Official alerts

What they are

An official alert is what a national weather service has issued: a Winter Storm Warning, a Wind Advisory, a Tornado Watch. Windshield Weather shows the alerts the US National Weather Service has in force, on the map and on your drive, and names who issued each one.

They sit beside the forecast and never change it. Your drive’s ratings, from Calm to Extreme, are our forecast for when you get there; an alert is the weather service’s own statement. A section can be Mild inside a Winter Storm Warning that starts after you have passed, or rated Hazard where no alert is in force. Read both.

How they look

Official alerts are always hatched, with diagonal stripes, and tagged OFFICIAL with the issuer’s name. Our forecast never is.

RED

The most dangerous warnings: tornado, extreme wind, blizzard, ice storm, flash flood, hurricane.

ORANGE

Other warnings: the hazard is happening or about to.

YELLOW

Advisories, hatched, and watches, outlined only: conditions are favourable for the hazard, nothing more yet.

INFO

Statements, such as a Special Weather Statement or an Air Quality Alert.

Each also carries its word — warning, watch, advisory or statement — so the level never rests on colour alone.

On the map

Turn on weather alerts in the map’s layers to see every alert area in force in the United States. Tap an area to open the alert; where several overlap, you get a list, worst first. Map layers and radar says where the switch is.

Official alerts are reaching accounts gradually. Until yours has them, the weather alerts row in the map’s layers says it is not available yet.

On your drive

When your route passes through an alert while it is in effect, the drive says so: a row such as “2 official alerts on your drive”, each section inside one tagged OFFICIAL, and the route hatched along that stretch. An alert counts when you are inside its area within half an hour of when it starts or ends.

Open an alert to see:

• who issued it, and its name exactly as issued;
• a one-line summary in your language;
• when it is in effect, from when until when, or until further notice;
• when it was issued, and the area it covers;
• the weather service’s full text and instructions, as issued, in English;
• a link to read it on weather.gov.

When alerts are unavailable

If we could not read the weather service’s alerts recently, the drive says “Official alerts unavailable” with a link to weather.gov, rather than showing none. An alert past the time the weather service promised to update it is greyed, and then hidden.

Where they come from

The US National Weather Service, part of NOAA: public domain, credited as “Source: NOAA National Weather Service”. Canada, Europe and South America are planned.