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Weekly Look Ahead

November 24, 2021 (Updated Every Thursday)

5–7 Day Outlook

A frontal system will sweep across the eastern contiguous U.S. (CONUS) during November 24–30, with another Pacific weather system moving into the Pacific Northwest near the end of the period. They will be moving through a circulation pattern consisting mainly of an upper-level ridge in the West and trough in the East. One to two inches of precipitation are forecast to fall along the Texas coast to east Texas and over northern portions of the Northeast, with half an inch or more stretching from the southern Rio Grande Valley to New England. Half an inch to an inch of precipitation is expected over the northern Rockies and coastal sections of Oregon and Washington, with up to 5 inches in the forecast for northwest portions of Washington. Up to half an inch is predicted for parts of the Four Corners states in the Southwest, parts of the Great Lakes, and coastal parts of the Mid-Atlantic to Northeast states. Little to no precipitation is expected for much of the West, Great Plains, Upper Mississippi Valley, and Southeast. Temperatures are expected to be warmer than normal in the western and central CONUS and cooler than normal along the East Coast.

6–10 Day Outlook

The Climate Prediction Center's 6–10 day outlook for December 1–6 shows drier-than-normal weather favored from the Southwest to Great Lakes, from the Ohio Valley to Southeast, and the western half of Alaska. Odds favor wetter-than-normal weather over the Pacific Northwest to northern Rockies, parts of southern Texas, and southeast Alaska.

Colder-than-normal weather is favored over the East Coast and warmer-than-normal weather over the western and central contiguous U.S., with the warmer-than-normal conditions shifting eastward as the period progresses. Colder-than-normal temperatures dominate Alaska in the outlook.

 

This weekly look ahead is modified from the U.S. Drought Monitor's National Drought Summary for November 23, 2021, written by Richard Heim (NOAA's National Centers for Environmental Information) and Richard Tinker (NOAA's Climate Prediction Center).

Data and Maps

Predicting drought depends on the ability to forecast precipitation and temperature within the context of complex climate interactions. Many different datasets and maps are available that predict how precipitation and temperature may change in the future.

Featured Outlooks and Forecasts

Drought Outlooks & Forecasts

NOAA's Climate Prediction Center's Monthly Drought Outlook is issued at the end of each calendar month and is valid for the upcoming month. The Outlook predicts whether drought will emerge, stay the same, or get better over the next 30 days or so. Learn more.

NOAA's Climate Prediction Center's Seasonal Drought Outlook is issued monthly on the third Thursday of each month. The Outlook predicts whether drought will emerge, stay the same, or get better in the next three months. Learn more.

Taking the U.S. Drought Monitor as a starting point, the Climate Prediction Center's Objective Drought Tendency Forecast is an integrated product that combines information from the flash drought development tool and subseasonal SPI3 forecasts. The forecast synthesizes information through a decision-tree process to determine whether drought will emerge, stay the same, or get better in the next 30 days, on a rolling basis. This tool is used to inform the official forecasts. Learn more.

Drought Outlook

The color with the hex code #9b634a identifies:
Drought persists
The color with the hex code #ded2bc identifies:
Drought remains but improves
The color with the hex code #b2ad69 identifies:
Drought removal likely
The color with the hex code #ffde63 identifies:
Drought development likely

Drought Outlook

The color with the hex code #9b634a identifies:
Drought persists
The color with the hex code #ded2bc identifies:
Drought remains but improves
The color with the hex code #b2ad69 identifies:
Drought removal likely
The color with the hex code #ffde63 identifies:
Drought development likely

Drought Outlook

The color with the hex code #8c645a identifies:
Drought persists
The color with the hex code #e1beb4 identifies:
Drought remains but improves
The color with the hex code #1eb41e identifies:
Drought removal likely
The color with the hex code #ffe878 identifies:
Drought development likely
The color with the hex code #c00000 identifies:
Drought intensification likely

Evaporative Demand and Flash Drought

The Evaporative Demand Drought Index (EDDI) is an experimental drought monitoring and early warning guidance tool. It examines how anomalous the atmospheric evaporative demand (E0; also known as "the thirst of the atmosphere") is for a given location and across a time period of interest. This experimental subseasonal EDDI forecast shows projected evaporative demand for the next 28 days from the CFS-gridMET dataset at 4-km gridded resolution. Learn more.

Created by NOAA’s Climate Prediction Center (CPC), this subseasonal tool predicts the areas susceptible for flash drought development. The real-time product started running in April 2018 and has been used to support CPC’s Monthly Drought Outlook efforts. The tool, which is used to inform official forecasts, calculates the rapid change index (RCI) using 7-day mean evapotranspiration anomalies. RCI is the accumulated magnitude of moisture stress changes occurring over multiple weeks, and drought is likely to develop when RCI is negative. In the legend below, a higher number of non-exceedances indicates a greater potential for flash drought development. Learn more.

Drought Categories

The color with the hex code #ffff00 identifies:
ED0
The color with the hex code #ffd37f identifies:
ED1
The color with the hex code #ffaa00 identifies:
ED2
The color with the hex code #e60000 identifies:
ED3
The color with the hex code #730000 identifies:
ED4

Wetness Categories

The color with the hex code #8ccdef identifies:
EW0
The color with the hex code #00bfff identifies:
EW1
The color with the hex code #1d90ff identifies:
EW2
The color with the hex code #4169e1 identifies:
EW3
The color with the hex code #0000ff identifies:
EW4

Number of Non-Exceedances (Range: 0-30)

The color with the hex code #ffffff identifies:
≤ 2
The color with the hex code #ffff99 identifies:
2 - 5
The color with the hex code #ffcc33 identifies:
5 - 10
The color with the hex code #ff6633 identifies:
10 - 15
The color with the hex code #cc3300 identifies:
15 - 20
The color with the hex code #990000 identifies:
20 - 25
The color with the hex code #663333 identifies:
≥ 25
Experimental

Challenges with Predicting Drought

Pressure Systems

High pressure systems, which hinder cloud formation and lead to low relative humidity and precipitation, can cause drought. When large-scale anomalies in atmospheric circulation patterns last for months or seasons, prolonged drought occurs (NDMC).

Temperate Zone Forecast Reliability

In temperate regions (above 30 north latitude), long-range forecasts have limited reliability. Due to differences in observed conditions and statistical models, reliable forecasts for temperate regions may not be attainable for a season or more in advance (NDMC).

Interconnected Variables

Anomalies in precipitation and temperature may last from several months to several decades, and how long they last can depend on air–sea interactions, soil moisture, land surface processes, topography, and weather systems at the global scale (NDMC).

ENSO and Global Weather Patterns

Teleconnections, such as ENSO and La Niña events, are atmospheric interactions between widely separated regions. Understanding these teleconnections can help in forecasting droughts, floods, tropical storms, and hurricanes (NDMC).