Do you know the difference between a watch, warning and an advisory?
The National Weather Service is the go-to government agency for alerting the public about various weather-related hazards. You’re probably most familiar with what they do when they issue a Flash Flood Watch or a Severe Thunderstorm Warning.
You’ll likely get an alert on your phone or will see the messaging pop up on your TV when that happens. But do you know the difference between a watch, warning and an advisory?
I recently sat down with Phil Hysell – the Warning Coordination Meteorologist for the National Weather Service office in Blacksburg – and Eric Seymour – who holds the same position for the agency’s office in Wakefield.
NOAA's Climate Prediction Center has released its seasonal outlook for both precipitation and temperature. And the data suggests that most of the Commonwealth is looking to be warmer than average and have a bit more precipitation than normal in the coming months.
To give you an idea of what that means -- the average maximum temperature for Blacksburg from 2000 to this year in May, June and July is 73 degrees, 80 degrees and 83 degrees respectively.
That is partly to be expected with the summer months around the corner when it comes to temperatures. But, so far, 2023 has been pretty warm across the Commonwealth.
This graphic (courtesy of NCEP/NOAA) shows that Virginia had its warmest January-April period ever recorded. That's a pretty significant bar to cross, as the record for this particular measurement goes all the way back to 1895.
Those two offices cover a significant portion of the Radio IQ listening area, so I thought it would be good to get insight on that question from the people who play a role in watches and warnings getting to Virginians.
Off the bat, Seymour says the public – for the most part – doesn’t understand the difference between a watch and an advisory. He offers up a great analogy on how to understand what the difference is. Think of it as fixing tacos…
“The watch phase is you have all the ingredients together – you’ve got meat, you’ve got the cheese, you’ve got the salsa, the tomatoes, the lettuce – but they’re all in their own individual containers still," he explains. "When we get to the warning phase, we’ve actually taken all of those and we’ve actually built the taco. All that stuff is actually in the taco and we’re about to eat.”
In other words, a watch is just that – conditions are present that need to be watched out for that could led to hairy weather later on. Warnings mean those conditions have come together.
Hysell adds some information about advisories.
“Those are issued for things like minor flooding or maybe a winter weather event. And these are issued for nuisance events that should not be life threatening if – and this is a big if – if caution is exercised.”
Seymour and Hysell say the actual issuance of watches, warnings and advisories is often a large collaboration between national sources and the local forecast offices. For example, Severe Thunderstorm Watches come from the Storm Prediction Center in Norman, Oklahoma. And the SPC does that for the entire country. It then falls to the local forecast offices to issue a Severe Thunderstorm Warning as the conditions come together and storms begin to form.
At the national and local level, NWS is constantly monitoring conditions to issue all of those watches, warnings and advisories – also known as products. But, they also have to follow up when they do that.
Using the Severe Thunderstorm Warning as an example, the Weather Service defines a severe storm as one with winds 58 mph or greater and/or hail that is the size of a quarter or larger.
Hysell says local offices have to comb through the area – through cold calls to people living there or to weather spotters – to verify if those things actually occurred.
Seymour adds that can be especially difficult in rural parts of the state.
“Folks in the rural areas in a lot of cases are really resilient. So sometimes, the flooding occurs, but they know how to mitigate what’s going on," Seymour says. "So, it is harder to get the information in those areas. I think one of the things that we can stress is if you see something, call it in.”
That verification information is used by Congress to determine how well the National Weather Service is doing its job of protecting life and property. It is also used by local governments as they apply for hazard mitigation grants.
I looked into it and there are about 120 different products or headlines that NWS can issue a watch, warning or advisory for. Some of those aren’t exactly weather-related – like a Civil Emergency or Law Enforcement Warning – and others like the Severe Thunderstorm Warning mentioned above aren’t issued at the local level.
Still, Hysell says the National Weather Service has been working to simplify.
“We have an initiative called Hazard Simplification. And what we’ve done is already reduced the number of hydrologic products – like, we used to have Urban and Small Stream Flood Advisories, Flood Advisories – now it is just simply a Flood Advisory to eliminate that confusion," he explains. "We are aware of that, and we are taking steps to reduce the number of headlines that we could potentially issue.”
He adds the agency is currently looking at consolidating its winter weather and extreme temperature-related suite of products as well.
Both of these Warning Coordination Meteorologists stress that the public plays a role in this process as well. It’s important to have some level of education about the information that comes out of the National Weather Service – which often is as simple as knowing the difference between a watch and a warning. The pair says it’s vital to have multiple ways to get that information, too, and to just be weather-aware on days when you know there is the potential for conditions outside to be bad.
Hysell adds that anyone can help the National Weather Service with its verification process as well. They have a program called SKYWARN, which allows people to voluntarily report weather conditions to the agency following a training course.