U.S Drought Highlights Since U.S Drought Highlights Since October 2006October 2006

Douglas Le ComteDouglas Le Comte

NOAA/CPCNOAA/CPC

32nd Annual Climate Diagnostics and Prediction Workshop32nd Annual Climate Diagnostics and Prediction Workshop

October 22-26, 2007October 22-26, 2007

Morristown,Morristown,TN, Sep. 12,TN, Sep. 12,20072007

waterban_2web.movGeorgia gets toughGeorgia gets toughon water use!on water use!

OutlineOutline

• Current Drought and 12-month EvolutionCurrent Drought and 12-month Evolution

• Drought in Historical PerspectiveDrought in Historical Perspective

• Selected Drought ImpactsSelected Drought Impacts

• Current Drought OutlookCurrent Drought Outlook

• Recent Changes to the OutlookRecent Changes to the Outlook

• Some ideas for future OutlooksSome ideas for future Outlooks

Recent U.S. Drought MonitorRecent U.S. Drought Monitor

Year-to-Date Drought Change:Year-to-Date Drought Change: Wetness Plains Book-ended by Droughts West and Wetness Plains Book-ended by Droughts West and

EastEast

October vs April DroughtOctober vs April Drought

Winter Percent of Normal Winter Percent of Normal PrecipitationPrecipitation

Downtown Los Angeles had driest“rain season” since at least1877: 3.21 in., 21% of normal.

Western Snowpack 2007 vs 2006Western Snowpack 2007 vs 2006

Streamflow Forecasts 2007 vs 2006Streamflow Forecasts 2007 vs 2006

Spring-Summer ChangesSpring-Summer Changes

Fires Spread Dramatically Across Fires Spread Dramatically Across the West in Julythe West in July

Mid-Atlantic Drought Worsens Mid-Atlantic Drought Worsens Sep-OctSep-Oct

5 Maryland wells at5 Maryland wells atRecord lows mid-OctoberRecord lows mid-October

Charles CountyCharles Countywell sets recordwell sets record

Record 34 daysRecord 34 dayswithout measurablewithout measurablerain at DCA thrurain at DCA thruOctober 18, 2007October 18, 2007

Southeast Virginia:Southeast Virginia: Little Creek Reservoir Little Creek Reservoir

near Newport Newsnear Newport NewsOctober 15, 2007October 15, 2007

Photo byPhoto byDon AspinallDon Aspinall

Historical Drought in AlabamaHistorical Drought in Alabama

http://http://lwf.ncdc.noaa.gov/img/climate/research/2007/sep/Reg001Dv00_palm06_01000907_pg.giflwf.ncdc.noaa.gov/img/climate/research/2007/sep/Reg001Dv00_palm06_01000907_pg.gif

One of 2 worstOne of 2 worstdroughts past droughts past 50 years50 years

Georgia DroughtGeorgia Drought

Lake LanierLake LanierOctober, 2007October, 2007

90-day supply 90-day supply left for Atlanta?left for Atlanta?

Tennessee DroughtTennessee Drought

Worst inWorst inover 50 yrs.over 50 yrs.

Cherokee Lake in E. TennesseeCherokee Lake in E. Tennessee Sep 12, 2007 Sep 12, 2007

Photo byPhoto byBrian BoydBrian Boyd

North Carolina DroughtNorth Carolina Drought

22ndnd worst in worst inover 50 yearsover 50 years

Driest May-SepDriest May-Sep

Kentucky DroughtKentucky Drought

22ndnd worst worstin over 50 yrsin over 50 yrs

RankingsRankings

http://lwf.ncdc.noaa.gov/oa/climate/research/2007/sep/national.htmlhttp://lwf.ncdc.noaa.gov/oa/climate/research/2007/sep/national.html

Lake Okeechobee Drops to New LowsLake Okeechobee Drops to New Lows

Levels remainLevels remain~ 5 feet lower ~ 5 feet lower than normal inthan normal inOctober 2007October 2007

Selected Drought Impacts to Crops in the Selected Drought Impacts to Crops in the SoutheastSoutheast

• Corn Yield vs 2006Corn Yield vs 2006

• Virginia -33%Virginia -33%

• Maryland -40%Maryland -40%

• North Carolina -33%North Carolina -33%

• Tennessee -15%Tennessee -15%

• Kentucky -15%Kentucky -15%

• Alabama +1%Alabama +1%

• Georgia +5%Georgia +5%

• Peanut Yields vs 2006Peanut Yields vs 2006

• Virginia -37%Virginia -37%

• North Carolina -25%North Carolina -25%

• Georgia +6%Georgia +6%

The Seasonal Drought OutlooksThe Seasonal Drought Outlooks

Last Night’s 5-Day QPFLast Night’s 5-Day QPF

One Week Soil Moisture ForecastOne Week Soil Moisture Forecast

                                                                                                              

                                                                                        

                                                                                                              

                                                                                        

Recent ChangesRecent Changes

• Began twice/month schedule (1Began twice/month schedule (1stst and 3 and 3rdrd Thursday)Thursday)

• Expanding CPC authorsExpanding CPC authors

• Changed wording of headings Changed wording of headings (“Tendency”, valid dates)(“Tendency”, valid dates)

Drought Verification Drought Verification Jul-Sep 2007Jul-Sep 2007

Improvement over PersistenceImprovement over PersistencePercent of Grid Points Correct vs a Forecast Based on Persisting DroughtsPercent of Grid Points Correct vs a Forecast Based on Persisting Droughts

Drought Outlook -- Forecast minus Persistence

-20

-10

0

10

20

30

40

50

60

Jul '03 Nov'03

Mar'04

Jul '04 Nov'04

Mar'05

Jul '05 Nov'05

Mar'06

Jul '06 Nov'06

Date of Forecast

Fo

reca

st L

ess

Per

sist

ence

Skill MEAN Linear (Skill)

Long-term mean = 13%Long-term mean = 13%

Two Path Approach to Improving Two Path Approach to Improving Drought Forecasts at CPCDrought Forecasts at CPC

• Continue to produce and refine seasonal drought outlooks for the Continue to produce and refine seasonal drought outlooks for the general publicgeneral public

a. Consider adding monthly forecastsa. Consider adding monthly forecasts

b. Consider adding probability information to mapb. Consider adding probability information to map

• Develop Develop objective seasonal probabilityobjective seasonal probability forecasts for drought forecasts for drought (guidance useful for an array of users)(guidance useful for an array of users)

a. Drought probabilities (soil moisture, runoff, drought a. Drought probabilities (soil moisture, runoff, drought indices) at some point in the futureindices) at some point in the future

b. Probabilities for changeb. Probabilities for change

c. Consider NIDIS goalsc. Consider NIDIS goals

d. Climate Test Bed products to contribute d. Climate Test Bed products to contribute

One Prototype Suggestion of a One Prototype Suggestion of a Probabilistic ForecastProbabilistic Forecast

University of Washington ForecastsUniversity of Washington Forecasts

http://www.hydro.washington.edu/forecast/monitor/outlook/index.shtml

““Prediction is very difficult, especially Prediction is very difficult, especially about the futureabout the future” ” Niels Bohr, Danish Niels Bohr, Danish

physicist (not Yogi Berra)physicist (not Yogi Berra)