# Presentation: 239339

## The Great Floods of 1993 and 2008 : The Roles of ENSO and the MJO/GWO

*Venice, Iowa (was Cedar Rapids) *

- NOAA 33rd  Annual Climate Diagnostics and Predictability Workshop
- Lincoln, Nebraska
- October 20th, 2008

**Edward Berry, NOAA/NWS DDC and Klaus Weickmann, NOAA/ESRL PSD**

**Notes:**
Cedar Rapids, IA on June 13, 2008, looking south on Second Street (?).  

## 	      OUTLINE

- 	      OUTLINE

**The Global Wind Oscillation: Introduction**
**     **
**Schematic GWO/MJO phase spaces**
** **
**ENSO precipitation signals for 1993 and 2008   **
**   **
**GWO/MJO phase spaces during 1993 and 2008**
**May 22-26 case study: SNR 250 hPa PSI composites and potential predictability      **
**Summary **
**    ****	**

## Purpose is to examine the interannual-subseasonal relationships of the global atmospheric circulation that may have contributed to the “great floods.” 

- Purpose is to examine the interannual-subseasonal relationships of the global atmospheric circulation that may have contributed to the “great floods.”

## L

**The Global Wind “Oscillation”**

- Want:
-  > 1 region
-  monopole

**L**

**L**

**L**

**L**

**H**

**H**

**Notes:**
Independent subseasonal oscillation!!!

## Models Struggle

**Models Struggle**

**Notes:**
Add some information about model performance – Done.  These phase plots are derived from the correlations of GWO1 and RMM2 (see WB (2008)).  We are still not plotting the MJO and GWO in real-time (online GSDM web link) with these “lined-up” phase spaces.  

## Models Struggle

**Models Struggle**

## La-Nina

- El-Nino

- 1993

- 2008

**Notes:**
The ENSO composites are for May-September, and all plots are with respect to the 1971-2000 climatology.  The warm event years are 1964, 71,81,86,90,92,93,96 and 2001.  The cold event years are 1950,55,56,64,71,74,88,98 and 99.  All these plots are courtesy of ESRL/PSD.  These composites are based on Nino 3.4 and the SOI.  

## GWO 2008

- La-Nina

- El-Nino

- El-Nino

- La-Nina

- GWO 1993

- June

- July

- May

- June

- Weak subseasonal variations.

- Large subseasonal variations

**Notes:**
The plots show the differences in the base states, and the shift toward adding more global westerly wind flow during May-June 2008.  

## MJO 1993

- MJO 2008

- June

- May

- July

- June

- Weak subseasonal variations

- Large subseasonal  variations

**Notes:**
MJO activity more robust 2008 vs. 1993, including the 7-8-1 May transition which contributed to the GWO starting around May 10th.  

## Case Study 

- Severe Local Storms/Heavy Rainfall May 22-26

- Case Study

**Notes:**
The first EF-5 tornado for 2008 and since Greensburg, KS (5/4/2007).  I will need to get rainfall data for this period -- Done.  

## Slide 11

**Notes:**
Insert a “weather map” after this figure to support 8-1-2 during this period – Done. The purple ovals are the approximate initial times (15 May) for a week-2 prediction during the period of 23-29 May.   

## MJO

- GWO

- Centered on 15 May

- H

- H

- H

- H

- H

- H

- H

- H

- L

- L

- L

- L

- L

- L

- L

- H

**Notes:**
This is MJO and GWO 7-8-1 centered on 15 May 2008.  The GWO is more representative, since the WH (2004) MJO composite has ENSO removed (?).  

## H

**H**

**H**

**H**

**H**

**L**

**L**

**Notes:**
Synoptic response to GWO/MJO 7-8-1 transition.  

## WK-2: May 23-29

**WK-2: May 23-29**
**See May 10****th**** and 15****th**** blog postings for details**

- WK-2 GEFS

- WK-2 CPC

- WK-2 500mb Za OBS

- WK-2 500mb Zt OBS

**Notes:**
Week-2 means for May 23-29, 2008.  Major SLS outbreak on the Plains May 25th including Parkersburg, IA.  There were several rounds of SLS from May 22-26 including major outbreak across SW KS May 23rd.  

## May 23-29 Air Temperature Anomaly Forecasts 

**CPC**

**OBS**

**May 23-29 Air Temperature Anomaly Forecasts **

**Notes:**
There was opportunity to do “better” than this.  

## Summary

**Summary**
**Jun-Jul 1993 mean anomalies imply “flood”; May-Jun 2008  anomalies do not => suggests larger subseasonal role in 2008**
**“****Synoptics” of these spring-summer central USA floods may be similar when ENSO decays rapidly and during a large subseasonal oscillation **
**Real-time monitoring utilizing SNR composites for both the GWO and MJO offered ~week-2 forecast opportunities at times when operational model predictions failed **
**250 hPa PSI SNR for tropics ~0.6-0.8σ versus ~0.2-0.3****σ**** across the extratropics for both MJO and GWO => weak but useful signals**

**Notes:**
Be sure to include future work, etc.  We will link the GWO to model performance and extreme wx events.  It is understandable if a seasonal outlook cannot be made which would tilt the odds toward excessive precipitation and severe local storms.  However, there was “enough” subseasonal information to indicate the latter for week-2 predictions, including the CPC USA Hazards Assessment.  

## Questions ? 

**Questions ?**

**Notes:**
Slides after this are extras

## Slide 18