TROPICAL STORM DEBBY (2024)

Wind SpeedProbabilities	Arrival Time of Winds	WindHistory	Warnings/ConeInteractive Map	Warnings/ConeStatic Images	Warnings andSurface Wind	KeyMessages
MensajesClaves	PeakSurge	RainfallPotential	Flash FloodingPotential	U.S. TornadoPotential

Arrival Time of Tropical-Storm-Force Winds

Forecast Length*	Arrival Time of TS Winds	5-day Windspeed Probabilities
Full Forecast 3 days	Earliest Reasonable Most Likely	On Off

* If the storm is forecast to dissipate within 3 days, the "Full Forecast" and "3 day" graphic will be identical

About this product:

The timing graphics are created using the same Monte Carlo wind speedprobability model that is currently used to determine the risk of tropical-storm-and hurricane-force winds at individual locations – a model in which 1000 plausiblescenarios are constructed using the official NHC tropical cyclone forecast and its historicalerrors. Additional information on this product and the underlying technique is available on the NHC website.

There will be two versions of the Arrival of Tropical-Storm-Force Winds Graphicavailable on the NHC website for all tropical cyclones, post-tropical cyclones, and potentialtropical cyclones for which NHC is issuing advisories:

1. Earliest Reasonable Arrival Time: the primary graphic, which identifies the time windowthat users at individual locations can safely assume will be free from tropical-storm-force winds.Specifically, this is the time before which there is no more than a 1-in-10 (10 percent) chance ofseeing the onset of sustained tropical-storm-force winds – the period during which preparationsshould ideally be completed for those with a low tolerance for risk.


2. Most Likely Arrival Time: the graphic that identifies the time before or after which theonset of tropical-storm-force winds is equally likely. This graphic would be more appropriate for userswho are willing to risk not having completed all their preparations before the storm arrives.

Timing information will only be available for locations that have at least a 5 percent chance ofexperiencing sustained tropical-storm-force winds during the next 5 days.

Each of these versions will also be available overlaid on top of the cumulative 5-day probabilityof tropical-storm-force winds, providing a single combined depiction of the likelihood oftropical-storm-force winds at individual locations, along with their possible or likely arrival times.

The graphics will be updated with each new NHC full advisory package. Arrival times will bedepicted with higher temporal resolution (i.e., in 6-hour intervals) during the first day of the 5-dayforecast, increasing to lower temporal resolution (i.e., in 12-hour intervals) after the first day of the5-day forecast period. Arrival times will be referenced to 8 AM and 8 PM local time, using a constanttime zone that corresponds to where the cyclone is located at the time of the advisory. For example, ifa cyclone is located in the Eastern Time Zone at the time of an advisory but is forecast to move into theCentral Time Zone during the 5-day forecast period, all times on the graphic will be referenced to theEastern Time Zone.

Considering the combined forecast uncertainties in track, intensity, and size, thechances that any particular location will experience winds of 34 kt (tropical storm force),50 kt, or 64 kt (hurricane force) from this tropical cyclone are presented intabular form for selected locations and forecast positions. This information is also presented ingraphical form for the 34 kt, 50 kt,and 64 kt thresholds.

Note: This information is also available in PDF format.