1. Weather in your back yard: Observations Ray Martin Lead Forecaster

2. The circle of forecast meteorology Observations Computer simulations Forecast

3. Where do weather observations come from? ALL OVER! Common sources… Airports Cooperative weather stations Professional electronic weather stations People like you!

4. Airport Weather Data - Most commonly cited - Primarily automated Major airports supplemented by FAA contractor - Main systems used: - ASOS (NWS) Automated Surface Observing Systems - AWOS (Not-NWS) Automated Weather Observation Systems ASOS

5. Airport weather data - A few “airport-type” stations are not at airports - Baltimore Science Center - Central Park in NYC - high passes in Colorado AWOS

6. ASOS sensors HO-1088 Thermometer -Uses electrical resistance to measure temperature -Sensor within: -Sheltered from direct sun -Fan circulates air to prevent overheating

7. ASOS sensors DTS-1 Dew point sensor - -Uses electrical capacitance (ability to hold a charge) to measure humidity - -The measured humidity & separate thermometer allow conversion to dew point

8. ASOS sensors Present Weather Sensor -Infrared sensor analyses how flashes of light are affected by precipitation. -Particle size & fall speed determine if precipitation is rain, snow or “other”

9. ASOS sensors Visibility Sensor -Bursts of light are sent from one end of the sensor toward the other -Offset from a straight line -Amount scattered by particles in the air is proportional to visibility.

10. ASOS sensors Freezing Rain Sensor -Frequency sensor resonates at changes with ice accretion. -To report freezing rain: -ASOS combines this sensor’s output with present weather sensor output

11. ASOS sensors CL25 Ceilometer -A laser beam pointed up detects cloud: -Coverage -Distance (height) -Uses “time averaging” to compensate for the limited field-of-vision -Only clouds directly overhead detected

12. ASOS sensors Ice-Free Wind Sensor -No moving parts -Ultrasonic pulses sent between 3 post sensors -Time needed for each pulse to reach another sensor, converted into wind speed & direction

13. ASOS sensors Heated Tipping Bucket Rain Gauge Funnel directs water into one of two small “buckets” inside Funnel directs water into one of two small “buckets” inside When 0.01” of liquid precipitation accumulates When 0.01” of liquid precipitation accumulates 1 bucket “tips” & 1 bucket “tips” & other bucket moves under funnel other bucket moves under funnel Operates like a see-saw Operates like a see-saw Funnel heated to melt snow Funnel heated to melt snow Green screen limits wind impact Green screen limits wind impact

14. ASOS sensors All-Weather Precipitation Accumulation Gauge -Precipitation falls into the gauge and weighed continuously -Increasing weight is converted into precipitation -Orifice is heated to prevent snow & ice from building up

15. What ASOS can’t observe We still need people to report… -Tornadoes -Shallow or patchy fog -Blowing dust -Smoke -Falling ash / volcanic eruptions -Hail, sleet, and snow grains -Mixed precipitation types -Snowfall & Snowpack -Lightning that doesn’t reach the ground -Clouds: -not directly overhead -> 25,000’ -what kind of clouds

16. Cooperative Weather Stations The Cooperative Observer Program (COOP) : network of approximately 11,000 volunteer observers provides much of the climate record of the U.S. The program (est. 1890) under the Organic Act, currently has a twofold mission. To provide data that helps: Define the climate of the U.S. & measure long-term climate changes Support NWS forecasts & warnings in real-time

17. COOP equipment Liquid-in-glass max/min thermometers (Cotton Region Shelter) - -Thermometers have small bulbs within. - -Bulbs can only go easily in one direction (up for max, down for min). - -Thermometers are spun around rapidly to reset them. - -They are sheltered in a white box with slits called a Cotton Region Shelter.

18. COOP equipment Maximum/Minimum Temperature System (NIMBUS) - -Platinum wire measures electrical resistance, which is converted into air temperatures. - -Air flows freely over the sensor due to slits in the shelter.

19. COOP equipment Standard 8-inch Rain Gauge - -Rain falls through the funnel into the inner cylinder. - -Measured with a measuring dip stick. - -Overflow is measured after the inner cylinder is emptied. - -In winter, only the outer can is left out. Can is brought inside, precip melted, and is then measured in the inner cylinder.

20. COOP equipment Snow board and snow stick - -New snowfall is measured on a snow board. - -Depth on board measured with snow stick, then it is cleared and replaced on top of the snow. - -Snow depth measured by averaging several measurements on natural ground, taking care not to include grass.

21. COOP equipment Evaporation Pan - -A large metal pan filled with water. - -The loss of water is measured daily with water added back in as it evaporates. - -Wind across the surface is measured with an anemometer to determine the wind’s influence on evaporation.

22. COOP equipment Soil temperature Soil temperature is measured with an analog thermometer probe set into the ground. Some stations have several at multiple depths.

23. COOP equipment Recording Rain Gauge (Fischer-Porter) - -Weighing gauges that accumulate precipitation within - -Uses anti-freeze to keep the precipitation in liquid form - -Formerly using punch tapes, current gauges have an electronic recorder

24. COOP equipment River Gauge A manual river gauge is ruler placed along a solid object in the river or stream. Observers simply view the gauge and enter the current reading into their report.

25. Professional Electronic Weather Stations Many other organizations deploy electronic weather stations and share data with the NWS, including: Wildland firefighters Natural resource managers Farmers Departments of transportation ClimatologistsMariners

26. You can help! Citizen Weather Observing Program (CWOP) If you have a home weather station, (connected to the internet) your data can go right to our forecasters! More information can be found at the CWOP home page: www.wxqa.com

27. You can help! CoCoRaHS If you’d like to report daily rain, snow & hail to the volunteer site: Community Collaborative Rain, Hail & Snow (CoCoRaHS) Community Collaborative Rain, Hail & Snow (CoCoRaHS) Observers purchase low-cost equipment to measure precipitation and report their data via a simple web site interface. More information: www.cocorahs.org www.cocorahs.org

28. When observing… Siting is key! Your site: Your site: Level area Level area Over natural vegetation / grass Over natural vegetation / grass As far from pavement, structures & trees as possible As far from pavement, structures & trees as possible How high? How high? Snow: ground level Snow: ground level Rain Gauge: 2-4’ above ground Rain Gauge: 2-4’ above ground Thermometers: 5-6’ above ground Thermometers: 5-6’ above ground Wind: 33’ (10 meters) above ground Wind: 33’ (10 meters) above ground Perfection is rarely possible in the city & suburbia. Do the best you can in placing your gear. Perfection is rarely possible in the city & suburbia. Do the best you can in placing your gear.

29. Questions ? / Remember This… ASOS stations are NWS owned & maintained ASOS stations are NWS owned & maintained High precision & quality High precision & quality Many at airports Many at airports Not a very dense national network Not a very dense national network Other observations (like yours) help supplement! Other observations (like yours) help supplement! Good placement Good placement Away from pavement / trees / structures Away from pavement / trees / structures Do your best Do your best Join wxqa.com (CWOP) if on-line Join wxqa.com (CWOP) if on-line Thanks for attending! Thanks for attending!