Skywarn Training 2022

Submitted by rbosaz on Thu, 01/20/2022 - 13:08

Weather Spotter's Field Guide

 

The following are my notes taken during an MMRA meeting where Robert Macedo (KD1CY) presented the first Skywarn training of 2022 on January 19 at 7pm. These notes also include material from NWS Boston refresher video.

Training Objectives (below bullets taken from Skywarn website)

  • Understand the how the NWS Integrated Warning System works and how the spotter fits into this system
  • Identify the ingredients needed for organized thunderstorms
  • Recognize the visual and environmental clues suggestive of severe weather
  • Distinguish between legitimate clues and non-significant features associated with severe weather
  • Learn how to stay safe when storm spotting
  • Learn proper storm reporting procedures

After passing the quiz you'll get a spotter number. The first two digits are the year you received your spotter number. You should take the test every five years.

National Weather Service (NWS)

  • Federal government agency part of NOAA sponsored by U.S. Dept. of Commerce
  • Purpose is to provide timely weather and river forecasts in order to protect life and property.
  • They have 122 local forecast offices and 11 national prediction centers.

Skywarn is composed of civilian volunteers trained by NWS, who report the following weather conditions: Wind gusts, hail size, rainfall and cloud formations.

Preparedness

Ingredients of a thunderstorm

  • Moisture: Forms the clouds. Primary sources Atlantic and Pacific oceans, Gulf of Mexico and Great Lakes (limited).
  • Lift: Force that causes air to rise leading to thunderstorms. Typically a cold front, but warm fronts as well. Some sources include:
    • Weather Fronts: Boundary between two air masses. Classified by which type (cold or warm) is replacing the other.
      • Warm: have a more gentle slope than cold fronts leading to a gradual air rise. Generally favors widespread, continuous precipitation often occurring along and ahead of the front.
      • Cold: have a steep slope forcing warm air rise rapidly which can lead to band of shoers and thunderstorms along leading edge of front. Wind direction shifts and pressure falls and then rises as front passes.
    • Dryline: Boundary (typically north-south) separating moist and dry air (not really a factor in New England). Mainly in Plains states. Moist air rises above dry air.
    • Sea Breeze: Breeze coming from ocean (day) or breeze coming from land (night). Definitely a factor in New England.
    • Orographic: Air is force to rise and cool due to terrain (i.e., Berkshires, Worcester Hills). Side of terrain where air is rising is the precipitation side.
  • Instability: Cooling aloft and warm moist air at the surface. Warm air rises mixing with cool air causing atmospheric instability. The more unstable, the great er chance for thunderstorm. Note: When cold air is at the surface and warm air is aloft, cold air will not mix with warm and so will be stable.

Thunderstorm Stages

  1. Cumulus
  2. Mature: Full developed thunderclouds anvil shaped with overshooting top beyond the tropopause.
    • Life: As vapor condenses it will release heat (increasing energy) and fuel the storm eventually the rain cools the entire process down and the energy is gone.
  3. Dissipating 

Thunderstorm Types

  • Single Cell: Occasional Severe Threat. Lasts about half an hour. Has gust front. 
    • Small Hail
    • Gusty Winds
    • Minor Flooding
  • Multicell Cluster: Greater Severe Threat. Lasts one to several hours. Has gust front (or outflow boundary) and a shelf cloud on the leading edge of the storm where underneath you have strong to damaging straight line winds.
    • Hail
    • Strong Winds
    • Flooding
  • Also know as Squall Lines are a line of severe thunderstorms forming along  and/or ahead of a front. Linear and can be greater  than 100 miles. Often preceded by a shelf cloud which usually extends from horizon to horizon. Sometimes they can be low topped (only 20,000 feet high).
  • Multicell Line: Even Greater Severe Threat. Can last hours to days. Most common type of severe weather in Southern New England. Has gust front (or outflow boundary) and a shelf cloud.
    • Hail
    • Damaging Winds
    • Flooding
  • Squall Line - Shelf Cloud
    • Leading edge of gust front. Marks the leading edge of updraft/downdraft region of a squall line. Slope down and away from precipitation.
    • Multi-shaped cloud attached to storm base usually produced by rain cooled air.
    • Straight lined winds are the main threat.
    • Can look scary and resemble snow plows and big waves. Routinely have low hanging clouds on the underside which can be mistaken for funnel clouds or tornadoes.
    • The upper winds will not always be constant along a squall. Where these winds are stronger the line will surge forward. (Bow Echo).
  • Supercell: Significant Sever Threat. Least common in the Northeast. Most likely to produce tornadoes due to ...
    • Anvil is in the tropopause (stable) overshooting top is unstable feature.
    • Hook Echo can lead to tornado, but may not. All Tornados have a hook echo, but not all hook echos have a tornado.
    • Supercell features
      • Wall Cloud: Abrupt lowering from arain-free base. Exhibits rapid upward motion and sometimes cyclonic rotation. Slope toward the rain. These should be reported.
      • Rain Free Base: Dark horizontal cloud base with no visible precipitation. Typically marks the location of the thunderstorm updraft. Wall cloud attached to it.
      • Funnel Cloud: Rotating column of air not in contact with the ground. As the funnel descends the water vapor within it condenses into droplets making the funnels visible. Can be confused with a SCUD, which is essentially a cloud fragment.
      • Tornado: Violently rotating column of air that is contact with the ground.
        • EF Scale: EF0 65-85mph (minor damage) to EF5 >200mph (incredible damage)
    • Wind shear: Directional or speed shear where winds change with height in the atmosphere. This wind profile allows for horizontally oriented rolls to develop.
      • Increases storm organization and longevity.
      • Increases threat for severe storms.
      • Better chance for rotation and tornado development.
    • Large Hail
    • Damaging Wind
    • Tornadoes

Wall Cloud vs Shelf Cloud: Using radar can help you define which one you are looking at.

  • Wall Cloud: Outflow feature, slopes away from rain, associated with squall line and at the leading edge of storm.
  • Shelf Cloud: Inflow feature, Slopes toward rain, associated with supercell and at the rear of the storm where wind shear is.

Rain Wrapped Tornado: Common in New England. Tornado aren't easily visible.

Waterspouts

  • Fair weather: Traditional Cold Air. Form over water. Grow form water to cloud, vice versa. <60mph typically 30-40mph.
  • Tornadic: Form just like tornadoes, just over water. 65mph or greater.

Microburst (definition taken from weather.gov): A convective downdraft with an affected outflow area of less than 2½ miles wide and peak winds lasting less than 5 minutes. Microbursts may induce dangerous horizontal/vertical wind shears, which can adversely affect aircraft performance and cause property damage.

  • Evaporation can cool a parcel of air causing it to become heavier, then drops toward ground and spreads out. Creates vortex ring.

Macroburst (definition taken from weather.gov): A convective downdraft with an affected outflow area of at least 2½ miles wide and peak winds lasting between 5 and 20 minutes. Intense macrobursts may cause tornado-force damage of up to F3 intensity.

Look-alike clouds: spotters should use patience to avoid false reports to NWS.

  • Cloud fragments at based of parent cloud but not truly attached. SCUD clouds.
  • Rain/Hail Shaft: Rain is darker and hail is lighter in color. Only downward motion.
  • Low clouds and fog can look like tornado.

Be aware of your Surroundings!!!

  • Don't put yourself in harms way
  • Where is the primary threat compared to where I am?
  • What direction is the storm moving relative to me?

This can be determined by cloud formation and radar.

  • Shelf Cloud
  • Bow Echo behind the bow is an inflow notch.
  • SCUD clouds and cloud fragments typically are ahead of the cloud shelf.
  • Notice the movement via radar relative to your position. 

Tornado Safety - Indoors: shelter or place to take cover should include first aid kit, shoes and whistle.

  • DUCK
    • Down to the lowest level
    • Under something sturdy
    • Cover your head
    • Keep in shelter until storm passes

Tornado Safety - Cars

  • Get out of your car and into a ditch or ravine
  • As a last resort (if ditch isn't available), buckle in and lower head below window level.
  • Find reinforced shelter if possible
  • DON'T go under an overpass!!!

Lightning Safety

  • Lightning #2 weather killer
  • When thunder roars go indoors
  • Remain in cover until 30 minutes after last thunder clap

High Wind and Hail Safety

  • Most manufactured homes not able to withstand hurricane winds
  • know where you are in relation to storm
  • stay inside and away from windows

Flooding Safety: Turn Around Don't Drown

  • six inches of fast moving water can knock an adult of their feet
  • Two can move most cars and trucks

Hurricane Safety

  • Any hurricane with a name in the bahamas can quickly affect New England
  • Do focus on the eye of the storm
  • Where with respect of the track of the storm
  • Run from the water and hide from the wind
  • Prep for at least 3+ days

Winter Safety

  • Winterize disaster kit for home and car
  • Know what to do if you're caught driving or outside.

Spotter Reporting: prefer reports in real time but will take them anytime

NWS Severe Classification

  • Winds >= 58mph
  • Hail >= 1 inch
  • Tornado
  • Widespread Damage

Reporting (TELL): be specific

  • Time of event
  • Event type
  • Location of you
  • Location of the weather event

Reporting (Three W's)

  • What type of event
  • When did the event occur
  • Where are you locate? Where did it happen?

Reporting Tornado:

  • Tornado, Funnel or wall cloud

Reporting High Winds:

  • Healthy branches 4" or larger down
  • Measured gusts 40mph or greater
  • Building Damage
  • Power lines down
  • Healthy trees down

Reporting Hail

  • Hail pea size or larger
  • Prefer inches but can use common objects (except marbles)

Reporting Rainfall

  • Rainfall - using rain gauge 
    • 2" or more, anytime
    • 1" or more if occurs in an hour or less
  • Observed river or small stream flooding
  • Streams out of their banks

Reporting Flooding

  • Cars floating
  • River over banks
  • Road washed out - Call police if not cordoned off

Reporting Street Flooding

  • 6" or more across the whole road
  • Road closed due to flooding

 

Reporting Winter Storms

  • Ice Jams
    • any flooding upstream due jam
    • If/when jam breaks
    • Describe:
      • How much of the river is blocked
      • Near any bridges or bends
  • Snow
    • Report when at least 2" has fallen
    • Report if you get an inch or more an hour
    • Report a final total at end of storm
    • Snow Squalls - often causes chain reaction accidents resulting injuries and death
      • Intense short-lived burst of heavy snowfall accompanied by gusty winds, reduced visibility and quick snow fall accumulation 
      • Similar to blizzard but localized and shot lived
      • Visibility <1/4 mile
    • Thunder Snow
    • Quick change from rain to snow or back
    • Measurements
      • Clear flat open
      • away from trees and buildings
      • several measurements
      • Avoid drifts and bare spots
      • Report the average
      • Tenths of an inch
      • Not necessary to clear area, if you do wait 6 hours between cleanings
  • Coastal Flooding
    • Structural Damage
    • Beach Erosion
  • Ice
    • Elevated Horizontal ice (thickness): this is the best
    • Elevated (mean) radial ice
    • Always send a picture how you measured the thickness
    • If twigs and branches are downed due to ice

Reporting Hurricanes

  • Rainfall
  • Wind
  • Structural Damage
  • Stream Flooding, Coastal Flooding and Extent

 

Ways to report:

  • 1-800 number on spotter card, especially for non-hams
  • Do not call 911 unless it's a major catatrophe
  • Internet:
    • weather.gov/box/spotterreportform --> now https://inws.ncep.noaa.gov/report/
    • Social Media
  • Amateur Radio

Join https://cocorahs.org/

Report what you see, NOT what you think you see!!!!