Radar is the last tool you use on a hurricane, not the first. For most of a storm’s life it is far out at sea beyond any radar station, tracked entirely by satellite and reconnaissance aircraft. Radar takes over in the final day or so — and that is exactly when the detail it provides matters most.
Important: this page explains how to read radar during a tropical system. It is not a warning service. Follow your national hurricane authority — the National Hurricane Center, your national meteorological service, or local emergency management — and evacuate when told to, regardless of what any map appears to show.
Overview
Weather radar has a useful range of roughly 150–250 km from each ground station. A hurricane 800 km offshore is therefore invisible to it. Once the outer bands come within about 200 km of a coastal station, radar begins to resolve the storm’s internal structure in a way satellite never can: individual rainbands, the eyewall, and any embedded rotation.
When Each Tool Is Useful
- Days 5 to 2 out: satellite and forecast models. The storm is mid-ocean. Track and intensity forecasts come from official agencies.
- Day 1: outer rainbands reach radar range. Structure becomes visible.
- Final 12 hours: radar is the primary tool for timing — when bands arrive, where the eyewall is heading, and which side of the storm you are on.
- During and after: radar shows the inland rainfall that frequently causes more deaths than the wind.
What to Look For on Radar
The eye and eyewall
In a well-organised hurricane the eye appears as a clear circle with little or no return, surrounded by a ring of intense red and purple — the eyewall, where the strongest winds and heaviest rain occur. A sharp, circular eyewall indicates a strong, well-organised storm. A ragged or open one suggests weakening or disruption.
Rainbands
Spiral bands extend outward, often hundreds of kilometres from the centre. They arrive well before the core and can produce damaging gusts, torrential rain and tornadoes in their own right. Conditions deteriorating hours ahead of landfall is normal, not a sign the forecast was wrong.
The dangerous side
In the northern hemisphere the right side of the track relative to the storm’s motion is generally worse, because the storm’s forward speed adds to its rotational wind there. In the southern hemisphere it is the left. Being 50 km on one side or the other is a materially different experience.
Embedded tornadoes
Outer rainbands frequently spawn brief tornadoes, especially in the right-front quadrant. These are difficult to see on standard reflectivity and are identified by forecasters using Doppler velocity data.
The eyewall replacement cycle
Intense hurricanes sometimes form a second eyewall outside the first, which contracts and replaces it. On radar this appears as a double ring. During the cycle peak winds usually ease slightly while the wind field broadens — often meaning a larger storm surge over a wider stretch of coast.
The Hazard Radar Cannot Show
Storm surge is the leading cause of death in hurricanes, and radar cannot see it at all. Surge is ocean water pushed ashore by wind and low pressure. It depends on storm size, track, forward speed, coastal shape and seafloor depth — none of which appear on a precipitation map. Surge forecasts come from dedicated models run by official agencies, and surge evacuation orders should never be second-guessed using radar.
Radar also cannot show wind speed at the surface, inland freshwater flooding potential, or infrastructure damage.
Inland Rain Is Often the Bigger Story
Storms weaken over land but do not stop raining. A decaying tropical system can drift slowly inland and produce catastrophic freshwater flooding hundreds of kilometres from the coast, often days after landfall and long after the wind threat has passed. Radar is genuinely valuable here, showing where the heaviest rain is stalling. The patterns to watch are the same ones covered in flash flood warning signs on radar.
Frequently Asked Questions
Can weather radar track hurricanes?
Only within roughly 150 to 250 km of a coastal radar station, which in practice means the final day before landfall. Hurricanes are tracked across open ocean by satellite and reconnaissance aircraft, then handed over to radar as they approach the coast.
What does the eye of a hurricane look like on radar?
A clear circular area with little or no radar return at the centre, ringed by intense red and purple marking the eyewall. A sharp, symmetrical eye indicates a strong, well-organised storm; a ragged or open one suggests weakening.
Which side of a hurricane is worse?
In the northern hemisphere, the right side relative to the direction of travel, because forward motion adds to rotational wind speed there. In the southern hemisphere it is the left side.
Can radar show storm surge?
No. Radar detects precipitation in the atmosphere, not ocean water. Storm surge is the deadliest hurricane hazard and is forecast using separate models run by official agencies. Never use radar to judge surge risk or to question an evacuation order.
Do hurricanes produce tornadoes?
Yes, commonly in the outer rainbands and most often in the right-front quadrant. They are usually brief and relatively weak but can occur with little warning.
Why is it raining hours before the hurricane arrives?
Because spiral rainbands extend hundreds of kilometres ahead of the centre. Deteriorating conditions well in advance of landfall are normal and expected.