Tropical Storm Tornadoes – WFO Perspective Bart Hagemeyer NOAA/NWS Melbourne, Florida

“Working Together To Save Lives”

Tropical Storm Tornadoes – WFO PerspectiveBart Hagemeyer

NOAA/NWS Melbourne, Florida


10 DEADLIEST FLORIDA TORNADO OUTBREAKS

FEBRUARY 1998 42 DEADMARCH 1962 17 DEADAPRIL 1966 11 DEADJUNE 1972 7 DEAD HURRICANE AGNESJANUARY 1936 7 DEADSEPTEMBER 1882 6 DEAD HURRICANESEPTEMBER 2004 6 DEAD HURRICANE IVAN*APRIL 1925 5 DEADMARCH 1939 4 DEADOCTOBER 1992 4 DEAD Un-Named HybridAPRIL 1988 4 DEAD

(* Compare total of 7 direct wind-related deaths from Charley)


Increasing Population - Increasing Tropical CycloneActivity - Greater Documentation - Greater Risk

18801890

19001910

19201930

19401950

19601970

19801990

20002010

0

20

40

60

80

100

120

140

0

5

10

15

20

25

Tornado Events (85) (Y1)

Tornadoes (437) (Y1)

Population (Y2)

Through 2004 Season

Tropical and Hybrid Events by Decade

85 Cases (1882-2004)


Bonnie – Charley – Frances – Ivan - JeanneRecord Season with 74 Florida Tornadoes

54 F0, 17 F1, 3 F2

2004 Tornado Producing Tropical Cyclones


Types of Tornado-Producing Systems (1882-2004)

Hurricane 42

Tropical Storm 22

Tropical Depression 8

Sub-Tropical/Hybrid 8

Tropical Disturbance 5

Virtually all Tropical Systems produce tornadoes


694

1 2

RightFront

Location of Tornadoes Relative to Cyclone CenterWith Respect to Cyclone Motion (1882-2004)

9*

85 Cases


Tropical Cyclone Destructive Wind Forecast and Preparedness Challenges are:

-Tornadoes Associated With Dominant Outer Rainbands in the Right Front Quadrant.

-Extreme Winds of the Eyewall and Innermost Rainbands at Landfall.


FOCUS ON SIGNIFICANT TROPICAL/HYBRIDCYCLONE TORNADO EVENTS!

Any Tornado-Related Death

Five or More Tornadoes in 24-Hour Period With atLeast One Tornado of F2 or Greater Intensity

Any F3 Tornado

20 Significant Cases in Recorded History:

10 Huricanes, 6 Tropical Storms, and 4 Hybrid Cyclones

Most TC Tornadoes are Weak and Short-Lived


Track Segments of Significant Tropical/Hybrid CasesDuring Florida Tornado Production Phase 1882-2004

Charley

Ivan

All Significant Tornado Cases Began Well Before Landfall


Ivan Pre-Landfall Jeanne Pre-Landfall

Differences in Gulf and Atlantic Pre-Storm Environment


Significant Tornadoes - Focus on Outer Rainbands

Very Different Storms - Same Tornado

Result

OPAL

GORDON


Hurricane Opal 10/4/95F2 Tornado 1 Dead


Tropical Storm Gordon 11/15/94F2 Tornado 1 Dead


The Central Characteristic of a Tropical Cyclone is not a Reliable Indicator of

Tornado Potential – It is the Mesoscale Environment of the Dominant Outer Rainbands, Often 100 or More Miles

Away That Determines Tornado Potential.

Tornadoes are Typically the First Threat to Arrive


Hurricane Agnes June 1972 (Category 1) Tropical Cyclone Tornado Archetype


Hurricane Agnes June 1972

Deadliest Tropical Cyclone Tornado Outbreak in Florida History...28 Tornadoes in 26 hours... (2 F3, 9F2, 11 F1, 6 F0). 10 killer/injury tornadoes.


Experiences From 2004 Hurricane Season

Ivan Images – Irv Watson, SOO, WFO TLH


Ivan – Agnes Clone – Missed Peninsula!3 Killer Tornadoes - 2 F2 and 1 F1 – 6 Dead


0704 UTC 9/15/04


Blountstown Killer F2

0208 UTC 9/16/04


Irv Watson WFO TLH


20 Hours of Severe Weather Signatures


Note: Ivan also produced a tornado outbreak in VA and MD a day later!


*includes Georgia and Alabama Tornadoes

TLH CWAPOD 0.913FAR 0.846CSI 0.152AVG Lead Time 11.2 MinutesWarnings in Effect for Killers

Ivan Tornado Stats Summary

(MLB also had high FAR for Charley and Frances)


Hurricane Charley 8/13/04 – Late Morning

Classic Situation


MLB Graphical Hurricane Hazards 8/13/04

1130 AM


PrimaryOuter Rainband

EyeWall

2+ Million People

Friday Evening 8/13/04


BULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING

*AT 642 PM EDT...THE NATIONAL WEATHER SERVICE HAS ISSUEDA TORNADO WARNING FOR DESTRUCTIVE WINDS OVER 100 MPH AND TORNADOES IN THE EYE WALL AND INNER RAIN BANDS OFHURRICANE CHARLEY.

* THE LEADING EDGE OF HURRICANE CHARLEYS DESTRUCTIVE WINDS IS EXPECTED TO MOVE INTO THE KISSIMMEE AND GREATER ORLANDO AREA BY 715 PM.


Costliest Severe Storm in Orlando area history!

No Direct Lives Lost!

Customers Responded And requested we issue “eyewall” warning again for Frances and Jeanne.

LP1 station liked EAS


The Eyewall and innermost rainbands of landfalling hurricanes are extremely dangerous mesoscale phenomena that produce very localized devastation!

Charley – Metro Orlando


Hurricane Jeanne 25 SEP 2004


Conceptual Model of Hurricane Eyewall “Mini-Swirls”


Jeanne


BULLETIN - EAS ACTIVATION REQUESTED

TORNADO WARNING

NATIONAL WEATHER SERVICE MELBOURNE FL

858 PM EDT SAT SEP 25 2004

THE NATIONAL WEATHER SERVICE IN MELBOURNE HAS ISSUED A

* TORNADO WARNING FOR...

MARTIN COUNTY

ST. LUCIE COUNTY

IN EAST CENTRAL FLORIDA

* UNTIL 1000 PM EDT

* AT 855 PM EDT...THE NATIONAL WEATHER SERVICE HAS ISSUED A TORNADO WARNING FOR MARTIN AND ST LUCIE COUNTIES MAINLY FOR THE ONSET OF EXTREME HURRICANE WINDS AND EMBEDDED TORNADOES ASSOCIATED WITH THE INNER CORE OF HURRICANE JEANNE AS THE CENTER NEARS THE COAST. WINDS TO 100 MPH WITH GUSTS TO 120 MPH ARE EXPECTED...ALONG WITH TORNADOES.


• We are not attempting to warn for the individual enhanced convective features within the eyewall – They are ephemeral and moving at 100 mph.

• We are warning prior to the impact of the eyewall and/or innermost rainbands


Survey results -Jeanne

One Lucky Row of Manufactured Homes – Barefoot Bay


Eyewall “Mini-swirls”

And Some Not so Fortunate


• Eyewalls and innermost rainbands are dangerous mesoscale phenomena.

• Damage gradient extreme, destruction localized – county scale and lower.

• Historic severe weather events where they occur.

• Hurricane Warnings may have been out for 24 hours or more.

Extreme Hurricane Winds


• Power may be out and information lacking just before the worst hits (NWR, TV Re-broadcast).

• Citizens need final warning – last chance to save lives ~ 1-2 Hours. Need EAS.

• Not talking about track – but impact!

• WFO mission is suited for this role.


There is no reason to believe that in the future, a TC tornado outbreak could not kill more people than the February 1998 Extratropical Outbreak (42).

Remembering Agnes, and now Ivan, is useful as a planning metric – The outer rainband tornado archetypes – to realize what is really possible.

Concluding Thoughts – TC Tornadoes

We Now Know a Lot About Tornadoes and Tropical Cyclones...but Major Issues Remain.


The ability to separate the typical TC tornado from the truly dangerous outbreaks is improving.High resolution models and continued research provideour best chance for improvement.

Extended threat period with lengthy periods of inactivity followed by brief periods of strong tornadoes – hard to keep guard up that long - desensitizing risk is high.

Forecast ability has improved significantly: TornadoWatches are put up for most tropical cyclones. TornadoWarnings must be taken seriously, but potential for false alarms can be high in some cases. In other cases tornadoes can spin up rapidly with little warning.


Significant Tornado Parameter

CAPE, 0-6 km Shear, 0-1 km SRH, LCL hgt

(From SPC: Thompson et al., 2004)

Hurricane Charley

Local Analysis and Diagnostics


T.S. Gabrielle September 2001

ARPS Radar Reflectivity Simulation


Evacuation and Sheltering - Evacuate mobile -manufactured homes in threat area? - This could be 200 miles from landfall and 24 to 36 hours before landfall?

Safe Rooms in homes built for hurricanes will perform well for about 99% of Florida Tornadoes. Shelters in manufactured home parks would be beneficial.

Shelters don’t exist in most cases. But there are recent success stories: Gulfstream Harbor Manufactured Home Park – Orange Co. Florida Warning & Information Network Grant

700 Weather Radios for all residentsHardened Community Club HouseComprehensive Plan

Concluding Thoughts – Preparedness


Thank You!

Bart [email protected]

Tropical Storm Tornadoes – WFO Perspective Bart Hagemeyer NOAA/NWS Melbourne, Florida

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