Hurricane Ida made landfall along the Louisiana coast on 29 August 2021 as a category 4 Hurricane packing sustained wind speeds of 150 mph. Numerous wind gusts over 60 mph were measured at the surface onshore, including a few measured gusts over 100 mph. There were numerous reports of flash flooding, with a large swath of 6+” rainfall falling in the <24-hr period (Fig 1). There was also significant storm surge along the coast. This post will share select NOAA satellite imagery capturing Hurricane Ida. All imagery was created in AWIPS (unless otherwise noted).
GOES-East mesoscale sector (1-min) imagery was available for Ida throughout its evolution. The center of circulation (eye) cleared out quickly during a 2.5-hour period on the 28th, shown here in 1-min VIS (Fig 2). The health of the eye and surrounding thunderstorm activity can be studied in detail with the 1-min, 500 m resolution imagery.
At sunrise on the 29th, GOES-East 1-min VIS revealed the mature eye of the now major hurricane as it approached the Louisiana coast. Smaller scale circulations (mesovorticies) can be diagnosed in the 1-min VIS within the eye of the hurricane from sunrise on the 29th through landfall (Fig 3). The sun angle at sunrise allows the opportunity to investigate eyewall thunderstorm activity in better detail given the shadowing, as well as abundant gravity wave activity atop the clouds emanating away from the eye.
During a similar time period, a zoomed out view of GOES-East Natural Color Imagery characterizes the size of the storm with respect to the 1000 km x 1000 km mesoscale sector. GOES-East GLM Flash Points are overlaid (Fig 4).
A longer, 2-min resolution animation of visible imagery captures the period of Ida evolution from sunrise around 1217 UTC to to landfall at 1655 UTC (Fig 5).
GOES-East 2-min VIS+IR sandwich imagery combines the high detail of the VIS with the qualitative (brightness temperature) information of the IR into a single image during the period following landfall (Fig 6).
The full daytime evolution of the Ida is shown in 5-min CONUS VIS imagery in the following feature relative animation (Fig 7). The eye of the storm maintains itself well inland, possibly due in part to the marshlands along/near the coast.
An animation of VIS during the day and IR during the night with GLM flash points presents the evolution of Tornado (red), Severe Thunderstorm (yellow), Extreme Wind (magenta), Marine (cyan) and Flash Flood (green) Warnings with respect to the path of the hurricane and lightning progression (Fig 8).
The full evolution of Ida from just prior to becoming a hurricane to just after being downgraded to a tropical storm is shown in 30-min Geocolor+GLM Imagery (Fig 9) and VIS+IR sandwich daytime imagery transitioning to IR at night (Fig 10).
S-NPP and NOAA-20 VIIRS instruments also captured detailed views of Ida. The Day Night Band Near Constant Contrast product provided a detailed (750 m) “visible” imagery at night (Fig 11; expand Aug 28, 29, 30).
A VIIRS pass shortly after landfall on the 30th depicted the detailed IR structure of the storm (Fig 12).
Hurricane Ida made landfall in Louisiana on the 16-year university of Hurricane Katrina. A comparison between GOES-12 imagery of Katrina and GOES-16 imagery of Ida can be found on the STAR website, courtesy of Matthew Jochum, STAR.
GOES-17 (GOES-West) full disk imagery also captured Hurricane Ida with 10-min resolution (Fig 13 and 14). The high viewing angle provides an alternative perspective of the storm compared to that from GOES-East and VIIRS, specifically additional texture detail within the eye and surrounding convection. Full resolution GOES-17 iamgery created in McIDAS.
Ida Remnants continued north across the eastern United States through the early week. On 01 Sep, the storm brought an abundance of moisture to the northeast, resulting in heavy rain and widespread flash flooding, in addition to severe thunderstorms and tornados. A long animation of GOES-East IR and GLM flash points with NWS warning polygons overlaid captures the evolution of the storm through the northeast on the 1st and associated NWS warnings (Fig 15).
Focusing on the New York City area, GOES-East IR imagery reveals Ida associated thunderstorms that resulted in considerable flash flooding. Persistent cold and cooling cloud tops (< -70C) and overshooting tops can be diagnosed in the imagery over the region during the 4-hour period.
GOES-East hourly upper-level water vapor imagery shows the evolution of Ida from landfall on the 29th through exit of the northeast US on the 2nd (Figure 17). The imagery shows the increase in deep moisture across the eastern US during the period, and interaction of Ida with a shortwave trough and increasing mid-upper-level flow as the storm progressed north. Dry/descending air is diagnosed expanding across the eastern US in the wake of Ida.
ill Line, NESDIS and CIRA