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 Hazardous Weather Outlook or the Special Weather Statement (which also contain 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
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 Flash Flood Watch Rapidly developing and life-threatening flooding is possible due to a hydrologic event (e.g. heavy rain) or dam or levee failure. 6 to 48 hours FF.A FFA Flash Flood Watch WFO MEG
Flood Watch Flood Watch (Areal): Flooding of land and/or rivers and streams is possible. Flood Watch (Forecast Point): Flooding is possible at a particular point on a river or stream. 6 to 48 hours 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
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
Hard Freeze Watch Minimum shelter temperatures may drop to 28°F or lower during the growing season which poses an especially high risk to plants and crops.  18 to 48 hours HZ.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
Hard Freeze Warning Minimum shelter temperatures are expected to drop to 28°F or lower during the growing season which poses an especially high risk to plants and crops.  12 to 36 hours HZ.A 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
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 Extreme Wind Warning A landfalling hurricane is expected to spread sustained surface winds of 115 mph or greater onshore within one hour.  In order to be issued, the NHC must designate the storm as a category 3 (115 mph or greater).   1 to 2 hours EW.W EWW Severe Weather Statement WFO MEG
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
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 Blizzard Watch Possibility of sustained winds or wind gusts above 35 mph causing falling and/or blowing snow to reduce visibilities below 1/4 mile for 3 hours or longer. 12 to 48 hours BZ.A WSW Winter Weather Message WFO MEG
Wind Chill Watch Possibility of very cold temperatures and brisk winds causing dangerously cold wind chills of -18°F or colder.  12 to 48 hours WC.A WSW Winter Weather Message WFO MEG
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 -18°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 Freezing Rain Advisory Ice accumulation less than 1/4 inch due to freezing rain is imminent or occurring. 8 to 24 hours ZR.Y WSW Winter Weather Message WFO MEG
Wind Chill Advisory Cold temperatures and brisk wind causing hazardous wind chills of zero to -17°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
Winter Weather Advisory Snow and/or sleet and 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


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