1	The Official National Weather Service Spotter Presentation Weather Forecast Office Old Hickory, Tennessee
2	What we see
3	What you see
4	Your National Weather Service Office in Old Hickory, Tennessee Located at Langford’s Cove on Old Hickory Lake near Nashville Operates 3 shifts a day, 24 hours a day, 7 days a week
5	Your National Weather Service Office in Old Hickory, Tennessee Comprises 39 counties in Middle Tennessee Total land area: 18,085 square miles, from the Tennessee River to the Cumberland Plateau Total population (2000): 2,133,315
6	NWS Mission “…provide weather, hydrologic, and climate forecasts and warnings for the United States…for the protection of life and property and the enhancement of the national economy…”
7	Products We Issue Warnings Tornado Severe Thunderstorm Flash Flood Winter Storm Non Precipitation Watches Flash Flood Winter Storm Outlooks Hazardous Weather Winter Weather Flood Potential
8	Products We Issue Forecasts Zone State Short Term Fire Weather Statements Severe Weather Special Weather Public Information Hydrologic River Flood Warnings River Stage Forecasts
9	Your National Weather Service Office in Old Hickory, Tennessee
10	NOAA Weather Radio (NWR) Twelve transmitters across the mid state Automated with the Console Replacement System Operates 24 hours a day, 7 days a week
11	NOAA Weather Radio – The Fastest Way To Get Your Warnings Available at: Sams Radio Shack midlandradio.com
12	County Warning & Forecast Area
13	NWR – Routine Broadcast Cycle Hourly Weather Roundup (many locations) Short Term Forecast Selected Cities Forecast Local & Extended Forecast Hazardous Weather Outlook (mornings only) Nashville Climate Summary Station Identification Current Local Time
14	NWR – Severe Weather Broadcast Cycle Tornado Watches & Warnings Severe Thunderstorm Watches & Warnings Flash Flood Watches & Warnings Statements (severe weather, special weather, flash flood) Short Term Forecasts River Flood Warnings Winter Weather Messages
15	NWS Nashville on the Internet Current Doppler radar imagery (near real-time imagery) Clickable forecast map Latest NWS products, including warnings Extensive climate database NOAA weather radio page River information Spotter class schedule Research projects
16	Middle Tennessee Skywarn Homepage Designed for EMA, Spotters, and weather enthusiasts across Middle Tennessee. Advance notification of severe weather activation. Frequency database for Middle Tennessee. SimuAwips – Auto-updated internet based weather center. Recognized nationally as the fastest way to obtain your weather warnings over the internet for the Middle TN area. Hamfest information, mesocam, news articles, spotter criteria and much more.
17	SimuAwips – Middle TN Online Weather Center www.mtsh.org
18	Middle Tennessee Emergency Amateur Radio Society (MTEARS) Link System NWS monitors the main repeater hub 443.725 Mhz located in Nashville. MTEARS Link System designed to cover the CWA of the Nashville NWS office. System designed to allow individual spotter nets to run locally. An appointed liaison or Net Control Operator funnels pertinent traffic directly to the NWS, keeping frequencies clear for emergency traffic. Link System available for use 24 hours a day, 7 days a week.
19	MTEARS Link System
20	How can you get NWS Products? NOAA Weather Radio Local Media Weather Channel, on the 8's (8, 18, etc.)... Not anymore!!! The Internet (www.srh.noaa.gov/ohx) SimuAwips (www.mtsh.org) Data/Forecast Vendors EMWIN
21	Middle Tennessee Tornado Database Can you guess how many tornadoes have occurred in your county?
22	Distribution of Tornadoes across the U.S.
23	Tornado Safety Rules Go to the basement or an interior room on the lowest floor of your home or business. Wrap yourself in overcoats or blankets. In larger buildings (schools, hospitals), go to interior rooms and halls on the lowest floor. In high-rise buildings, go to lower interior rooms. In cars or mobile homes, get out. If no suitable structure is nearby, lie flat in a ditch and use your hands to cover your head.
24	Tornado Safety Rules Do not take shelter beneath an overpass!
25	High Wind & Hail Safety Rules Take shelter in a sturdy building. If outside in a hailstorm, cover your head. Stay away from glass. Get away from trees and power lines. If high winds are expected, move your vehicle into a garage, and bring loose items inside.
26	Flash Flood Safety Rules When inside, if ordered to evacuate, or if rising water threatens, seek higher ground. If outdoors, seek higher ground. Avoid small rivers, streams, dry beds, and low water crossings. Do not try to walk through flowing water. Be careful around drainage ditches/viaducts. Statistically, flash flooding is the number 1 weather killer.
27	Do Not Drive Through a Flooded Stretch of Road….EVER! Photograph courtesy of thunderstormchaser.com, flooding, Williamson County (2/14/01)
28	Flash Flood Safety Rules Do not drive through flooded areas, even if it looks shallow enough to cross.
29	Lightning Safety Rules When inside, avoid telephones, & do not take a shower. If outside, get in a sturdy building or car. If boating or swimming, get out of the water. In a wooded area, take cover under a thick growth of small trees. Statistically, lightning is the number 2 weather killer.
30	Lightning Safety Rules If you feel your hair stand on end, squat down. Do not lie flat.
31	Lightning – It’s Hot! Avoid water, fences, and ESPECIALLY TREES! Lightning can reach temperatures as high as 50,000°F.
32	Night Spotting Spotting for key storm features at night can be difficult and dangerous…When the only light available comes from lightning.
33	Winter Weather If going outside in snow or ice, call 1-800- 342-3258 for Tennessee road conditions. Carry along a winter storm survival kit, and a NOAA weather radio. Please call any snow or ice reports to the NWS at 1-800-267-8144.
34	What Is a Severe Thunderstorm? Wind gusts at least 50 knots (58 mph) Hail at least 3/4" in diameter (penny) Tornado - A violently rotating column of air in contact with the ground and extending from the base of the thunderstorm.
35	The Hazardous Weather Outlook (HWO) Issued at least once a day, normally at 5:30 Describes the potential for hazardous weather the next 24 hours Played on NOAA Weather Radio every morning between 5:30 am & 9:30 am Available on our website at www.srh.noaa.gov/ohx
36	Severe Thunderstorm & Tornado Watches Mean that conditions are favorable for severe weather in and close to the watch area. Comprise a large area Valid for several hours Issued by the Storm Prediction Center Tone alerted on NOAA Weather Radio
37	Sample Severe Weather Watch
38	Severe Thunderstorm & Tornado Warnings Severe weather is occurring or imminent Can be issued for one county or several counties at a time Valid for no more than an hour Issued by the NWS in Old Hickory Tone alerted on NOAA Weather Radio
39	Sample Tornado Warning
40	Sample Severe Weather Statement
41	Flash Flood Warnings Flash flooding is occurring or imminent Can be issued for one county or several counties at a time Valid for up to six hours Issued by the NWS in Old Hickory Tone alerted on NOAA weather radio
42	We Need Spotter Reports! Reports from law enforcement and emergency managers are great, but they often have more pressing tasks. Trained spotter reports are our BEST resource for issuing and updating warnings. If you observe strong to severe weather please call us at 1-800-267-8144 or report to us via our website and the MTEARS Repeater System.
43	Storm Spotter Criteria & Reference Guide for Middle Tennessee Who, What, When, Where Type of severe weather Estimate hail size, wind speeds Avoid non-severe reports Spotter safety Mobile spotter equipment
44	Effective Spotter Communications Just how big is marble size hail?
45	Effective Spotter Communications Ambiguous Reports High Wind Damaging Wind Rotating Debris Effective Reports - Indicative of magnitude of the event/damage Trees Uprooted Windows Broken Mobile Home Overturned
46	Why should I bother to call the National Weather Service with my storm report? Your storm reports lend “ground truth” to what forecasters see (or don’t see) on radar. Your reports can help us issue life-saving warnings and statements. Do not assume a report has been called in. We can always use additional reports. Call 1-800-267-8144 or go to our website to report severe weather to the National Weather Service. Your reports are included in our official local storm reports, which, in turn, become part of NOAA’s Storm Data publications.
47	Quick Quiz Which indicates an immediate threat - a Watch or Warning? What “heads up” product is issued whenever thunderstorms are forecast? Also, what time is this product issued? What role does a spotter report have when the NWS considers issuing a warning?
48	Before venturing out – always think about safety! Photograph courtesy of Carrie S. Kinslow, 4/16/98, Lawrence County, TN
49	Conditions Needed for Thunderstorms Lift Moisture (low-level) Instability Lifting mechanisms include: Cold Front Warm Front Gust Front/Outflow Boundary Orographic/Upslope (Cumberland Plateau) Daytime Heating
50	Fronts
51	Cross-Section of a Cold Front
52	Cross-Section of a Warm Front
53	The perfect setup for tornadoes
54	Towering Cumulus Stage
55	Mature Stage
56	Severe Storms - Hail Formed by either rotating around in an updraft or repeatedly rising and falling through the storm.
57	Dissipating Stage
58	Thunderstorm Spectrum
59	Single Cell A thunderstorm consisting of a single updraft
60	Multi-Cell Cluster A thunderstorm consisting of two or more cells, of which most or all are visible as distinct domes or towers in various stages of development
61	Squall Line A solid or nearly solid line or band of active thunderstorms
62	Downburst Definitions Downburst A strong downdraft with an outflow of damaging wind on or near the ground Macroburst Swath of damaging wind is more than 2.5 miles wide Microburst Swath of damaging wind is 2.5 miles wide or less. Due to their small size and short lifetime, microbursts are difficult to detect and warn for.
63	Downburst Life Cycle
64	Microburst Example
65	Wet Microburst Sequence 1
66	Wet Microburst Sequence 2
67	Wet Microburst Sequence 3
68	Wet Microburst Sequence 4
69	Bow Echo Diagram Bow echoes can form from individual storms…or from individual storms along a squall line.
70	Bow Echo Examples Imagery from the Old Hickory WSR-88D Wilson County bow echo from an individual storm (6/9/96)
71	Bow Echo Examples Bow Echoes from a Squall Line (May 6, 1999)
72	The Supercell A thunderstorm with a persistent rotating updraft (mesocyclone)
73	The Supercell: Side View
74	The Supercell: Top View
75	The Supercell: Distant View Photograph courtesy of thunderchaser.com, 8/15/00, I-65, Nashville
76	The Supercell: Nearby View
77	Upper Level Storm Clues Overshooting Top A dome-like protrusion above a thunderstorm anvil representing a very strong updraft and a higher potential for severe weather Anvil The flat, spreading top of a cumulonimbus
78	Upper Level Storm Examples Here, the anvil is very well-defined with crisp edges, and there is an obvious overshooting top indicating a strong updraft region.
79	Mid Level Storm Clues Main Storm Tower Solid appearance with cauliflower-like texture Flanking Line A line of cumulus or towering cumulus clouds connected to and extending outward from the most active part of a supercell, normally on the southwest side Mid Level Cloud Striations Main storm tower exhibits a “swirling” effect
80	Mid Level Storm Examples
81	Low Level Storm Clues Rain-Free Base A dark, horizontal cloud base with no visible precipitation beneath it (typically marks the location of the thunderstorm updraft) Wall Cloud An isolated cloud lowering attached to the rain free base. Wall clouds are typically 1-3 miles in diameter. Shelf Cloud A low, horizontal wedge-shaped cloud associated with a thunderstorm gust front or cold front.
82	Rain Free Base
83	Rotating Wall Cloud Rotating Wall Cloud means a tornado can form from a matter of minutes to as long as an hour.
84	Shelf Cloud
85	Shelf Clouds vs. Wall Clouds Shelf Clouds Suggest downdraft and outflow Move away from precipitation area Slope downward, away from precipitation Wall Clouds Suggest updraft and inflow Maintain position with respect to precipitation area Slope upward, away from precipitation
86	Shelf Cloud and Wall Cloud A very rare and unusual phenomenon
87	The Supercell on Doppler Radar
88	High Precipitation (HP) Supercell
89	HP Supercell, Example 1
90	HP Supercell, Example 2
91	HP Supercell, Example 3
92	HP Supercell, Example 4
93	Low Precipitation (LP) Supercell
94	Hybrid LP-HP Supercell
95	How Do Tornadoes Form?
96	How Do Tornadoes Form?
97	How Do Tornadoes Form?
98	Funnel Cloud A condensation funnel extending from the base of a towering cumulus or cumulonimbus, associated with a rotating column of air that is not in contact with the ground
99	Tornado A violently rotating column of air in contact with the ground and extending from the base of a thunderstorm
100	Roll Cloud A low, horizontal tube-shaped arcus cloud associated with a thunderstorm gust front or cold front
101	Mammatus Rounded, smooth, sack-like protrusions hanging from the underside of a cloud, usually a thunderstorm anvil
102	Weak Tornadoes 69% of all tornadoes Less than 5% of tornado deaths Lifetime 1-10+ minutes Path length up to 3 miles Wind speed 40 to 112 mph
103	Strong Tornadoes 30% of all tornadoes Less than 30% of tornado deaths Last 20 minutes or longer Path length 15+ miles Wind speed 113 to 206 mph
104	Violent Tornadoes 3% of all tornadoes Nearly 70% of tornado deaths Last an hour or longer Path length 50+ miles Wind speed 207 to 318 mph
105	F4/F5 Damage, 4/16/98 Wayne County (F4) & Lawrence County (F5)
106	Tornado – 50% Rule
107	Spotter Positioning, Example 1
108	Spotter Positioning, Example 2
109	Spotter Positioning, Example 3
110	Four Tornadic Wall Cloud Characteristics Watch until you are sure the lowered cloud base is rotating. Persistent Rotation: Visible & Violent Strong Surface Inflow: 20-30+ mph Rapid Vertical Motion: Clouds
111	Middle Tennessee 4/16/98 Wall Cloud Sequence 1
112	Middle Tennessee 4/16/98 Wall Cloud Sequence 2
113	Middle Tennessee 4/16/98 Wall Cloud Sequence 3
114	Middle Tennessee 4/16/98 Wall Cloud Sequence 4
115	Tornado Life Cycle (Wall Cloud)
116	Tornado Life Cycle (Funnel Cloud)
117	Tornado Life Cycle (Mature)
118	Tornado Life Cycle (Dissipating)
119	Cyclic Tornadoes, Stage 1
120	Cyclic Tornadoes, Stage 2
121	Cyclic Tornadoes, Stage 3
122	Look Alikes Rotation Is there any? How strong is it? Orientation Where is the feature with respect to... The rain-free base? The Precipitation Shaft? What direction are you looking? Rapid Vertical Motion Is it visible and violent?
123	Look Alikes
124	Look Alikes
125	Look Alikes Small, ragged, low cloud fragments that are unattached to a larger cloud base and often seen with and behind cold fronts and thunderstorm gust fronts
126	Look Alikes
127	Look Alikes
128	Look Alikes
129	Look Alikes
130	Look Alikes
131	Quiz
132	Quiz
133	Quiz
134	Sequence: Satellite, Radar, and Storm Photo in Real-Time
135	Sequence: Satellite, Radar, and Storm Photo in Real-Time
136	Sequence: Satellite, Radar, and Storm Photo in Real-Time
137	In Summary
138	The NWS Needs Your Reports of These Weather Hazards
139	We Want Severe Weather Pictures from Middle Tennessee
140	Contact Us National Weather Service 500 Weather Station Road Old Hickory, TN 37138 (615) 754-4633 online at: www.srh.noaa.gov/ohx e-mail: Jerry.Orchanian@noaa.gov