1. ANNUAL TROPICAL CYCLONE, DISASTER PREPAREDNESS & CLIMATE WORKSHOP
GUAM
Chip Guard
Warning Coordination Meteorologist
Weather Forecast Office Guam

2. Purpose of the Workshop
Familiarize you with tropical cyclone hazards, characteristics, and behavior
Familiarize you with the tropical cyclone program and products for Guam
Discuss typhoon risks & vulnerabilities for Guam
Familiarize you with causes of weather around Guam
Familiarize you with other weather and ocean hazards, including rip currents, tsunamis, volcanoes
Familiarize you with Guam’s climate
Provide an opportunity for you to ask questions on weather- or climate-related topics

3. Tropical Cyclone Topics
Tropical Cyclone Characteristics, Behavior and Hazards
NWS Tropical Cyclone Program
NWS Tropical Cyclone Products
Timing of Products

4. Tropical Cyclone Characteristics
Tropical Cyclone Structure and Behavior
Hazards Associated with a Tropical Cyclone—The Triple Threat

5. What Is A Tropical Cyclone?
It’s a large area of clouds with a warm core low pressure center, which usually forms over tropical waters and has an organized circulation.
It is like a pancake!

6. Stages of Tropical Cyclones
TROPICAL CYCLONE...a general term that includes tropical depressions, tropical storms, typhoons and super typhoons
TROPICAL DEPRESSION...a tropical cyclone with maximum sustained winds of 38 mph or less
TROPICAL STORM...a tropical cyclone with maximum sustained winds within the range 39 to 73 mph
TYPHOON...a tropical cyclone with maximum sustained winds of 74 mph or greater
SUPER TYPHOON...a typhoon with maximum sustained winds of 150 mph or greater

7. Different Stages of Tropical Cyclone Development

8. Different Shapes and Sizes of Tropical Cyclones

9. Necessary Ingredients
a pre-existing disturbance
warm ocean water...temperature at least
80 degrees F down to a depth of 150 ft
light upper level winds...little or no wind
shear

10. Typhoon Structure

11. Typhoon Structure

12. THE TRIPLE THREAT Winds Storm surge and surf
Heavy rain producing floods and
mudslides

13. Winds: Sustained and Gusts
wind dir 07 11 15 19 23 03
85(100)
70(80)
50(60)
35(40)
17(20)
0(0)
105(120)
ktmph
29.770
29.495
29.220
28.945
28.670
28.395
28.120
stn pres
direction
pressure
speed

14. Tropical Cyclone Winds
150
feet
Few People Live Here
700 feet--
Most People
Live Here
15 feet-----
Most tourists stay here

15. Types of Wind Damage

16. Types of Wind Damage

17. Wind Damage

18. Wind Asymmetry Associated With Tropical Cyclones
“Right side of the storm" is defined with respect to the storm's motion: if the cyclone is moving to the west, the right side would be to the north of the storm; if the cyclone is moving to the north, the right side would be to the east of the storm, etc.
In general, the strongest winds are found on the right side of the cyclone because the motion of the cyclone also contributes to its swirling winds.

19. Wind Intensity and Distribution in a Tropical Cyclone
Strongest winds are located in right quadrant because of effect of speed of movement is added to wind distribution. (Likewise, winds are weaker in left quadrant because effect of the speed of movement is subtracted from the wind field. )
Therefore, if cyclone passes south or west of island, then winds may be stronger than forecast. Or, if a cyclone passes north or east of island, then winds may be weaker than forecast.

20. Tropical Cyclone Wind Asymmetries
100 MPH
60 MPH
75 MPH
125 MPH
(a)
(b)
(d)
(c)

21. Wind Direction if a TC Passes North or East or North of Your Island
Bay Ballot’s Law: Face into wind and low pressure is to your right (in the northern hemisphere)
If winds are from the NE, the TC is SE of island
If winds are from the N, the TC is E of island
If winds are from the NW, the TC is NE of island
If winds are from the W, the TC is N of island
If winds are from the SW, the TC is NW of island

22. Wind Direction if a TC Passes South or West of Your Island
Bay Ballot’s Law: Face into wind and low pressure is to your right (in the northern hemisphere)
If winds are from the NE, the TC is SE of island
If winds are from the E, the TC is S of island
If winds are from the SE, the TC is SW of island
If winds are from the S, the TC is W of island
If winds are from the SW, the TC is NW of island

23. HIGH SEAS—Small Craft Stay in Port!!!! Inter-Island Travel is Dangerous!!!!
Guam

24. STORM SURGE
Storm surge is the increase is sea height above the normal tide level, caused by the tropical cyclone’s low pressure and strong winds.
Low pressure component ft elevation per 50 mb drop in pressure
Wind component…strong winds cause water to pile up in the right front quadrant.
Inundation is the water that penetrates into normally dry land. Depends on speed and duration of the wind; TC size, speed of motion; shape of coast, slope of bottom, width of the reef; and tidal state (high or low) are all important. The storm surge plus the tide is the storm tide.

25. Storm Surge: Affects of Reefs

26. Storm Surge

27. Surf and Storm Surge

28. Heavy Rainfall Rainfall produced by cyclones can be highly variable
Amounts depend on the size of the storm, the speed at which it is moving, and the location of its rain bands
Typically 6 to 12 inches of rain can fall as a storm passes
Rain rates can be 6+ inches per hour, 20+ inches total
Coastal flooding will occur when the ocean level is elevated and rain cannot flow back to the sea
Flash flooding many occur as streams and rivers overflow
Mudslides may result due to saturated soils and wind stress on trees and foliage

29. Heavy Rainfall Producing Floods and Flash Floods
Heavy rains are rapidly directed to the base of the mountain causing flash floods
Elevated sea levels prevent rains from draining to the sea causing coastal flooding

30. Heavy Rainfall Contributes to Coastal Flooding and Inland Flooding

31. Heavy Rainfall Producing Mudslides

32. Heavy Rainfall Producing Mudslides
Estimated Critical Parameters
~ 15” rain falls in 36 hours
continued 1” per hour rain
We Will Issue a Special Weather Statement for Mudslides When:
~ 10” rain falls in 36 hours or less
rainfall greater than 0.50” per hour is expected to continue

33. Heavy Rainfall Producing Mudslides

34. Heavy Rainfall Producing Mudslides

35. Heavy Rainfall Producing Mudslides

36. Heavy Rainfall Producing Mudslides
Most Vulnerable Areas
where a slide occurred before, but bedrock is not exposed
the steeper areas made of clay
where vegetation has been removed

37. How Do Tropical Cyclones Get Named?
JTWC used to name them
Now the World Meteorological Organization names them through
the Japan Meteorological Agency
Five lists of names taken from 12 countries
Does anyone know the Chamorro names?

38. How Do Tropical Cyclones Get Named?
Does anyone know the Chamorro names?
Roke, Francisco, Maria, Vicente

39. Break Time

40. WEATHER FORECAST OFFICE (WFO) GUAM’S TROPICAL CYCLONE PROGRAM FOR GUAM

41. Weather Forecast Office Guam

42. Guam’s Area of Responsibility

43. WFO Guam Tropical Cyclone Warning Points

44. TROPICAL CYCLONE PROGRAM
Tropical cyclone watch and warning procedures
Tropical cyclone program products/messages
Products schedule

45. Warning Process
Starts with the Products of the Joint Typhoon Warning Center in Hawaii
Weather Service Forecast Office in Guam Analyzes JTWC Products and Issues Watches and Warnings
Weather Forecast Office Guam Notifies Guam Civil Defense

46. Warning Process
Homeland Security/Office of Civil Defense Works with the Governor’s Office to set CORs

47. Warning Process
Civil Defense informs the general public and government agencies, and provides preparedness instructions

48. Joint Typhoon Warning Center (JTWC):
Located at Pearl Harbor, Hawaii; area of responsibility is 110 million square miles
Consists of a team of Navy and Air Force meteorologists who use numerous tools to analyze TC location, intensity and wind distribution, and computer models to help predict the future movement
JTWC responsible for all US tropical cyclone forecasting in the Northwest Pacific

49. Joint Typhoon Warning Center (JTWC):
Monitors region for developing tropical weather systems—Significant Tropical Weather Advisory
Alerts that systems are showing the potential for development into SIGNIFICANT tropical cyclones within the next 12 to 24 hours—Tropical Cyclone Formation Alert
Issues track and intensity forecasts for all tropical cyclones (30 mph and stronger) in the region—Tropical Cyclone Warnings

50. NWS WFO Guam:
Monitors Area of Responsibility (AOR) for weather systems showing signs of developing into tropical cyclones—Satellite Interpretation Message.
Maintains direct communications with JTWC regarding these areas of disturbed weather.
Will issue Special Weather Statements to cover areas not yet warned on by JTWC. We may change to a Tropical Disturbance Advisory

51. NWS WFO Guam:
Evaluates JTWC warnings for potential effect upon specific islands within the AOR. Based on assessments, WFO Guam sets tropical cyclone watches and warnings, and issues other products.
Tropical Cyclone Public Advisories (WTPQ31-35 PGUM)
Typhoon Local Statements (WTPQ81-85 PGUM)
We watch out for Micronesia and will deviate from the JTWC warnings if we deem it necessary.

52. TROPICAL CYCLONE WATCH AND WARNING PROCEDURES
DEFINITIONS
ISSUING WATCHES AND WARNINGS FOR THE ISLANDS
CANCELING WATCHES AND WARNINGS

53. Definitions
Damaging Winds: Sustained surface winds of 39 mph or more (averaged over a 1-minute period).
Destructive Winds: Sustained surface winds of 60 mph or more (averaged over a 1-minute period).
Tropical Storm Watch: An announcement for specific islands that a tropical storm or developing tropical storm (winds 39 to 73 mph inclusive) poses a possible threat generally within 48 hours.
Typhoon Watch: An announcement for specific islands that a typhoon or developing typhoon (winds 74 mph or more) poses a possible threat generally within 48 hours.

54. Definitions
Tropical Storm Warning: A warning for tropical storm conditions, including 1-minute sustained surface winds within the range of 39 to 73 mph, that are expected at specified islands within 24 hours or are occurring.
Typhoon Warning: A warning that typhoon conditions, including 1-minute sustained surface winds of 74 mph or more, are expected at specified islands within 24 hours or are occurring.

55. Issuing Watches and Warnings
The goal of timing the typhoon warning on initiation of 39 mph winds is to provide the people about 24 hours—12 hours of daylight—to complete preparations before weather conditions begin to deteriorate significantly.
If we issued the warning 24 hours prior to the expected start of typhoon force winds (74 mph or more), final preparations might not be completed before the arrival of damaging winds, exposing people to dangerous conditions. This could happen with a typhoon that speeds up or rapidly intensifies.

56. Issuing Watches and Warnings
Criteria for issuing a Watch: When damaging winds are possible within 48 hours.
A Tropical Storm Watch is issued when a JTWC forecast indicates that a tropical cyclone will be at tropical storm intensity when it passes and damaging winds (39 mph or more) are possible within 48 hours. The tropical cyclone may currently be a tropical storm or a tropical depression that is forecast to intensify.

57. Issuing Watches and Warnings
Criteria for issuing a Watch: When damaging winds are possible within 48 hours.
A Typhoon Watch is issued when a JTWC forecast indicates that a tropical cyclone will be at typhoon intensity when it passes and damaging winds (39 mph or more) are possible within 48 hours. The tropical cyclone may currently be a typhoon or a tropical storm that is forecast to intensify.

58. Issuing Watches and Warnings
Criteria for issuing a Warning: When damaging winds are expected within 24 hours.
A Tropical Storm Warning is issued when a JTWC forecast indicates that a tropical cyclone will be at tropical storm intensity when it passes and damaging winds (39 mph to 73 mph) are expected within 24 hours. The tropical cyclone may currently be a tropical storm or a tropical depression that is forecast to intensify.

59. Issuing Watches and Warnings
Criteria for issuing a Warning: When damaging winds are expected within 24 hours.
A Typhoon Warning is issued when a JTWC forecast indicates that a tropical cyclone will be at typhoon intensity when it passes and damaging winds (39 mph or more) are expected within 24 hours. The tropical cyclone may currently be a typhoon or a tropical storm that is forecast to intensify into a typhoon.

60. Issuing Watches and Warnings
Criteria for issuing a Warning: When damaging winds are expected within 24 hours.
Tropical Storm Warning and Typhoon Watch: If the forecast winds are being produced by a typhoon passing at some distance, the pre-existing typhoon watch is also maintained (remains in effect). (Note that the Typhoon Watch indicates that typhoon strength winds are still possible at the location but not currently expected.) Thus, a Tropical Storm Warning and Typhoon Watch may be in effect simultaneously for an island.

61. Canceling Watches and Warnings
WATCHES are canceled when the threat of the tropical storm or typhoon ends, either by moving away or by dissipating
WARNINGS are canceled when damaging winds (39 mph) cease and the potential for coastal flooding/inundation by the sea has subsided or when damaging winds are no longer expected.
In either case, there is close coordination with HS/OCD.

62. Canceling Watches and Warnings
A typhoon warning will not normally be stepped down to a tropical storm warning as winds diminish to below typhoon intensity at an island. Rather, the typhoon warning will remain in place until winds are less than damaging (below 39 mph), and coastal flooding has ended.
A typhoon warning may be downgraded to a tropical storm warning only if a typhoon changes direction or weakens significantly, and typhoon conditions are deemed no longer possible.

63. Conditions vs. Watch/Warnings Based on onset of damaging winds…
Condition 4: within 72 hours
Condition 3: within 48 hours
Condition 2: within 24 hours
Condition 1: within 12 hours
Watch: within 48 hours
Warning: within 24 hours

64. Summary
Watch indicates damaging winds (39 mph) are possible within 48 hours or less.
Types of watches: Tropical Storm (39 to 73 mph) or Typhoon (74 mph or greater); provides an indication of the tropical cyclone’s possible sustained wind threat.
Warning indicates damaging winds (39 mph) are expected within 24 hours or less.
Types of warnings: Tropical Storm (39 to 73 mph) or Typhoon (74 mph or greater); provides an indication of the expected sustained winds at an island as the tropical cyclone passes.

65. TROPICAL CYCLONE PRODUCTS
JTWC Bulletin
Public Advisory
Local Statements
Position Estimates

66. JTWC Bulletin

67. JTWC Bulletin (cont’d)

68. JTWC Warning

69. Tropical Cyclone Public Advisory
Primary source of cyclone information

70. Public Advisory
Used to issue and cancel all tropical cyclone watches and warning
Provides essential information about tropical cyclone:
Location; movement; intensity
Gives general forecast information: timing of damaging and typhoon winds, storm surge height, and precipitation amounts
Provides general call to action statements/ precautions that the public should take

71. Types of Public Advisories
Standard Public Advisory:
Issued every 6 hours (2 pm, 8 pm, 2 am, and 8 am) after receipt of new JTWC warning
Used to place an island in under a watch or warning
Intermediate Public Advisory
Issued between Standard Advisories (11 am, 5 pm, 11 pm, and 5 am)
Used to update TC location and track information
May be used to clear watches and warnings
Special Public Advisory
Issued to provide significant TC forecast changes (can be any time except Standard Public Advisory times)
May be issued to set new watches or warnings between Standard Advisory times

72. Public Advisory Layout
...HEADLINE...
SUMMARY OF WATCHES AND WARNINGS IN EFFECT
CALL TO ACTION STATEMENTS
LOCATION, MOVEMENT & CURRENT INTENSITY
FORECAST INFORMATION
NEXT ADVISORY TIME

74. Tropical Cyclone Local Statement
Detailed bulletin containing tropical cyclone information

75. Local Statements
Provides detailed local information regarding the expected magnitude and timing of the tropical cyclone’s threat to each affected island
Lists all watches and warnings in effect
Provides evacuation and other information from OCD
Presents storm specific information: location, movement and intensity
Wind information: current wind, onset time of damaging and typhoon winds, maximum wind, potential damage from forecast winds, ending times
Storm surge, surf, and inundation information
Expected precipitation amounts and potential for flooding and mudslides

76. Local Statement Layout
...HEADLINE...
WATCHES AND WARNINGS IN EFFECT
STORM SPECIFIC INFORMATION
FOR INDIVIDUAL ISLANDS:
PRECAUTIONARY ACTIONS (EMO PROVIDED COR/EVACUATION INFO)
STORM SURGE/SURF INFORMATION
WIND INFORMATION
PRECIPITATION FORECAST
NEXT LOCAL STATEMENT ISSUANCE TIME

78. Universal Time Coordinated (UTC) or Zulu (Z) Time
What is UTC or Z time?
It is the time at Greenwich, England
It is the time on the Zero (0o) Meridian
It is 12 hours from the Date Line (180o) Meridian
Why use UTC or Zulu time?
So we can compare times anywhere in the world.
How does Guam/Chamorro time differ from UTC?
We are 10 hours ahead.
00 UTC = 10 am; 12 UTC = 10 pm; 14 UTC = 12 am
the next day; 20 UTC = 6 am the next day

79. Product Schedule Tropical cyclone warnings are valid at:
00Z (10 am), 06Z (4 pm), 12Z (10 pm), and 18Z (4 am)
Tropical cyclone warnings are issued at:
03Z (1 pm), 09Z (7 pm), 15Z (1 am), and 21Z (7 am)

80. Product Schedule

81. Position Estimates

82. Position Estimates
Only issued when tropical cyclone is within radar range (230 miles) and radar info is reliable
Short bulletin that updates the center location
Lat/long info and as a distance and bearing from one of the Mariana Islands (typically Guam)
Updated hourly
This position data will be used as the location information in succeeding Public Advisories and Local Statements

83. Position Estimates

84. Position Estimates

85. Position Estimates USER BEWARE!
Short term variations may not be indicative of changes in overall motion of the tropical cyclone

86. Product Schedule

87. Product Schedule

88. WFO Guam Office Information
OPERATIONS HOURS: OPEN 24 HOURS
IMPORTANT PHONE NUMBERS:
Warning Coordination Meteorologist: (671)
Guam Duty Forecaster: (671)
Guam FAX: (671)
Guam HS/OCD (671)
WFO GUAM INTERNET ADDRESS:
JTWC PRODUCTS:

89. Any Questions?

90. Now HS/OSD Will Discuss Its Operations and Coordination

91. LUNCH BREAK