Satellite Liaison Blog

Hurricane Ian made landfall along the Florida Gulf Coast near Cayo Costa at 1905 UTC on 28 September 2022 as a strong category 4 Hurricane, bringing with it intense winds, storm surge, and rainfall amounts. NOAA GOES and JPSS satellites provided imagery and products that weren’t only visually pleasing, but were critical to operations in tracking the storm.

In the days leading up to, and including, landfall, the National Hurricane Center continuously requested 30-second mesoscale sector imagery from GOES-East (GOES-16). The imagery captured the storm in tremendous detail, helping forecasters to pinpoint the center of circulation in real-time, track thunderstorm activity both in the eyewall and in the tornado-producing outer rain bands, and help to determine when landfall occurs. The high temporal resolution imagery was also leveraged in communicating the storm via social media and other media outlets.

Starting with the last sequence of images prior to landfall, GOES-East 30-second-updating 500-meter-spatial-resolution Channel 02 Visible imagery provided the best detail of Hurricane Ian. Focusing on the center of circulation, or eye, one can diagnose a fairly large eye, the presence of meso-vorticies within the eye, and thunderstorm activity within the eyewall (Fig 1).

Now stepping back a few days, GOES-East 1-min VIS/IR sandwich imagery from the morning of the 26th captured active convection in great detail, as was noted in the NHC 11 AM forecast discussion (Fig 2): “The satellite presentation of Ian has improved this morning. Deep convection has increased within the inner core during the past several hours, with an expanding central dense overcast noted in recent satellite imagery.” The sandwich imagery combines the benefits of great spatial detail from the VIS with quantitative brightness temperature information from the IR.

GOES-East began collecting 30-second imagery later in the day on the 26th. The imagery toward sunset captures the center of circulation and associated convection, but no clear eye yet (Fig 3). The 5 PM update from NHC provides a basic view into how the satellite imagery was being leveraged: “The 18 UTC satellite classifications from SAB and TAFB were a consensus T4.5/77 kt, but the continued improvement in satellite structure warrants raising the initial intensity to 85 kt for this advisory.”

The NWS Weather Prediction Center routinely leveraged GOES Satellite imagery while monitoring Ian, including during the preparation of their Mesoscale Precipitation Discussions (MPDs). For example, from early on the 27th discussing thunderstorms over Florida: “These storms were tied to distant outer rainbands to the north of Hurricane Ian (Ian’s center located just south of western Cuba at 06Z) within a broad region of divergence aloft / northern outflow channel noted on infrared satellite imagery. (Fig 3.2)”

During the evening of the 26th into the 27th, Ian advanced across western Cuba. By the morning of the 27th, Ian emerged off the coast of Cuba, with NHC noting at 11 AM: “The well-defined eye of Ian emerged off the coast of western Cuba about an hour ago.” GOES-East 30-second visible imagery reveals this evolution (Fig. 4).

By 5 PM on the 27th, the storm continued to strengthen, and NHC states: “The eye of Ian remains well-defined on visible imagery, although radar data from Key West suggest that an eyewall replacement could be in the initial stages.” GOES-East 30-second Geocolor imagery zoomed out demonstrates the massive size of Ian (Fig. 5). NHC forecast track, cone, and intensity can be loaded into AWIPS and displayed with imagery in order to provide additional context.

A zoomed out full-day GOES-East 2-min VIS/IR sandwich animations shows the evolution of the storm on the 27th, including the large and open eye, and outer rain bands and convection (Fig 6). The Storm Prediction Center had a Slight Risk for severe thunderstorms (driven by the tornado threat) across all of south Florida. Numerous Tornado and Marine Warnings were issued by local NWS offices for supercells associated with Ian (plotted in the below animation), and 11 tornadoes were reported.

By sunrise on the 28th, Hurricane Ian was making it’s final approach toward the Florida Gulf Coast. Early GOES-East 30-second visible imagery captured a very large eye, initially obscured by cirrus but clearing (Figure 7).

Refer back to Figure 1 for 30-second imagery capturing the landfall of Hurricane Ian during the early afternoon of the 28th.

After landfall, NHC noted in the 5 PM discussion: “While there hasn’t been much in situ data recently, satellite images show that the eye has become more cloud filled, and Tampa Doppler radar data is indicating a gradual reduction in winds.” A full day, 1-min-updating visible animation of Hurricane Ian’s evolution on the 28th is shown in Fig 7.5. Note the filling of the eye after landfall as was noted in the NHC discussion.

A zoomed out, full-day 2-min VIS/IR Sandwich imagery animation from the 28th from GOES-East is shown in Fig 7.3.

A longer-term animation of GOES-East Ch-13 IR animation shows the organization of Hurricane Ian within the GOES-East CONUS sector from the morning of the 25th in the Caribbean when Ian was a Tropical Storm, to around landfall during the afternoon of the 28th when Ian was a Major Hurricane (Figure 8).

An animation covering the time period from early on the 27th through landfall on the 28th shows the total lightning activity, captured from the GOES-East GLM (Figure 9). Throughout the progression through the Gulf, there were numerous bursts of lightning associated with eyewall convection and with thunderstorms in the outer bands.

GOES-18, currently in post-launch testing, also collected 30-second imagery of Hurricane Ian as it made it’s approach through the Gulf of Mexico into Florida (Figure 10). From the GOES-West position, the imagery was captured at a steep viewing angle (far from the satellite subpoint), providing a unique perspective of the storm. GOES-18 ABI Imagery during this period was preliminary and non-operational.

A zoomed out animation of GOES-18 VIS/IR Sandwich Imagery captures the storm in the 5 hours leading up to landfall (Fig 10.2).

VIIRS imagery from the NOAA-20 and S-NPP satellites provided very high resolution (375-m) imagery of Hurricane Ian as the storm was making landfall on the 28th. The IR imagery measured cloud top brightness temperatures colder than -73C, and the high spatial resolution IR and VIS and overhead (near nadir) look provided details about the shape and size of the eye, and thunderstorms within the eyewall and outer bands (Fig 11). The VIIRS Natural Color RGB from NOAA-20 provided additional details about the clouds (ice vs water) and surrounding clear sky areas by combining multiple channels into a single multispectral imagery product (Fig 12).

By the late morning/early afternoon of the 29th, Ian had traversed across the Florida Peninsula and progressed back over water in the Atlantic. With land and increasing shear taking its toll on the storm, the low-level circulation was now exposed. Day Cloud Phase Distinction RGB imagery combines the Ch13 IR, Ch05 NIR, and Ch02 VIS into a single image in order to provide information about cloud top phase. With tropical cyclones such as Ian at this point, the imagery helps to differentiate ice/high clouds (bright red/green/yellow) vs water/low clouds (bright blue/cyan), which itself makes it easier to identify the low-level circulation, thunderstorms, and low stratus clouds (Fig 13).

Bill Line, NESDIS/STAR