Winter Weather Spotter Course National Weather Service Northern Indiana

Course Outline Introduction to NWS Winter Weather Advisories/Watches/Warnings Introduction to NWS Winter Weather Advisories/Watches/Warnings Snow Spotters – our network today Snow Spotters – our network today Reporting real time information – what do we need to know about? Reporting real time information – what do we need to know about? What to report after the storm is over What to report after the storm is over How to measure snow How to measure snow How to report your information How to report your information

Definitions Freezing Rain – Rain falls as liquid and then freezes on contact Freezing Rain – Rain falls as liquid and then freezes on contact Sleet – Rain drops freeze into ice pellets prior to reaching ground. Sleet – Rain drops freeze into ice pellets prior to reaching ground. Snow – An aggregation of many ice crystals Snow – An aggregation of many ice crystals Graupel – Snowflakes which have been heavily rimed. Also called snow pellets, soft hail, and hominy snow. Looks like uncooked white grits. Graupel – Snowflakes which have been heavily rimed. Also called snow pellets, soft hail, and hominy snow. Looks like uncooked white grits.

Definitions (cont.) Snowfall – Amount of new snow which has fallen. Measured to the nearest tenth of an inch. Snowfall – Amount of new snow which has fallen. Measured to the nearest tenth of an inch. Snow Depth – Total amount of snow on the ground (old and new). Measured to the nearest inch. Snow Depth – Total amount of snow on the ground (old and new). Measured to the nearest inch.

Precipitation Type Diagram

Dec 5, 2002 Raleigh, NC

Jan 30, 2002 North Webster, IN

NWS Winter Weather Products

Watches/Warnings/Advisories Hazardous Weather Outlook Hazardous Weather Outlook Winter Storm Watch Winter Storm Watch Winter Storm Warning Winter Storm Warning Lake Effect Snow Warning Lake Effect Snow Warning Blizzard Warning Blizzard Warning Winter Weather Advisory Winter Weather Advisory

Hazardous Weather Outlook Issued each day between 5am and 6am Issued each day between 5am and 6am Outlines potential weather hazards expected over the next 7 days Outlines potential weather hazards expected over the next 7 days The potential for major storms beyond 2 days will be discussed in the HWO The potential for major storms beyond 2 days will be discussed in the HWO

Winter Storm Watch Typically issued 24 to 36 hours in advance of the storm Typically issued 24 to 36 hours in advance of the storm Issued when potential exists for: Issued when potential exists for: 6 inches or more of snow in 12 hours 6 inches or more of snow in 12 hours 8 inches or more of snow in 24 hours 8 inches or more of snow in 24 hours Significant mixed precipitation Significant mixed precipitation

Winter Storm Warning Typically issued 6 to 12 hours in advance of the storm Typically issued 6 to 12 hours in advance of the storm Issued when the following are likely: Issued when the following are likely: 6 inches or more of snow in 12 hours 6 inches or more of snow in 12 hours 8 inches or more of snow in 24 hours 8 inches or more of snow in 24 hours 0.25 inches or more of freezing rain 0.25 inches or more of freezing rain

Lake Effect Snow Warning Same criteria as a Winter Storm Warning Same criteria as a Winter Storm Warning 6 inches in 12 hours 6 inches in 12 hours 8 inches in 24 hours 8 inches in 24 hours Lake effect snow warning implies the localized nature of the heavy snow – in most cases not everyone in a county will receive warning criteria snowfall Lake effect snow warning implies the localized nature of the heavy snow – in most cases not everyone in a county will receive warning criteria snowfall

Blizzard Warning Wind speeds of 35 mph or greater AND Wind speeds of 35 mph or greater AND Visibility of ¼ mile or less in blowing snow Visibility of ¼ mile or less in blowing snow Conditions must persist for at least 3 hours Conditions must persist for at least 3 hours Blizzards may or may not be accompanied by falling snow (Ground Blizzard) Blizzards may or may not be accompanied by falling snow (Ground Blizzard)

Winter Weather Advisory Typically issued 6 to 12 hours in advance of storm Typically issued 6 to 12 hours in advance of storm Issued when the following are likely: Issued when the following are likely: 4 to 5 inches of snow in 12 hours 4 to 5 inches of snow in 12 hours Light accumulation of freezing rain Light accumulation of freezing rain (less than 0.25 inches) (less than 0.25 inches)

Where We are Today Existing Snow Spotter Network At NWS Northern Indiana

Existing Coop Spotters

2002 Snow Spotters

Need for More Spotters Existing COOP network is evenly spread over our County Warning Area (CWA) Existing COOP network is evenly spread over our County Warning Area (CWA) We need to fill in the gaps between COOP and official NWS observing sites – as you well know, snowfall can vary widely within the same county, especially in areas which receive lake effect snow We need to fill in the gaps between COOP and official NWS observing sites – as you well know, snowfall can vary widely within the same county, especially in areas which receive lake effect snow This is where YOU come in! This is where YOU come in!

Reporting Real time Information What type of Information can be useful to us?

Real Time Information Heavy Snow – for example, snow falling at the rate of 1 inch per hour Heavy Snow – for example, snow falling at the rate of 1 inch per hour Precipitation type change – snow to rain, rain to snow, freezing rain, etc. Precipitation type change – snow to rain, rain to snow, freezing rain, etc. Is the precipitation causing problems on roads? Is the precipitation causing problems on roads? Significant Blowing and Drifting Snow – Is drifting making travel difficult (or impossible)? Significant Blowing and Drifting Snow – Is drifting making travel difficult (or impossible)?

Freezing Rain Is there a glaze accumulation on roads and sidewalks or only on elevated surfaces, such as trees and power lines? Is there a glaze accumulation on roads and sidewalks or only on elevated surfaces, such as trees and power lines? How much ice has accumulated on surfaces. This can be difficult to measure directly, but can be easily estimated. How much ice has accumulated on surfaces. This can be difficult to measure directly, but can be easily estimated. Measuring trick – Crack a piece of ice off a railing and measure the thickness. Measuring trick – Crack a piece of ice off a railing and measure the thickness.

What to Report After the Storm

When the Snow Lets Up Get a final measurement. Get a final measurement. Report your total snowfall for the event, and how long it was snowing. Report your total snowfall for the event, and how long it was snowing. For example: 7 inches in 10 hours. For example: 7 inches in 10 hours. In the case of freezing rain, also report the total amount of glaze on surfaces. In the case of freezing rain, also report the total amount of glaze on surfaces.

What Do We Use Your Reports For? Update forecasts, warnings, and advisories to better match conditions being reported Update forecasts, warnings, and advisories to better match conditions being reported Our updated forecasts and warnings in turn allow local officials to make better decisions Our updated forecasts and warnings in turn allow local officials to make better decisions We use storm total snowfall and ice accumulation data to verify forecasts and warnings We use storm total snowfall and ice accumulation data to verify forecasts and warnings

How to Measure Snow Yes, that says 54 inches!

Before the Snow Flies Place a snowboard outside. Choose a location away from trees, shadows, and known drifting areas. Place a snowboard outside. Choose a location away from trees, shadows, and known drifting areas. A snowboard can be any light colored board, about 2 feet by 2 feet. A piece of plywood painted white works great! A snowboard can be any light colored board, about 2 feet by 2 feet. A piece of plywood painted white works great! Mark the snowboard location with a stake so you can find it easily in the snow. Mark the snowboard location with a stake so you can find it easily in the snow.

Typical Snow Board

Measuring the Snow If it is windy, it can be more accurate to take several measurements on the board and take an average. If it is windy, it can be more accurate to take several measurements on the board and take an average. After you measure, sweep the snow board clean. After you measure, sweep the snow board clean. You can clean the snow board off up to 4 times in 24 hours, but no more than once in 6 hours. You can clean the snow board off up to 4 times in 24 hours, but no more than once in 6 hours.

Take a Measurement

Sweep the Snow Board

Special Cases If snow falls and accumulates, then melts, the total snowfall will be the maximum measured before the snow melts If snow falls and accumulates, then melts, the total snowfall will be the maximum measured before the snow melts If snow falls and melts on contact, never reaching 0.1 inch depth, a trace of snow is recorded. If snow falls and melts on contact, never reaching 0.1 inch depth, a trace of snow is recorded. Sleet counts towards the snowfall total, but freezing rain does not. Sleet counts towards the snowfall total, but freezing rain does not.

Let the Snow Fly!