# Presentation: 071086

## Improved Statistical Intensity Forecast Models:

**A Joint Hurricane Testbed Project Update **

- Mark DeMaria, NOAA/NESDIS, Fort Collins, CO
- John A. Knaff, CIRA/CSU, Fort Collins, CO
- John Kaplan, NOAA/AOML/HRD, Miami, FL

- Presented at the
- Interdepartmental Hurricane Conference
- March 22, 2006

## Outline

- Current Status of SHIPS and the Rapid Intensity Index (RII)
- Project Goals
- New decay model in SHIPS
- Modified vertical shear calculation
- Discriminant analysis version of the RII
- Progress and Plans for the 2006 Season
- Additional SHIPS modifications from 2005 results

## 2005 Operational Version of SHIPS

- 16 basic predictors
- atmospheric from GFS forecast fields
- oceanic from Reynold’s weekly SST
- climatology and persistence from ATCF input
- Correction for ocean heat content (Atlantic only) and GOES predictors
- previous JHT project
- Adjusted SST from Joe Cione cooling algorithm
- previous JHT project, Atlantic only
- New decay model formulation
- Less decay over islands and narrow landmasses
- current JHT project

## SHIPS Skill in 2005

## Impact of New Decay Model and Cione Ocean Cooling(based on re-runs of 2005 Atlantic forecasts)

## Vertical Shear Evaluation 

- Shear evaluated from GFS forecast along OFCI track
- Large annulus utilized
- 200-800 km radius
- Proposed new method
- Remove vortex from GFS fields
- Test other averaging areas
- Smaller radii
- Elliptical region aligned with storm motion (Stacy Stewart method)

## SHIPS Shear Calculation Region200 hPa Wind Wilma 24 Oct 2005 06 UTC

**SHIPS Shear Calculation Region****200 hPa Wind Wilma 24 Oct 2005 06 UTC**

## Impact of OFCI and GFS Track Mismatch96 h Forecast for Frances from 27 Aug 2004 12 UTC

**Impact of OFCI and GFS Track Mismatch****96 h Forecast for Frances from 27 Aug 2004 12 UTC**

**850 hPa                                                              200 hPa**

**G**

**G**

**O**

**O**

- G = GFS position    O = OFCI Position

## GFS Fields After Vortex Removal Procedure 96 h Forecast for Frances from 27 Aug 2004 12 UTC

**GFS Fields After Vortex Removal Procedure**** ****96 h Forecast for Frances from 27 Aug 2004 12 UTC**

**G**

**G**

**O**

**O**

**850 hPa                                                              200 hPa**

- G = GFS position    O = OFCI Position

## Additional Changes based on 2005 Season

- Add storm translation to MPI calculation
- Wilma (2005), Florence (1994)
- Add 250 hPa temperature predictor for cold upper atmosphere, but low tropopause
- Epsilon and Zeta (2005)
- Print recon variables for qualitative use
- GRIP model sample too small
- Test forecast with more general predictive equation
- Will be run after SHIPS run, but saved for evaluation

## Storm Translational Speed and MPI

- Current version adds constant 12 kt to         DK (1994) and WH (1997) formulas
- Acceleration not accounted for
- Add fraction of translational speed from Schwerdt formula (a = 1.5c0.63) to MPI
- Improves fit to 1982-2005 sample

## Hurricane Epsilon and Tropical Storm Zeta(motivation for 250 hPa T predictor) 

- Zeta   03 Jan 2006 1745 UTC
- Max Wind = 55 kt
- SST = 24.3 oC
- T’(200 hPa) = -4.1oC
- T’(250 hPa) = -6.6oC

- Epsilon  04 Dec 2005 1445 UTC
- Max Wind = 70 kt
- SST = 21.7 oC
- T’(200hPa) = -1.8oC
- T’(250hPa) = -6.4oC

## Recon and Additional GOES Predictors

- GOES and Recon Intensity Prediction (GRIP) Model
- Part of previous JHT project
- 808 cases 1995-2004
- 6554 for total SHIPS sample
- Significant new predictive information in recon data
- Independent tested on 2005 Atlantic forecasts
- Improvement only at 12-24 hours
- Developmental sample still too small

## Error Reduction of SHIPS Model Fit From Inclusion of Recon and Satellite Data 

- Intensification is favored with large symmetric tangential
- wind near the RMW, but small area-integrated KE

- 2005 Evaluation

- Variance Increase for
- Developmental Sample

## Max Wind vs. KE categories of 1995-2005 U.S. Landfalling Hurricanes

- Katrina2 05

- Ivan 04

- Rita 05

- Fran 96

- Wilma 05

- Isabel 03

- Jeanne 04

- Floyd 99

- Frances 04

- Georges2 98

- Georges1 98

- Bonnie 98

- Lili 02

- Opal 95

- Dennis 05

- Bret 99

- Bertha 96

- Charley1 04

- Erin1 95

- Charley2 04

- Earl 98

- Claudette 01

- Erin2 95

- Katrina1 05

- Danny1 97

- Danny2

- Gaston 04

- KE-5

- KE-4

- KE-3

- KE-2

- KE-1

- KE-0

-    SS-0                 SS-1   SS-2  SS-3    SS-4         SS-5

**Max Wind vs. KE categories of 1995-2005 U.S. Landfalling Hurricanes**

## Generalized Prediction Equation

**dV/dt = ********(t)     Continuous form of SHIPS model**
** ****assumed constant over entire forecast interval**
**e.g.,   V(96) = V(0) + ******** ********t  **
**Replace with generalized prediction equation**
**                 ****dV/dt = ********V - ********(V/V****mpi****)****n****V **
**n=3, ********-1**** = 26 hr, V****mpi**** from MPI formula**
**estimate ********(t) statistically.**

## 	Analytic Solution for Constant Vmpi and 

**V****s**** = Steady State V = V****mpi****(********/********)****1/3**** **
**V/V****s**** = (V****o****/V****s****)e********t****/[1 + (e****3********t****-1)(V****o****/V****s****)****3****]****1/3**

-                           ****** ******** ****0                                            ******** ******** 0**

## Plans for 2006 SHIPS Model

- Operational Version
- 16 basic predictors + OHC/GOES correction
- New speed adjusted MPI
- New 250 hPa T predictor
- Cione SST cooling algorithm (pending JHT approval)
- New decay formulation (pending JHT approval)
- Recon info included on SHIPS output, but not included in the prediction
- Can also show forecast with generalized prediction equation
- Parallel version
- Modified shear calculation

## Rapid Intensity Index

- Uses subset of SHIPS input most correlated with rapid intensity change
- Estimates probability of 25 kt increase in next 24 hours
- Original version used 30 kt threshold
- Atlantic and east Pacific versions
- Results included on SHIPS text output

## RII Brier Skill Score 2004-2005

## RII Improvements

- Original version used binary method
- 0 or 1 depending on if predictor exceeded  threshold
- Updated version scales predictors between 0 and 1
- Current project
- Use discriminant analysis to determine optimal weights for combining predictors
- To be developed during J. Kaplan visit to CIRA April 10-14th
- Will be evaluated on independent 2006 cases

## Acknowledgments

- Thanks to the TPC and JHT support staff
- Chris Sisko
- Alison Krautkramer
- Chris Lauer
- Jim Gross
- Michelle Mainelli