The Making of the
Drought Monitor
The U.S. Drought Monitor
Since 1999, NOAA/CPC and NCDC, USDA, and the NDMC have produced a composite drought map--the Drought Monitor—each week with input from numerous
federal and non-federal agencies
• A partnership between the NDMC, USDA and NOAA’s CPC and NCDC
• Incorporate relevant information and products from all entities (and levels of government)
dealing with drought (RCC’s, SC’s, federal/state agencies, etc.)
• The Drought Monitor is updated weekly and provides a general up-to-date summary of
current drought conditions across the 50
The Drought Monitor Concept
A A partnership partnership between the NDMC, USDA and between the NDMC, USDA and NOAA’s CPC and NCDC
NOAA’s CPC and NCDC
Incorporate relevant information and products Incorporate relevant information and products from all entities (and levels of government)
from all entities (and levels of government) dealing with drought (RCC’s, SC’s,
dealing with drought (RCC’s, SC’s, federal/state agencies, etc.)
federal/state agencies, etc.)
The The Drought Monitor Drought Monitor is is updated updated weekly weekly and and provides a general up-to-date summary of
provides a general up-to-date summary of current drought conditions across the 50 current drought conditions across the 50
states and Puerto Rico states and Puerto Rico
The Drought Monitor Concept
A consolidation of indices and indicators into one A consolidation of indices and indicators into one comprehensive national drought map
comprehensive national drought map
The intent is to provide an The intent is to provide an assessment assessment product product NOT NOT a a forecast forecast ! !
Trying to capture these characteristics: Trying to capture these characteristics:
the drought’s magnitude (duration + the drought’s magnitude (duration + intensity)
intensity)
spatial extent spatial extent
The Drought Monitor Concept
Integrates Integrates daily daily rainfall reports from thousands of rainfall reports from thousands of stations
stations
Rates drought intensity by Rates drought intensity by percentile percentile ranks ranks
Uses weekly feedback from Uses weekly feedback from local experts local experts to reflect to reflect impacts and for “ground truthing” the product
impacts and for “ground truthing” the product
The Drought Monitor—
A new way of looking at
drought in the U.S.
Original Objectives
• “ “ Fujita-like” scale Fujita-like” scale
U.S. Drought Monitor Map
Drought Intensity Categories
D0 Abnormally Dry
D1 Drought – Moderate D2 Drought – Severe
D3 Drought – Extreme
Original Objectives
• “ “ Fujita-like” scale Fujita-like” scale
• Identify impacts (A, W, F) Identify impacts (A, W, F)
Original Objectives
• “ “ Fujita-like” scale Fujita-like” scale
• Identify impacts (A, W, F) Identify impacts (A, W, F)
• Assessment of current conditions— Assessment of current conditions—
NOT a forecast!
NOT a forecast!
Original Objectives
• “ “ Fujita-like” scale Fujita-like” scale
• Identify impacts (A, W, F) Identify impacts (A, W, F)
• Assessment of current conditions— Assessment of current conditions—
NOT a forecast!
NOT a forecast!
• A general assessment—not intended A general assessment—not intended to capture all local details
to capture all local details
Original Objectives
• “ “ Fujita-like” scale Fujita-like” scale
• Identify impacts (A, W, F) Identify impacts (A, W, F)
• Assessment of current conditions—NOT a Assessment of current conditions—NOT a forecast!
forecast!
• A general assessment—no local details A general assessment—no local details
• Incorporates local expert input Incorporates local expert input
Monitor Development
Monday Monday
• Draft map sent to local experts Draft map sent to local experts
Tuesday Tuesday
• Local expert feedback Local expert feedback
• Draft map sent to local experts Draft map sent to local experts
• Draft text sent to local experts Draft text sent to local experts
Wednesday Wednesday
• Local expert feedback Local expert feedback
• Final map and text sent to local experts Final map and text sent to local experts
Thursday Thursday
• Map and text released to public on website Map and text released to public on website
Original Objectives
• “ “ Fujita-like” scale Fujita-like” scale
• Identify impacts (A, W, F) Identify impacts (A, W, F)
• Assessment of current conditions—NOT a Assessment of current conditions—NOT a forecast!
forecast!
• A general assessment—no local details A general assessment—no local details
• Local expert input Local expert input
• As objective as possible As objective as possible
Creating the Drought Monitor
Interagency Partners:
•NWS/CPC
•USDA/JAWF
•NDMC
Outside Experts:
•USGS
•State Climos
•RCCs
•NWS Hydros
Posted on the Internet every Thursday morning
Newspapers TV Stations
Government officials Public
(http://enso.unl.edu/monitor/)
USGS Streamflow
CPC Daily Soil Model
30-day Precip .
USDA Soil Ratings
Principal Drought Monitor Inputs Principal Drought Monitor Inputs
Palmer Drought Index
USGS Streamflow April 19, 2002
Category Description Possible Impacts
Palmer Drought
Index
CPC Soil Moisture
Model (Percentiles)
USGS Weekly Streamflow (Percentiles)
Percent of Normal Precipitation
Standardized Precipitation Index (SPI)
Satellite Vegetation
Health Index D0 Abnormally
Dry Going into drought: short- term dryness slowing planting, growth of crops or
pastures; fire risk above average. Coming out of drought: some lingering water deficits; pastures or
crops not fully recovered
-1.0 to -1.9
21-30 21-30 <75% for
3 months
-0.5 to -0.7
36-45
D1 Moderate Drought
Some damage to crops, pastures; fire risk high;
streams, reservoirs, or wells low, some water shortages
developing or imminent;
voluntary water-use restrictions requested
-2.0 to -2.9
11-20 11-20 <70% for
3 months
-0.8 to -1.2
26-35
D2 Severe
Drought
Crop or pasture losses likely; fire risk very high;
water shortages common;
water restrictions imposed
-3.0 to -3.9
6-10 6-10 <65% for
6 months
-1.3 to -1.5
16-25
D3 Extreme
Drought Major crop/pasture losses;
extreme fire danger;
widespread water shortages or restrictions
-4.0 to -4.9
3-5 3-5 <60% for
6 months
-1.6 to -1.9
6-15
D4 Exceptional Drought
Exceptional and widespread crop/pasture losses;
exceptional fire risk;
shortages of water in reservoirs, streams, and
wells creating water emergencies
-5.0 or less
0-2 0-2 <65% for
12 months
-2.0 or less
1-5
Additional indices used, mainly during the growing season, include the USDA/NASS Topsoil Moisture, Crop Moisture Index (CMI), and Keetch Byram Drought Index (KBDI). Indices used primarily during the snow season and in the West include the River Basin Snow Water Content, River Basin Average Precipitation, and the Surface Water Supply Index (SWSI).
Drought Severity Classification
Blending it all together…the Blending it all together…the
Objective Blend of Drought Objective Blend of Drought
Indicators (OBDI)
Indicators (OBDI)
Current Operational OBDI
• First attempt at operationally integrating multiple indicators in an
automated weekly update using a percentile ranking method
• Combines and weights the 30-day precipitation (1/6), the Modified
Palmer Drought Index (5/12), and the
CPC Soil Moisture (5/12)
A New Breed of Experimental Blends
“The Short, Long, and Unified of It”
The New Blends
• Produced weekly using CPC’s real- time daily and weekly climate
division data and NCDC’s monthly archive of indices for 1932-2000
• All parameters are first rendered as
percentiles w/ respect to 1932-2000
data using a percent rank method
Indices used in the Blends and their Weights:
• Short-term Blend: 35% Palmer-derived Z-index; 25% 3-month precipitation; 20%
1-month precipitation; 13% CPC soil
moisture model; and 7% Palmer (Modified) Drought Index
• Long-term Blend: 30% Palmer Hydrologic Index; 20% 12-month precip;
15% 6-month precip; 10% Palmer (Modified);
10% 24-month precip; 10% 60-month precip;
and 5% CPC Soil Model
• Unified Blend: the “raw” Unified
blend is the average of the short- and long-term blends
• The “finished” Unified product plots the percentile of the current “raw”
values relative to the 1932-2000
distribution of monthly values archived at NCDC
The New Blends
Next Steps
Support and utilize the development of a western Support and utilize the development of a western
Implement the new blend products into the process Implement the new blend products into the process SWSI tool SWSI tool
Incorporate USDA soil measurements (SCAN) Incorporate USDA soil measurements (SCAN)
Incorporate USGS groundwater data as real-time Incorporate USGS groundwater data as real-time data become available data become available
Efforts underway to take daily climate data from Efforts underway to take daily climate data from
NOAA’s Cooperative Network to produce a regional/national coverage of station- NOAA’s Cooperative Network to produce a regional/national coverage of station- based SPI
based SPI maps on a
maps on a weekly weekly basis (http://nadss.unl.edu) basis (http://nadss.unl.edu)
National Drought Mitigation Center
http://drought.unl.edu/monitor
The Latest Weekly Assessment From t
he United States Drought Monitor The Latest Seasonal Outlook
