Tropical Storm Cristobal makes landfall along the coast of Louisiana

June 7th, 2020 |

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 “Red” Visible (0.64 µm) images (above) revealed low-level vortices that were pivoting around the analyzed center of Tropical Storm Cristobal as it approached the coast of Louisiana on 07 June 2020, making landfall at 2200 UTC. Wind gusts were as high as 57 mph in Louisiana and 64 mph in Mississippi.

GOES-16 Visible images with overlays of GLM Flash Extent Density (below) indicated that there was very little satellite-detected lightning associated with Cristobal.

GOES-16 “Red” Visible (0.64 µm) images, with overlays of GLM Flash Extent Density and surface reports [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images, with overlays of GLM Flash Extent Density and surface reports [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images (below) showed numerous cloud-top infrared brightness temperatures as cold as -70 to -77ºC (darker shades of red) within some of the convective bands.

GOES-16 “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

GOES-16 Longwave Infrared Window (11.2 µm) images with plots of Derived Motion Winds (below) showed the broad low-, mid- and upper-level circulation of the tropical storm.

GOES-16 Longwave Infrared Window (11.2 µm) images, with plots of Derived Motion Winds [click to play animation | MP4]

GOES-16 Longwave Infrared Window (11.2 µm) images, with plots of Derived Motion Winds [click to play animation | MP4]

Rich tropical moisture was being transported northward across the Gulf of Mexico by Cristobal — the Blended Total Precipitable Water (TPW) and Percent of Normal TPW product (below) portrayed a large area with TPW values in the 2.5-3.0 inch range, which represented departures of 175-200% of normal. This led to areas of flash flooding along parts of the Gulf Coast, with some locations receiving 4-8 inches of rainfall.

Blended TPW and Percent Normal TPW images [click to play animation | MP4]

Blended TPW and Percent of Normal TPW images [click to play animation | MP4]

The MIMIC TPW product during the period 03-07 June (below) provided a larger-scale view of the origins of the tropical moisture associated with Cristobal.

MIMIC TPW product, 03-07 June [click to play animation | MP4]

MIMIC TPW product, 03-07 June [click to play animation | MP4]

Tropical Storm Cristobal in the southern Gulf of Mexico

June 2nd, 2020 |

Suomi-NPP Day Night Band visible imagery (0.7 µm) overlain with ACSPO SSTs, 0752 UTC 2 June 2020 (Click to enlarge)

The tropical system in the southern Gulf of Mexico that owes part of its genesis to Eastern Pacific Tropical Cyclone Amanda has been named tropical storm Cristobal, the third named storm of the Atlantic Season.  Day Night band imagery from Suomi NPP, shown above from 0753 UTC on 2 June 2020 (when the system was still an un-named depression), shows abundant strong convection over and adjacent to the Yucatan Peninsula and in the Bay of Campeche.  The western edges of clouds were very well-illuminated because the >80% Full Moon was setting and approaching the western horizon;  moonset at New Orleans’ longitude on 2 June was shortly after 3:30 AM (i.e., 0830 UTC).  Lights from cities surrounding the Gulf and from Oil platforms within the Bay of Campeche are also apparent.

The Advanced Clear-Sky Processor for Oceans (ACSPO) Sea-Surface Temperature field (this VIIRS-based field is available in AWIPS via an LDM feed from CIMSS) shows few pixels of information because of the extensive cloud shield.  However, the pixels that do show through the clouds reveal SSTs between 82 and 84º F.

The storm is just south of a region of strong shear, as shown below (source) and over very warm waters (albeit close to land) and slow strengthening is forecast as it drifts northward in the next days (interests along the Gulf Coast should pay special attention to this system;  refer to the National Hurricane Center for more information).

Wind Shear analysis at 1500 UTC on 2 June 2020 (Click to enlarge)

GOES-16 Atmospheric Motion Vectors (below, from 350-450 mb in red, and from 775-900 mb in lavender) also suggest shear over the central Gulf of Mexico.

GOES-16 ABI Band 13 (10.3 µm) at 1626 UTC on 2 June, along with upper-level (350-450 mb) atmospheric motion vectors (in red) and low-level (775-900 mb) atmospheric motion vectors (in lavender) (Click to enlarge)

The Air Mass RGB animation, below, shows Cristobal’s convection developing within a moisture-rich tropical airmass characterized by green shading in the RGB. Dry air — orange and red in the RGB — is present just west of the storm.

GOES-16 Air Mass RGB, 1401-1626 UTC on 2 June 2020 (Click to animate)

The dry air is even more obvious in the toggle below of the Air Mass RGB and the Low-Level water vapor imagery (Band 10, 7.34 ) at 1626 UTC on 2 June.  Color enhancements of yellow and orange over Texas and Mexico suggest dry air in the mid-troposphere.

GOES-16 Air Mass RGB and low-level water vapor (Band 10, 7.34 µm) at 1626 UTC on 2 June 2020 (Click to enlarge)

For more information on this storm, refer to the National Hurricane Center, the CIMSS Tropical Weather Page, or your favorite Tropical Weather site.

The (mp4) video below, generated by CSPP-Geo and from an experimental CIMSS website, shows Cristobal in True Color from GOES-16.

Tropical Cyclone Bertha

May 27th, 2020 |

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed Tropical Storm Bertha as it moved inland across South Carolina on 27 May 2020. The clusters of deep convection rapidly dissipated after landfall, revealing the low-level circulation. Bertha did produce heavy rainfall and high winds.

A GMI Microwave (85 GHz) image at 1416 UTC from the CIMSS Tropical Cyclones site (below) displayed an arc of moderate to heavy precipitation less than an hour following landfall.

GMI Microwave (85 GHz) image at 1416 UTC [click to enlarge]

GMI Microwave (85 GHz) image at 1416 UTC [click to enlarge]

Cyclone Amphan in the Bay of Bengal

May 18th, 2020 |

Meteosat-8 Infrared Window (10.8 µm) images [click to play animation | MP4]

Meteosat-8 Infrared Window (10.8 µm) images [click to play animation | MP4]

EUMETSAT Meteosat-8 Infrared Window (10.8 µm) images (above) showed Cyclone Amphan during the period when it was rapidly intensifying to a Category 5 storm (ADT | SATCON) by 06 UTC on 18 May 2020. In fact, Ampham became the strongest tropical cyclone on record in the Bay of Bengal basin.

NOAA-20 VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images as viewed using RealEarth (below) provided a more detailed view of Amphan shortly before the time of its peak intensity.

NOAA-20 VIIRS True Color RGB and Infrared Window (11.45 µm) images [click to enlarge]

NOAA-20 VIIRS True Color RGB and Infrared Window (11.45 µm) images [click to enlarge]

On the following night, toggles between VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 (below) showed a subtle signature of mesospheric airglow waves propagating northward away from the center of Cyclone Amphan.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (credit: William Straka, CIMSS) [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (credit: William Straka, CIMSS) [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (credit: William Straka, CIMSS) [click to enlarge]