Experimental Tropical Cyclone Surface Wind Speed Probabilities
Graphics Product Description and
Call for Public Feedback
Contents
- Overview
- Description of the wind speed probabilities graphical products
- Potential advantages as compared to existing products
- Method for computing the Wind Speed Probabilities
Go to Experimental Text Product Description
3. Potential advantages as compared to existing products
The NHC already issues several products that help to convey the uncertainty in the track forecast. However, these products do not account for the
uncertainty that also exists in the forecast of the cyclone's intensity and size.
Watch/Warning Graphic for Ivan (2004) advisory #41: Indicates forecast track and long-term mean track forecast error (actual track lies within cone 2/3 of the time)
For the Ivan advisory #41 example of graphical wind speed probabilities shown earlier in section 2, the existing "watch/warning" or "cone of
uncertainty" graphic above indicates a
large region in which the center could move, but it only conveys the uncertainty in the track forecast. By comparison, the graphical wind speed
probabilities convey the combined uncertainty in track, intensity, and size at each point on the map, throughout the 5-day forecast period.
Strike Probability Graphic for Ivan (2004) advisory #41: Indicates likelihood of a "close approach" of the center of the cyclone
The existing strike probability graphic above depicts the chances of the "close" approach of the center of a tropical cyclone. However, the new experimental
probability graphics are about the weather. That is, the wind speed probabilities provide the chances of wind speeds equal to or exceeding familiar
thresholds (for example, tropical storm force and hurricane force) at individual locations on the map. Therefore, the wind speed probabilities likely
have more direct meaning and impact to users. Also, while the existing strike probability graphics only provide forecast information out to three days,
the experimental wind speed probability graphics provide information out to five days. Overall, the new wind speed probabilities have the potential
to provide users with information that enhances their ability to make preparedness decisions specific to their own situations.
Next: Method for computing the Wind Speed Probabilities
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