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Advanced SKYWARN
In this Advanced training session, I will focus on thunderstorm formation
mechanisms, and tropical weather, so that you can
Anticipate severe weather before it gets to you.
Primary Mission
Protect life and property by warning for hazardous weather
http://weather.gov
Hazardous Weather Warnings
We issue the warnings you hear on radio and TV
Why is the NWS Here Today?
We Need Your Reports to Help Warn the Public
Tornadoes, Waterspouts, Funnel Clouds
Flooding and 2” rain per hour
Thunderstorm wind damage, 58 MPH wind
Penny size hail, ¾” diameter
What is a Severe Thunderstorm?
50 Knot Wind58 MPH Wind
¾ Inch HailPenny Size
Thunderstorm Formation
Moisture (water vapor)Preferably in the lower levels of the atmosphere
Source of Lift (sea breeze, etc)Something to lift moist air so it becomes unstable. The Trigger.
Unstable AirAbility for air to accelerate upward/downwardwhen given a push
Unstable vs Stable Atmosphere
Which one of these pictures shows a stable atmosphere?
Unstable Stable
How Do We Measure Stability?
We Launch Weather Balloons
Balloon
Parachute
InstrumentPackage
Upper Air Sounding
Launched at 73 U.S. Cities
Let’s Go Back to Stability
Parcel Theory Let’s Us Compute Stability
• A parcel is a small baggie of air (size of cubic foot)• Acts like a hot air balloon, does not let air in or out
• The bag will rise if it is warmer than the surrounding air• The bag will sink if it is colder than the surrounding air
Cold Air is Heavy and Sinks
50 at 10,000 ft
60
70 at 5000 ft
80
90 at surface
70
70
Will this bag rise or sink?
The bag will rise because the temperature inside the bag > air outside (70 > 60 )
Will this bag rise or sink?
The bag will sink because the temperature inside the bag < air outside (70 < 80 )
Instability & Temperature Inversions
• As you go aloft, temperature normally decreases at a rate of 5.5° F per 1000 feet
• Temperature inversion occurs when the temperature increases with height instead of decreasing
Instability & Temperature Inversions
50
60
70
85 80
90 92
82
10,000 feet
Surface
Stable Layer
Unstable, Moist, but no Storms?
Temperature Inversion
Need additional lift to get thunderstorms to develop
Visually See a Temperature Inversion
Inversion
Lifting Mechanism – Sea Breeze Front
50
60
70
85 80
90 Surface
10,000 feet
Stable Layer82
92
Need lifting to get bag above inversion
50
60
70
78
80
77
63
55
Sea Breeze Front
1,000 to 3,000 Feet Thick
Sea Breeze Front on Satellite
3-D View of a Sea Breeze
3-D View of a Land Breeze
Sea and Bay Breezes
10 AM10 AM
Where will the first storms start?
Sea and Bay Breezes
1 PM1 PM
Position of High Pressure andEffect on Sea Breeze
• Calm Flow (light morning winds)
• High Pressure Ridge to the North(light east morning winds)
• High Pressure Ridge to the South (light west morning winds)
Weak High Pressure Ridge
CalmFlow
Weak High Pressure Ridge
7 AM7 AM
Weak High Pressure Ridge
3 PM3 PM
Calm Flow Lightning Activity
High Pressure Axis to North
High Pressure Axis to North
Low Level Flow
8 AM8 AM
High Pressure Axis to North
Low Level Flow
11 AM11 AM
High Pressure Axis to North
Low Level Flow
1 PM1 PM
High Pressure Axis to North
Low Level Flow
4 PM4 PM
Lightning Activity
High Pressure Axis to South
High Pressure Axis to South
Low Level Flow
8 AM8 AM
High Pressure Axis to South
Low Level Flow
11 AM11 AM
High Pressure Axis to South
Low Level Flow
1 PM1 PM
High Pressure Axis to South
Low Level Flow
4 PM4 PM
Lightning Activity
Thunderstorm Gust Front
Dense, rain-cooled air under the
storm rushes out in all
directions
Sea Breeze and Outflow Boundaries
Putting It All Together
Click on image to start video
Switch Gears
Hurricanes, Where and When
The Atlantic Hurricane Season is
June through November
Hurricanes, Where and When
Hurricane Strikes – 1950-2005
Hurricane Risk
Are hurricanes getting stronger?
What about the coastal population trends?
Florida Coastal Population
Hurricane Development
Warm ocean water is the fuel for the storms
Northern Hemisphere Tilted Toward the Sun in our Summer
Heat surplusSUN
More sun energy
Less sun energy
Typical Track by Month
Why is Forecasting Hard?
12
3
12
3
Katrina 5 Day Forecast Model Plots
08/24/2005 1:00 pm CDT.
NATIONAL HURRICANE CENTER ATLANTIC TRACK FORECAST ERRORS
NATIONAL HURRICANE CENTER ATLANTIC TRACK FORECAST ERRORS
12 24 36 48 72 96 120
Forecast Period (hours)
0
100
200
300
400
500
Err
or
(nau
tica
l mile
s)
1964-1973
1984-1993
1974-1983
1994-20032003-2004Katrina(preliminary)
Rita(preliminary)
250 NM
100 NM
Why are we getting better at predicting forecast tracks?
How about tropical cyclone strength prediction?
Hurricane Hunter Aircraft
Fly into hurricane to get information that make forecasts better.
Better remote sensing and faster computers
We’ve gone from old, slow,
bulky…
…to advanced, fast, compact computing
hardware.
Advanced GOES imaging and sensing
Hurricane Dangers
• Evacuations• Storm Tide• Wind• Fresh Water Flooding• Tornadoes• Cleanup
Direct Tropical Cyclone Fatalities in FL1957 -2006, 33 Cases and 317 Fatalities
96
22
4
2
42
• 38 Marine craft• 32 Rip currents• 26 Fresh water flooding
Hurricane Dangers
• Evacuations
Run from the water, hide from the wind!
Hurricane Dangers - Evacuation
Motorists trapped on I-26 as Hurricane Floyd approached
Charleston, SC in 1999
Evacuation was a problemin Houston as HurricaneRita approached in 2004
Evacuation Called for Only 2 Reasons
1. For People in the Storm Surge Zone
Hurricane Charley - 2004Motorists Fleeing
Pinellas County on the Howard Franklin Bridge
Evacuation Called for Only 2 Reasons
2. For People in Manufactured Homes
Evacuate as Short of Distance as Possible
• Use public shelters if you have to• Not the most pleasant of conditions
•Make friends with someone outsidethe surge zone in a well built home
Hurricane Dangers
•Storm Tide
Storm Tide
Storm Tide = Surge + Tide + Anomaly
Katrina Hurricane Chasers
UltimateChase.com
Storm Surge
Storm Tide Beach Erosion
2004 Hurricane Ivan Damage in Orange Beach, AL
Hurricane Rita Storm Surge
Our Barrier Islands Are No Different
St Pete Beach
Fort Myers Beach
St. Armands Circle
Cedar Key
Google Maps
Google Maps
Google Maps
Hurricane Dangers
• Wind
Saffir-Simpson Scale
Taking Shelter From the Storm, FEMA publication (320)http://www.fema.gov/pdf/fima/fema320.pdf
74-95 MPH
96-110 MPH
111-130 MPH
131-155 MPH
155+ MPH
Hurricane Wilma
October 16-25, 2005
CAT 1 Hurricane Wind Damage
2005 Hurricane Wilma – Ft. Myers, FL Area
CAT 4 Hurricane Wind Damage
2004 Hurricane Charley in Punta Gorda, FL
Manufactured Homes – Evacuate!
Hurricane Charley – 2004Punta Gorda, FL
March 2000 Ft. Worth, TXF2 intensity
(115-140 mph) tornado damage
What about a Category 4 (131-155 mph) hurricane
for a half hour?
Hurricanes & High Rise Buildings
Hurricane Dangers
• Fresh Water Flooding
Hurricane Danger Fresh Water Flooding
Jerry Padgett Jr. was killed when his car went into the water covered hole in Lake Wales during Charley.
Lannis WatersThe Palm Beach Post
Hurricane Dangers
• Tornadoes
Tornadoes in Hurricaes
• Right front quadrant of the storm relative to the storm motion
• 100 miles away from the center of the storm
Greatest Tornado Threat
2005 Tropical Cyclone Tornadoes
221 Total
Tornadoes in Hurricane Dennis
Tornado damage in Brandon
Hurricane Dangers
• Cleanup stage
• Dangers from:• debris removal• ladder falls• shutter removal• shortage of goods and services• crime and looting?
The NWS Needs Your Reports and Pictures
• Rainfall• Wind Speed and Direction• Damage• Flooding• Pressure
Our statements and your reports go directlyto the broadcast and print media.
Safety First
Hurricanes: When and Where?
2008 Hurricane Forecast
2008 Hurricane Forecast
2-3
6
10
NormalDr. Gray’s
Forecast
3Major Hurricanes
(>110 mph)
7Hurricanes
13Named Storms
As of 12/07/2007
NOAA issues its hurricane season forecast in May NOAA issues its hurricane season forecast in May during Hurricane Preparedness Weekduring Hurricane Preparedness Week
Switch Gears
CoCoRaHSCoCoRaHS“Because every drop counts”“Because every drop counts”
Weather observer
s to measure rain, hail,
and snow.
Community Collaborative Rain, Hail & Snow Network
http://www.cocorahs.orghttp://www.cocorahs.org
What Is CoCoRahs?““CoCoRaHS is aCoCoRaHS is a
grassroots, non-profit, grassroots, non-profit, community-based, community-based,
high-density high-density precipitation precipitation
networknetwork
made up of made up of volunteers of all volunteers of all
backgrounds and ages . . .backgrounds and ages . . .
. . . who take daily measurements of . . . who take daily measurements of
Rain, hail, and snow right in their own backyards”Rain, hail, and snow right in their own backyards”
How Does It Work?
High QualityVolunteers
Report their daily observation on
interactive web site:www.cocorahs.org
Data available immediately in map and Data available immediately in map and table form for the public to viewtable form for the public to view
Frequently Asked Questions
Do I have to be home everyday for CoCoRaHS?No. Report when you can. If you are gone, report a multi-day total when you return.
What if I don’t have a good place to put my gauge?Few people have ideal locations. Do your best.
What if it hails when I’m not home?Still send in your hail report. Report as much as you can find out from your friends and neighbors.
What Does It Take?
• Sign-up at http://www.cocorahs.org• Complete the online training
• Log into site and send in your reports
Easy Online Training
Florida has 428 volunteers since
October 1!
Any Questions?