# Presentation: 000292

## On the Quality of Pre-Advisory Model Guidance

**Mike Fiorino**
**michael.fiorino@noaa.gov**
**Techniques Development and Applications Unit**
**National Hurricane Center**
**Miami, FL**
- 5 March 2008

## We don’t know why...

**Global TC Activity 2007 - 34% below normal, lowest since...**

**two cat5 TCs in the NIO -- 02A (Gonu) and 06B (Sidr)**

**“****crash of 1999”**

**“****crash of 2007?”**

## Motivations

***Forecasting as a data assimilation problem – update previous forecast with new information.  The ******first forecast jump starts the process****** and because forecast-to-forecast consistency is a (strong) constraint, a good initialization is desirable.  ******Guidance on the guidance in particular CON_***
***Many models are first influenced by the first advisory.  The transition from an INVEST (9?B) to a numbered system ([0-4]?B and from non-TC (LO, WV, DB, EX) to TC (TD,TS,HU,SD,SS). ******Diagnosis of the models***
***Focus on ******medium-range track****** (72-h FE):***
**Extend warning time**** ******** 72 h (Jack Hayes), MRT still first-order foreast problem**
**83% of major hurricanes have 1 or more ****Rapid Intensity**** events and ****60%**** occur as the TC first ****reaches hurricane state**** (~ 3d), e.g., FELIX - 06L.2007**
***Answer the mail – availability of 9X trackers from NCEP for JTWC***

## Error growth OFCL (analysis) v OFCI (background)

**~8% / 6 h ; highest 36-48 **

**WPAC/EPAC/LANT 2005-2007**** **

## 25W.2004 MEARI – my first WPAC forecast, first JTWC 72-h

## Mike’s Lessons Learned from 25W.2004

***first advisory jump starts****** the 6-h forecast cycle of ******OFCL****** ******correcting****** ******OFCI****** with new data and guidance***
***Know ******CONW****** is ******best****** aid...but wanted some guidance on what models were part of the consensus, should I do an SCON? (RYOC), favor one model?***
***Intensity forecast****** at 72-h was ******very bad (50 kt******), based on synoptic reasoning.  did not account for the “flavor” of the TC development in WESTPAC (generally look for reasons NOT to intensify T# / day) – character of TC activity on seasonal time scales a factor (weak constraint)***
**OFCL 72-h intensity forecasts in the LANT: -17% bias in 2005, +27% bias in 2006,  -5% in 2007 – TC development on seasonal time scales a factor?**

## TC Operational State – Pre/Post Advisory 2007 LANT

**time axis (d): 0.0 = time of first advisory**

**CARQ**** **
**BT (best track)**** **
**Advisories**

## Model Availability: -24 h – +24 h :: 2007 LANT

**no 72-h forecast to verify**

**GFSN06**
**NGPN06**
**GFDL06**
**CONU**

## 04L.2007 DEAN

**all models available -24 h**

**NGPN06**

**GFSN06**

**GFDL06**

**CONU**

**GFSN06**
**missing**
**+0 h**

**NGPS06**
**missing +6h**

## GFSN06 (~AVNI) 04L.2007 DEAN :: -24 h (pre-adv)

**MEAN FE ~ 50 nm**

## GFSN06 04L.2007 DEAN :: +24 h (POST-adv)

**MEAN FE ~ 290 nm**

## GFSN06 06L.2007 FELIX :: -24 h (pre-adv)

**model run at all times, but only one verifiable 72-h forecast**

**Notes:**
initialization....

## GFSN06 06L.2007 FELIX :: -24 h (pre-adv)

***GFSN06 06L.2007 FELIX :: -24 h (pre-adv)***

**model run at all times, three made verifiable 72-h forecasts**
**72-h FE MEAN ~ 75 nm**

**Notes:**
initialization....

## 72-h mean FE Pre v Post (red); Pre v ALL (blue)EASTPAC/LANT 2005-2007

**PRE**
**>**
**post**

**POST**
**>**
**Pre**

**blue circles scaled by # of postitions**

## Model (un)availability in WESTPAC 2007

***Model (un)availability in WESTPAC 2007***

**GFSN06**
**JGFS06**
**EGRR06**
**JUKM06**
**CONW**

## Summary

***Pre-advisory MRT guidance does have value...***
**dependence on initial vortex not strong**
**pre-adv GFS (before relocation) error much lower than post-adv for FELIX (after relocation)**
- HWRF/GFDL pre- and post- skill impacted similarly
- more diagnostics of the model TC vortex analysis
**diagnostics of CON**
**local trackers can fill gaps and should be run based on “bdecks” (working best track) in addition to the CARQ**
*** ******Next steps...***
**comm of CARQ to NCEP, monitor running of the NCEP trackers**
**improve my local tracker – when all else fails**
**diagnostics of initial TC in the models**