Snow Across the Great Lakes, Central Appalachians, and Northeast; Unsettled Weather in the West

Light to moderate snow will continue into Saturday over the Great Lakes, Central Appalachians, and Northeast. This weekend into next week, a series of atmospheric rivers will bring gusty winds, periods of heavy rain, and mountain snow to northern California and the Pacific Northwest. Colder temperatures are in store for the weekend from the Great Lakes to East Coast. Read More >

Risk Level - Legend
None	Limited	Elevated	Significant	Extreme

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Last Updated: 04:15 AM, Sunday, August 27, 2017
Click on risk level to display risk map and proper legend				Spotter Outlook
Risk	Level	Risk	Level
Tornado		Fog
Hail		Non - Thunderstorm Winds
Thunderstorm Wind Gusts		Excessive Heat
Flooding		Snow and Sleet
Lightning		Ice Accumulation
Spotter Outlook		Frost and Freeze
Fire Weather		Excessive Cold

Risk Level		Definition
	None	No tornado risk.
	Limited	Probability of a tornado within 25 miles of a point: less than 10 percent.
	Elevated	Probability of a tornado within 25 miles of a point: Equal to or greater than 10 percent.
	Significant	Probability of a tornado within 25 miles of a point: Equal to or greater than 30 percent.
	Extreme	Probability of a tornado within 25 miles of a point: Equal to or greater than 45 percent.

Risk Level		Definition
	None	No risk of fog.
	Limited	Fog with visibilities less than or equal to 1 mile.
	Elevated	Fog with visibilities less than or equal to 1/2 mile.
	Significant	Fog with visibilities less than or equal to 1/4 mile.
	Extreme	Fog with near zero visibilities.

Risk Level		Definition
	None	No risk of hail.
	Limited	Risk of sub-severe hail (less than 1") or Probability of severe hail (1" or greater) within 25 miles of a point: less than 15%
	Elevated	Probability of severe hail (1" or greater) within 25 miles of a point: Equal to or greater than 15%
	Significant	Probability of severe hail (1" or greater) within 25 miles of a point: Equal to or greater than 45%
	Extreme	Probability of severe hail (1" or greater) within 25 miles of a point: Equal to or greater than 60%

Risk Level		Definition
	None	Sustained winds < 20 mph and Wind gusts < 30 mph.
	Limited	Sustained winds 20-29 mph or Wind gusts 30-44 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	Risk for sub-severe wind gusts (less than 58 mph) or Probability of severe wind gusts (58 mph or greater) within 25 miles of a point: Less than 15%
	Elevated	Probability of severe wind gusts (58 mph or greater) within 25 miles of a point: Equal to or greater than 15%
	Significant	Probability of severe wind gusts (58 mph or greater) within 25 miles of a point: Equal to or greater than 45%
	Extreme	Probability of severe wind gusts (58 mph or greater) within 25 miles of a point: Equal to or greater than 60%

Risk Level

Definition

None

Maximum Apparent Temperature < 90

Limited

Maximum Apparent Temperature 90 to 99

Elevated

Maximum Apparent Temperature 100 to 104
OR
Maximum Apparent Temperature greater than or equal to 95 for 5 consecutive days.

Significant

Maximum Apparent Temperature 105 to 114
OR
Maximum Apparent Temperature greater than or equal to 100 for 5 consecutive days.

Extreme

Maximum Apparent Temperature greater than or equal to 115
OR
Maximum Apparent Temperataure greater than or equal to 105 for 5 consecutive days.

Note:	Apparent Temperature is defined as:
		Wind Chill Temperature during the cold season.
		Heat Index Temperature during the warm season.

Risk Level		Definition
	None	No Flooding risk.
	Limited	Risk of localized flash flooding of small streams and low water crossings, and minor flooding of poor drainage or urban areas.
	Elevated	Risk of flash flooding of several low water crossings, roads, and small streams, or Minor River Flooding.
	Significant	Risk of flash flooding of numerous roads, low water crossings, and small streams, or Moderate river flooding.
	Extreme	Risk of widespread flash flooding of low water crossings, roads, and small streams. or Major river flooding.

Risk Level		Definition
	None	No snow or sleet.
	Limited	Snow and/or sleet with less than 3 inches of accumulation expected.
	Elevated	Snow and/or sleet with 3 to 5.9 inches of accumulation expected.
	Significant	Snow and/or sleet with 6 to 11.9 inches of accumulation expected.
	Extreme	Snow and/or sleet with greater than or equal to 12 inches of accumulation expected.

Risk Level		Definition
	None	No lightning risk
	Limited	Thunderstorms expected to be isolated to scattered in coverage. Atmospheric conditions support cloud to ground lightning strikes in and near thunderstorms.
	Elevated	Thunderstorms expected to be numerous in coverage. Atmospheric conditions support cloud to ground lightning strikes in and near thunderstorms.
	Significant	Widespread thunderstorms are expected. Atmospheric conditions support cloud to ground lightning strikes in and near thunderstorms.
	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 up to a thin glaze, OR Freezing Fog.
	Elevated	Freezing rain or drizzle with accumulation less than 1/4 inch.
	Significant	Freezing rain with accumulation of 1/4 inch to less than 1 inch.
	Extreme	Freezing rain with accumulation of greater than or equal to 1 inch.

Risk Level		Definition
	None	No danger of frost or freeze causing damage to vegetation.
	Limited	Patchy frost during the growing season with minor damage to unprotected vegetation.
	Elevated	Frost expected during the growing season with damage to unprotected vegetation. This may include temperatures less than or equal to 32 degrees F for less than 3 hours.
	Significant	*Freeze expected (less than or equal to 32 degrees F for 3 or more hours) during the growing season with significant damage to unprotected vegetation.*
	Extreme	*Hard freeze (less than or equal to 28 degrees F) during the growing season with catastrophic damage to unprotected vegetation.*

Risk Level		Definition
	None	Severe thunderstorms are not expected today or tonight.
	Limited	Severe thunderstorms will be possible later today or tonight .
	Elevated	Severe thunderstorms will be possible in the next 6 hours.
	Significant	Severe thunderstorms will be possible in the next 3 hours.
The Spotter Outlook is a resource for municipalities, counties, and SKYWARN storm spotters to plan for possible storm spotter activation on the current calendar day. Other interests can also use the Spotter Outlook to determine the expected time frame for severe thunderstorm potential.

Risk Level

Definition

None

Open burning is usually safe with proper containers and precautions under low fire danger conditions.
Residents should always check on local ordinances that prohibit open burning under any conditions.

Limited

Open burning is usually safe with the proper precautions.
Burning should be done in the early morning and late evening to avoid windier and drier conditions from midday through mid-afternoon.
Residents should always check on local ordinances that prohibit open burning under any conditions.

Elevated

Any open burning is discouraged due to increased wind and lower humidity - except by experienced fire personnel.
Increasing winds and lower humidity contribute to drying fuels. Fires escape control more easily and containment is difficult for inexperienced fire personnel.
Approaching Red Flag conditions.

Significant

Open burning should not be attempted.
High winds and extended dry periods lead to extreme burning conditions. Open fires can quickly escape and are very difficult to control, even for experienced fire fighters.
Conditions exceed minimum criteria for a Red Flag Warning in most cases.

Extreme

Very strong winds, well in excess of Red Flag Criteria combined with moderate to low humidity.
Fires will spread very quickly with spot fires common. Fire control is extremely difficult due to very strong winds.

***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 does not account for fuel moisture from recent precipitation, snow cover and recently melted snow. Appropriate adjustments to the fire environment must be made.

Fire weather hazard categories will normally be more restricted, generally in the "none" or "limited" categories from May 1st to September 30th due to normally predominant green and moist live vegetation. This will be subject to change during unusual severe Spring and/or Summer drought.

Risk Level

Definition

None

Minimum apparent temperature greater than or equal to -4 degrees F.

Limited

Minimum apparent temperature -5 to -24 deg F.

Elevated

Minimum apparent temperature -25 to -34 deg. F

Significant

Minimum apparent temperature -35 to -44 deg. F.

Extreme

Minimum apparent temperature less than or equal to -45 degrees F

Note:	Apparent Temperature is defined as:
		Wind Chill Temperature during the cold season.
		Heat Index Temperature during the warm season.

Risk Level		Definition Severe Thunderstorm Risk Day 2 to 7
	None	No risk of severe thunderstorms.
	Limited	Risk for severe thunderstorms with the Probability of severe thunderstorms within 25 miles of a point:* Less than 15%
	Elevated	Probability of severe thunderstorms within 25 miles of a point:* Equal to or greater than 15%
	Significant	Probability of severe thunderstorms within 25 miles of a point:* Equal to or greater than 45%
	Extreme	Probability of severe thunderstorms within 25 miles of a point:* Equal to or greater than 60%

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.

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Snow Across the Great Lakes, Central Appalachians, and Northeast; Unsettled Weather in the West

Experimental Enhanced Hazardous Weather Outlook - NWS Twin Cities