Increase in Turbidity near the Texas Gulf Coast following Hurricane Harvey

August 30th, 2017 |

Terra MODIS True-Color imagery off the Texas Gulf Coast on 23 and 30 August, 2017 (Click to enlarge)

MODIS Today imagery from 23 August (pre-Harvey) (cropped) and 30 August (post-Harvey) (cropped), above, show an enormous increase in turbidity in the nearshore waters off the coast of Texas. Further, many of the rivers change their appearance to brown and flooding in the post-Harvey image. (River gauges in flood stage; Source)

A similar toggle using Suomi NPP VIIRS Imagery, from this site, also from 23 August and 30 August, is shown below. The increase in turbidity was due to a combination of strong winds and runoff from very heavy rainfall associated with the hurricane.

Suomi NPP True-Color imagery off the Texas Gulf Coast on 23 and 30 August, 2017 (Click to enlarge)

Suomi NPP VIIRS Products include a River Flood estimate, developed by Sanmei Li and others at George Mason University. The toggle below from RealEarth shows Suomi NPP VIIRS True Color at 1904 UTC, and the River Flood Product for the same time.

Suomi NPP VIIRS True-Color imagery off the Texas Gulf Coast, 1904 UTC on 30 August, 2017, and the Suomi NPP River Flood Product at the same time (Click to enlarge)

(Thanks to Bill Taylor and John Stoppkotte, NWS in N. Platte NE, for noting this!)

Hurricane Harvey Power Outages

August 30th, 2017 |

Suomi NPP VIIRS Day/Night Band (0.7 µm) imagery, below, from before (23 August) and after (30 August) Hurricane Harvey’s 26 August landfall, shows changes in city light illumination associated with power outages. Click and drag the slider bar to swipe between the two images. A toggle between larger versions of the two images is available here.

(Imagery courtesy of William Straka, SSEC/CIMSS)

Harvey near the coast of Texas

August 28th, 2017 |

GOES-16 ABI Band 8 (6.19 µm, “Upper Level Water Vapor”, lower left), ABI Band 10 (7.3 µm, “Lower Level Water Vapor”, upper left), ABI Band 13 (10.3 µm, “Clean Window Infrared”, upper right) and ABI Band 5 (1.61 µm, “Snow/Ice Channel”, lower right) from 1542-1857 UTC on 28 August (Click to animate)

GOES-16 data (ABI and GLM) posted on this page are preliminary, non-operational and are undergoing testing

Meandering Tropical Storm Harvey is near the Gulf Coast of Texas during the day on Monday 28 August as shown in the 4-panel Animation above. The Four panels include, clockwise from lower left, Upper Level Water Vapor (6.19 µm), Lower Level Water Vapor (7.3 µm), Clean Window (10.3 µm) and Snow/Ice Channel (1.61 µm) (ABI Bands 8, 10, 13 and 5, respectively). The deepest and strongest convection with Harvey has shifted eastward into Louisiana; dry mid-tropospheric air is apparent in both water vapor infrared images; Convection continues near the center of the storm; onshore low-level flow is apparent in the Snow/Ice channel. Total Precipitable Water computed from Microwave Imagery (at this site), below, shows that abundant moisture remains over southeast Texas and Louisiana.

Morphed Total Precipitable Water for the 24 hours ending 28 August 2017 (Click to enlarge)

GOES-16 Visible Imagery (0.64 µm), below, show the center of Harvey to be just offshore (Click here for the latest National Hurricane Center advisories on Harvey), with moist low-level flow from the Gulf into southeast Texas and southwest Louisiana. Geostationary Lightning Mapper (GLM) observations of Lightning Groups (Events are grouped into Groups, Groups are grouped into Flashes), show scant lightning associated with the center of Harvey. More lightning activity is apparent over southeastern Louisiana (including some apparently spurious signals near Baton Rouge). A similar animation over Infrared Imagery is here.

GOES-16 ABI Visible Imagery (0.64 µm) and GLM Observations of Lightning Groups from 1842-1927 UTC on 28 August (Click to enlarge)

For the latest on Harvey and its dangerous rainfall, consult the National Hurricane Center website, or the CIMSS Tropical Weather Website, or the Hydrologic Prediction Website.

Hurricane Harvey makes landfall

August 26th, 2017 |

* GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing *

As Hurricane Harvey moved across warm waters in the northwestern Gulf of Mexico (SST | OHC), it continued to intensify (ADT | SATCON) to a Category 4 hurricane just before making landfall (which occurred around 03 UTC on 26 August 2017, or 10 pm local time on 25 August). A GOES-16 Mesoscale Sector had been positioned over Harvey, providing images at 30-second intervals; some of these are shown with “Red” Visible (0.64 µm) images prior to sunset (below). A GOES-16 vs GOES-13 (GOES-East) Visible image comparison is available here.

GOES-16 Visible (0.64 µm) images, with hourly surface ports plotted in yellow (Click to play MP4 animation)

GOES-16 “Red” Visible (0.64 µm) images, with hourly surface ports plotted in yellow [click to play MP4 animation]

Hurricane Harvey had a large eye on GOES-16 “Clean” Infrared Window (10.3 µm) images at landfall, which persisted — albeit becoming smaller with time — for many hours after it moved inland (below). A longer-term animation of 5-minute GOES-16 Infrared Window images (covering the period 23-27 August) is available here.

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images, with hourly surface reports plotted in yellow [click to play MP4 animation]

A sequence of 4 Infrared Window images, from Suomi NPP VIIRS and Terra/Aqua MODIS, covering the period 0419-0851 UTC (below) showed the shrinking eye and the erratic path of Harvey once it moved inland.

Terra/Aqua MODIS (11.0 µm) and Suomi NPP VIIRS (11.45 µm) Infrared Window images [click to enlarge]

Terra/Aqua MODIS (11.0 µm) and Suomi NPP VIIRS (11.45 µm) Infrared Window images [click to enlarge]

A recap of the torrential rainfall amounts and maximum wind gusts caused by Hurricane Harvey can be seen in the WPC Storm Summary. A map showing the final storm total rainfall from Harvey is available here.