Category Archives: Heavy rain / flooding

Flooding in Southern California

1-minute GOES-16 Infrared Window (10.3 µm) images; with hourly reports of surface weather type plotted in yellow [click to play MP4 animation]

1-minute GOES-16 Infrared Window (10.3 µm) images; with hourly reports of surface weather type plotted in red [click to play MP4 animation]

An onshore flow of moisture (MIMIC TPW) in tandem with forcing for ascent with the approach of an upper-level low and a surface cold/occluded front brought heavy rainfall and some higher-elevation snowfall (NWS LOX/SGX | WPC) to much of Southern California on 09 January 2018. To help monitor the event, a GOES-16 (GOES-East) Mesoscale Sector was positioned over the region, providing images at 1-minute intervals. “Clean” Infrared Window (10.3 µm) images (above) showed the colder clouds associated with periods of moderate to heavy rainfall. Some of this precipitation fell over burn scar areas from wildfires that occurred in December 2017 — including the Thomas fire, which was the largest on record for the state of California — resulting in numerous mud/debris slides that caused at least 17 fatalities, destroyed/damaged hundreds of homes, and closed many streets and highways.

GOES-16 “Red” Visible (0.64 µm) images (below) showed some of the features which helped produce heavier rainfall and snowfall during the daylight hours on 09 January.

1-minute GOES-16

1-minute GOES-16 “Red” Visible (0.64 µm) images; with hourly reports of surface weather type plotted in red [click to play MP4 animation]

The circulation of the upper-level low was easily seen on GOES-16 Mid-level Water Vapor (6.9 µm) images (below).

1-minute GOES-16 Water Vapor (6.9 µm) images; with hourly reports of surface weather type plotted in red [click to play MP4 animation]

1-minute GOES-16 Water Vapor (6.9 µm) images; with hourly reports of surface weather type plotted in red [click to play MP4 animation]

===== 10 January Update =====

Suomi NPP VIIRS True-color and False-color RGB images [click to enlarge]

Suomi NPP VIIRS True-color and False-color RGB images [click to enlarge]

On the following day, a toggle between Suomi NPP VIIRS True-color and False-color Red-Green-Blue (RGB) images from RealEarth (above) showed (1) the large burn scar from the Thomas Fire (shades of reddish-brown), and (2) snow cover in the higher terrain (darker shades of cyan) on the False-color image. The True-color image revealed sediment from runoff flowing into the nearshore waters from Santa Barbara to Oxnard (shades of brown to light green).

A closer look at the Thomas Fire burn scar was provided by 30-meter resolution Landsat-8 False-color RGB imagery (below), which showed thin filaments of muddy sediment just offshore, as well as fresh snow cover (shades of cyan) along or immediately adjacent to the northeastern edge of the burn scar (in the Hines Peak area). On 10 January, the fire was listed as 92% contained (100% containment was declared on 12 January).

Landsat-8 False-color RGB image [click to enlarge]

Landsat-8 False-color RGB image [click to enlarge]

===== 11 January Update =====

Suomi NPP VIIRS True-color images on 10 January and 11 January [click to enlarge]

Suomi NPP VIIRS True-color images on 10 January and 11 January [click to enlarge]

A comparison of Suomi NPP VIIRS True-color RGB images on 10 January and 11 January (above) showed that sediment was flowing farther offshore from the Thomas Fire burn scar area.

Farther to the south, offshore sediment transport was also seen in the San Diego area (below).

Suomi NPP VIIRS True-color image on 11 January [click to enlarge]

Suomi NPP VIIRS True-color image on 11 January [click to enlarge]

Heavy rain in Florida

Aided in part by precipitation associated with Hurricane Irma, some areas of Florida have received record rainfall during the June-October 2017 period:

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

GOES-16 Visible (0.64 µm, left), Near-Infrared

GOES-16 Visible (0.64 µm, left), Near-Infrared “Vegetation” (0.86 µm, center) and Near-Infrared “Snow/Ice” (1.61 µm, right) images [click to play animation]

A comparison of GOES-16 “Red” Visible (0.64 µm), Near-Infrared “Vegetation” (0.86 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (above) showed that water was a strong absorber of radiation at 0.86 µm and 1.61 µm wavelengths — therefore wet ground, rivers, lakes and the oceans appeared dark in those images. This makes those two GOES-16 ABI spectral bands useful for identifying areas of flooding.

Two areas in Florida are noteworthy on the images: the St. Johns River in the northeast part of the state (where Moderate Flooding had been occurring), and parts of South Florida (which had just received an additional 1-5 inches of rain on  the previous day).

A closer look at those 2 areas using Terra MODIS Visible (0.65 µm) and Near-Infrared “:Snow/Ice” (1.61 µm) images are shown below.

Terra MODIS Visible (0.65 µm) and Near-Infrared :Snow/Ice

Terra MODIS Visible (0.65 µm) and Near-Infrared :Snow/Ice” (1.61 µm) images, showing central and northeastern Florida [click to enlarge]

Terra MODIS Visible (0.65 µm) and Near-Infrared :Snow/Ice" (1.61 µm) images, showing southern Florida [click to enlarge]

Terra MODIS Visible (0.65 µm) and Near-Infrared :Snow/Ice” (1.61 µm) images, showing southern Florida [click to enlarge]

In stark contrast to the periods of heavy rain, a strong cold front brought clear skies and very dry air over Florida, as seen in MIMIC Total Precipitble Water product (below).

MIMIC Total Precipitable Water product [click to enlarge]

MIMIC Total Precipitable Water product [click to enlarge]

This dry air evoked enthusiasm in least one South Florida resident:


Increase in Turbidity near the Texas Gulf Coast following Hurricane Harvey

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!)

1 week of Upper Midwest MCS activity: a GOES-16 overview

GOES-16 Infrared Window (10.3 µm) images [click to play MP4 animation]

GOES-16 Infrared Window (10.3 µm) images [click to play MP4 animation]

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

During the week of 19 July26 July 2017, the Upper Midwest was affected  by a number of strong to severe Mesoscale Convective System (MCS) events, as shown in an animation of GOES-16 “Clean” Infrared Window (10.3 µm) images (above).

At the beginning of that time period, a derecho moved across the region on 19 July producing widespread damaging winds, large hail and a few tornadoes (blog post).

Following the derecho, a separate outbreak of thunderstorms exhibited well-defined “enhanced-V” storm top signatures in western Wisconsin (below).

GOES-16 Infrared Window (10.3 µm) image [click to enlarge]

GOES-16 Infrared Window (10.3 µm) image [click to enlarge]

Another MCS produced tornadoes and damaging winds across eastern Iowa and northern Illinois on 21 July (SPC storm reports) — at one point a storm in northern Illinois exhibited a seldom-seen “warm trench” surrounding an overshooting top (below).

GOES-16 Infrared Window (10.3 µm) image [click to enlarge]

GOES-16 Infrared Window (10.3 µm) image [click to enlarge]

Early in the day on 23 July, “transverse banding” — a signature indicating the likelihood of high-altitude turbulence — was seen around the northern periphery of an MCS that was centered in southern Illinois (below).

GOES-16 Infrared Window (10.3 µm) image [click to enlarge]

GOES-16 Infrared Window (10.3 µm) image [click to enlarge]

A pattern of mesoscale banding was displayed by thunderstorms that produced localized 1-2″ amounts of rainfall across southern Wisconsin on 26 July (below).

GOES-16 Infrared Window (10.3 µm) image [click to enlarge]

GOES-16 Infrared Window (10.3 µm) image [click to enlarge]

Also noteworthy was the swath of very heavy rainfall during this 1-week period across eastern Iowa, far southwestern Wisconsin and northern Illinois (below), which was responsible for flash flooding in those areas.

7-day total precipitation, departure from normal and percent of normal [click to enlarge]

7-day total precipitation, departure from normal and percent of normal [click to enlarge]

Using GOES-16 Baseline Products to anticipate where heavy rain might fall

GOES-16 10.3 µm “Clean Window” Superimposed on the Clear-Sky Baseline Total Precipitable Water Product, 0107 – 1337 UTC on 10 July (Click to play large animated gif)

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

Very heavy rain (4-5″) fell over parts of southwestern Wisconsin early on 10 July 2017 as a Mesoscale Convective System traversed the Upper Midwest (0831 UTC VIIRS Infrared vs Day/Night Band). The animation above blends the Clean Window (10.3 µm) from GOES-16 with the Total Precipitable Water Baseline Product (This product is available online — with a time delay — here). Note that the largest values of Precipitable Water are diagnosed to be over southern and western of Wisconsin. Looking at the animation of the 10.3 µm imagery, can you decide where the heaviest rain fell?

A screen capture from this website, below, shows 24-hour precipitation over the Upper Midwest, with a northwest-to-southeast oriented maximum near the northwest-to-southeast gradient of diagnosed total precipitable water field shown in the animation above. (This summary from the National Weather Service in Milwaukee shows accumulated precipitation ending at 0900 Central Time).

The Hazardous Weather Testbed at the Storm Prediction Center evaluates GOES-16 (and other satellites, such as Suomi NPP) products. There have been many instances that noted convection was most intense along the gradient of the moisture (See this summary, for example, or this one.) When GOES-16 Baseline Products indicate a gradient, pay close attention when strong convection develops upstream.

24-hour Precipitation over the Upper Midwest ending at 1200 UTC on 10 July 2017 (Click to enlarge)

Added: One day later, again, convection initiated (and/or persisted) north of the diagnosed Total Precipitable Water maximum over Illinois and Iowa (link), i.e., in the gradient of Total Precipitable Water.

Severe thunderstorms in the Northeast US

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

As noted in the Tweet above from NWS Gray/Portland ME, a record number of tornado warnings were issued by that office on 01 July 2017. According to their damage surveys, the tornadoes were rated EF-0 to EF-1, with some straight-line wind damage also seen. GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images with plots of SPC storm reports (below; also available as a 98-Mbyte animated GIF) displayed the overshooting tops and colder cloud-top infrared brightness temperatures associated with some of the thunderstorms. Note the significant offset between cloud-top features and storm reports — this is due to parallax from the large viewing angle of the GOES-16 satellite (which is positioned over the Equator at 105º West longitude).

GOES-16 Visible (0.64 µm, top) and Infrared Window (10.3 µm, bottom) images, with plots of SPC storm reports in red on Visible, and in black on Infrared [click to play MP4 animation]

GOES-16 Visible (0.64 µm, top) and Infrared Window (10.3 µm, bottom) images, with plots of SPC storm reports in red on Visible, and in black on Infrared [click to play MP4 animation]

A comparison of Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images at 1744 UTC (below) showed the early stages of convective development in far southwestern Maine, in addition to well-developed thunderstorms in eastern New York (which would later move northeastward to produce a swath of heavy rainfall that caused flooding at some locations).

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11..45 µm) images [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11..45 µm) images [click to enlarge]

Thunderstorm development was fueled by high amounts of moisture that had moved into the Northeast US, as shown below by the Blended Total Precipitable Water product (values in the 40-50 mm or 1.6-2.0 inch range) and the Blended Total Precipitable Water Percent of Normal product (with values in excess of 200%).

Blended Total Precipitable Water product [click to enlarge]

Blended Total Precipitable Water product [click to enlarge]

Blended Total Precipitable Water Percent of Normal product [click to enlarge]

Blended Total Precipitable Water Percent of Normal product [click to enlarge]

The hourly evolution of moisture was depicted by the MIMIC Total Precipitable Water product (below).

MIMIC Total Precipitable Water product [click to play animation]

MIMIC Total Precipitable Water product [click to play animation]

Tropical Storm Cindy

GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images, with hourly surface//ship/buoy reports plotted in yellow [click to play MP4 animation]

GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images, with hourly surface//ship/buoy reports plotted in yellow [click to play MP4 animation]

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

As Tropical  Storm Bret was forming off the coast of South America, Potential Tropical Cyclone 3 (PTC3) was becoming more organized as it moved from the western Caribbean Sea across the Yucatan Peninsula of Mexico and into the Gulf of Mexico on 19 June 2017 (MIMIC TPW). On 20 June, one of the GOES-16 Mesoscale Sectors was positioned  over PTC3 and  provided 1-minute imagery — Visible  (0.64 µm)  and  Infrared Window (10.3  µm) images (above) showed deep convective bursts moving northward to reveal an exposed Low Level Circulation Center (LLCC).

GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images, with hourly surface/buoy/ship reports plotted in yellow [click to play MP4 animation]

GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images, with hourly surface/buoy/ship reports plotted in yellow [click to play MP4 animation]

Early in the day on 21 June, 1-minute GOES-16 Visible and Infrared Window images (above) showed multiple LLCC features associated with PTC3, with deep convection remaining well to the north/northwest. In addition, Mid-level Water Vapor (6.9  µm) images (below) indicated that a large amount of dry air had wrapped into the southern and eastern portions of the storm circulation.

GOES-16 Visible (0.64 µm, left) and Water Vapor (6..9 µm, right) images [click to play MP4 animation]

GOES-16 Visible (0.64 µm, left) and Water Vapor (6..9 µm, right) images [click to play MP4 animation]

However, by mid-day a more consolidated central circulation had developed, as seen on Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images (below) — and PTC3 was upgraded to Tropical Storm Cindy.

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images, with surface pressure plotted in yellow and station identifiers plotted in cyan [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images, with surface pressure plotted in yellow and station identifiers plotted in cyan [click to enlarge]

Hourly images of the MIMIC Total Precipitable Water product covering the 19-24 June period (below) showed  the northward transport of rich tropical moisture into the Gulf  Coast states, which then moved northeastward toward the Northeast US bringing heavy rainfall and flooding to many locations (WPC storm summary).

MIMIC Total Precipitable Water [click to play animation]

MIMIC Total Precipitable Water [click to play animation]

Maps of daily rainfall during the 21-24 June period (along with 7-day rainfall totals, departure from normal and percent of normal) are shown below.

21-24 June daily precipitation, along with 7-day Precipitation Total, 7-day Departure from Normal and 7-day Percent of Normal [click to enlarge]

21-24 June daily precipitation, along with 7-day Precipitation Total, 7-day Departure from Normal and 7-day Percent of Normal [click to enlarge]

Using GOES-16 visible and near-infrared imagery to diagnose areas of flooding

Flood Warnings (green) in effect at 7:43 pm CDT on 06 April 2017 [click to enlarge]

Flood Warnings (green) in effect at 7:43 pm CDT on 06 April 2017 [click to enlarge]

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

Following several days of heavy rainfall across northwestern Missouri, Flood Warnings remained in effect for many areas on 06 April 2017 (above).

A comparison of GOES-16 Visible (0.47 µm and 0.64 µm) and Near-Infrared (0.86 µm and 1.61 µm) images at 1507 UTC (below) shows that the Vegetation and Snow/Ice spectral bands are useful for identifying areas of swollen rivers and adjacent flooded lands (since water appears darker on those 2 images).

GOES-16 Visible (0.47 µm and 0.64 µm) and Near-Infrared (0.86 µµ and 1.61 µm) images [click to enlarge]

GOES-16 Visible (0.47 µm and 0.64 µm) and Near-Infrared (0.86 µµ and 1.61 µm) images [click to enlarge]

 

 

Cyclone Debbie makes landfall in Queensland, Australia

Himawari-8 Visible (0.64 µm) and Infrared Window (10.4 µm) images [click to play animation]

Himawari-8 Visible (0.64 µm) and Infrared Window (10.4 µm) images [click to play animation]

Cyclone Debbie formed in the Coral Sea on 22 March 2017, and eventually intensified to a Category 3 storm (ADT | SATCON) as it moved southward toward Australia. Himawari-8 Visible (0.64 µm) and Infrared Window (10.4 µm) images (above) showed the eye of Debbie as it was making landfall in Queensland, near Prosperpine (YBPN).

Landsat-8 false-color, with Himawari-8 Visible (0.64 µm) and Infrared Window (10.4 µm) images [click to enlarge]

Landsat-8 false-color, with Himawari-8 Visible (0.64 µm) and Infrared Window (10.4 µm) images [click to enlarge]

The Landsat-8 satellite made an overpass of the eye at 2358 UTC (above), as a large convective burst had developed within the northern semicircle of the eyewall (which was also evident in the corresponding Himawari-8 Visible and Infrared Window images viewed using RealEarth).

Himawari-8 Infrared Window (10.4 µm) and GMI Microwave (85 GHZ) Images around 1430 UTC on 27 March [click to enlarge]

Himawari-8 Infrared Window (10.4 µm) and GMI Microwave (85 GHZ) Images around 1430 UTC on 27 March [click to enlarge]

Debbie was undergoing an eyewall replacement cycle as the storm center approached the coast — this was evident in Microwave (85 GHz) images from GMI at 1425 (above) and SSMIS at 2017 UTC (below) from the CIMSS Tropical Cyclones site.

Himawari-8 Infrared Window (10.4 µm) and DMSP-18 SSMIS Microwave (85 GHz) images around 2017 UTC on 27 March [click to enlarge]

Himawari-8 Infrared Window (10.4 µm) and DMSP-18 SSMIS Microwave (85 GHz) images around 2017 UTC on 27 March [click to enlarge]

The MIMIC Total Precipitable Water product (below; also available as an MP4 animation) showed copious tropical moisture associated with Cyclone Debbie, which led to rainfall accumulations as high as 780 mm (30.7 inches) — with rainfall rates up to 200 mm (7.9 inches) per hour — and record flooding along the coast from Brisbane to Lismore.

MIMIC Total Precipitable Water product [click to play animation]

MIMIC Total Precipitable Water product [click to play animation]

 

 

 

Heavy Rains over southern California

GOES-15 Water Vapor (6.5 µm) images [click to play animation]

GOES-15 Water Vapor (6.5 µm) images [click to play animation]

The GOES-15 Water Vapor animation, above, shows a potent cold front moving through southern California late on 27 February. This front that passed through San Diego at 0500 UTC on 28 February (9 PM PST) was accompanied by abundant precipitation, the heaviest rainfall in 13 years at the San Diego airport (link), with widespread 2+-inch rains that caused power outages and flooding. The image below (from this site), shows the 24-hours precipitation ending at 1200 UTC on 28 February 2017. Values in excess of 6″ occurred in the mountains east of San Diego.

Accumulated Precipitation for 24 hours ending 1200 UTC on 28 February 2017 [click to enlarge]

Accumulated Precipitation for 24 hours ending 1200 UTC on 28 February 2017 [click to play animation]

Hourly MIMIC Total Precipitable Water estimates for the 72 hours ending 1400 UTC on 28 February 2017 [click to enlarge]

Hourly MIMIC Total Precipitable Water estimates for the 72 hours ending 1400 UTC on 28 February 2017 [click to play animation]

Satellite estimates of Total Precipitable Water (TPW) suggested that heavy rains were likely. MIMIC total precipitable water plots, above (source), show a moisture source that tapped the rich moisture of the Intertropical Convergence Zone. NOAA/NESDIS Blended Precipitable Water Percent-of-Normal plots (source, at this site), shown below, show values exceeding 200% of normal over southern California. Both MIMIC and Blended TPW products offer excellent situational awareness.

NOAA/NESDIS Blended Total Precipitable Water Percent-of-Normal, times as indicated [click to play animation]

NOAA/NESDIS Blended Total Precipitable Water Percent-of-Normal, times as indicated

An interesting aspect of the GOES-15 Water Vapor animation, at the top of this post, is the appearance of land features. The spine of the mountains over Baja California appears throughout the animation, for example, as does the Front Range of the Rockies from Colorado southward to New Mexico. Should land features be visible in water vapor imagery? An answer to that lies in computed weighting functions, shown below (from this site), that describe from where in the atmosphere energy at a particular wavelength is being detected by the satellite.

At the start of the water vapor animation, near 0000 UTC, thick clouds cover southern California (and the sounding from San Diego shows saturated conditions); dry layers in the sounding appear by 1200 UTC. The 7.4 µm weighting function shows that information is detected by the satellite from lower down in the atmosphere; energy detected at 6.5 µm comes from higher in the atmosphere. This difference arises because of the better absorptive qualities of water vapor gas for 6.5 µm radiation vs. 7.4 µm radiation. By 1200 UTC, sufficient drying has occurred that the 7.4 µm Sounder Channel is detecting radiation that emanates from sea level. Note also at 1200 UTC that each individual moist layer influences the weighting function — but there is insufficient moisture at 1200 UTC in those moist layers that they are opaque to energy at either 6.5 µm or 7.4 µm.

Note: GOES-R Series satellites, including GOES-16, have ‘water vapor’ channels at 6.2 µm, 6.9 µm and 7.3 µm.

Water Vapor Weighting Functions at 72293 (San Diego) for GOES Imager (6.5 µm) (Black Line) and GOES Sounder (7.4 µm) (Red Line) at 0000 UTC 27 February (Left) and 1200 UTC 28 February (Right). The Sounding for San Diego is also indicated [click to enlarge]

Water Vapor Weighting Functions at 72293 (San Diego) for GOES Imager (6.5 µm) (Black Line) and GOES Sounder (7.4 µm) (Red Line) at 0000 UTC 27 February (Left) and 1200 UTC 28 February (Right). The Sounding for San Diego is also indicated [click to enlarge]