12.2: Tracking and forecasting hurricanes

Tracking hurricanes

Because of its cold ocean waters and the typical east-to-west tracks of tropical cyclones, California is spared most of the hazards produced by Hurricanes. This isn’t the case across the entire East and Gulf Coasts of the United States. In early October 2018, the Florida Panhandle experienced the wrath of Hurricane Michael, which intensified rapidly prior to landfall. Figure 12.2.1 is an advisory map for Michael that includes its location, intensity, wind speed, and direction of travel, projected path and intensity, and any watches or warnings issued for the storm. This advisory was issued at 7 pm Central Daylight Time on Sunday, October 7, 2018.

Figure \(\PageIndex{1}\): Advisory Map of Michael issued at 7 pm CDT on Sunday, October 7, 2018. (Public Domain; Hurricane Michael Archive via National Hurricane Center). Alternative description of the image. 

6. At the time of this advisory (Figure 12.2.1), Michael was a:
   1. Tropical Depression (D)   
   2. Tropical Storm (S)
   3. Hurricane (H)   
   4. Major Hurricane (M)

The scale used to rate tropical cyclones is the Saffir-Simpson scale, which classifies storms by current wind speed. The list of classifications are provided in Table 12.2.1.

Table 12.2.1: Tropical cyclone intensities according to the Saffir-Simpson hurricane scale.

Classification	Wind Speed
Tropical Depression	Below 39 mph
Tropical Storm	39-73 mph
Category 1 Hurricane	74-95 mph
Category 2 Hurricane	96-110 mph
Category 3 Major Hurricane	111-129 mph
Category 4 Major Hurricane	130-156 mph
Category 5 Major Hurricane	Above 156 mph

7. The storm was located (the orange circle with the black dot in the middle):
   1. In the Western Gulf of Mexico
   2. Just off the coast of Florida
   3. Between the Yucatan Peninsula and Cuba   
   4. Near Antarctica
8. The blue outlining on the coastlines mentioned in Figure \(\PageIndex{1}\) indicates that those regions were under a ________ .
   1. Tropical Storm Watch   
   2. Tropical Storm Warning
   3. Hurricane Watch   
   4. Hurricane Warning

Watches and Warnings are issued by local governments (in the United States, the National Hurricane Center is responsible for issuing watches) based on the following criteria in Table 12.2.2.

Table 12.2.2: Different tropical cyclone advisories and what they mean.

Advisory Type	What it means
Tropical Storm Watch	Tropical Storm Conditions Possible within 48 hours
Tropical Storm Warning	Tropical Storm Conditions Expected within 36 hours
Hurricane Watch	Hurricane Conditions Possible within 48 hours
Hurricane Warning	Hurricane Conditions Expected within 36 hours

9. At 7 pm CDT on Sunday, October 7, 2019 (Figure \(\PageIndex{1}\)), the storm was _________ from striking the U.S. Gulf Coast. Therefore, watches and warnings could not yet be issued.
   1. Less than 36 hours away
   2. Between 36 and 48 hours away
   3. More than 48 hours away
10. At 7 pm CDT on Sunday, October 7, 2019, Michael was forecast to ____ on Wednesday:
    1. Hit Texas as a Tropical Storm   
    2. Hit Florida as a Hurricane
    3. Completely dissipate (die off)   
    4. Hit Florida as a Major Hurricane 

Let's move forward in time to Michael’s forecast position and intensity at 1 am on Tuesday, as shown in Figure 12.2.1. The location is shown by a big black dot with an “H” in the middle. Figure 12.2.2 is the advisory issued at 1 am on Tuesday, October 9, 2018.

Figure \(\PageIndex{2}\): 1 am CDT Advisory for Michael on October 9, 2018. (Public Domain; Hurricane Michael Archive via National Hurricane Center). Alternative description of image. 

11. By the time of Figure 12.2.2, Michael had:
    1. Weakened into a Tropical Depression
    2. Remained a Tropical Storm
    3. Strengthened into a Hurricane
    4. Strengthened into a Major Hurricane (to check, look at the wind speed).
12. It’s location at the time of Figure 12.2.2 was ________ from the forecast location at 7pm on Sunday, October 7, 2018 (Figure 12.2.1).
    1. Within a few degrees of longitude and latitude
    2. Many degrees of longitude and latitude
13. At this point, _____ have been issued for parts of the United States, particularly Florida and Alabama. 
    1. Hurricane Warnings
    2. Tropical Storm Warnings
    3. Tropical Storm Watches
    4. All of these
14. As of this time, Michael was expected to strike the Florida Panhandle as a:
    1. Tropical Storm
    2. Hurricane   
    3. Major Hurricane

Let's move on to Figure 12.2.3, the 7 am CDT Advisory for Wednesday, October 10, 2018, issued just hours before Michael made landfall.

Figure \(\PageIndex{3}\): 7 am CDT Advisory map for Michael on Wednesday, October 10, 2018. (Public Domain; Hurricane Michael Archives via National Hurricane Center). Alternative description of image.

15. At the time of Figure 12.2.3, Michael __________ intensify into a Major Hurricane, as was forecasted in Figure 12.2.2 (Hint: Check the current wind speed.)
    1. did
    2. did not
16. At the time, Michael was a __________ hurricane (refer to table 12.2.1 for classification).
    1. Category 1   
    2. Category 2   
    3. Category 3   
    4. Category 4
17. After making landfall, Michael was forecast to:
    1. Travel west and strike Texas as a Major Hurricane
    2. Travel northeast and gradually weaken
    3. Remain stationary near the Florida Coastline as a Major Hurricane

Any time an active storm is present, you can visit the National Weather Service’s National Hurricane Center (NHC) webpage, which provides a map of current storms and a plethora of information about the current and forecast position and intensity of hurricanes. Hurricane outlooks from prior storms can be retrieved from the archive page, accessible via the Archive link on the NHC homepage.