (a) 0630 UTC, (b) 0930 UTC,
(c) 1230 UTC, and (d) 1530 UTC (Kocin 1995).
Fig. 4.1. Features critical to the occurrence of heavy precipitation over the northeast US
accompanying landfalling and transitioning tropical cyclones. Enhanced upper-level jet
winds are represented by the blue-hatched area, maximum upper-level divergence is
represented by the magenta circle, enhanced low-level jet winds are represented by the
orange-hatched area, the broad precipitation shield is represented by the light green
dashed line, the heaviest precipitation is represented by the dark green dashed line, the
western Atlantic ridge is represented by the blue “H”, and the approximate coastal front
location is represented by the pink line extending northward from the center of
circulation, which is denoted by the red hurricane symbol.
xvi