Heavy floods episodes on the 11 th and 12 th November 2008 South African case study Isaac Ngwana
Outline Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August General rainfall patterns Main weather systems Observation network Case study Model results and verification Conclusion
Rainfall patterns in SA Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August
Main weather systems- responsible for flooding events TTT Tropical cyclones Cut off low Frontal system Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August
Weather observation stations in South Africa Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August SURFACE OBSERVATIONS 23 climate stations 23 sea surface temperature stations 25 weather offices 35 electric _manual (aws manned) 156 automatic weather stations – unmanned 165 automatic rainfall stations 1257 rainfall (monthly; ~50 provide daily data) UPPER AIR OBSERVATIONS 9 Upper air stations ( Including the ISLANDS – Marion and Gough)
Weather observation stations in South Africa Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August Weather observation stations in South Africa Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August
RADAR NETWORK in South Africa Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August
Case study (11 & 12 Nov 2008) - general damage Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August people were killed Thousands evacuated Roads and bridges swept away
Warning System-print media Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August
Early Warning System-print media cont… Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August
11 November 2008 Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August Observations - 11 November
Observed 24 hr rainfall 11 & 12 Nov 2012 Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August
11 November 2008 Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August Observations -12 November
Weather systems – 11 Nov 2012 Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August
Observed weather -11 Nov 2008 Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August
Observed weather 12 Nov 2008 Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August
Observed weather -12 Nov 2008 Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August
NWP Modeling in South Africa Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August
NWP Modeling in South Africa Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August ModelDomainAssimilation UM SA12LargeNo data assimilation UM SA12LargeData assimilation UM SA15SmallNo data assimilation WRF SA12LargeNo data Assimilation WRF SA15SmallNo data assimilation
Modeling - weather systems hr forecast Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August
12 November 2008 Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August
12 November 2008 Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August
Model -12 November 2008 Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August
Eye ball verification Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August
Warning System-SAWS website Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August
Conclusion Document Reference: SMRF-PSN-NGW Document Template Reference: AWC-PSN Date of last revision: 26 August &12 Nov 2008 flooding events were well forecast by the model Forecast warning were issued in time Necessary steps were taken by government dept. even though 47 people lost their lives Good observation data bank, but sparse Local data ingest might improve model forecast