“Those two pieces of information, the intensity and the center location, are provided to the modelers and the National Hurricane Center (NHC) itself every six hours or so. Because if you get the location wrong or you get the intensity wrong at the beginning, you’re initializing the model, or the NHC official forecast that uses the model, in the wrong place or at the wrong intensity.”
“The model then would say the storm is going one way with this intensity when in fact, if you put in the correct location, it may have gone a different way. It’s important to get the initial conditions right of what’s happening now, where is the storm now, how strong is the storm now. If you do that well, then it gives the models a much better chance of forecasting the track and intensity correctly down the road.”
Additionally, GOES data regarding sea surface temperature, wind shear, atmospheric moisture levels, and nearby dominating weather systems that can strengthen or weaken and steer a storm are also integral for forecasting and modeling.
“The ultimate track of a storm, where will it be in five days, often will depend on some weather feature, some trough of low pressure or ridge of high pressure, that currently is way up over maybe the Northwest U.S. or even Alaska or Canada. It may depend on a jet stream that’s way far away at that time. Therefore, we need to get that right, too,” said Dr. Lindsey.
“We need to know where the jet [stream] is in a correct location far away from the storm because the model forecast will then say, ‘take the jet stream and move it down,’ or ‘take the trough,’ or ‘take the ridge,’ and in five days it may begin interacting with the storm itself.”
“The data assimilation system, which the satellite data feeds, will help you get all of that right. It gets the whole global model picture correct, which is important.”
This morning, #GOESEast is looking at atmospheric moisture across North America. A slow-moving front is bringing thunderstorms and heavy rain (white and green) over the Southeast while drier air (yellow) is providing clear skies over the central and southern Plains. pic.twitter.com/gUkrtlaWgA
— NOAA Satellites (@NOAASatellites) October 5, 2021
(Caption: While the GOES satellites are instrumental in hurricane tracking and forecasting, they serve a vital, daily role in continental weather system monitoring and forecasting as well.)
Given how important the GOES platforms are for hurricane forecasting, what’s the contingency if one were to suffer an issue during hurricane season — especially given that GOES East cannot see most of the Eastern Pacific and GOES West cannot really see the Atlantic basin?
On July 22, 2021, a memory bit-error on GOES-17, currently in the GOES West position, was detected, triggering a safe mode event that shut down the satellite to protect its systems. NOAA was able to recover the satellite and return it to service the following day — a significant period of time on tropical timescales.
The previous year, in June 2020 during the most active Atlantic hurricane season on record, GOES-16’s (in the GOES East location) ABI sensor malfunctioned. The satellite was returned to operations within hours.
Thankfully, these issues were minor and not full-scale failures. But such scenarios are planned for.
“It’s important to always have a backup,” said Dr. Lindsey. “Therefore, we do always have a backup satellite on orbit. Right now, the backup satellite is in the center of the country; it’s GOES-14. It serves as our on-orbit spare. It’s sitting at 105 degrees West and is ready to be used if we have a problem with either [GOES] East or West.”
“Let’s say there is a problem with GOES East, something bad happens and we just can’t get it back online. In that situation, if that happened today, we would turn on GOES-14, and [it] would be able to take [GOES East’s] place. It doesn’t have the same instruments exactly, but it has the key instruments, especially the imager. The imager is able to track the storm and do intensity estimates and all of the other things.”
To the point of maintaining and operating the best GOES network possible, due to persistent ABI issues with GOES-17 since its launch, NOAA plans to replace it with GOES-T (to be renamed GOES-18 once it reaches orbit). GOES-T has a modified ABI cooling system to negate a repeat of the ongoing issue.
GOES-T is planned to take up the GOES West position and GOES-17 will replace GOES-14 as the backup satellite.
Future GOES and upgrades to NOAA weather satellites
GOES-T is the next GOES in the series and is currently set to launch on an Atlas V rocket no earlier than February 16, 2022.
GOES-U (to be GOES-19 once in orbit) is slated to follow in 2024 on a Falcon Heavy rocket; it will be checked out and then placed in “storage” in geostationary orbit until it is needed as GOES East or GOES West.
Following GOES-U’s launch, the next generation of NOAA weather satellites for the 2030s and beyond is still awaiting official approval.
Known as Geostationary Extended Observations, or GeoXO, these new weather satellites are proposed to include new and upgraded instruments to improve observations and forecasts.
“We are going to look at some upgrades to the imager, and we’re also looking at flying some new Earth-pointing instruments that we do not have currently, including an infrared hyperspectral sounder, an atmospheric composition instrument, and an ocean color instrument,” related Dr. Lindsey.
“The sounder certainly will help with hurricanes,” said Dr. Lindsey. “This is a program which we’re currently seeking approval for, and we hope to launch the first of those around 2032.”
(Lead image: Hurricane Florence nears the Carolina coast in mid-September 2018 as seen by GOES-16 in the GOES East location. Credit: NOAA)