Michael L. Jurewicz, Sr. NOAA/NWS, Binghamton, NY Northeast Regional Operational Workshop

1. 2008 “PRE-Season” In Review: A Comparison of Tropical Cyclones Fay, Hanna, and Ike with Regards to Predecessor Rainfall Event (PRE) Development Michael L. Jurewicz, Sr. NOAA/NWS, Binghamton, NY Northeast Regional Operational Workshop November 5-6, 2008

2. Fay

3. Fay Overview • Fay came ashore as a Tropical Storm over the FL Keys on Aug. 19, then slowly meandered across the FL Peninsula the next several days • Synoptic Back-drop: • Cutoff low over the southern plains • Large, building anticyclone over the eastern U.S., to the north and northeast of Fay

4. 700 mb Analysis, 1200 UTC, 19 Aug. Ridge Axis L Fay

5. 925 mb Analysis, 1200 UTC, 19 Aug. Ridge Axis L Fay

6. 300 mb Analysis, 1200 UTC, 19 Aug.

7. SR Null-Case Composites 700 mb heights (dam) and upward vertical motion (shaded, μb s-1) 925 mb heights (dam), θe (K), and 200 mb winds (shaded, m s-1) Center of composite TC

8. 24-Hour QPE Through 1200 UTC, 20 Aug. Fay’s Direct Rainfall

9. Radar Mosaic, 2100 UTC, 20 Aug.

10. Parcel Trajectories Red – About 925 mb Blue – About 700 mb Green – About 500 mb

11. 700 mb Analysis, 1200 UTC, 21 Aug. Ridge Axes L Fay

12. 24-Hour QPE Through 1200 UTC, 21 Aug. Disorganized Convection Fay’s Direct Rainfall

13. Radar Mosaic, 1800 UTC, 21 Aug.

14. Parcel Trajectories Red – About 925 mb Blue – About 700 mb Green – About 500 mb

15. 700 mb Analysis, 1200 UTC, 22 Aug. Ridge Axes L Fay

16. 24-Hour QPE Through 1200 UTC, 22 Aug. Still Disorganized Convection Fay’s Rainfall

17. Radar Loop – 20 Aug. to 24 Aug.

18. A Classic Null-Case • Fay produced tremendous rainfall across parts of the Southeastern U.S. • Several day totals of 20”+ in parts of FL • Due to the direct impacts of Fay’s rainfall shield and her slow movement • PRE development not observed • Expansive mid-level ridge was in place; nearly enveloped Fay • Precipitation maxima stayed tightly clustered around the circulation center

19. Hanna

20. Hanna Overview • Hanna came ashore as a Category 1 Hurricane near the NC/SC border around 0600 UTC, 6 Sept. • Synoptic Back-drop: • Large western Atlantic ridge and central U.S. troughiness • Deep southerly flow regime over the eastern states

21. 700 mb Heights/Winds, 0000 UTC, 6 Sept.

22. 925 mb Heights/Theta-E and 200 mb Winds, 0000 UTC, 6 Sept. Theta-E Ridge Line

23. Hanna Falls Within the SR Category; SR TC Tracks and PRE Locations All SR PPTC Tracks; with PRE centroids (colored dots) All SR TC Tracks

24. SR PPTC Composites (PRE - 12) Trough axis Ridge axis θe-Ridge axis 700 mb heights (dam) and upward vertical motion (shaded, μb s-1) 925 mb heights (dam), θe (K), and 200 mb winds (shaded, m s-1) Center of composite TC

25. Conceptual Model: LOT PRE Ahead Of SR Or AR TC UL Jet LL θe-Ridge Axis PREs See inset Mid-level Streamlines TC Rainfall Revised and updated from Fig. 13 of Bosart and Carr (1978) Representative TC Tracks

26. PRE Outlook • Synoptic setting seemed somewhat favorable for potential PRE development poleward of Hanna • TC embedded within southerly 700 mb flow, with short wave upstream • However, trough was less amplified than the composites • Strengthening upper-level jet streak to the north • Developing 925 mb theta-e ridge, although a little broader and farther east than the composites • Proximity of low-level boundary

27. 850 mb Moisture Transport, 0000 UTC, 6 Sept.

28. 850 mb Moisture Transport, 1200 UTC, 6 Sept.

29. Precipitable Water and Low-Level Winds, 0000 UTC, 6 Sept.

30. Precipitable Water and Low-Level Winds, 1200 UTC, 6 Sept.

31. Radar Loop, 0000 – 1500 UTC, 6 Sept.

32. QPE, 0600-1200 UTC, 6 Sept. “PRE-like” Rainfall

33. A Quick PRE • A band of heavy rainfall did develop north of Hanna from late Friday, 9/6 into Sat., 9/7 • However, it was transient in nature; almost like a progressive warm front feature • Limited rainfall in most areas to 1” or less • Parts of RI/southeast MA did get heavier amounts (2-3” and locally higher, in just a 3-6 hour period) • Best combination of moisture inflow and jet dynamics

34. Hanna’s Direct Rainfall Shield • A narrow band of heavy rain accompanied Hanna up the Eastern Seaboard • Maximum rainfall shifted increasingly just to the left of track with poleward extent • Typical of transitioning TC • Generally, 3-6” of rain fell within a 6-10 hour period • Dry antecedent conditions and the lack of a significant “Along-Track” PRE mitigated any serious flood problems

35. Radar Loop from 1200 UTC, 6 Sept. to 0600 UTC, 7 Sept.

36. QPE, 1200 UTC, 6 Sept. to 1200 UTC, 7 Sept. Where heavier rains fell earlier

37. Ike

38. Ike Overview • Ike came ashore as a Category 2 Hurricane along the TX coast around 0600 UTC, 13 Sept. • Synoptic Back-drop: • Large southeastern U.S. ridge and western states troughiness • Deep southerly flow regime over the southern Plains and up the Mississippi Valley

39. 700 mb Heights/Winds, 0600 UTC, 12 Sept.

40. 925 mb Heights/Theta-E and 200 mb Winds, 0600 UTC, 12 Sept. Theta-E Ridge Line

41. Ike Falls Within the CG Category; CG TC Tracks and PRE Locations All CG PPTC Tracks; with PRE centroids (colored dots) All CG Tracks

42. PRE Outlook • Synoptic setting seemed favorable for potential PRE development poleward of Ike • TC embedded within southerly 700 mb flow, with trough upstream • Strengthening upper-level jet streak to the north/northeast • Sharpening 925 mb theta-e ridge axis • Nearly stationary low-level boundary

43. Derived Total Precipitable Water, 0600 UTC, 12 Sept. Channel of Moisture Inflow L Ike

44. Precipitable Water, 0600 UTC, 12 Sept.

45. 850 mb Moisture Transport, 0600 UTC, 12 Sept.

46. Radar Loop, 0000 – 1800 UTC, 12 Sept.

47. Parcel Trajectories Red – About 850 mb Blue – About 700 mb Green – About 500 mb L Ike

48. Total Rainfall for PRE in Southern KS

49. Flood Pictures (West Wichita, KS)

50. 700 mb Analysis, 1200 UTC, 13 Sept. L Ike