Met office seasonal forecasting for winter 2010 11
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Met Office seasonal forecasting for winter 2010-11. Jeff Knight (with thanks to many colleagues). The main event: December. December 2010. Snow at Land’s End. Courtesy of Mike Kendon (NCIC). Public execution of Charles 1 st 1649 (only 10 years before series starts). December 2010.

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Met Office seasonal forecasting for winter 2010-11

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Met office seasonal forecasting for winter 2010 11

Met Office seasonal forecasting for winter 2010-11

Jeff Knight (with thanks to many colleagues)


The main event december

The main event: December


December 2010

December2010

Snow at

Land’s End

Courtesy of Mike Kendon (NCIC)


December 2010 central england temperature series

Public execution of Charles 1st 1649 (only 10 years before series starts)

December 2010

The coldest December since 1890

December 2010: Central England Temperature series

3 voyages of Captain Cook 1768 - 1779

Queen Victoria’s coronation 1838

World War 11914-1918

The second coldest December in a series from 1659

Courtesy of Mike Kendon (NCIC)


Uk temperatures recent winters

UK Temperatures: recent winters


Met office seasonal forecasting for winter 2010 11

2009-10 and 2010-11

Christmas Eve 2010 Satellite Receiving Station, Dundee University

1150 GMT 7 January 2010Photo: NASA/GSFC, MODIS Rapid Response.


Met office winter forecast 2010 11

Met Office Winter Forecast 2010-11


Djf met office seasonal forecast for uk government

DJF Met Office Seasonal Forecastfor UK Government

Outlook for December 2010 – February 2011

For the period December 2010-February 2011, there is a 25% chance of mild conditions, a 30% chance of near-average and a 45% chance of cold conditions over northern Europe.

For precipitation, there is a 25% chance of wet conditions, a 35% chance of near-average and a 40% chance of dry conditions over northern Europe.


Glosea4 november ensemble

GloSea4 ‘November’ ensemble

DJF

GloSea4 L85


Temperature terciles from nov

Temperature terciles from Nov

L85 GloSea (1996-2009 climate)


Precipitation terciles from nov 1996 2009 climatology

Precipitation terciles from Nov(1996-2009 climatology)

L85 GloSea (1996-2009 Climate)


Nino3 4 plumes glosea4 ec eurosip

Nino3.4 plumes: GloSea4-EC-EUROSIP

Charts courtesy of ECMWF


Cluster analysis fereday et al 2008 j climate

Cluster analysisFereday et al. (2008), J. Climate

  • 6 two month seasons, 10 clusters per season

  • North Atlantic / Europe region

  • Clusters from observed 1850-2003 daily mean MSLP dataset

  • For 2004 onwards use NCEP reanalysis

  • Remove seasonal mean from NCEP MSLP

  • Assign each field to closest cluster


Nd 2010 cluster frequencies

ND 2010 cluster frequencies

Highest number of days for ~100 and ~50 years respectively


Nd 2010 clusters

ND 2010 Clusters


Oct nov north atlantic sst

Oct-Nov North Atlantic SST

October 2011

14-21 Nov 2011


North atlantic sub surface temperature

North Atlantic Sub-Surface temperature

October

May

Rodwell and Folland (2002), Q. J. R. Meteorol. Soc.


Quasi biennial oscillation

Quasi-Biennial Oscillation

W phase of QBO → stronger polar vortex, less chance of a stratospheric warming event

So perhaps switch to zonal at end of winter?

This is also the signal from La Niña


Canonical jf la ni a clusters

‘Canonical’ JF La Niña clusters


Later forecasts

Later Forecasts


Jfm fma from preceding month

JFM, FMA from preceding month

JFM

FMA

D-J-F


Stratosphere

Stratosphere?


Jf 2011 cluster frequencies

JF 2011 cluster frequencies


Jf 2011 clusters

JF 2011 Clusters


Worldwide

Worldwide


La ni a teleconnections

La Niña Teleconnections

  • During La Niña the rainfall that normally falls out over the Pacific shifts west


Global precipitation

Global precipitation


Queensland

Queensland


Conclusions

Conclusions

  • GloSea4 did a reasonable job in predicting the likelihood of a cold winter

  • In later forecasts, however, it wanted to retain the cold for too long

  • Consistency with EuroSIP and other models

  • Other factors such as La Niña, Atlantic SSTs and the QBO were considered alongside models

  • Potential additional influences were the continuing low solar activity (Ineson et al., 2011), low sea-ice, ...


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For various long-range forecasts including decadal global temperature forecasts and seasonal tropical storm forecasts:

http://www.metoffice.gov.uk/science/specialist/long-range

For the seasonal probability maps, ENSO forecast and skill scores:

http://www.metoffice.gov.uk/science/specialist/seasonal


Questions and answers

Questions and answers


Title

Title


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