National Weather Service United States Department of Commerce

Severe Weather Awareness Week in Iowa & Nebraska, March 27-31, 2017

March 27th - 31st is Severe Weather Awareness Week across the States of Iowa & Nebraska. Read More >

Risk Level - Legend
None
Limited
Elevated
Significant
Extreme
Risk - Limited
Risk - Elevated
Risk - Significant
Risk - Excessive
Click tabs to switch between Graphical and Text:
Click on risk level to display risk map and proper legend
Spotter Activation
Risk
Level
Risk
Level
Tornado
Fog
Hail
 
Non - Thunderstorm Winds
 
Thunderstorm Wind Gusts
Excessive Heat
Flooding
Snow and Sleet
Lightning
Ice Accumulation
Spotter Activation
Frost and Freeze
Fire Weather
Excessive Cold
Risk Level
Definition
None
No tornadoes are expected.
Limited
Brief tornadoes are possible, but not likely.
Elevated
Tornadoes are possible.
Significant
Long-lived & damaging tornadoes are possible.
Extreme
Long-lived & damaging tornadoes are likely.
Risk Level
Definition
None
No fog expected.
Limited
Patchy fog. Visibility generally greater than 1/2 mile.
Elevated
Areas of fog. Isolated visibility less than 1/4 mile possible.
Significant
Widespread fog. Areas of visibility less than 1/4 mile.
Risk Level
Definition
None
No hail is expected.
Limited
Isolated severe storms may produce hail up to 1" in diameter.
Elevated
Hail of 1" in diameter or greater is possible.
Significant
Large and destructive hail is possible.
Extreme
Very Large and destructive hail is likely.
Risk Level
Definition
None
Sustained winds < 25 mph
and
Wind gusts < 35 mph.
Limited
Sustained winds 25-29 mph
or
Wind gusts 35-44 mph.
Elevated
Sustained winds 30-39 mph
or
Wind gusts 45-57 mph.
Significant
Sustained winds 40-49 mph
or
Wind gusts 58-64 mph.
Extreme
Sustained winds > 50 mph
or
Wind gusts > 65 mph.
 Risk Level
Definition
None
No thunderstorm wind risk.
Limited
Isolated severe storms may produce thunderstorm wind gusts up to 60 mph.
Elevated
Thunderstorm wind gusts of 60 mph or greater are possible.
Significant
Widespread damaging winds are possible.
Extreme
Widespread damaging winds are likely.
Risk Level
Definition
None
Maximum Heat Index < 95 degrees F.
Limited
Maximum Heat Index of 95 to 99 degrees F.
Elevated
Maximum Heat Index 100 to 104 degrees F
OR
Maximum Heat Index greater than or equal to 95 degrees F for 4 consecutive days.
Significant
Maximum Heat Index 105 to 114 degrees F
OR
Maximum Heat Index greater than or equal to 100 degrees F for 4 consecutive days.
Extreme
Maximum Heat Index greater than or equal to 115 degrees F
OR
Maximum Heat Index greater than or equal to 105 degrees F for 5 consecutive days.
 Risk Level
Definition
None
No Flash Flooding risk.
Limited
Minor Flash Flooding or Urban Flooding is POSSIBLE.
Elevated
Minor Flash Flooding or Urban Flooding is LIKELY; Flash Flood Watch is in effect or expected.
Significant
Widespread or Major Flash Flooding is LIKELY; Flash Flood Watch or Warning is in effect or expected.
Extreme
Flash Flood Emergency conditions are LIKELY; Flash Flood Watch or Warning is in effect or expected.
Risk Level
Definition
None
Little or no snow or sleet accumulation.
No blowing snow expected.
Limited
Snow and/or sleet with less than 3 inches of accumulation expected
OR
Areas of blowing snow.
Elevated
Snow and/or sleet with 3 to 5 inches of accumulation expected
OR
Widespread blowing snow causing drifting.
Significant
Snow and/or sleet with 6 to 10 inches of accumulation expected
OR
Widespread blowing snow with whiteout conditions possible in open & rural areas.
Extreme
Snow and/or sleet with greater than 10 inches of accumulation expected
OR
Blowing snow causing widespread whiteout conditions.
Risk Level
Definition
None
No lightning expected.
Limited
Thunderstorms expected to be isolated to scattered in coverage.
Elevated
Thunderstorms expected to be numerous in coverage.
Significant
Widespread thunderstorms are expected.
Extreme
Thunderstorms are expected with nearly continuous cloud to ground lightning strikes in and near thunderstorms.
Risk Level
Definition
None
No freezing rain or drizzle.
Limited
Very light freezing rain or drizzle with light ice accumulation.
Elevated
Freezing rain or drizzle with ice accumulation less than 1/4 inch.
Significant
Freezing rain with ice accumulation of 1/4 inch to 1/2 inch.
Extreme
Freezing rain with ice accumulation of greater than 1/2 inch.
Risk Level
Definition
None
No danger of frost or freeze causing damage to vegetation.
Limited
Areas of frost are possible during the growing season.
Elevated
Widespread frost is likely during the growing season. 
This may include temperatures less than or equal to 32 degrees F for less than 3 hours.
Significant
Freeze likely (less than or equal to 32 degrees F for 3 or more hours) during the growing season.
Extreme
Killing freeze likely (less than or equal to 28 degrees F) during the growing season.
Risk Level
Definition
None
Spotter activation is not expected today or tonight.
Limited
Spotter activation is possible today or tonight.
Elevated
Spotter activation is likely today or tonight.
The Spotter Activation is a resource for municipalities, counties, and storm spotters to plan for possible storm spotter activation on the current calendar day. Other interests can also use the Spotter Activation to determine the expected time frame for severe thunderstorm potential.
 Risk Level
Definition
None
Low to Moderate Fire Danger. Fire starts are low. Open burning is usually safe with proper precautions. 
Residents should always check on local ordinances that prohibit open burning under any conditions.
Limited
High Fire Danger. Fire starts are medium to high. Open burning is discouraged - except by experienced fire personnel - due to increased wind and moderate to low humidity. 
Fire containment is difficult for inexperienced fire personnel.
Elevated
Very High Fire Danger. Fire starts are high. Open burning should be postponed for another day.
Strong winds and dry humidity lead to dangerous burning conditions. Open fires can quickly escape and are very difficult to control, even for experienced fire fighters.
Significant
Extreme Fire Danger/Red Flag Warning. Fire starts are very high. Open burning should NOT be attempted.
Very strong winds and dry humidity lead to extreme fire behavior characteristics, including spot fires and fire whirls. Fire control can be deadly, even for experienced fire fighters. Open fires quickly escape and will exhibit a very rapid rate of spread on the flaming front.
Extreme
Extreme Red Flag conditions. Fire starts are very high. Open burning should NOT be attempted.
Very strong winds, well in excess of Red Flag criteria, and/or excessively dry humidity lead to extreme fire behavior characteristics, including long-range spotting and fire whirls. Fire control can be deadly, even for experienced fire fighters. Open fires quickly escape and will exhibit a very rapid rate of spread on the flaming front. 
***These definitions are geared towards the general public and general emergency management and should not be confused with the standard National Fire Danger Rating System (NFDRS) adjectives used by wildland fire personnel.
The fire weather category for the Enhanced Hazardous Weather Outlook is based primarily on predicted wind, humidity and temperature, and may not account for fuel moisture from recent precipitation, snow cover and recently melted snow.  Adjustments to the fire environment may be needed in these situations.
Fire weather hazard categories will normally be more restricted, generally in the "none" or "limited" categories from June 1st to August 15th, due to normally predominant green and moist live vegetation.  This will be subject to change during unusual severe Summer drought.
Risk Level
Definition
None
Minimum wind chill or temperature above 0 degrees F.
Limited
Minimum wind chill or temperature 0 to -19 degrees F.
Elevated
Minimum wind chill or temperature -20 to -34 degrees F.
Significant
Minimum wind chill or temperature -35 to -39 degrees F.
Extreme
Minimum wind chill or temperature -40 degrees F or colder.
Risk Level
Definition Severe Thunderstorm Risk Day 2 to 7
None
No risk of severe thunderstorms.
Limited
Isolated severe storms may produce thunderstorm wind gusts up to 60 mph and/or hail up to 1" in diameter.
Elevated
Severe thunderstorms (wind gusts of 58 mph or greater/hail 1" or greater in diameter) are possible.
Significant
Widespread severe thunderstorms are possible.
Extreme
Widespread severe thunderstorms are likely.
Risk
Level
Severe Thunderstorms
Lightning
Flooding
Fire Weather
Fog
Non - Thunderstorm Winds
Excessive Heat
Snow and Sleet
Ice Accumulation
Frost and Freeze
Excessive Cold
 

The Experimental Enhanced Hazardous Weather Outlook is an experimental product that will be posted to this page for evaluation. We encourage your comments or suggestions for improvements using the electronic survey provided. Your feedback will help us determine product utility, if modifications are needed, and whether the product should become part of our operational suite. | Product Description Document

The Experimental Enhanced Hazardous Weather Outlook is a decision support service that supports preparedness and response efforts prior to and during hazardous weather.  This service provides decision makers with convenient access to potential weather hazard information by graphically depicting the risk of weather hazards out through seven days.