U.S%20Drought%20Highlights%20Since%20October%202006

1
U.S Drought Highlights Since October 2006

• Douglas Le Comte
• NOAA/CPC
• 32nd Annual Climate Diagnostics and Prediction
  Workshop
• October 22-26, 2007

Morristown, TN, Sep. 12, 2007
2
Georgia gets tough on water use!
3
Outline

• Current Drought and 12-month Evolution
• Drought in Historical Perspective
• Selected Drought Impacts
• Current Drought Outlook
• Recent Changes to the Outlook
• Some ideas for future Outlooks

4
Recent U.S. Drought Monitor
5
Year-to-Date Drought Change Wetness Plains
Book-ended by Droughts West and East
6
October vs April Drought
7
Winter Percent of Normal Precipitation
Downtown Los Angeles had driest rain season
since at least 1877 3.21 in., 21 of normal.
8
Western Snowpack 2007 vs 2006
9
Streamflow Forecasts 2007 vs 2006
10

Spring-Summer Changes
11
Fires Spread Dramatically Across the West in July
12
Mid-Atlantic Drought Worsens Sep-Oct
5 Maryland wells at Record lows mid-October
Record 34 days without measurable rain at DCA
thru October 18, 2007
Charles County well sets record
13
Southeast Virginia Little Creek Reservoir near
Newport NewsOctober 15, 2007
Photo by Don Aspinall
14
Historical Drought in Alabama
One of 2 worst droughts past 50 years
http//lwf.ncdc.noaa.gov/img/climate/research/2007
/sep/Reg001Dv00_palm06_01000907_pg.gif
15
Georgia Drought
16
Lake LanierOctober, 2007
90-day supply left for Atlanta?
17
Tennessee Drought
Worst in over 50 yrs.
18
Cherokee Lake in E. Tennessee Sep 12, 2007
Photo by Brian Boyd
19
North Carolina Drought
2nd worst in over 50 years
Driest May-Sep
20
Kentucky Drought
2nd worst in over 50 yrs
21
Rankings
http//lwf.ncdc.noaa.gov/oa/climate/research/2007/
sep/national.html
22
Lake Okeechobee Drops to New Lows
Levels remain 5 feet lower than normal
in October 2007
23
Selected Drought Impacts to Crops in the Southeast

• Corn Yield vs 2006
• Virginia -33
• Maryland -40
• North Carolina -33
• Tennessee -15
• Kentucky -15
• Alabama 1
• Georgia 5
• Peanut Yields vs 2006
• Virginia -37
• North Carolina -25
• Georgia 6

24
The Seasonal Drought Outlooks
25
Last Nights 5-Day QPF
26
One Week Soil Moisture Forecast
27
Recent Changes

• Began twice/month schedule (1st and 3rd Thursday)
• Expanding CPC authors
• Changed wording of headings (Tendency, valid
  dates)

28
Drought Verification Jul-Sep 2007
29
Improvement over PersistencePercent of Grid
Points Correct vs a Forecast Based on Persisting
Droughts
Long-term mean 13
30
Two Path Approach to Improving Drought Forecasts
at CPC

• Continue to produce and refine seasonal drought
  outlooks for the general public
• a. Consider adding monthly forecasts
• b. Consider adding probability information to
  map
• Develop objective seasonal probability forecasts
  for drought (guidance useful for an array of
  users)
• a. Drought probabilities (soil moisture,
  runoff, drought indices) at some point in the
  future
• b. Probabilities for change
• c. Consider NIDIS goals
• d. Climate Test Bed products to contribute

31
One Prototype Suggestion of a Probabilistic
Forecast
32
University of Washington Forecasts
http//www.hydro.washington.edu/forecast/monitor/o
utlook/index.shtml
33
Prediction is very difficult, especially
about the future Niels Bohr, Danish physicist
(not Yogi Berra)