Re-certification Course Fall 2017
Oklahoma’s First-response Information Resource System using Telecommunications
Photo by Eric Nguyen OK-First Contact Information
Who Number Hours Best for:
Mesonet Operator (405) 325-3231 8:00a-7:00p Technical support and data operator@mesonet.org weekdays; issues 9:00a-12:00p weekends
James Hocker (405) 325-3230 8:00a-5:00p Questions, suggestions, or [email protected] weekdays comments about the OK-First program; technical support
Robert MacDonald (405) 325-2665 Portions of Questions about scheduling and (student) 8:00a-5:00p upcoming OK-First classes; [email protected] weekdays technical support; general information
Andrea Melvin (405) 325-2652 8:30a-5:00p Technical support; general [email protected] weekdays information
Brad Stanley (405) 325-5270 9:00a-5:00p Technical support [email protected] weekdays
OCS/Mesonet Main (405) 325-2541 8:00a-5:00p Tracking down answers and OK- Office weekdays First people!
Note: Voice mail for OCS Main Office and OCS staff is checked Monday-Friday only
After-Hours Emergencies (405) 364-6364 Data outages and issues outside (Pager) business hours
OK-First Social Media
Facebook: https://www.facebook.com/groups/okfirst/ (closed group; have to request access)
Twitter: https://twitter.com/okfirstmanager
Mesonet Social Media
2 National Weather Service Norman Critical Information Sheet
Mailing Address: National Weather Service 120 David L. Boren Blvd, Suite 2400 Norman, OK 73072
Website: weather.gov/norman
Twitter: twitter.com/NWSNorman Facebook: facebook.com/NWSNorman YouTube: youtube.com/NWSNorman
Spotter Report E-Mail: [email protected]
Main Phone: 405-325-3816 (can be given to public) Main Fax: 405-325-0901
UNLISTED – Do not distribute! 405-325-3659 (restricted to EM/public safety) or 800-275-1136
NWS Norman Management Team:
Meteorologist in Charge David Andra 405-325-3318 [email protected]
Warning Coordination Meteorologist Rick Smith 405-325-3395 [email protected]
Science and Operations Officer Todd Lindley 405-325-3527 [email protected]
3
National Weather Service Tulsa Critical Information Sheet
Mailing Address: National Weather Service 10159 East 11th Street, Suite 300 Tulsa, OK 74128
Administrative Phone: 918-832-4115 Administrative FAX: 918-832-4101 Unlisted Ops Phone: 918-832-4116 Operations FAX: 918-832-4138 Public Forecast Line: 918-838-7838 (6am to 6pm)
UNLISTED EMERGENCY: 1-800-697-2636 (Restricted Access) SEVERE REPORTS ONLY: 1-800-722-2778 (Can be given to public)
Web Site: weather.gov/tulsa Spotter Report E-mail: [email protected]
Twitter: twitter.com/NWSTulsa Facebook: facebook.com/NWSTulsa Youtube: youtube.com/NWSTulsa
NWS Tulsa Management Team:
Meteorologist in Charge Steve Piltz 918-832-4132 (voice mail) [email protected]
Warning Coordination Meteorologist Ed Calianese 918-832-4133 (voice mail) [email protected]
Science and Operations Officer vacant
For contact information for additional National Weather Service offices visit: http://www.stormready.noaa.gov/contact.htm
4 Lightning!
Copyright Jason Keller
What We’ll Cover
1. Lightning Basics – How it forms – Types 2. Lightning Detection – Ground based and satellites – Lightning climatology 3. Lightning Safety – Fatality stats, ways people are struck, medical impacts – Safety tips and common myths 4. Lightning Data in OK-First
5 Learning Objectives
1. Form a basic understanding of how lightning forms 2. Be able to name the different types of lightning 3. Become aware of the most common ways in which people are struck by lightning 4. Become very familiar with lightning safety tips and common myths 5. Understand how lightning is displayed in OK-First tools
Lightning Basics
6 What is Lightning?
• Simple definition: – A giant spark of electricity in the atmosphere between clouds, the air, or the ground • Technical definition: – The series of electrical processes taking place by which charge is transferred along a discharge channel between electric charge centers of opposite sign
Bottom line: Lightning is the result of a build up of opposing electrical charges. Lightning exists to re- establish charge equilibrium (albeit briefly)!
You’ve experienced small scale “lightning” before (Stop dragging those feet on the carpet!)
Before zap After zap
Image Source: http://mrcc.isws.illinois.edu/living_wx/lightning/StaticElectricity.png
7 So How Do Storms Get Opposing Charges?
• Precipitation theory: – Updraft causes a collision between graupel (also called “soft hail” or “snow pellets”) and smaller ice/snow crystals which results in charge separation – Heavier particles acquire – charge – Lighter particles acquire + charge Image Source: https://upload.wikimedia.org/wikipedia/common • Convection theory: s/6/61/Graupel_animation_3a.gif – Updrafts transport positive charge found near the ground – Downdrafts transport negative charges downward
Conceptual Model of Electrical Charge in T-Storms
Image Source: http://www.nssl.noaa.gov/education/svrwx101/lightning/img/tstm- lightning-structure-800.png
8 The Result of Charge Separation: An Electric Field
• The separation of positive and negative charges creates an electric field – Continued charge separation strengthens the electric field • Air is an excellent electrical insulator – Which means that electricity does not flow freely within it – So tremendous amounts of charge have to be built up before lightning can occur • But once a charge threshold is reached… – The electric field overpowers the air’s insulating properties and we get lightning
Lightning Types
• Cloud-to-ground (CG) – Approximately 20% of lightning • In-cloud (IC) • Cloud-to-cloud (CC) • Cloud-to-air (CA)
9 Cloud-to-ground (CG)
Image Source: http://ngm.nationalgeographic.com/wallpaper/img/2012/08/12- ground-fire-ignited-by-lightning_1600.jpg
In-cloud (IC)
Image Source: http://travel.nationalgeographic.com/u/TvyamNb- BivtNwcoxtkc5xGBuGkIMh_nj4UJHQKuoXI5LoZHrdV9Ze5CIgWzS4a_e-bwZBEtNVNmMA/
10 Cloud-to-cloud (CC)
Image Source: http://ngm.nationalgeographic.com/wallpaper/img/2012/08/05- horizontal-cloud-to-cloud-lightning_1600.jpg
Cloud-to-air (CA)
Image Source: http://www.nssl.noaa.gov/education/svrwx101/lightning/types/img/IMG_0200.jpg
11 Cloud-to-ground Lightning: How Does it Happen?
• Step 1: – The collection of charge at the bottom of the cloud causes a pool of positive charge to collect along the ground – This positive charge travels with the storm as it moves
Image Source: http://www.srh.noaa.gov/jetstream/lightning/lightning.html
Cloud-to-ground Lightning: How Does it Happen?
• Step 2: – As the electric field strengthens a channel of negative charge descends from the bottom of the storm toward the ground – this is called a “stepped leader” – Meanwhile positive charge begins to rise from the ground, particularly from taller objects
Image Source: http://www.srh.noaa.gov/jetstream/lightning/lightning.html
12 Cloud-to-ground Lightning: How Does it Happen?
• Step 3: – Positive charge from the ground begins extending upward towards the approaching stepped leader – these are called “streamers” – When the stepped leader and streamer connect (usually 30-50 m above ground) lightning occurs – After the initial stroke if enough charge remains, additional strokes will occur on the same channel, which can cause flickering
Image Source: http://www.srh.noaa.gov/jetstream/lightning/lightning.html
Stepped Leaders and Streamers: A Closer Look
Streamers Stepped leader
Image Source: http://www.srh.noaa.gov/jetstream/lightning/lightning_max.html
13 A Connection is Made: The Return Stroke
Image Source: http://www.lightningsafety.noaa.gov/science/science_return_stroke.shtml
Lightning Development in Super Slow Motion
Open “1.1_Slow_Motion_Lightning_Animation.mov”
14 Negative vs. Positive Lightning Strikes
• Lightning can be positively or negatively charged – If lightning transfers – charge from one location to another it is negative lightning – If lightning transfers + charge from one location to another it is positive lightning • Most C-G strikes are negative lightning – Peak current averages 30,000 amps (can be as high as 120,000 amps) • Positive lightning is less common but very powerful – Approximately 5-10% of lightning strikes – Peak current of 300,000 amps
Remember This?
One region where positive lightning initiates
One region where negative lightning initiates
Image Source: http://www.nssl.noaa.gov/education/svrwx101/lightning/img/tstm- lightning-structure-800.png
15 Image Source: http://images.nationalgeographic.com/wpf/media- live/photos/000/208/custom/20849_1600x1200-wallpaper-cb1275419114.jpg
Lightning Detection
16 How is Lightning Detected
• Ground-based detection systems – Earth Networks Total Lightning Network and Vaisala National Lightning Detection Network (U.S. networks) – Use network of sensors that detect high-frequency radio signals (in the VHF band) emitted by lightning – Triangulation used to determine location of lightning • Satellite-based detection systems – New U.S. GOES-R satellite has a Geostationary Lightning Mapper (GLM) – The GLM detects lightning using a single-channel, near- infrared optical detector – Detects total lightning – it cannot distinguish CG, IC, and CC
How is Lightning Detected
Image Source: http://www.geek.com/wp-content/uploads/2014/06/lightning- 625x350.jpg
17 Lightning Climatology
Image Source: https://upload.wikimedia.org/wikipedia/commons/c/c5/Global_lightning_strikes.png
Lightning Climatology
Image Source: Email correspondence with Melanie Scott ([email protected] )
18 Lightning Safety
Lightning in the United States: By the Numbers (Based on 2006-2015 averages)
• Lightning strikes ~25 million times each year • Lightning kills an average of 31 people each year • Lightning injures 279 people each year – So roughly 90% of those that experience a strike in some form survive • Lightning kills more males (79%) than females (21%) • Odds of being struck in any given year: 1 in 1,042,000 • Odds of being struck in a lifetime: 1 in 13,000
19 Image Source: http://www.lightningsafety.noaa.gov /slideshows/Lightning%20Safety%20 Statistic%20Graphics16.pptx
Image Source: http://www.lightningsafety .noaa.gov/slideshows/Light ning%20Safety%20Statistic %20Graphics16.pptx
20 Image Source: http://www.lightningsafety.noaa.g ov/slideshows/Lightning%20Safety %20Statistic%20Graphics16.pptx
Lightning Fatalities (By State)
Image Source: http://www.lightningsafety.noaa.gov/light- images/15deaths_bystatemap.png
21 Lightning Fatalities (By Year)
Image Source: https://www.washingtonpost.com/news/capital-weather- gang/wp/2015/07/09/lightning-deaths-year-to-date-are-the-highest-theyve-been- since-2007/?utm_term=.32c36eda723b
Lightning Fatalities (By Year and Gender)
Image Source: http://www.cdc.gov/mmwr/preview/mmwrhtml/figures/m6228qsf.gif
22 Understanding the Threat
Image Source: http://www.lightningsafety.noaa.gov/animations/Animation%2031a.gif
The Five Ways Lightning Strikes People
• 1. Direct strike: – 3 to 5% – Very uncommon!
Image Source: http://www.lightningsafety.noaa.gov/struck.shtml Image Source: http://i.imgur.com/izG6E7L.jpg
23 The Five Ways Lightning Strikes People
• 2. Side flash: – 30 to 35%
Image Source: http://www.lightningsafety.noaa.gov/struck.shtml Image Source: http://images.fineartamerica.com/images/artworkimages/mediuml arge/1/a-lightning-scarred-tree-in-a-forest-taylor-s-kennedy.jpg
The Five Ways Lightning Strikes People
• 3. Ground current: – 50 to 55% – Most common!
Image Source: Image Source: http://www.lightningsafety.noaa.gov/struck.shtml http://nols.blogs.com/.a/6a00d83451b4f069e20177445e975c970d-pi
24 The Five Ways Lightning Strikes People
• 4. Conduction/contact voltage: – 3 to 5%
Image Source: http://www.lightningsafety.noaa.gov/struck.shtml Image Source: http://www.thelivingmoon.com/45jack_files/04images/Biolog y/Dead_Cows_Fence1.jpg
The Five Ways Lightning Strikes People
• 5. Upward streamer: – 10 to 15%
Image Source: http://www.lightningsafety.noaa.gov/struck.shtml Image Source: https://pbs.twimg.com/media/CJpBO_XVEAAjX2X.png
25 Medical Impacts of Lightning
• Death due to cardiopulmonary arrest • Injuries to nervous system • Short-term issues: – Muscle soreness – Headache, nausea, dizziness, balance problems • Longer-term issues (not all): – Irritability and personality change – Chronic pain from nerve injury – Headaches and ear/balance problems – Memory issues – Sleep issues
Lightning Victims
Image Source: http://ichef.bbci.co.uk/news/1024/media/images/69194000/jpg/_69194715_624_lightning-burn.jpg
26 Lightning Safety Tips – Outdoors
• There is NO safe place outside when thunderstorms are in the area – Make a lightning safety plan – Have a way to get up-to-date weather information – Have a safe place to get to: an enclosed building or a vehicle • If you absolutely cannot get to safety… – Avoid open fields and hill tops – Avoid isolated tall objects (towers, poles, trees, etc.) – If in a group – spread out to avoid ground current – Stay away from water, wet items, and metal
Image Source: http://www.lightningsafety.noaa.gov/ signs/thunder_roars.jpg
27 Lightning Safety Tips – Indoors
• Safe shelters are: – Buildings with electricity and/or plumbing – Metal-topped vehicle with windows closed • Unsafe structures: – Picnic shelters, dugouts, small buildings without plumbing/electricity • When in a safe shelter… – Stay off corded phones – Don’t touch electrical equipment (computer, tv, cords) – Stay dry – do not wash hands, take shower, etc. – Stay away from windows and doors
Common Lightning Myths
• Myth: Lightning never strikes the same place twice – Fact: Lightning strikes many tall objects multiple times • Myth: Rubber tires on a car protect you from lightning – Fact: Your car’s metal roof is what keeps you safe • Myth: A lightning victim can electrocute you – Fact: It is safe to touch a lightning victim • Myth: If caught out in a storm, crouching reduces risk – Fact: Crouching doesn’t make you any safer. You are not safe anywhere outside! • Myth: If caught in a storm lay flat on the ground – Fact: Laying flat increases potential of deadly ground current
28 Lightning Data in OK-First
Lightning Data in RadarFirst/Wx Briefing
• About OK-First’s lightning data – Provider: Weather Decision Technologies – 1-minute data • Lightning data is displayed as – or + icons – Minus icons denote negative strikes – Plus icons denote positive strikes • Cloud-to-ground (CG) strikes shown differently – CGs will appear as – or + icons with a circle around them – All other strike types (in-cloud, cloud-to-cloud, cloud-to-air) will appear only as – or + icons • Higher amperage strikes are larger icons
29 Lightning Data in RadarFirst
• Two ways to display lightning data: – In the preferences: Go to “Edit” à “Options…” and check lightning – Keyboard shortcut: Hold “Shift” and press “L”
Lightning Data in RadarFirst
Because lightning can clutter the map it will only appear in the left pane when in 2-pane mode
30 Lightning Data in RadarFirst
To quickly turn lightning off and on use “Shift L”
Lightning Data in Weather Briefing
Lightning data available in the Radar Console and Combo products
31 Lightning Summary • Lightning is the result of… – Charge separation in thunderstorms caused by the collision of precipitation particles above the freezing level • Lightning types include… – Cloud-to-ground, in-cloud, cloud-to-cloud, and cloud-to-air • Lightning can be… – Positively or negatively charged • Detection methods include… – 1) Ground-based systems that measure high frequency radio signals and 2) satellite-based methods that measure optical changes
Lightning Summary • Lightning fatalities in the United States… – Average 31 people per year – Comprise more males (79%) than females (21%) • Lightning strikes people in the following ways… – Ground current (most common), side flash, upward streamer, conduction, and direct strike (least common) • Regarding lightning safety… – NO place outside is safe from lightning – Metal-topped vehicles & buildings w/ electricity are safest – When thunder roars, go indoors!! • Lightning data is in RadarFirst and Weather Briefing
32 Some Excellent Resources on Lightning
• http://www.lightningsafety.noaa.gov/ • http://www.srh.noaa.gov/jetstream/lightning/lightning_intro. html • http://www.nssl.noaa.gov/education/svrwx101/lightning/ • http://mrcc.isws.illinois.edu/living_wx/lightning/index.html
33 RadarFirst and Weather Briefing Updates Spring/Fall 2017 Re-certification Classes
RadarFirst (1.7) Updates
New Features
• Windows only (10, 8, and 7)
• Lightning data a. Updates as frequently as the radar data updates b. Appears in only one window (left in 2-pane mode) c. Icons are + or – to indicate charge of the strike d. Icons with circle around them are cloud-to-ground strikes e. Larger icons indicate larger electrical discharge
• Screenshot feature – saves screen capture of the software while in use a. Saves to your “Pictures” folder on your computer b. Saves as 1 or 2 images
• Hotkeys – keyboard shortcuts for different software functions (e.g., Shift L to turn lightning on/off)
Relatively New Features/Changes (Starting in RadarFirst1.6)
• New map navigation a. Panning i. Mouse – left button click to pan ii. Touchscreens – move your finger on the screen to pan b. Zooming i. Mouse – double left button click zooms in, double right button click zooms out ii. Mouse – scroll wheel zooms in and out iii. Touchscreens – two finger pinch to zoom in and out
• Zooming limits a. Cannot zoom out beyond continental United States b. Cannot zoom in within 1 radar pixel
• Multiple instances – RadarFirst can be opened more than once.
• Automatic menu closing a. Radar selector menu automatically closes after selecting a radar site b. Radar product selector menu automatically closes after selecting a specific radar product
• Time appearing in the black bar near the top previously would switch between local and UTC time when clicking it. This feature has been disabled, but you can still switch times in the Options area
1 34 Weather Briefing Updates
New Features/Improvements
• New lightning data feed (available in: radar console and any combination map with radar) that updates every 1 minute over Oklahoma and surrounding areas. New lightning data includes: o + or – icons to indicate charge of the strike, o Icons with a circle around them to indicate cloud-to-ground strikes, and o Larger icons indicate larger electrical discharge
• An ability to drag and drop KML files onto interactive maps has been added. Build your own KML files and then you can drag and drop them onto any interactive map on Weather Briefing (if you log out and log back in, you have to drag and drop the file in again)
2 35
RadarFirst Cheat Sheet For Version 1.7, January 2017 (Note: RadarFirst 1.7 is Windows Only) Using the Map • To move the map: o [Mouse] Left mouse click, hold, and drag o [Touch screen] Finger touch and drag across the screen • To zoom the map in: o [Mouse] Double left mouse click OR mouse scroll wheel o [Touch screen] Finger pinch apart • To zoom the map out: o [Mouse] Double right mouse click OR mouse scroll wheel o [Touch screen] Finger pinch together • To animate the map: o Click the play button in the black bar at the bottom (default: 1-hour animation). For 2- or 3-hour animations click “2” or “3” at the bottom right (animation start/stop short cut: space bar) • To view data in one or two panes: o Go to View à One Pane or View à Two Panes (short cut: Shift 1 or Shift 2) • To view more than one radar site: o Open the RadarFirst software additional times and view different radars on each
Changing Radar Sites/Products • To change a radar site: click the radar name (e.g. KTLX – Oklahoma City) in the black bar that appears near the top. Click any 3 letter radar identifier to change radars. Drag the map to see and select additional radars. • To change a radar product: click the radar product name (e.g., “BREF1”) in the black bar near the top and then click any radar product to change to it. For products with multiple tilts (e.g., BREF1, 2, 3, 4) only click the number.
Changing Options • To change RadarFirst options: go to Edit à Options… (short cut: Shift O) • Options include showing/hiding different map elements (e.g., cities, storm tracks, lightning, etc.), setting up audible alerts for counties of your choosing, proxy server settings, and graphics settings
Changing the Date • To change the time/date: go to Edit à Date… (short cut: Shift D) • Note: radar is only available for a limited set of events. Changing the time/date and seeing nothing means we do not have radar data archived for that particular event.
Short Cuts • A total of 11 “hot key” short cuts are available in the software, including: 1. Animation start/stop: Space bar 7. City names shown/hidden: Shift C 2. Date: Shift D 8. Storm warnings shown/hidden: Shift W 3. Options: Shift O 9. Storm tracks shown/hidden: Shift T 4. One pane mode: Shift 1 10. Spotter locations shown/hidden: Shift P 5. Two pane mode: Shift 2 11. Lightning shown/hidden: Shift L 6. Snapshot: Shift S (saves images to “Pictures” folder)
Hidden Features • To return to Oklahoma in the radar product selector window: right mouse click within the window • To change color scale on BREF, BVEL, or SRVEL products: right mouse click while mouse cursor is over the color bar at the bottom. Additional right clicks will return to the original color scale. 36 The Oklahoma Mesonet: Research-Quality Data for Decisions Dr. Kevin Kloesel, Director, Oklahoma Climate Survey
37 } 121 remote weather stations } 3300 sensors and 250 computers linked } About 700,000 observations ingested each day } 2-way communications } Solar powered } 30-day storage in on-site dataloggers } Produce ~63,000 products and files for users each day } $2.5M annually to operate/maintain/deliver/train/etc.
Technical Details
38 } Every Five Minutes: } Every Fifteen Minutes: } Air Temperature — 1.5 m and 9 } 5 cm soil temperature — m bare soil/natural sod } } Relative Humidity— 1.5 m 10 cm soil temperature — bare soil/natural sod } Rainfall (tipping bucket) } 30 cm soil temperature — } Barometric Pressure natural sod } Solar Radiation 1.8 m } Wind Speed/Direction — 10 m } Every Thirty Minutes: } Wind Speed – 2 m } 5 cm soil moisture } 25 cm soil moisture } 60 cm soil moisture
Calibrated, Quality Assured, Research Quality…
39 National Academies: “The Oklahoma Mesonet..gold standard..”
National Mesonet Consortium – National Weather Service
40 } MESOscale – Referring to phenomena in the atmosphere on the size of 10s to 100s of kilometers, and lasting hours to a day. (Thunderstorms, cold fronts, warm fronts, dry lines, etc.)
} NETwork – Many stations communicating weather information synchronously in time (every 1 min, 5 min) across a large domain (State of Oklahoma).
What does MESONET Mean?
Have you ever noticed? The larger the weather phenomena, the longer it lasts?
41 MESOSCALE
The Mesoscale covers from thunderstorms to fronts.
“sweet spot” for Oklahoma Mesoscale processes is about a 30km spacing
30km was selected for meteorological reasons
42 121 Sites: Average Spacing is ~30 km (19 miles)
What are those yellow areas?
43 “Micronets” with a station spacing of 5km - paid for annually by a specific user (USDA) for research! These are not full-blown Mesonet stations.
What do we gain by 5km spacing state-wide?
Do we gain anything meteorologically by going from a station spacing of 30km to 5km?
44 It would take approximately 150 more sites, another $3M up front just for the stations. (Not to mention Comms, doubling of the work force, more techs, lab space, calibration equipment, sustainable maintenance funds, etc. to keep the “gold standard.”) We would go from a $2.5M/yr to a $5-6M/yr operation.
What if we simply tried 15 km (from 30km) spacing?
Temperature and moisture patterns tend to be spatially coherent. So adding stations doesn’t make sense in Oklahoma.
45 Unless you purchase a piece of crap, amateur weather station.
But I need one in my back yard!!!
46 Calibration is the key to observations that can be trusted.
Even products that combine multiple variables have coherency.
47 It’s rainfall that is the challenge!
Precipitation is NOT spatially coherent!
48 AND! Rainfall is a pain in the _ _ _ to measure accurately
My intent is not to deter you from buying your own weather station.
49 But to advise you that “set it and forget it” does NOT apply to weather stations!
http://www.cocorahs.org/
Here’s how you can help! Be a CoCoRaHS observer!
50 Questions?
51 Wet Bulb Globe Temperature
Image Source: http://www.edisonpower.com/file/heat-stress-prevention.jpg
Wet Bulb Globe Temperature (WBGT)
• A comprehensive human heat stress index based on – Air temperature – Relative humidity – Wind speed – Sunlight • Developed largely for military purposes – Increasing use in other areas including athletics • How is it different from heat index? – Heat index only accounts for temperature and humidity and is calculated only in shady areas
52 Wet Bulb Globe Temperature (WBGT)
• WBGT is not a value the Mesonet measures directly – Calculated using different measurements • WBGT is calculated using: – “Black globe temperature” (Mesonet calculates) – Air temperature (Mesonet measures) – Wet-bulb temperature (Mesonet calculates) • Special project with NWS Tulsa on WBGT – A special “Black globe temperature” sensor was temporarily installed at the Tulsa Mesonet site to calibrate the calculation of the Black globe temperature
Black Globe Temperature
Experiment at Tulsa Mesonet site involved one of these black globe temperature sensors
Image Source:https://s.campbellsci.com/images/10-2837.jpg
53 WBGT Risk Map
WBGT Work/Rest Hydration Table Assumes healthy, hydrated person wearing lightweight summer working clothes
Wet Bulb Light Work Moderate Work Heavy Work Heat Risk Category Globe Water Intake Water Intake Water Intake Temp Work/Rest Work/Rest Work/Rest (quart/hr) (quart/hr) (quart/hr) Unacclimated 78 – 79.9 50/10 min ½ 40/20 min ¾ 30/30 min ¾ No Risk Acclimated 78 – 79.9 continuous ½ continuous ¾ 50/10 min ¾ Unacclimated 80 – 84.9 40/20 min ½ 30/30 min ¾ 20/40 min 1 Low Acclimated 80 – 84.9 continuous ½ 50/10 min ¾ 40/20 min 1 Unacclimated 85 – 87.9 30/30 min ¾ 20/40 min ¾ 10/50 min 1 Moderate Acclimated 85 – 87.9 continuous ¾ 40/20 min ¾ 30/30 min 1 Unacclimated 88 – 90 20/40 min ¾ 10/50 min ¾ avoid 1 High Acclimated 88 – 90 continuous ¾ 30/30 min ¾ 20/40 min 1 Unacclimated > 90 10/50 min 1 avoid 1 avoid 1 Extreme Acclimated > 90 50/10 min 1 20/40 min 1 10/50 min 1 • Heat acclimation takes 5-10 days of heat exposure • Start acclimation during low (green) WBGT level before shifting to moderate (yellow) WBGT level
54 WBGT Work/Rest Hydration Table
• The WBGT work/rest hydration table assumes lightweight summer clothing. Adjust as follows for different clothing: – Cotton coveralls: add 2 WBGT units – Heavy, winter-type clothing: add 4 WBGT units – Water repellent, semi-permeable clothing: add 6 WBGT units – Full-body, waterproof, impermeable, protective clothing (e.g., Tyvek coveralls and hood): • Add 10 WBGT units for “Light Work” • Add 20 WBGT units for “Moderate” to “Hard Work”
Hydration
• How to know if you are hydrated? – Monitor your water intake and determine your water needs for normal activity – Monitor your hydration by your urine color • For proper hydration consume only water or sports drinks – Avoid drinks that contain Image Source: alcohol or high in sugar https://phc.amedd.army.mil/topics/discond/hipss/PublishingImages/0270A.jpg
55 Heat Stress • Signs of heat stress – Lack of focus or thought process – Headache – Skin flushing – Very dry lips – Sweating has stopped • What to do if you are experiencing heat stress – Take a break immediately and drink water – Remove head coverings and extra clothing – If available use water to cool your face, neck, wrists, and forearms
WBGT Risk Map on OK-First Wx Briefing
56 WBGT Risk Map on OK-First Wx Briefing
Wet Bulb Globe Temperature Summary
• Comprehensive human heat stress index based on… – 1) Air temperature, 2) relative humidity, 3) wind speed, and 4) sunlight – Heat index based on air temperature & relative humidity • The Mesonet calculates WBGT every 5 minutes • WBGT values and 4 risk categories… – 80 to 84.9F: low risk – 85 to 87.9F: moderate risk – 88 to 90F: high risk – 90F+: extreme risk • Use WBGT table to determine rest/hydration needs
57 References and For More Information
• OSHA Technical Manual Section III: Chapter 4 Heat Stress. (https://www.osha.gov/dts/osta/otm/otm_iii/otm_iii_4.html) • Prevention of Heat and Cold Casualties. U.S. Army and Air Force. July 18, 2016. (http://www.tradoc.army.mil/tpubs/regs/tr350- 29.pdf) • Heat and Exercise: Keeping Cool in Hot Weather. Mayo Clinic Staff. Mayo Foundation for Medical Education and Research. ART-20048167. May 16, 2014. (http://www.mayoclinic.org/healthy-lifestyle/fitness/in- depth/exercise/art-20048167?pg=1) • NWS Wet Bulb Globe Temp (http://www.weather.gov/tsa/wbgt)
58 Oklahoma’s Weather Network
Heat Acclimation and Hydration with Wet Bulb Globe Temperature 08/25/16
WBGT available on mesonet.org and Mesonet mobile apps – under Air Temperature
Wet bulb globe temperature (WBGT) is a comprehensive human heat stress index based on air temperature, relative humidity, wind speed, and sunlight. It was developed to better assess outdoor human heat risk. The traditional “Heat Index” adjusts air temperature only by relative humidity. While the wet bulb globe temperature helps you avoid dangerous heat conditions, it can also be used as a guide to safely acclimate to heat and to better pace your outdoor work or play.
To acclimate to heat, you want to expose yourself to hot conditions, yet avoid heat severe enough to cause exertional heat illness. Acclimating to heat is not just a safety issue, outdoor summer activities will be more enjoyable too. Heat acclimation is a process that is different for each individual. It varies with age, medications, overall health, genetics, and hydration.
Heat acclimation typically takes 5-10 days of heat exposure. Start your acclimation during times when the wet bulb globe temperature is between 80 and 85 WBGT Fahrenheit index. This is the green, Low Risk category in the Wet Bulb Globe Temperature map above. As you become more heat acclimated, shift your heat exposure to times when conditions are in the Moderate Risk category of 86-88 WBGT Fahrenheit index. Stay outdoors to take breaks or rest. Choose a shady spot with good air movement. You are striving for extended periods outdoors. Going in and out of air conditioning does not push the body to acclimate to heat. For unacclimated people, OSHA recommends a 5-day acclimation program starting with 20% of outdoor work time on day 1 and increasing 20% each day1.
Your heat risk is highly dependent on your hydration level. Even if you have acclimated to heat, adequate hydration is critical to avoid exertional heat illness. The Wet Bulb Globe Temperature Work/Rest Hydration Table on the next page includes water recommendations during outdoor activities. To properly hydrate, drink water or alternate water with a sports drink. Avoid drinks that are high in sugar or contain alcohol. If you experience a lack of focus or thought process, headache, skin flushing, or feel like you have stopped sweating, take a break immediately and drink water. Remove head coverings and extra clothing. If available, use water to cool your face, neck, wrists, and forearms. Placing your hands and forearms in cool water for 5-10 minutes has been shown to be an effective way to cool the body2.
59 Wet Bulb Globe Temperature Work/Rest Hydration Table Wet Bulb Light Work Moderate Work Heavy Work Heat Risk Category Globe Work/Rest Water Intake Work/Rest Water Intake Work/Rest Water Intake Temp (quart/hr) (quart/hr) (quart/hr) Unacclimated 78 – 79.9 50/10 min ½ 40/20 min ¾ 30/30 min ¾ No Risk Acclimated 78 – 79.9 continuous ½ continuous ¾ 50/10 min ¾ Unacclimated 80 – 84.9 40/20 min ½ 30/30 min ¾ 20/40 min 1 Low Acclimated 80 – 84.9 continuous ½ 50/10 min ¾ 40/20 min 1 Unacclimated 85 – 87.9 30/30 min ¾ 20/40 min ¾ 10/50 min 1 Moderate Acclimated 85 – 87.9 continuous ¾ 40/20 min ¾ 30/30 min 1 Unacclimated 88 – 90 20/40 min ¾ 10/50 min ¾ avoid 1 High Acclimated 88 – 90 continuous ¾ 30/30 min ¾ 20/40 min 1 Unacclimated > 90 10/50 min 1 avoid 1 avoid 1 Extreme Acclimated > 90 50/10 min 1 20/40 min 1 10/50 min 1 Adapted from: 1) USGS Survey Manual, Management of Occupational Heat Stress, Chapter 45, Appendix A. 2) Manual of Naval Preventive Medicine, Chapter 3: Prevention of Heat and Cold Stress Injuries. 3) OSHA Technical Manual Section III: Chapter 4 Heat Stress. 4) National Weather Service Tulsa Forecast Office, Wet Bulb Globe Temperature.
Recommendations in the Wet Bulb Globe Temperature Work/Rest Hydration Table above are for healthy, hydrated humans fully clothed with lightweight summer working clothes. Add 2 WBGT units when wearing cotton coveralls. Add 4 WBGT units when wearing heavy, winter-type clothing. Add 6 WBGT units when wearing water repellent, semi-permeable clothing. When wearing full-body, waterproof, impermeable, protective clothing (e.g. Tyvek coveralls and hood), increase WBGT by 10 units while conducting “Light Work” and increase WBGT by 20 units when doing “Moderate to Hard Work” tasks.
How do you know if you are hydrated? First monitor your water intake. Determine your water needs for your normal activity level. Secondly, monitor your hydration by urine color. This provides you a way to monitor fluid intake through the day and adjust quantity and type of fluid as needed. The chart to the right was developed by the U.S. Army. It uses urine color as a guide to hydration and dehydration. This chart is a useful tool, but it is not a definitive indicator of hydration status and is not for clinical use. Urine color can be affected by certain food, medications, vitamins, or supplements. Urine color will take some time to change after consumption of fluids or after high physical activity.
References and More Information: 1) OSHA Technical Manual Section III: Chapter 4 Heat Stress. (https://www.osha.gov/dts/osta/otm/otm_iii/otm_iii_4.html) 2) Prevention of Heat and Cold Casualties. U.S. Army and Air Force. July 18, 2016. (http://www.tradoc.army.mil/tpubs/regs/tr350-29.pdf) 3) Heat and Exercise: Keeping Cool in Hot Weather. Mayo Clinic Staff. Mayo Foundation for Medical Education and Research. ART-20048167. May 16, 2014. (http://www.mayoclinic.org/healthy-lifestyle/fitness/in- depth/exercise/art-20048167?pg=1)
mesonet.org
60 Tools for Monitoring Winter Storms
What We’ll Cover
1. Winter Precipitation Ingredients and Types 2. Skew-T Diagrams 3. Mesonet Products – Air temperature and 32F contour – Wind – Wet bulb temperature 4. Radar Products – Reflectivity – Correlation coefficient
61 Learning Objectives
1. Understand the key ingredients needed for winter storms 2. Form a basic understanding of what causes different winter precipitation types 3. Know key features to look for on a Mesonet map during a winter storm 4. Understand what snow vs. non-snow look like in base reflectivity 5. Be able to identify the melting layer in correlation coefficient
Winter Precipitation Ingredients and Types
62 Winter Precipitation Ingredients
• Rising motion/lift – Needed to form clouds and precipitation • Freezing conditions – Where in the atmosphere is it below freezing? – Above freezing? How deep? – What about at the ground? • The temperature “profile” determines the precipitation type
63 Rising Motion: Ahead of Trough Axis
Trough Axis Area of rising motion ahead of trough
Winter Precipitation Types
Snow Sleet Freezing Rain Rain & Drizzle
Snowflakes survive Snowflakes fall from the Snowflakes fall from the Snowflakes fall from the entire trip from clouds, melt in a warm clouds, melt in a warm the clouds, melt, and cloud to surface layer, and then freeze layer, and then freeze on reach the ground as into ice pellets (sleet) contact with the ground rain above the ground
64 Skew-T Diagrams
Charting Weather Balloon Data: Skew-T’s
The skewed lines are temps in Celsius
Going up in the sky
The horizontal lines are pressures in millibars
65 Skew-T Diagrams
Air Temperature
Winds
Dew Point Temperatures
Skew-T Diagrams
Below Above Freezing Freezing
66 Mesonet Products
Mesonet Products
• No better way to keep tabs on changing surface conditions than the Mesonet • Things to watch in Mesonet data: – Air temperatures and the freeze line – Wind directions and missing wind data – Wet bulb temperature freeze line
67 Mesonet Air Temps: Jan 28, 2010 at 2AM
Freeze line
Wind shift with cold northerly winds behind it
Mesonet Air Temps: Jan 28, 2010 at 7AM
Where did the wind barbs go?
Freeze line moves south
68 Mesonet Air Temps: Jan 28, 2010 at 7AM
Freezing rain!!
Why Wind Barbs Disappear: Ice on Mesonet Stations
69 Where to Find the Freeze Line
Available in: Air Temperature, Air Temperature + Radar, and the Radar Console
Wet Bulb Temperature
• The Oklahoma Mesonet calculates the wet bulb temperature – It tells us how cold air could get due to evaporative cooling – It is an excellent indicator of cooling potential • Wet Bulbing happens when precipitation occurs in a region where the air is not saturated
70 Why We Call it the Wet Bulb Temperature
Sling Psychrometer: the traditional way to measure the wet bulb temperature
Wet Bulb
Dry Bulb
An Example of Using the Wet Bulb Temperature
Air temp freeze line
Wet bulb temp freeze line is several counties further south
71 Where to Find Mesonet Wet Bulb Temperature
Mesonet Data During Winter Precipitation: Some Misconceptions
• Air temperature sensors “freeze up” – Sensors are inside a protective shield and do not freeze up – Sensors can handle temperatures as low as -40F – If you see no temp data at a site, the most likely cause is a communications issue with the site • Mesonet measures frozen precipitation during events – Mesonet rain gauges are not heated – Frozen precipitation piles up in the rain gauge while surface temperature is freezing – Liquid equivalent is measured after the precipitation melts
72 Frozen Precipitation and Mesonet Rain Gauges: Snow Cones
Radar Products
73 Winter Precipitation on Radar
• Radar provides a wealth of useful information – Location of precipitation – Appearance of echoes in reflectivity provide hints on precipitation type – Dual-polarization products reveal additional information such as the possibility of a melting layer • Recommended radar products: – Base Reflectivity – Correlation Coefficient (dual-polarization product)
Winter Precipitation in Base Reflectivity
• Non-snow (rain, sleet, or freezing rain) – Sharp edges – Higher reflectivity values – Look like storms • Snow – Softer edges – Much lower reflectivity values – Smoother/brushed appearance
74 Winter Precipitation in Base Reflectivity
• Look like storms à non-snow! • Wind barbs are there • Sleet was occurring
Feb 21, 2013 5:00 AM
Winter Precipitation in Base Reflectivity
• Look like storms à non-snow! • Wind barbs are missing north of 32F • Freezing rain north of 32F line
Jan 28, 2010 10:00 AM
75 Winter Precipitation in Base Reflectivity
• Lower reflectivity values and very smooth à snow! • Note: Missing wind barbs from freezing rain that occurred before the snow
Jan 29, 2010 12:00 PM
Dual-Polarization (Dual-Pol) Radar • Dual-pol products utilize radar pulses that are polarized in both horizontal AND vertical directions • Helps determine target shape and variety • There are many dual-pol products but most useful for winter precipitation is Correlation Coefficient
National Weather Service Warning Decision Training Branch, http://www.wdtb.noaa.gov/courses/dualpol/Outreach/non-mets- intro/player.html (slide 10), retrieved July 6, 2012
76 Correlation Coefficient (CC)
• What it Measures: – How uniform or diverse radar targets are – Uniform targets are precipitation! – Non-uniform targets are not precipitation • Range of Values: 0.2 to 1.05 (unitless)
National Weather Service Warning Decision Training Branch, http://www.wdtb.noaa.gov/courses/dualpol/Outreach/non-mets- intro/player.html (slide 6), retrieved July 6, 2012
What do the values mean?
• High CC (greater than 0.97) – Targets are highly uniform, which occurs with a pure precipitation type – Just rain, just snow, etc. • Moderate CC (0.8 to 0.97) – Targets are quite uniform, however, they are some sort of mix – Hail and rain, melting snow and rain, etc. • Low CC (less than 0.8) – Targets are more diverse à not precipitation – Birds, insects, smoke, tornado debris, etc.
National Weather Service Warning Decision Training Branch, http://www.wdtb.noaa.gov/courses/dualpol/Outreach/non-mets- intro/player.html (slide 6), retrieved July 6, 2012
77 Correlation Coefficient Example
Base Reflectivity (Tilt 1) Correlation Coefficient (Tilt 1)
Higher reflectivity echoes. CC values > 0.97 Are these all precipitation? The only precipitation!
A Key Use of CC: Identifying the Melting Layer
Uniform precipitation
Mixed precipitation
Uniform precipitation
78 Identifying the Melting Layer
Base Reflectivity 2 Correlation Coefficient 2
Uniform up here à snow!
Lower CC values here so mixed precipitation à Uniform again here melting snow! (closer to the ground) à not snow!
Skew-T from this Event (6AM)
79 Cautions on Using CC to Detect Melting Layers
• Below Beam Effects – Changes in precipitation can and do occur below the radar beam • The melting layer is not always a perfect ring – Cold air may be moving in/out – Precipitation may not be widespread • Bottom Line – The melting layer tells us only one thing with certainty – that snow will not be the precipitation type within the ring
Tools for Monitoring Winter Storms Summary
• Ingredients for winter storms – Approaching trough/lift – Freezing temperatures • Skew-T’s help to identify precipitation type – Main limitations: only 1 in Oklahoma and launched only twice a day • Mesonet data to the rescue – Missing wind barbs = icing at the ground – Watch the 32F line – Wet bulb temperature gives indication of cooling potential
80 Tools for Monitoring Winter Storms Summary
• Reflectivity can give us some hints on precip type… – Rain, sleet, and freezing rain have higher reflectivity values and look like storms – Snow has lower reflectivity values and looks brushed • If you are up for it try Correlation Coefficient (CC) – Check out CC2 (or higher) during precipitation and look for yellow ring or half ring shape à melting layer – Melting layer means it won’t be snow at ground near radar • The best data combination? – Look at Mesonet and radar data together on Wx Briefing!
81 Lab: Using Correlation Coefficient During Winter Events
Objective:
In this lab exercise we will investigate a couple winter weather events from late 2013 to see how the correlation coefficient radar product could be used to help us identify changes in precipitation type. We will also take a look at Skew-T’s and Mesonet data to diagnose precipitation type.
Instructions:
You will need to use the latest version of RadarFirst to complete this lab. Please read each question carefully and answer them as best you can in the space provided. You are welcome to work on your own or in a group.
Region of Focus for this Exercise:
For the purposes of this lab we will keep our attention on central Oklahoma and will only use the KTLX (Oklahoma City) radar.
Terminology:
The following are definitions of several meteorological terms you may see during this lab:
• Base Reflectivity (BREF) – Radar product that measures how much of the radar’s energy is reflected back to the radar. More particles and/or bigger particles reflect more energy. This is the most common radar product shown on TV.
• Correlation Coefficient (CC) – Dual-pol radar product that measures how uniform or diverse radar targets are. The following are values and what they mean: o Values greater than 0.97 – uniform precipitation o Values between 0.8 and 0.97 – mixed precipitation (such as snow and sleet, sleet and freezing rain, etc.) o Values less than 0.8 – non-precipitation targets
• Skew-T Diagram – A way to plot information from a weather balloon that shows how temperatures, dew point temperatures, and winds change going upward in the atmosphere. Temperature lines are “skewed” diagonally – giving this chart its funny name. Conditions nearest the ground are at the bottom of the chart, while conditions higher in the atmosphere are found by moving up the chart.
82 Cheat Sheets:
83 Lab Exercise:
Open RadarFirst. Put the software in 2-pane mode (View à Two Panes) and make cities visible (Edit à Options… à Show Cities).
At the top of RadarFirst Go to Edit à Date... and set your date to 11/22/2013 and your time to 12:00PM. For your radar, choose KTLX – Oklahoma City. In the left radar window pick radar product BREF2 and in the right radar window pick CC2. Your software should be set as follows:
Radar Date Time Left Pane Right Pane KTLX – BREF2 CC2 11/22/2013 12:00PM Oklahoma City (Base Reflectivity 2) (Correlation Coefficient 2)
Question 1. Base Reflectivity shows what looks to be precipitation going through central Oklahoma. Looking at Correlation Coefficient in the right window, what do the dark red colors mean? What do the yellow colors in the right window mean?
Question 2. What do we call the yellow area in Correlation Coefficient in the right window? Scroll your mouse over this yellow area in Correlation Coefficient. About how high up is it?
Question 3. At the top of RadarFirst go to Edit à Date… and change your time to 2:00PM. How has the shape of the yellow area in Correlation Coefficient changed since 12:00PM? Briefly describe.
Question 4. Relying only on radar (not something we should do in reality!) make a prediction of the type of precipitation you think might be occurring in the OKC metro area that afternoon.
84 Question 5. 2PM Mesonet surface temperatures, freezing line (yellow), and winds plus radar Correlation Coefficient 2 are shown below in the top image. The 6PM Skew-T (with freezing line in blue) from Norman is shown below in the bottom image. Given this added information, what type of precipitation do you think occurred in the OKC metro that afternoon?
85 Let’s check out another event. At the top of RadarFirst go to Edit à Date… and change your date to December 5, 2013 and the time to 3:00PM. Make sure your software is set as follows:
Radar Date Time Left Pane Right Pane KTLX – BREF2 CC2 12/5/2013 3:00PM Oklahoma City (Base Reflectivity 2) (Correlation Coefficient 2)
Question 6. Describe what you are seeing in the Correlation Coefficient product in the right window. Again, what do the dark red colors mean? The yellow colors?
Question 7. Scroll your mouse over the yellow area in Correlation Coefficient in the right window. About how high up is it?
Question 8. Look at the reflectivity data in the left window. Describe what you are seeing.
Question 9. Relying only on radar (again, not something we should do in reality!), make a prediction of the type of precipitation you think might be occurring in the OKC metro area that afternoon.
86 Question 10. 3PM Mesonet surface temperatures, freezing line (yellow), and winds plus radar Correlation Coefficient 2 are shown below in the top image. The 6PM Skew-T (with freezing line in blue) from Norman is shown below in the bottom image. Given this added information, what type of precipitation do you think occurred in the OKC metro that afternoon?
87 Let’s move forward in time to the next morning. At the top of RadarFirst go to Edit à Date… and change your date to December 6, 2013 and the time to 6:00AM. Make sure your software is set as follows:
Radar Date Time Left Pane Right Pane KTLX – BREF2 CC2 12/6/2013 6:00AM Oklahoma City (Base Reflectivity 2) (Correlation Coefficient 2)
Question 11. We have moved forward in time 15 hours. Describe how the Correlation Coefficient product in the right window has changed from earlier. What is different?
Question 12. Base Reflectivity data has a different appearance than it did 15 hours ago. Describe it. What is the highest reflectivity value you can find?
Question 13. Again only using radar, what is your prediction of precipitation type in the OKC metro area that morning?
88 Question 14. 6AM Mesonet surface temperatures, freezing line (yellow), and winds plus radar Correlation Coefficient 2 are shown below in the top image. The 6AM Skew-T (with freezing line in blue) from Norman is shown below in the bottom image. Given this added information, what type of precipitation do you think occurred in the OKC metro that morning?
89 CC Winter Wx Lab De-Brief
Question 1 – CC color meanings?
• What do the dark red colors mean? – Uniform precipitation • What do the yellow colors mean? – Mixed precipitation
90 Question 2 – What is the yellow area?
“Melting Layer” at about ~11,000 feet
Question 3 - Changes in yellow area?
Precipitation covers the region
The entire melting layer is now visible
91 Question 4 – Precipitation type?
Well, we know it won’t be snow! Either rain, freezing rain, or sleet.
Question 5 – Precipitation type?
Freezing rain in OKC Metro!
Sub-freezing surface temps and Large “warm nose” missing wind data
92 Question 6 – Describe CC
Uniform precip down here.
Mixed precip in yellow à melting snow Uniform precip up here à snow
Question 7 – Height of melting layer?
Melting layer somewhere between 5,500 to 7,500 feet
93 Question 8 – Describe reflectivity
Ring of higher values in reflectivity – this is called a “bright band.” Happens when snow gets coated with water.
Question 9 – Precipitation type?
Again, not snow. Either rain, freezing rain, or sleet.
94 Question 10 – Precipitation type?
Sleet in OKC Metro! Maybe also some snow on northwest side.
Well below freezing surface temps. Wind Deep below data not missing! Brief melting freezing layer
Question 11 – How has CC changed?
No more melting layer. Just high CC values à uniform precipitation.
95 Question 12 – How has BREF changed?
Smooth/brushed appearance. Highest BREF values of only ~33 dBZ.
Question 13 – Precipitation type?
No melting layer, so not sleet. BREF suggests snow but need temperature data to be certain.
96 Question 14 – Precipitation type?
Snow in OKC Metro!
Temperatures stay below Well below freezing freezing throughout surface temperatures
97