Code Gray Watch- Indicates a High Probability of a Tornado in the Area of the Watch
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National Weather Service Reference Guide
National Weather Service Reference Guide Purpose of this Document he National Weather Service (NWS) provides many products and services which can be T used by other governmental agencies, Tribal Nations, the private sector, the public and the global community. The data and services provided by the NWS are designed to fulfill us- ers’ needs and provide valuable information in the areas of weather, hydrology and climate. In addition, the NWS has numerous partnerships with private and other government entities. These partnerships help facilitate the mission of the NWS, which is to protect life and prop- erty and enhance the national economy. This document is intended to serve as a reference guide and information manual of the products and services provided by the NWS on a na- tional basis. Editor’s note: Throughout this document, the term ―county‖ will be used to represent counties, parishes, and boroughs. Similarly, ―county warning area‖ will be used to represent the area of responsibility of all of- fices. The local forecast office at Buffalo, New York, January, 1899. The local National Weather Service Office in Tallahassee, FL, present day. 2 Table of Contents Click on description to go directly to the page. 1. What is the National Weather Service?…………………….………………………. 5 Mission Statement 6 Organizational Structure 7 County Warning Areas 8 Weather Forecast Office Staff 10 River Forecast Center Staff 13 NWS Directive System 14 2. Non-Routine Products and Services (watch/warning/advisory descriptions)..…….. 15 Convective Weather 16 Tropical Weather 17 Winter Weather 18 Hydrology 19 Coastal Flood 20 Marine Weather 21 Non-Precipitation 23 Fire Weather 24 Other 25 Statements 25 Other Non-Routine Products 26 Extreme Weather Wording 27 Verification and Performance Goals 28 Impact-Based Decision Support Services 30 Requesting a Spot Fire Weather Forecast 33 Hazardous Materials Emergency Support 34 Interactive Warning Team 37 HazCollect 38 Damage Surveys 40 Storm Data 44 Information Requests 46 3. -
SKYWARN Detailed Documentation
SKYWARN Detailed Documentation NWS Terminology Convective Outlook Categories Risk Description 0 - Delineates, to the right of a line, where a 10% or greater probability of General thunderstorms is forecast during the valid period. 1 - An area of severe storms of either limited organization and longevity, or very low Marginal coverage and marginal intensity. An area of organized severe storms, which is not widespread in coverage with 2 - Slight varying levels of intensity. 3 - An area of greater (relative to Slight risk) severe storm coverage with varying Enhanced levels of intensity. An area where widespread severe weather with several tornadoes and/or numerous 4 - severe thunderstorms is likely, some of which should be intense. This risk is Moderate usually reserved for days with several supercells producing intense tornadoes and/or very large hail, or an intense squall line with widespread damaging winds. An area where a severe weather outbreak is expected from either numerous intense and long-tracked tornadoes or a long-lived derecho-producing thunderstorm complex that produces hurricane-force wind gusts and widespread damage. This 5 - High risk is reserved for when high confidence exists in widespread coverage of severe weather with embedded instances of extreme severe (i.e., violent tornadoes or very damaging convective wind events). Hazardous Weather Risks Risk Description An advisory is issued when a hazardous weather or hydrologic event is occurring, imminent, or likely. Advisories are for "less serious" conditions than warnings that may cause significant inconvenience, and if caution is not exercised could lead to Advisory situations that may threaten life or property. The National Weather Service may activate weather spotters in areas affected by advisories to help them better track and analyze the event. -
Warning Uses Definition of Terms
Warning Uses Convective Weather Flooding Winter Weather Non-Precipitation Tornado Watch Flash Flood Watch Blizzard Warning Tornado Warning Flash Flood Warning Winter Storm Watch Severe Thunderstorm Watch Flood Watch Winter Storm Warning High Wind Warning Severe Thunderstorm Warning Flood Warning Snow Advisory Small Stream Flood Freezing Rain Advisory High Wind Advisory Advisory Ice Storm Warning Winter Weather Advisory Definition of Terms Term Definition Winter Weather There is a good chance of a major winter storm developing in the next several days. Outlook Winter Storm Watch There is a greater than 50% chance of a major winter storm in the next several days Winter Storm Any combination of winter weather including snow, sleet, or blowing snow. The Warning snow amount must meet a minimum accumulation amount which varies by location. Blizzard Warning Falling and/or blowing snow frequently reducing visibility to less than 1/4 mile AND sustained winds or frequent gusts greater than 35 mph will last for at least 3 hours. Ice Storm Warning Freezing rain/drizzle is occurring with a significant accumulation of ice (more than 1/4 inch) or accumulation of 1/2 inch of sleet. Wind Chill Warning Wind chill temperature less than or equal to -20 and wind greater than or equal to 10 mph. Winter Weather Any combination of winter weather such as snow, blowing snow, sleet, etc. where Advisory the snow amount is a hazard but does not meet Winter Storm Warning criteria above. Freezing Light freezing rain or drizzle with little accumulation. Rain/Drizzle Advisory . -
Winter Weather Preparation
Upshur County Office of Emergency Management Winter Weather Preparation Before Winter Storms and Extreme Cold To Prepare For A Winter Storm You Should Add The Following Supplies To Your Emergency Kit: • Rock salt or more environmentally safe products to melt ice on walkways • Sand to improve traction • Snow shovels and other snow removal equipment • Sufficient heating fuel - You may become isolated in your home and regular fuel sources may be cut off. Store a good supply of dry, seasoned wood for your fireplace or wood-burning stove. • Adequate clothing and blankets to keep you warm • Make a Family Communications Plan. Your family may not be together when disaster strikes, so it is important to know how you will contact one another, how you will get back together and what you will do in case of an emergency. • Listen to a NOAA Weather Radio or other local news channels for critical information from the National Weather Service (NWS). Be alert to changing weather conditions. Upshur County Residents can receive free Weather Alerts by signing up for NIXLE at http://www.NIXLE.com and entering your zip code. • Minimize travel - If travel is necessary, keep a disaster supplies kit in your vehicle. • Bring pets/companion animals inside during winter weather. Move other animals or livestock to sheltered areas with non-frozen drinking water. Winterize Your Vehicle Check or have a mechanic check the following items on your car: • Antifreeze levels - ensure they are sufficient to avoid freezing. • Battery and ignition system - should be in top condition and battery terminals should be clean. -
REFERENCE SHEET for NWS TAUNTON WARNING/ADVISORY THRESHOLDS (Last Updated: June 1, 2018)
REFERENCE SHEET FOR NWS TAUNTON WARNING/ADVISORY THRESHOLDS (Last Updated: June 1, 2018) The following are National Weather Service criteria for issuing Watches/Warnings/Advisories: Watches: 50% confidence of meeting Warning criteria (generally within 36-48+ hours). Advisories and Warnings: 80% confidence in the event occurrence (generally within 24-36 hours). TYPE OF ISSUANCE WHEN ISSUED FOR SOUTHERN NEW ENGLAND WINTER WEATHER ADVISORY More than one predominant hazard Winter weather event having more than one predominant hazard (ie., snow and ice, snow and sleet, or snow, ice & sleet) meeting or exceeding advisory criteria for at least one of the precipitation elements, but remaining below warning criteria. Snow, Ocean Effect Snow, and/or Sleet 3 inches averaged over a forecast zone in 12 hours Snow and Blowing Snow Sustained or frequent gusts of 25 to 34 mph accompanied by falling and blowing snow occasionally reducing visibility to ≤ 1/4 mile for ≥ 3 hours Blowing Snow Widespread or localized blowing snow reducing visibility to ≤ ¼ mile with winds < 35 mph Freezing Rain or Freezing Drizzle Any accretion of freezing rain or freezing drizzle on road surfaces Black Ice A Special Weather Statement will usually be issued when sufficient moisture is expected to cause a thin layer of ice on road surfaces, typically on cloudless nights (“black ice”). At forecaster discretion a formal Winter Weather Advisory may be issued instead. WIND CHILL ADVISORY Wind chill index between -15°F and -24°F for at least 3 hours using only the sustained wind WINTER STORM WARNING More than one predominant hazard Winter weather event having more than one predominant hazard {ie. -
Quick Hitting Winter Storm Today
Quick Hitting Winter Storm Today Current Hazards Winter Storm Warnings and Advisories Continue for a Moderate to Heavy Snowfall today. Weather Forecast Office Presentation Created New York, NY Follow us on Twitter Follow us on Facebook 2/7/2021 4:20 AM Main Points Hazard Impacts Location Timing • Snowfall rates of 1-2”/hr • NE NJ, NYC Metro, Coastal • Onset- This Morning possible. Westchester, SW CT and W • Heavy Snow- This morning Heavy Snow LI – around 6” • Visibilities of 1/4 miles or less. thru afternoon. • Difficult travel. • E LI and SE CT- 6-9” • Snow ends- This evening • • Snowfall of up to 1”/hr possible. Interior portions of NE Onset- This Morning • Snow • Visibilities down to 1/2 mile at NJ, Lower Hud and SW Moderate Snow- This times. morning into early aft. CT – 3-6 • Hazardous travel. ” • Snow ends- Late this aft. Marine • Wind gusts of 35 KT. Ocean Waters East of This Morning thru This • Seas of 5-8 ft. Moriches Inlet Afternoon Gale Warning Weather Forecast Office Presentation Created New York, NY Follow us on Twitter Follow us on Facebook 2/7/2021 4:20 AM Summary of Greatest Impacts Heavy Snow: NYC Metro, NE NJ, S Westchester, S CT, LI None Limited Elevated Significant Extreme Snow: Interior portions of Lower Hud, SW CT, NE NJ None Limited Elevated Significant Extreme Marine: Ocean Waters East of Moriches Inlet None Limited Elevated Significant Extreme Weather Forecast Office Presentation Created New York, NY Follow us on Twitter Follow us on Facebook 2/7/2021 4:20 AM Snow Winter Storm Warning in Effect from Hazards: Total Snowfall in Warned Area – 6am to 9pm Today for much of the Area Around 6” for NE NJ, NYC, S Westchester, W LI, and SW CT 6-9” for E LI and SE CT. -
Winter Weather Definitions and Terms
Definitions of Winter Weather Terms used by the National Weather Service As winter approaches, you should understand winter weather terms and be aware of winter weather hazards. The National Weather Service uses several terms to tell you exactly what kind of weather to expect, please review the terms below to familiarize yourself with them. 1) WINTER STORM OUTLOOK This is a statement issued when there is a chance of a major winter storms from 3 to 5 days in the future. This is meant to assist people with their long range plans. However, since the outlook is issued so far in advance, the accuracy of the prediction may be limited. 2) WINTER STORM WATCH This means there may be hazardous winter weather due to various elements such as heavy snow, sleet, or ice accumulation from freezing rain. In our region, heavy snow means 7 inches or more of accumulation in 24 hours or less. A "WATCH" is a long range prediction. They are issued at least 12 hours before the hazardous winter weather is expected to begin. When the storm becomes imminent, or has a high probability of occurring, the watch will be upgraded to a "WARNING". 3) WINTER STORM WARNING FOR HEAVY SNOW Seven inches or more of snow will fall within a 24 hour period. 4) WINTER STORM WARNING FOR SEVERE ICING Heavy accumulation of ice due to freezing rain will down trees and power lines. Electricity, or telephone communications, may be out for a long period of time. Roads may become impassable for most vehicles. 5) BLIZZARD WARNING This is issued for a combination of strong winds averaging or frequently gusting to, or above, 35 miles an hour and very low visibility due to blowing or falling snow. -
Weather Products
Forecast Products The Zone Forecast Product highlights the expected sky condition, type and probability of precipitation, visibility restrictions, and temperature Zone affecting individual counties for each 12-hour period out through 7 days. Forecast ZFP Wind direction and speed are also included in the forecast out to 60 hours. WFO Paducah issues the zone forecast by 4 a.m. and 3:30 p.m. under the Product header ZFPPAH. This forecast is updated as needed to meet changing weather conditions. Refer to Appendix A for a guide to ZFP terminology. WFO Paducah provides detailed digital forecast data via the Area/Point Forecast Matrices. These products display forecast weather parameters in 3, 6, and 12-hour intervals through 7 days. Incorporated into a matrix format, this product creates a highly detailed forecast, allowing for an at-a- Area/Point AFM glance view of a large number of forecast elements. The AFM contains Forecast forecasts for each county within the WFO Paducah forecast area, while PFM the PFM shows forecasts for specific cities. WFO Paducah issues the Matrices Area/Point Forecast Matrices by 4 a.m. and 3:30 p.m. under the respective headers of AFMPAH and PFMPAH. These products are updated every 3 hours and as needed to meet changing weather conditions. Refer to Appendix B for a detailed guide to interpreting the AFM and PFM. WFO Paducah issues the Area Forecast Discussion twice daily by 4 a.m. and 3:30 p.m. under the header AFDPAH. This product provides scientific Area insight into the thought process of the forecast team at Paducah. -
HOW to PREPARE for a WINTER STORM How to Prepare for a Winter Storm Winter Storms Can Bring Freezing Rain, Ice, Snow, High Winds, Or a Combination of These Conditions
HOW TO PREPARE FOR A WINTER STORM How to Prepare for a Winter Storm Winter storms can bring freezing rain, ice, snow, high winds, or a combination of these conditions. They can cause power outages that last for days, make roads and walkways very dangerous, and can affect community services. Planning and preparing can help you manage the impact of a winter storm and keep you and your family safe. A sustained power outage can have a significant impact on people who require electricity to power medical equipment, so make sure that you have a plan to take care of yourself and your family during an outage. KNOW YOUR RISK WHAT: A winter storm that lasts for several days, WHERE: Winter storms sometimes for several occurs when there is or be a combination of and colder than normal days. Driving and walking significant precipitation several winter weather temperatures can happen can become extremely and the temperature is conditions. Many winter in every region of the hazardous due to icy low enough that storms are accompanied country. conditions, snowfall precipitation forms as by dangerously low accumulation, low visibility, sleet or snow, or when temperatures. IMPACT: Extreme winter or extreme cold. People rain turns to ice. A winter weather can immobilize may need to stay at home storm can range from WHEN: Winter storms can an entire region. Ice and or work without utilities or freezing rain and ice, to occur from early autumn to heavy snowfall can knock other services, until moderate snowfall over a late spring depending on out heat, power, and driving is safe. -
Warning/Advisory Criteria
WARNING/ADVISORY CRITERIA Definitions: Watch – Conditions are favorable for weather hazard to occur. Prepare for warnings to be issued. Warning – Event is imminent, occurring close by, or, in the case of a winter storm/hurricane, has a high likelihood of occurrence. Take action to protect life and property. Marine Wind/Wave Criteria Headline Chesapeake Bay Currituck Sound & Maryland/Virginia/NC Virginia Rivers Coastal Waters Small Craft Advisory (use top of wind and seas range) 18-33 Kt/4+ Ft 18-33 Kt/None 25-33 Kt/5+ Ft Gale Warning 34-47 Kt Storm Warning ≥48 Kt Special Marine Warning (SMW) Thunderstorm winds ≥34 Kt; hail ≥¾” and/or waterspouts High Surf Advisory N/A N/A Surf 8 Ft Near Shore 10 Ft/10 second period 12 Ft/10 second period ** (** = Duration >12 hrs) Public Products Warning/Advisory Thresholds Warning/Advisory (Product ID) Snow Freezing Rain Combination of winter hazards Winter Storm Warning * (WSW) Average of forecast. range: At least 1/4" of Hazards judged to pose a threat to life MD/Interior VA 5"/24 hr or 4"/12 hr ice accretion (all and property NC/SE VA 4"/24 hr or 3"/12 hr areas) Sleet – 1”+ (all areas) Winter Weather Advisory * (WSW) Avg. of fcst range at least: Any accretion Hazards cause A significant 1-2" VA/MD/NC on sidewalks inconvenience, and warrant extra Sleet - .25” to 1” roadways caution Blizzard Warning (WSW) Sustained wind or frequent gusts ≥35 mph AND considerable blowing/drifting of snow/falling snow reducing visibilities frequently < 1/4 mile for > 3 hours Wind Chill Advisory (WSW) Wind Chill Index ≤ 0o F Wind Chill Warning (WSW) Wind Chill Index ≤ -15o F Frost Advisory (NPW) Issued at the end (fall) or beginning (spring) of the growing season when frost is expected, but severity not sufficient to warrant a freeze warning. -
Ensuring a Safe and Secure Homeland for All North Dakotans
■ Ensuring a safe and secure homeland for all North Dakotans ■ Winter Season - Watch The National Weather Service issues Watches when the risk of a hazardous winter weather event has increased, but the occurrence, location, and/or timing is still uncertain. Watches are issued to highlight significant and life threatening situations that may occur or are possible in the next several days. The significant winter weather could be heavy snow, freezing rain, sleet, blowing snow, extreme cold, blizzard, or combinations of these. Watches are issued for Winter Storms, Blizzards, and Extreme Cold, depending on what the threat is. Watches may be dropped (cancelled), or upgraded to advisories or warnings. ■ Winter Season - Warning The National Weather Service issues Warnings when life threatening winter weather is imminent, or occurring. Anytime you hear the National Weather Service has issued a Warning (winter or summer), you should be thinking of life threatening dangerous weather. There are four types of warnings issued for winter weather: Winter Storm Warning; Blizzard Warning; Ice Storm Warning; and Extreme Cold Warning. ■ Winter Storm Warning - 6 inches (or more) of snow is expected in a 12 hour (or less) period of time, OR, when 8 inches (or more) of snow is expected in a 24 hour (or less) period of time. Winter Storm Warnings may also be issued for combinations of snow, wind, blowing snow and dangerously cold conditions. ■ Blizzard Warning – (the most deadly winter events in North Dakota) –considerable falling and/or blowing snow combined with winds of 35 mph or more and reducing visibility to less than ¼ mile (near zero), and lasting at least 3 hours. -
Criteria for Winter Storm Watches/Warnings and Winter Weather Advisories
Criteria for Winter Storm Watches/Warnings and Winter Weather Advisories Winter Storm Watch: Winter Storm Watches are issued when conditions are favorable for hazardous winter weather conditions to develop over part or all of the County Warning Forecast Area. A watch is issued to give an advanced notice of the potential occurrence of a winter storm. Winter Storm Watches are issued for events in the 24 to 36 hour period from the start of the storm. Occasionally, a watch may be issued for time frames beyond 48 hours before the storms starts. Winter Storm Warning: Winter Storm Warnings are issued when hazardous winter weather is occurring, imminent, or highly likely over part or all of the County Warning Forecast Area. Winter Storm Warnings are usually issued in the period of 12 to 24 hours before the storm starts, and occasionally beyond that as much as 36 hours before the storm moves into the region. Criteria for Winter Storm Watches and Warnings Blizzard: 1. Sustained wind or frequent gusts to 35 mph or greater; and 2. Considerable falling and/or blowing snow reducing visibility frequently to less than 1/4 mile for 3 or more hours. Heavy snow: 1. For Randolph, Lawrence, Greene, Clay counties in Arkansas; the Missouri Bootheel; and Lake, Dyer, Obion, Gibson, Weakley, Henry, Carroll, and Benton counties in Tennessee: a. Accumulations of 4 inches or more in 12 hours; or b. Accumulations of 6 inches or more in 24 hours. 2. For Coahoma, Quitman, Panola, Tallahatchie, Lafayette, Yalobusha, Calhoun, Pontotoc, Chickasaw, Lee, Itawamba, and Monroe Counties in Mississippi: a.