1 . FY12-13 GIMPAP Project Proposal Title Page date: 7 August 2012

1. 1. FY12-13 GIMPAP Project Proposal Title Pagedate: 7 August 2012 Title: Developing GOES-Based Tropical Cyclone Recurvature Tools Status: Renewal Duration: Total of 2 years Project Leads: John Knaff NESDIS/StAR –RAMMB John.Knaff@noaa.gov Mark DeMaria NESDIS/StAR–RAMMB Mark.DeMaria@noaa.gov Other Participants: Dan Bikos CIRA/CSU Ed Fukada USN/Joint Typhoon Warning Center Chris Landsea NOAA/National Hurricane Center

2. 2. Project Summary Construct a GOES-based tool that improves forecasts of the short-term (0-48 hours) timing of TC recurvature* for • North Atlantic and • Northwest Pacific TC basins • Where the point of *recurvature is defined by the point along the track at which the meridional motion is poleward and the zonal component of motion changes from westward to eastward • By making uses of • GOES/MTSAT water vapor imagery • GFS analysis/forecast fields • Tropical cyclone databases • and by combining/leveraging • objective and subjective methods like those described in Hodanish and Gray (1993) and Dvorak (1995), respectively

3. 3. Motivation / Justification • Supports NOAA’s Mission and its Weather and Water strategic goal • Improved tropical cyclone track forecasts are a top NOAA/DOD priority. • Often the most difficult track forecasts involve the timing of recurving tropical cyclones (TCs). • Short-term accelerations can be very important when TCs are close to land areas. • Late Guidance: The most recent numerical track guidance is not available when the track forecasts are produced • Track changes are discrete in nature.

4. Positions (aircraft-based center locations ) Six-hourly best track positions Hurricane Earl (2010)

5. 4. Methodology • Combine three data types • Tropical cyclone tracks/locations • Information in the GOES/GMS/MTSAT water vapor imagery (2001-2010) (cf. Dvorak (1995)) • Patterns associated with mid-latitude troughs • Distance from a tropical cyclone • Speed of the storm and approach of the trough • Information from the GFS/NCEP Analyses (cf. Hodanish and Gray (1993)) • Distance and direction of the upper-level westerly winds from the TC center • Depth of the upper-level westerlies • Forecasts of these fields

6. Dvorak (1995) Water Vapor Imagery Subjective Technique TC translation speed

7. Example: Hurricane Bill (2009)

8. Basic findings : Recurvature in Rawindsonde Composites • Recurvature is preceded by increases in or occurrence of • 500 and 200-hPa zonal winds within 600 to 800 km west, northwest and north of the TC • 200-hPa meridional winds within 600 to 800 km northwest and north of the TC • An index constructed from these factors is related to the point of recurvature. • Real-time testing in the West Pacific showed promise

9. 5. Expected Outcomes • Development of GOES-based tools that improve the anticipation of the timing (and longitude) of TC recurvature. • Operational transition and use of these tools to improve track forecasts • The point of recurvature can be critical in the watch/warning process as storms approach land. • Large track errors are often associated with poor anticipation of TC recurvature

10. 6. First Year - Preliminary Results Note: Work on this project only recently started due to the arrival of funding Review of FY 12 Milestones: • Compile historical TC recurvature cases for Atlantic and West Pacific from the best tracks • Construct the storm relative WV data for those cases • Construct the NCEP reanalysis storm relative wind fields for those cases • Begin exploring the statistical relationships between the wind fields and water vapor features

11. Atlantic Cases (14) Batting average =.429 -- good only for a hitter

12. WV Image filtering, gradient detection Caption: Tropical cyclone Fabian at 17:45 UTC 5 September 2003 just prior to recurvature. The contours are gradients of a specified range of brightness temperatures from the water vapor imagery. The yellow line shows the distance between the gradient associated with the curved moisture boundary and the cyclone center.

13. Zonal Winds Caption: Tropical cyclone Igor example. Image is the GFS 200-500 mb layer average u-component of the wind at 1200 UTC 19 September 2010 (top) and 6 hours later at 1800 UTC (bottom). Blue corresponds to easterly zonal winds, while red values are associated with westerly zonal winds with increasing magnitude in darker shades. Yellow line denotes distance between cyclone center and the distance when recurvature typically occurs.

14. 7. Possible Path to Operations • If successful, GOES PSDI funding will be sought for implementation in operations. • Alternatively, this product could seek Joint Hurricane Testbed funding for transition.

15. 8. FY13 Milestones • Develop statistical relationships between the wind, water vapor features and the timing of recurvature • Develop tools for anticipating the timing (and longitude) of TC recurvature • Test the model on independent data. • Document in refereed journal

16. 9. Funding Request (K)

17. 10. Spending Plan FY13 • FY13 $57,000 Total Project Budget • Total Grant to CIRA $ 54K • 40% FTE (CIRA Research Scientist) $ 49 K • CIRA Travel - $ 2 K • Publication Charges $ 3 K • Federal Travel • Trip to NRLMRY Monterey CA June 2013 $ 3K or Trip to JTWC, Pearl Harbor, HI