Local Headline Definitions by NWS Memphis

Headlines Issued by NWS Memphis

The NWS issues watches, warnings, advisories, and statements to highlight potential for hazardous or dangerous weather conditions. These special products, often referred to as ‘headlines’, are issued when the forecaster feels there is sufficient confidence of an event occurring. The NWS warning program uses a multi-tiered concept to increase public awareness and promote proper response to the impending hazard. Generally, the multi-tiered concept conveys certain levels of urgency as described below:

1. Outlook/Statement: An outlook or statement is used to indicate that a hazardous weather event may develop, but there is still much uncertainty. Forecaster confidence of an event occurring is generally greater than 30 percent. This stage is intended to provide those who need considerable lead-time prepare for the possible event. Examples of statements include the the Special Weather Statement and the Significant Weather Advisory product.

2. Watch: A watch is used when the risk of a dangerous weather event has increased, but its occurrence, location, and/or timing are still somewhat uncertain. Forecaster confidence at this stage is generally 50 percent or greater that a warning will be issued at a later time. This stage is intended to provide enough lead-time so those who need to set their plans in motion can do so.

3. Warning/Advisory: A warning or advisory is used when a hazardous weather event is imminent, or is already occurring. Forecaster confidence is generally greater than 80 percent. A warning is used for conditions that pose a threat to life and property. An advisory is used for less serious conditions that cause significant inconvenience and, if proper precautions are not taken, could pose a threat to life and property. Preparations should be completed or rushed to completion. Some warnings, especially the short-fuse, convective ones, will be followed by statements that contain updated information.

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Convective
Fire Weather
Hydrology
Non-Precipitation
Tropical
Winter Weather
Other

	Convective
	Headline	Issuance Criteria	Typical Leadtime	VTEC Code	Product Acronym	Followup Product	Issued By
Watches	Severe Thunderstorm Watch	Conditions are favorable for thunderstorms containing 1 inch or larger hail and/or wind gusts of at least 58 mph (50 knots).	6 to 8 hours	SV.A	SVA	Watch County Notification	SPC (updates/ cancellations issued by MEG)
	PDS Severe Thunderstorm Watch	A particularly dangerous situation (PDS). Conditions are favorable for thunderstorms containing 1 inch or larger hail and/or wind gusts of at least 80 mph (64 knots). Typically issued for widespread, significant non-tornadic severe weather events. Note: "PDS" does not appear in the watch headline, but as a special line within the initial watch product.	6 to 8 hours	SV.A	SVA	Watch County Notification	SPC (updates/ cancellations issued by MEG)
	Tornado Watch	Conditions are favorable for thunderstorms producing tornadoes. Hail and strong winds are also possible.	6 to 8 hours	TO.A	TOA	Watch County Notification	SPC (updates/ cancellations issued by MEG)
	PDS Tornado Watch	A particularly dangerous situation (PDS). Conditions are favorable for thunderstorms producing destructive tornadoes. Hail and strong winds are also possible. Typically issued when there is a likelihood of multiple strong (damage of EF2 or EF3) or violent (damage of EF4 or EF5) tornadoes. Note: "PDS" does not appear in the watch headline, but as a special line within the initial watch product.	6 to 8 hours	TO.A	TOA	Watch County Notification	SPC (updates/ cancellations issued by MEG)
Warnings	Severe Thunderstorm Warning	A thunderstorm producing 1 inch or larger hail and/or wind gusts of at least 58 mph (50 knots) are occurring or imminent.	20 to 60 minutes	SV.W	SVR	Severe Weather Statement	WFO MEG
Warnings	Tornado Warning	A tornado has been reported or is highly likely to occur due to doppler radar signatures.	15 to 45 minutes	TO.W	TOR	Severe Weather Statement	WFO MEG
Advisories	Significant Weather Advisory	Issued under the Special Weather Statement product for strong thunderstorms producing winds between 40 and 57 mph, and/or hail less than 1 inch in diameter, and/or frequent or continuous lightning, and/or funnel clouds or cold air funnels.	Up to 1 hour	N/A	SPS	Special Weather Statement	WFO MEG

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	Fire Weather
	Headline	Issuance Criteria	Typical Leadtime	VTEC Code	Product Acronym	Followup Product	Issued By
Watches	Fire Weather Watch	A high potential for the development of a locally defined Red Flag Event. Red Flag Event criteria are determined by coordination between WFO personnel and land management users in the WFO fire weather service area.	12 to 96 hours	FW.A	RFW	Fire Weather Message	WFO MEG
Warnings	Red Flag Warning	The combination of dry fuels and weather conditions support extreme fire danger and/or fire behavior. These conditions alert land management agencies to the potential for widespread new ignitions or control problems with existing fires, both of which could pose a threat to life and property.	12 to 36 hours	FW.W	RFW	Fire Weather Message	WFO MEG

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	Hydrology
	Headline	Issuance Criteria	Typical Leadtime	VTEC Code	Product Acronym	Followup Product	Issued By
Watches	Flood Watch	Flooding of land and/or rivers and streams is possible.	6 to 48 hours	FF.A (flash), FA.A (areal), FL.A (forecast point)	FFA	Flood Watch	WFO MEG
Warnings	Flash Flood Warning	a. Flash flooding is reported; and/or b. A dam or levee failure is imminent or occurring; and/or c. A sudden failure of a naturally-caused stream obstruction (including debris slide, avalanche, or ice jam) is imminent or occurring, and/or d. Precipitation capable of causing flash flooding is indicated by radar, rain gages, and/or satellite; and/or e. Precipitation as indicated by radar, rain gages, satellite and/or other guidance is capable of causing debris flows, particularly (but not only) in burn areas; and/or f. Local monitoring and prediction tools indicate flash flooding is likely; and/or g. A hydrologic model indicates flash flooding for locations on small streams.	30 minutes to 6 hours	FF.W	FFW	Flash Flood Statement	WFO MEG
Warnings	Flood Warning	Flood Warning (Areal): issued for any high flow, overflow, or inundation in a geographic area which threatens life and property and is not appropriately covered by a flash flood warning or flood warning for forecast points. Flood Warning (Forecast Point): issued for any high flow, overflow, or inundation event threatening life and/or property which can be quantified or indexed at specific locations and is not accounted for in areal flood or flash flood warning products. Flood warnings for forecast points usually include information on upstream and/or downstream locations which are impacted.	3+ hours	FA.W (areal), FL.W (forecast point)	FLW	Flood Statement	WFO MEG
Advisories	Flood Advisory	Flood Advisory (Areal/Forecast Point/Urban and Small Stream): issued when flooding is expected to be of inconvenience, but not necessarily life-threatening.	30 minutes to 6 hours	FA.Y	FLS	Flood Statement	WFO MEG

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	Non-Precipitation
	Headline	Issuance Criteria	Typical Leadtime	VTEC Code	Product Acronym	Followup Product	Issued By
Watches	Excessive Heat Watch	Conditions are favorable for heat indices to reach 110°F due to a combination of heat and humidity.	24 to 72 hours	EH.A	NPW	Weather Message	WFO MEG
	Freeze Watch	Minimum shelter temperatures below 32°F are possible during the growing season which poses a threat to plants and crops.	18 to 48 hours	FZ.A	NPW	Weather Message	WFO MEG
	High Wind Watch	Conditions are favorable for sustained winds of at least 40 mph for one hour or longer, or wind gusts of at least 58 mph of any duration.	18 to 48 hours	HW.A	NPW	Weather Message	WFO MEG
Warnings	Dust Storm Warning	Widespread or localized blowing dust reducing visibilities to 1/4 mile or less. Sustained winds of 25 mph or greater are usually required.	6 to 24 hours	DS.W	NPW	Weather Message	WFO MEG
	Excessive Heat Warning	Heat index values of 110°F or higher during the day with low temperatures >= 75°F at night are occurring or imminent.	12 to 48 hours	EH.W	NPW	Weather Message	WFO MEG
	Freeze Warning	Minimum shelter temperatures below 32°F are expected during the growing season which poses a threat to plants and crops.	12 to 36 hours	FZ.W	NPW	Weather Message	WFO MEG
	High Wind Warning	Sustained winds of at least 40 mph for one hour or longer, or wind gusts of at least 58 mph of any duration are expected.	12 to 36 hours	HW.W	NPW	Weather Message	WFO MEG
Advisories	Air Quality Alert	Atmospheric conditions are stable enough to cause air pollutants to accumulate in a given area. Criteria developed in conjunction with the local or state EPA and the product is issued at their request.	0 to 18 hours	N/A	NPW	Weather Message	WFO MEG
	Ashfall Advisory	Airborne ash plume resulting in ongoing deposition at the surface. Ashfall may originate directly from a volcanic eruption or from the resuspension (by wind) of a significant amount of relic ash.	0 to 36 hours	AF.Y	NPW	Weather Message	WFO MEG
	Blowing Dust Advisory	Widespread or localized blowing dust reducing visibilities to one mile or less, but greater than 1/4 mile. Winds of 25 mph or greater are usually required.	0 to 36 hours	DU.Y	NPW	Weather Message	WFO MEG
	Dense Fog Advisory	Widespread or localized fog reducing visibilities to 1/4 mile or less.	6 to 36 hours	FG.Y	NPW	Weather Message	WFO MEG
	Dense Smoke Advisory	Widespread or localized smoke reducing visibilities to 1/4 mile or less.	0 to 36 hours	SM.Y	NPW	Weather Message	WFO MEG
	Freezing Fog Advisory	Very light ice accumulation resulting from freezing fog (no visibility requirement).	6 to 36 hours	ZF.Y	NPW	Weather Message	WFO MEG
	Frost Advisory	Minimum shelter temperature forecast to be 33 to 36°F during the growing season on nights with good radiational cooling making conditions condusive for frost formation (e.g., light winds, clear skies, high humidity).	12 to 36 hours	FR.Y	NPW	Weather Message	WFO MEG
	Heat Advisory	The combination of heat and humidity making for heat indices between 105°F to 109°F.	12 to 36 hours	HT.Y	NPW	Weather Message	WFO MEG
	Wind Advisory	Sustained wind speeds of 25 to 39 mph lasting for 1 hour or longer.	12 to 36 hours	WI.Y	NPW	Weather Message	WFO MEG

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	Tropical
	Headline	Issuance Criteria	Typical Leadtime	VTEC Code	Product Acronym	Followup Product	Issued By
Watches	Hurricane Watch	Hurricane conditions (sustained winds of 74 mph or higher) are possible. Because hurricane preparedness activities become difficult once winds reach tropical storm force, the hurricane watch is issued 48 hours in advance of the anticipated onset of tropical storm-force winds.	48 hours	HU.A	HLS	Hurricane Local Statement	WFO MEG
Watches	Tropical Storm Watch	Tropical storm conditions (sustained winds of 39 to 73 mph) are possible within 48 hours.	48 hours	TR.A	HLS	Hurricane Local Statement	WFO MEG
Warnings	Hurricane Warning	Hurricane conditions (sustained winds of 74 mph or higher) are expected. Because hurricane preparedness activities become difficult once winds reach tropical storm force, the hurricane warning is issued 36 hours in advance of the anticipated onset of tropical storm-force winds.	36 hours	HU.W	HLS	Hurricane Local Statement	WFO MEG
Warnings	Tropical Storm Warning	Tropical storm conditions (sustained winds of 39 to 73 mph) are expected within 36 hours.	36 hours	TR.W	HLS	Hurricane Local Statement	WFO MEG

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	Winter Weather
	Headline	Issuance Criteria	Typical Leadtime	VTEC Code	Product Acronym	Followup Product	Issued By
Watches	Wind Chill Watch	Possibility of very cold temperatures and brisk winds causing dangerously cold wind chills of -15°F or colder.	12 to 48 hours	WC.A	WSW	Winter Weather Message	WFO MEG
Watches	Winter Storm Watch	Possibility of accumulating snow, sleet, and/or freezing rain causing significant impacts to society and commerce.	12 to 48 hours	WS.A	WSW	Winter Weather Message	WFO MEG
Warnings	Blizzard Warning	Sustained winds or frequent gusts of 35 mph or higher causing falling and/or blowing snow to reduce visibilities below 1/4 mile for 3 hours or longer are imminent or occurring.	8 to 36 hours	BZ.W	WSW	Winter Weather Message	WFO MEG
	Ice Storm Warning	Heavy ice accumulation of 1/4 inch or greater due to freezing rain is imminent or occurring.	8 to 36 hours	IS.W	WSW	Winter Weather Message	WFO MEG
	Wind Chill Warning	Very cold air temperatures and brisk winds causing dangerously cold wind chills of -15°F or colder are imminent or occurring. Hypothermia, frost bite, or death is likely if proper precautions are not taken.	8 to 36 hours	WC.W	WSW	Winter Weather Message	WFO MEG
	Winter Storm Warning	Heavy snow and/or sleet and ice accumulations are imminent or occurring. Society and commerce is expected to be greatly impacted. Precipitation may be accompanied by gusty wind. For a mixture of snow, sleet, or freezing rain, only two inches of snow is required. Consult this link for a map of requirements for pure snowfall.	8 to 36 hours	WS.W	WSW	Winter Weather Message	WFO MEG
Advisories	Wind Chill Advisory	Cold temperatures and brisk wind causing hazardous wind chills of zero to -15°F are imminent or occurring. Hypothermia and frost bite are possible if proper precautions are not taken.	8 to 24 hours	WC.Y	WSW	Winter Weather Message	WFO MEG
Advisories	Winter Weather Advisory	Snow and/or sleet and/or ice accumulations causing an inconvenience to society and commerce are imminent or occurring.	8 to 24 hours	WW.Y	WSW	Winter Weather Message	WFO MEG

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	Other
	Headline	Issuance Criteria	Typical Leadtime	VTEC Code	Product Acronym	Followup Product	Issued By
Warnings	Airport Weather Warning	a. Surface wind gusts >= 40 knots b. Hail >= 3/4 inch c. Onset of freezing rain or sleet d. Snow accumulating 2 inches or more in 12 hours or less	About 1 hour	N/A	AWW	Airport Weather Warning	WFO MEG