SUNY-Albany: "The highly unusual early-morning super derecho severe weather event of 15 July 1995 over New York and western New England"

FINAL REPORT

1. Project
Our research on this project can be summarized by the preprints we wrote for the 19th Conference on Severe Local Storms, sponsored by the American Meteorological Society, that was held in Minneapolis, Minnesota, 14-18 September 1998. In Bosart et al. (1998) we summarized the large-scale control of the derecho events of 14-15 July 1995 over the Ohio Valley and New York and New England. Of particular importance was a large-scale continental anticyclone anchored over the central and eastern United States. By means of a dynamic tropopause analysis we were able to show that mesoscale disturbances could be followed from day-to-day as they rotated around the anticyclone and induced new outbreaks of convection. We were able to show that the derecho events of 14-15 July (and an earlier event over the Plains on 13 July) could be associated with disturbances that moved westward along the Gulf coast, then northward east of the Rockies, and then finally eastward from the High Plains to the Great Lakes and New England.

In Cannon et al. (1998) we summarized the mesoscale aspects of the derecho of 15 July 1995 over the Adirondacks and eastern New York on the basis of WSR-88D data from Rome (KRME) and Albany (KENX). We have mapped the locations of the strongest winds and the radar data makes very clear that the "wall of wind" (WOW) associated with the derecho behaves as a density current (with an elevated head) as it sweeps across the Adirondacks. The WOW is noteworthy for sustained winds in the 20-40 m s-1 range in a 20-35 km wide band that lasted for 10-20 minutes. The radar observations also suggest that new convection formed and remained quasi stationary along the upslope regions of the western Adirondacks prior to the arrival of the derecho. The mountain-induced convection was then absorbed into the leading edge of the bow echo marking the derecho.

2. Related Work by University Partner

A University at Albany doctoral student, W. Edward Bracken, took the lead on writing up for publication our previous COMET-funded research results on the Great Barrington, Massachusetts, tornado event of 29 May 1995. This paper, Bracken et al. (1999), was submitted to the Monthly Weather Review. Acceptance of this paper is awaiting our preparation of a suitable revision, which we expect to accomplish later this year. An abstract of this paper is attached for informational purposes.

We plan to continue working on the derecho case to complete some work in progress. Specifically, we plan to complete a composite of significant derecho events over the central and eastern United States (Bob Johns from the SPC/NSSL has given us the dates of many cases plus the dates of additional cases are available from the paper by Goody et al. that was published in the November 1998 issue of the Bulletin of the American Meteorological Society).

3. Related Work by Forecast Office Partner

• National Weather Service participants in this project have presented results of the research at a number of seminars and conferences:
  The 21st Northeast Storm Conference (March 1996)
• The 3rd Annual Weather at the Summit Conference in Warren, VT
• The 5th Great Lakes Operational Meteorological Workshop in Ann Arbor, MI (September 1996)
• A seminar hosted by NWSFO Albany attended by local Television Meteorologists and Meteorologists from the N.Y. State Department of Environmental Conservation (March 1996)
• NWSFO Boston MA (Taunton) Severe Weather Workshop (April 1996)
• NWSFO Albany Severe Weather Meetings (May 1996, May 1998)
• NWSFO Portland (Gray) ME Severe Weather Workshop (May 1996)
• NWSFO Buffalo Severe Weather Workshop (May 1996)
• The 7th Great Lakes Operational Workshop in Buffalo, NY (August 1998)

University at Albany students complete course work (three credit hours) by interning at NWSFO Albany and some students were shown data from the event. One University at Albany student accompanied several members of the research team on a damage survey in the Adirondacks during October of 1996.

4. Benefits to University

• The 2lst Northeast Storm Conference
• The 3rd Annual Weather at the Summit Conference in Warren, VT
• The Great Lakes Operational Meteorological Workshop in Ann Arbor, MI
• Research results from the derecho project (and the Great Barrington tornado project before that) have been used to help prepare a new COMET project proposal dealing with multiple aspects of severe weather in the northeastern United States. This proposal is now in submission.
• Seminar hosted by NWSFO Albany attended by local television Meteorologists and Meteorologists from the N.Y. State Department of Environmental Conservation

5. Benefits to Forecast Office

NWSFO participants feel collaboration with University at Albany has been very beneficial in fostering a two-way exchange of information and ideas. Working together has helped continue the cooperation begun during the COMET Partners Project (1995-96) that studied the 29 May 1995 Memorial Day tornado. Findings have been transferred to NWSFO forecasters through seminars (see number 3) and on station severe weather drills. The research and knowledge gained from this project was helpful to meteorologists who issued accurate warnings during two derecho events that affected NWSFO Albany's County Warning Area in September 1998.

6. Publications

Bosart, L. F., W. E. Bracken, and A. Seimon, Department of Earth and Atmospheric Sciences, University at
Albany/SUNY and J. S. Quinlan, K. D. LaPenta and J. W. Cannon, National Weather Service, 1996: Supercells over complex terrain: The Great Barrington Tornado of 29 May 1995. Poster presentation at the 21st National Weather Association Annual Meeting, 1-6 December 1996, Cocoa Beach, Florida.

Bosart, L. F., W. E. Bracken and Anton Seimon, Department of Earth and Atmospheric Sciences, University at Albany/SUNY and Cannon, J. W., K. D. LaPenta and J. S. Quinlan, National Weather Service, 1996: Large-scale conditions associated with the northwesterly flow intense derecho events of 14-15 July 1995 in the northeastern United States. Poster presentation at the 21st National Weather Association Annual Meeting, 1-6 December 1996, Cocoa Beach, Florida.

Bosart, L. F., W. E. Bracken and A. Seimon, Department of Earth and Atmospheric Sciences, University at Albany/SUNY and J. W. Cannon, K. D. LaPenta, and J. S. Quinlan, National Weather Service, 1996: The northwesterly flow extreme derecho event of 15 July 1995 across New York and New England. Oral presentation at the 21st National Weather Association Annual Meeting, 1-6 December 1996, Cocoa Beach,
Florida.

Seimon, A., 1996: An extreme supercell thunderstorm over complex terrain on 10 July 1989. Part II: Supercell evolution driven by terrain influences as revealed by storm scale analysis. Poster presentation at the 21st National Weather Association Annual Meeting, 1-6 December 1996, Cocoa Beach, Florida.

Cannon, J. W., K. D. LaPenta, and J. S. Quinlan, National Weather Service, L. F. Bosart, W. E. Bracken, Department of Earth and Atmospheric Sciences, University at Albany/SUNY, and A. Seimon, University of Colorado, 1998: "Radar characteristics of the 15 July 1995 Northeastern U.S. Derecho," oral presentation at the 19th American Meteorology Society, 14-18 September 1998, Minneapolis, MN.

Bracken, W. E., L. F. Bosart, Department of Earth and Atmospheric Sciences, University at Albany/SUNY, A. Seimon, University of Colorado, and K. D. LaPenta, J. S. Quinlan, and J. W. Cannon, National Weather Service, 1998: "Supercells and tornadogenesis over complex terrain: The Great Barrington (Massachusetts) Memorial Day (1995) Tornado," oral presentation at the 19th American Meteorology Society, 14-18 September 1998, Minneapolis, MN.

Bosart, L. F., and W. E. Bracken, Department of Earth and Atmospheric Sciences, University at Albany/SUNY, A. Seimon, University of Colorado, and K. D. LaPenta, J. S. Quinlan, and J. W. Cannon, National Weather Service, 1998: "Large-scale conditions associated with the Northwesterly flow intense derecho events of 14-15 July 1995 in the Northeastern United States," poster presentation at the 19th American Meteorology Society, 14-18 September 1998, Minneapolis, MN.

Bracken, W. E., L. F. Bosart, A. Seimon, K. D. LaPenta, J. S. Quinlan, and J. W. Cannon, 1999: Supercells and tornadogenesis over complex terrain: The Great Barrington (Massachusetts) Memorial Day (1995) Tornado. Mon. Wea. Rev., (In review).

7. Problems Encountered

No real problems with the NWS now co-located on the University at Albany campus with the exception of the usual difficulties finding common times to meet because of operational shift schedules.

Rotating shift schedules of NWS team members can make it difficult to schedule joint working time. The co-location of the office on University at Albany campus, the scheduling flexibility of the University at Albany participants and the cooperation of the Management of NWSFO Albany have all helped to alleviate this problem.