TROPICAL CYCLONE TORNADOES

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1 TROPICAL CYCLONE TORNADOES 2018 GOVERNOR S HURRICANE CONFERENCE TUESDAY, MAY 15, 2018 WILL ULRICH NWS FORECAST OFFICE MELBOURNE

2 WHERE ARE THE TORNADOES?

3 WHERE ARE THE TORNADOES? C B A

4 WEST MELBOURNE, FL Monday, October 24, :40 AM

5 Hurricanes: Multi-Hazard Emergencies High Wind Storm Surge High Surf/Large Waves Flooding Rain Tornadoes

6 THE CHALLENGE The essence of the tropical cyclone (TC) tornado challenge is 1) Predicting tornadoes outside the area where people are prepared for maximum winds from a strong storm 2) Predicting tornadoes from weaker systems where tornadoes may pose the greatest threat Hagemeyer (1998)

7 Public MIS-communication Hurricane Evacuation Message Evacuation orders are in effect. Leave soon as possible if you are in a mandatory evacuation zone.? Tornado Warning Call-to-Action Take cover now! Move to an interior room on the lowest floor of a sturdy building.

8 Tropical Cyclone Tornadoes Possible with any tropical system (disturbances, depressions, storms, hurricanes) Generally EF0-EF1 (about 85%), and normally only 1 or 2 per storm Occur without hail and often with no lightning Develop anytime, day or night

9 Tropical Cyclone Tornadoes Certain weather factors appear to enhance tornado potential with landfalling systems wind shear most favorable in front right (NE) region dry air can enhance instability interaction with other weather features (boundaries, fronts, troughs, etc.) Threat can linger for several days after landfall Could see an extended period under tornado watches, especially if storm stalls

10 Tropical Cyclone Tornadoes % of tornadoes occur within 350 to 120 relative to the storms motion (right front region)

11 Tropical Cyclone Tornadoes 11 am/pm 4 am/pm NORTHWARD MOVING SYSTEM

12 Tropical Cyclone Tornadoes 1 am/pm 8 am/pm WESTWARD MOVING SYSTEM

13 Tropical Cyclone Tornadoes 26% of TC tornadoes occur near the innercore of the storm (~125 miles) 125 mi Outer rain band tornadoes have occurred miles from a storm s center!

14 Greatest Tornado Threat? C A B

15 What About Florida? Studies have shown north to northeastward moving TCs are the most active tornado producers for FL. A storm moving N- NE over the Gulf places FL within favored tornado region the longest Figure 1. Plots of TC tracks associated with significant tornado events in Florida. Hagemeyer (1998)

16 Hurricane Ivan (2004) Wednesday 9/15/04 Thursday 9/16/04 Friday 9/17/04

17 Hurricane Agnes (1972) 28 tornadoes were reported in FL and adjacent southeast GA 2 (F3), 9 (F2), 11(F1), 6 (F0) 7 tornado fatalities, 140 injured

18 Hurricane Irma 2017

straight-line winds? Not all damage is from tornadoes!

19 Tornado Surveys Determine intensity (using EF scale) AFTER it hits Look at nature of the damage to make an assessment of: tornado or straight-line winds? Not all damage is from tornadoes! Difficult to decipher damage from long-duration (hurricane) versus short-duration winds (tornado)?

20 Your Help is Crucial! Makes the process more efficient by providing preliminary information Where does damage start/stop? Where are the worst hit areas? Emergency Management often see the damage first hand before it is cleaned up

21 Forecasting TC Tornadoes SPC Severe Weather Outlooks NOTE: THESE ARE NOT PROBABILITY OF A SINGLE OCCURRENCE WITHIN THE OUTLOOK AREA! Storm Prediction Center issues severe thunderstorm outlooks, beginning 8 days out. Forecasts use probability of large hail/damaging thunderstorm winds or tornadoes within 25 mi of a single point

22 Forecasting TC Tornadoes SPC/WFO Tornado Watches Issued by the SPC in close coordination with local NWS offices Often issued within the favored right-front quadrant of the storm or right of the center Watches typically issued as a hurricane (and most tropical storms) threaten the coast

23 Forecasting TC Tornadoes WFO Tornado Warnings CHALLENGING! Fast-moving w/ little advance notice Potential for large warnings Short-lived radar signatures

24 Warning on TC Tornadoes Typically more shallow and subtle features (depth of convection, mesocyclone) when compared to classic supercells Becomes even harder to interrogate when far away from the radar!

25 Warning on TC Tornadoes Spratt et al. (1997): Identify trackable features to help radar operators focus their attention Ensure not to miss the obvious events! Schneider & Sharp (2007): Used combination of mesocyclone and supercell properties to assist in warning decision making Devanas et al. (2008) Applied techniques from above authors during Tropical Storm Barry in 2007 Crowe et al. (2010) Used dual-pol radar to analyze three supercells during Hurricane Rita in 2005

26 Tornadoes: The Pinky Toe! Most landfalling tropical cyclones produce at least one tornado Certain factors appear to enhance potential Can occur within rainbands hundreds of miles from the cyclone s center! Most common in right-front region In Florida, tropical cyclones moving north to northeast tend to produce the most tornadoes

27 TROPICAL CYCLONE TORNADOES QUESTIONS?

Tropical Update. 5 PM EDT Sunday, September 10, 2017 Hurricane Irma, Hurricane Jose, Tropical Wave (60%)

Tropical Update. 5 PM EDT Sunday, September 10, 2017 Hurricane Irma, Hurricane Jose, Tropical Wave (60%) Tropical Update 5 PM EDT Sunday, September 10, 2017 Hurricane Irma, Hurricane Jose, Tropical Wave (60%) This update is intended for government and emergency response officials, and is provided for informational