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Numerical Prediction of Inland Tropical Cyclone (TC) Impacts Gary Lackmann North Carolina State University With Briana Gordon and Brian Etherton. RAH Barrett Smith. Thank You, NWS! - For providing excellent research topics and ideas - For organizing meeting, being here & participating
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Tropical Cyclone (TC) Impacts
North Carolina State University
With Briana Gordon and Brian Etherton
RAH Barrett Smith
- For providing excellent research topics and ideas
- For organizing meeting, being here & participating
- For helping realize the benefit of applied research
- For past and future collaborations
Part I: TC Initialization (Briana Gordon, yesterday)
Part II: Research Opportunity (the problem)
Part III: Collaboration
Acknowledgement to RAH (Barrett Smith, Jonathan Blaes), HPC (David Roth), OU NMQ
Barrett Smith, RAH
Rain ahead of Hanna: Evaporational cooling, boundary forms
Weak cold-air damming develops, enhanced thermal gradient
Boundary hypothesized to aid isentropic ascent
Inland wind prediction – also related to boundary?
Strong surface winds east of boundary (unstable), weaker winds to west (heavier precipitation there)
Verifying severe weather reports and wind analyses based on spotter reports and other available data: Boundary location not coincidental
- Outer circulation gives rise to boundaries, “preconditioning”
- Interactions with boundaries, synoptic flow: PREs
- Impact timing for approaching TC related to size of storm
Srock and Bosart (2009)
EARL: TPC Best Track: 948 mb
NAM, 9/3/00Z: 990 mb
GFS, 9/3/00Z: 982 mb
NAM 33-h forecast valid 09Z 3rd (212)
Improved TC initialization (both inner- and outer-core features)
Towards improved numerical prediction of inland TC impacts
RENCI computing resources allow high-resolution TC simulations (explicit convection)
27-km outer domain, 9-, 3-km mobile inner grids
Utilize large computational domain, moving nest vortex-tracking feature of WRF-ARW model
Spin up at high resolution offshore, strength, structure closer to observations at landfall
“Out-of-box” configuration: Promising (3 years)
Differences relative to NAM and GFS?
Moving-nest tracks TC (3 km): Explict convection
Ocean Mixed Layer: Accounts for wake cooling
Effective “dynamical downscaling”
Main limitation: Initial conditions, esp. with strong storm at initial time (use 0.5° GFS)
Ocean Mixed Layer: simple parameterization
Only mixing, no upwelling
No ocean currents
Initial SST field from GFS
Specify thermocline depth (m)
Specify temperature lapse rate (deg/m)
OML, 25 m mixed layer
OML, 50 m mixed layer
OML, 75 m mixed layer
Domain 1 composite reflectivity (27-km)
Domains 1, 2, 3 reflectivity (27/9/3) with D1 SLP
NCSU-RENCI HUR-NC 33-h Forecast, initialized 00 UTC 2 Sep, Valid 09Z Friday 3 Sep: 3-km domain
Best Track: 955 mb
33-h wind speed fcsts valid 09Z 3 Sept
- What features must be captured in IC for “good forecasts”?
- At what scale must DA be run to capture these features?
- What data are needed to capture these features?
- Inland impacts strongly sensitive to initial circulation size
- Inclusion of outer-core features required for prediction of synoptic/mesoscale preconditioning
When available, implement improved ICs in ensemble, HUR-NC (Deliverable)
Make ICs available for local modeling (Deliverable)
Retrospective & real-time runs, evaluate forecasts with various ICs to measure impact (Deliverable)
Work with NWS to identify ways to utilize NWP output in forecast process
How can the research plan be improved to optimize results, collaborative benefit?
What aspects of project would be most useful to the NWS, and in what form?
How often should research updates be shared?
What training materials, if any, would be helpful?
Jonathan Blaes for doing a fantastic job coordinating meeting, CSTAR input, etc. and RAH (Darin Figurskey) for hosting
NOAA CSTAR program, Sam Contorno, and USWRP, HMT-SE for support (Tim Schneider, Marty Ralph)
Regional CSTAR NWS offices (RAH, GSP, ILM, MHX, CAE, CHS, FFC, RNK, LWX, AKQ)
National Center Partners: Dave Novak (SPC), Mike Brennan (TPC), Steve Weiss (SPC)
NWS Eastern Region Headquarters – Jeff Waldstreicher
Barrett Smith (NWSFO RAH) for Hanna materials
NWSFO RAH Case Summary Archive: http://www4.ncsu.edu/~nwsfo/storage/cases/20080906/
NCSU-RENCI HUR-NC 78-h Forecast, initialized 00 UTC 31 Aug, Valid 06Z Friday: 27-km domain
NCSU-RENCI HUR-NC 51-h Forecast, initialized 00 UTC 1 Sep, Valid 03Z Friday: 27-km domain
NCSU-RENCI HUR-NC 27-h Forecast, initialized 00 UTC 2 Sep, Valid 03Z Friday: 27-km domain