Advanced SKYWARN Nick Petro Senior Forecaster National Weather Service, Ruskin, FL...

transcript

Advanced SKYWARN

Nick PetroSenior Forecaster

National Weather Service, Ruskin, FLNicholas.Petro@noaa.gov

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

70 at 5000 ft

90 at surface

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

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

90 Surface

10,000 feet

Stable Layer82

Need lifting to get bag above inversion

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

7 AM7 AM

3 PM3 PM

Calm Flow Lightning Activity

High Pressure Axis to North

Low Level Flow

8 AM8 AM

Low Level Flow

11 AM11 AM

Low Level Flow

1 PM1 PM

Low Level Flow

4 PM4 PM

Lightning Activity

High Pressure Axis to South

Low Level Flow

8 AM8 AM

Low Level Flow

11 AM11 AM

Low Level Flow

1 PM1 PM

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?

Katrina 5 Day Forecast Model Plots

08/24/2005 1:00 pm CDT.

NATIONAL HURRICANE CENTER ATLANTIC TRACK FORECAST ERRORS

12 24 36 48 72 96 120

Forecast Period (hours)

l mile

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

• 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

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

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?

Advanced SKYWARN Nick Petro Senior Forecaster National Weather Service, Ruskin, FL...

Documents