1. Michael L. Jurewicz, Sr. WFO Binghamton, NY Northeast Regional Operational Workshop November 5, 2009

2. AR TC Tracks and PRE Locations All AR TC TracksAll AR PPTC Tracks; with PRE centroids (colored dots)

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

4. Bill

5. Brief History of Bill Himself Bill was initially a Cape Verde tropical wave, which became a named storm on 15 August From 19-23 August, Bill attained hurricane status well off the U.S. East Coast (briefly reached Category 3) From 23-25 August, Bill transitioned to an extra- tropical system, as it recurved into the westerlies southeast of the Canadian maritime provinces

6. Bill’s Approximate Path

7. Heavy Rainfall Event across New England

8. Afternoon Rainfall on 22 August Up to 7” (175 mm) rainfall

9. Radar Loop

10. Water Vapor Loop

11. 250 mb at 12z, 22 August

12. 250 mb at 00z, 23 August

13. 200 mb Height/Wind/PV, 14z, 22 August

14. 200 mb Height/Wind/PV, 22z, 22 August Height Rises / PV Destruction

15. Surface Analysis, 18z, 22 August Possible PRE

16. 850 mb Moisture Transport Possible PRE

17. 700 mb Heights, 925 mb Winds/Theta-E, at 21z, 22 August Near intersection of Bill’s moisture and pre-existing moist plume

18. Parcel Trajectories into Central New England Bill’s Track

19. Bill Summary Bill fit into the AR track for potential PRE-producing systems One main heavy rain episode took place on the periphery of Bill’s influence Southern NH on 22 August 4-7” (up to 175 mm) of rain fell within just a few hours, causing flash flooding Transient nature of heavier rain bands precluded excessive rainfall/runoff problems elsewhere

20. Danny

21. Brief History of Danny Himself Danny was initially a Cape Verde tropical wave, and took several days to become a named storm Finally, on 26 August, it attained Tropical Storm status east of the Bahamas From 26-29 August, Danny remained a Tropical Storm well off the Southeast U.S. coast From 29-31 August, Danny weakened to a Tropical Depression, and ultimately transitioned to an extra- tropical system, as it recurved off the U.S. East Coast

22. Danny’s Approximate Path

23. Heavy Rainfall Event across the Mid-Atlantic Region

24. Late Night/Early Morning Rainfall, 27-28 August 4-8” (100- 200 mm) rainfall

25. Radar Loop

26. 250 mb at 00z, 28 August

27. Water Vapor Loop

28. 700 mb Heights, 925 mb Winds/Theta-E, at 05z, 28 August Axis of tro pical moisture Separate moist axis

29. 850 mb at 00z, 28 August

30. Parcel Trajectories into the Mid- Atlantic Region

31. 200 mb Height/Jet/PV, 02z, 28 August

32. 200 mb Height/Jet/PV, 09z, 28 August

33. SB CAPE Analysis, 06z, 28 August

34. Heavy Rainfall Event Just off the Mid-Atlantic Coast

35. Late Afternoon/Overnight Rainfall, 28-29 August Widespread 5-10” (up to 250 mm) rainfall

36. Radar Loop, 28-29 August

37. 250 mb at 00z, 29 August

38. Water Vapor, 28-29 August

39. 700 mb Heights, 925 mb Winds/Theta-E, at 03z, 29 August Tropical Moisture Axis

40. SB CAPE Analysis, 00z, 29 August Possible PRE

41. Surface Analysis, 00z, 29 August Possible PRE

42. 850 mb Analysis, 00z on 29 August

43. Parcel Trajectories into the Mid- Atlantic Coastal Region Danny’s Track

44. Danny Summary Danny fit into the AR track for potential PRE-producing systems Two distinct heavy rain episodes took place on the periphery of Danny’s influence Event that most resembled a PRE took place just offshore, 28- 29 August Heavy rain/flash flooding that occurred in the Baltimore area appeared to lack sufficient moisture contributions from Danny or jet interactions Lack of a direct moisture connection with the TC, as well as a relatively cool stable air mass, seemed to protect much of the Northeastern U.S. from excessive rainfall