Drought in the West: ShortRange Forecasts to Assist with Local and Regional Planning

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Drought in the West Short-Range Forecasts to
Assist with Local and Regional Planning

• Douglas Le Comte
• NOAA/CPC
• Association of Bay Area Governments Water/Land
  Use Collaboration
• August 7, 2008

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Outline

• Current Drought Situation
• Medium Range and Seasonal Forecasts
• Historical Perspective
• Climate Change

Dust Event Honda Proving Center June 4 2008
Cantil CA
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Water Year Precipitation
http//www.hprcc.unl.edu/maps/current/
High Plains Regional Climate Center
http//www.calclim.dri.edu/anommaps.html
California Climate Data Archive
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Wet WinterDry Spring
http//www.cpc.ncep.noaa.gov/products/global_monit
oring/precipitation/global_precip_accum.shtml
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Recent U.S. Drought Monitor
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Western Snowpack 2008 vs 2007
http//www.wcc.nrcs.usda.gov/snowcourse/snow_map.h
tml
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Western Streamflow Forecasts
http//www.wcc.nrcs.usda.gov/cgibin/sssf.pl
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California Drought Summary(from Dept of Water
Resources Executive Summary)

• Water Year precipitation 85 of average
• Runoff 60 of average
• Reservoirs 75 of average
• For Northern Sierra, March-June driest since
  records began in 1921 (3.4 in)

http//cdec.water.ca.gov/cgi-progs/reports/EXECSUM
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Two Looks at the Current Drought How Bad?
Multimodel Soil Moisture Percentiles (83 years of
data) Aug. 3, 2008
Palmer Hydro Drought Index
Arguably, the 4th worst drought since 1900!
http//www.ncdc.noaa.gov/oa/climate/research/preli
m/drought/state-reg-moisture-status.html
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Historical Drought River Runoff since 1900
http//meteora.ucsd.edu/cap/pdffiles/DroughtReport
2008.pdf
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The Seasonal Drought Outlook
http//www.cpc.ncep.noaa.gov/products/expert_asses
sment/seasonal_drought.html
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Web Resources for Drought and Forecasts

• Climate Prediction Center for Medium and Long
  Range Forecasts www.cpc.ncep.noaa.gov
• National Integrated Drought Informaton System for
  the new drought portal www.drought.gov
• California Applications Program and the
  California Climate Change Center
  http//meteora.ucsd.edu/cap/
• California Climate Tracker http//www.wrcc.dri.ed
  u/monitor/cal-mon/index.html

NIDIS
CPC
Drought Impact Reporter
droughtreporter.unl.edu
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ENSO (El Nino-Southern Oscillation) Status
Neutral
Thru Aug 3, 2008
La Nina last winter
http//www.cpc.ncep.noaa.gov/
http//www.bom.gov.au/climate/enso/indices.shtml
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El Nino and La Nina Winter (Jan-Mar)
Precipitation
El Nino
Frequency of occurrence
La Nina
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Pacific Niño 3.4 SST Outlook
A majority of ENSO forecasts indicate
ENSO-neutral conditions through Northern
Hemisphere spring 2009.
Figure provided by the International Research
Institute (IRI) for Climate and Society (updated
15 July 2008).
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6-10 Day and 8-14 Day Rainfall
http//www.cpc.ncep.noaa.gov/products/forecasts/
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CPC Seasonal Precipitation Forecasts
SON
ASO
OND
NDJ
http//www.cpc.ncep.noaa.gov/products/predictions/
90day/
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CPC Winter Outlook
DJF
JFM
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Experimental University of Washington Forecasts
http//www.hydro.washington.edu/forecast/monitor/o
utlook/index.shtml
Current Runoff
Forecast for Oct. 26, 2008 (Based on historical
data)
Tendency for improvement based on this
experimental forecast.
Improvement
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Palmer Drought Probabilities to October 2008
Courtesy R. Tinker, CPC
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Palmer Hydrologic Drought Index (PHDI)
Statistics for California Climate
Divisions Potential March 2009 Conditions Based
on July 2008 Conditions July-March Changes
Following Past Julys with Similar Conditions
Good odds for (Palmer) drought ending coastal
areas next winter
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CFS Model Winter Forecast
Probability of Anomalous Precipitation (as of
Aug. 5)
Bottom line History suggests significant relief
unlikely before December, and forecasts for next
winter are ambivalent, but some dynamic models
are tilting dry.
Tilt toward below normal in CA and the SW
Coupled (or Climate) Forecast System
http//www.cpc.ncep.noaa.gov/products/analysis_mon
itoring/lanina/ensoforecast.shtml
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Climate Model ForecastsPrecipitation
California Climate Change Center
http//meteora.ucsd.edu/cap/cat2008_peak.html
Precipitation forecast uncertain for next few
decades
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California Climate Model Forecasts Temperature
Temperatures should keep going up
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Projected Annual Runoff 2041-2060
Less runoff for California and the Southwest
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Prediction is very difficult, especially
about the future Niels Bohr, Danish physicist
(not Yogi Berra)