GOES-14 SRSO-R: Tropical Disturbance near the Caribbean

August 25th, 2016

GOES-14 Visible (0.63 µm) images [click to play animated gif]

GOES-14 Visible (0.63 µm) images [click to play animated gif]

GOES-14 SRSO-R Imagery is being produced over the Greater Antilles on 25 August 2016 to monitor a tropical wave (Invest 99L) that is moving towards Florida and the southeast United States. The visible animation above shows a highly sheared system: a low-level circulation center (LLCC) is evident north of Hispaniola and east of the Turks and Caicos, but strong convection (overshooting tops are readily apparent) is displaced well to the east of the system. There is also considerable convection over Hispaniola.

A 2-panel comparison of GOES-14 Visible and Infrared Window images, below (also available as a large 200 Mbyte animated GIF), provided a slightly closer view of the LLCC feature.

GOES-14 0.63 µm Visible (top) and 10.7 µm Infrared Window (bottom) images [click to play MP4 animation]

GOES-14 0.63 µm Visible (top) and 10.7 µm Infrared Window (bottom) images [click to play MP4 animation]

Wind shear analyses from the CIMSS Tropical Weather site, below, show the surface circulation is within a small ribbon of relatively strong shear. Development chances will increase if the wind shear relaxes. A GOES-13 Visible image with overlays of satellite winds and wind shear is available here.

Wind Shear Analysis, 1200 UTC on 25 August 2016 [click to play animated gif]

Wind Shear Analysis, 1200 UTC on 25 August 2016 [click to enlarge]

Metop-A overflew the system at about 0200 UTC on 25 August (link to orbit path), and winds near Tropical Storm Force cover a wide swath of the southwestern Atlantic. Even if this system does not develop into a Tropical Depression, gusty winds and abundant moisture (see the animation of MIRS Total Precipitable Water from this site, below) herald a weekend when it’s appropriate to pay attention to the weather because of the potential for rain and winds.

Morphed Observations of Total Precipitable Water from MIRS, 0000 UTC 24 August - 1500 UTC 25 August [click to play animated gif]

Morphed Observations of Total Precipitable Water from MIRS, 0000 UTC 24 August – 1500 UTC 25 August [click to play animated gif]

Tornado outbreak in Indiana/Ohio

August 24th, 2016

GOES-13 Visible (0.63 µm) images, with SPC storm reports [click to play animation]

GOES-13 Visible (0.63 µm) images, with SPC storm reports [click to play animation]

An outbreak of tornadoes (SPC storm reports) occurred during the afternoon/early evening hours of 24 August 2016 from central Indiana to northwestern Ohio (NWS Indianapolis | NWS Northern Indiana | NWS Cleveland). In terms of forcing mechanisms, while the supercell thunderstorms developed well in advance of a cold frontal boundary (surface analyses), GOES-13 Visible (0.63 µm) images (above) showed a mesoscale convective vortex or MCV moving eastward across northern Illinois which may have played a role in helping to initiate convection. Moisture was also abundant across the region, with Total Precipitable Water (TPW) values as high as 53.1 mm or 2.1 inches on the 1200 UTC Lincoln IL rawinsonde report and 60.7 mm or 2.4 inches just east of the convection developing over central Indiana on the 1941 UTC Aqua MODIS TPW product (below).

Aqua MODIS Visible (0.65 µm) image and Total Precipitable Water product [click to enlarge]

Aqua MODIS Visible (0.65 µm) image and Total Precipitable Water product [click to enlarge]

A closer view of the 1841 UTC Aqua MODIS Visible (0.65 µm) and Infrared Window (11.0 µm) images (below) showed the thunderstorm complex over central Indiana just after the time of the first EF2-rated tornado in Montgomery County — the coldest cloud-top infrared brightness temperature was -80º C (violet color enhancement) over the southeastern portion of that county. In addition, an “enhanced-V” cloud top signature was evident over northeastern Clinton County — the next EF3-rated tornado formed just to the northeast in Howard County at 1920 UTC.

Aqua MODIS Visible (0.65 µm) and Infrared Window (11.0 µm) images [click to enlarge]

Aqua MODIS Visible (0.65 µm) and Infrared Window (11.0 µm) images [click to enlarge]

The GOES-13 (GOES-East) satellite had been placed into Rapid Scan Operations (RSO) mode, providing images as frequently as every 5-7 minutes — in the Visible (0.63 µm) images with plots of preliminary SPC storm reports of tornadoes (red) and hail/wind (cyan) shown below (also available as an MP4 animation), numerous overshooting tops can be seen. These overshooting tops were often in the vicinity of the parallax-corrected SPC storm reports (assuming a mean cloud top height of 12 km).

GOES-13 Visible (0.63 µm) images, with SPC storm reports of tornadoes in red and hail/wind in cyan [click to play animation]

GOES-13 Visible (0.63 µm) images, with SPC storm reports of tornadoes in red and hail/wind in cyan [click to play animation]

The corresponding GOES-13 Infrared Window (10.7 µm) images (below; also available as an MP4 animation) revealed cloud-top IR brightness temperatures as cold as -67º C (darker black enhancement) over Indiana at 1845 and 1855 UTC; the location of parallax-corrected preliminary SPC storm reports of tornadoes (white) and hail/wind (cyan) are also plotted on the images.

GOES-13 Infrared Window (10.7 µm) images, with plots of SPC storm reports of tornadoes in white and hail/wind in cyan [click to play animation]

GOES-13 Infrared Window (10.7 µm) images, with plots of SPC storm reports of tornadoes in white and hail/wind in cyan [click to play animation]

GOES-14 SRSO-R: wildfire in Idaho

August 21st, 2016

GOES-14 0.63 µm Visible (top), 3.9 µm Shortwave Infrared (middle) and 10.7 µm Infrared Window (bottom) images, with surface reports plotted in yellow [click to play MP4

GOES-14 0.63 µm Visible (top), 3.9 µm Shortwave Infrared (middle) and 10.7 µm Infrared Window (bottom) images, with surface reports plotted in yellow [click to play MP4 animation]

The Pioneer Fire in central Idaho produced another pyroCumulonimbus (pyroCb) cloud on 21 August 2016 (the first was on 19 August). GOES-14 was in SRSO-R mode, and sampled the fire with 1-minute imagery (above; also available as a large 73 Mbyte animated GIF) — a large smoke plume was evident on 0.63 µm Visible images as it moved eastward; large fire hot spots (red pixels) were seen on 3.9 µm Shortwave Infrared images; on 10.7 µm Infrared Window images, the cloud-top IR brightness temperature cooled to -35º C (darker green enhancement) between 2249-2307 UTC as it moved over Stanley Ranger Station (KSNY), not quite reaching the -40º C threshold to be classified as a pyroCb.

However, a 1-km resolution NOAA-19 AVHRR 10.8 µm Infrared Window image (below; courtesy of René Servranckx) revealed a minimum cloud-top IR brightness temperature of -48.3º C (dark green color enhancement).

NOAA-19 AVHRR 0.64 µm visible (top left), 3.7 µm shortwave IR (top right), 10.8 µm IR window (bottom left) and false-color RGB composite image (bottom right) [click to enlarge]

NOAA-19 AVHRR 0.64 µm visible (top left), 3.7 µm shortwave IR (top right), 10.8 µm IR window (bottom left) and false-color RGB composite image (bottom right) [click to enlarge]

A larger-scale comparison of the NOAA-19 AVHRR visible, shortwave infrared and infrared window images is shown below.

NOAA-19 Visible (0.63 µm), Shortwave Infrared (3.7 µm) and Infrared Window (10.8 µm) images [click to enlarge]

NOAA-19 Visible (0.63 µm), Shortwave Infrared (3.7 µm) and Infrared Window (10.8 µm) images [click to enlarge]

===== 23 August Update =====

Suomi NPP VIIRS Shortwave Infrared (3.74 µm), Day/Night Band (0.7 µm) and 11.45-3.74 µm brightness temperature difference images [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.74 µm), Day/Night Band (0.7 µm) and 11.45-3.74 µm brightness temperature difference images [click to enlarge]

The Pioneer Fire continued to be very active on 22 August (exceeding 100,000 acres in total burn coverage since its start on 18 July), sending a large amount of smoke northeastward (OMPS Aerosol Index). During the following overnight hours, cold air drainage and the development of a boundary layer temperature inversion acted to trap a good deal of smoke in the Payette River valley to the west/southwest of Stanley KSNT. The active fire hot spots (black to yellow to red pixels) were evident on nighttime (1032 UTC or 4:32 AM local time) images (above) of Suomi NPP VIIRS Shortwave Infrared (3.74 µm) data, while illumination from the Moon (in the Waning Gibbous phase, at 69% of Full) showed the ribbon of smoke trapped in the valley (note that this signal was not due to fog, since it did not show up in the VIIRS 11.45-3.74 µm brightness temperature difference or “fog/stratus product”).

During the subsequent daytime hours of 23 August, 1-minute GOES-14 Visible (0.63 µm) images (below; also available as a large 114 Mbyte animated GIF) showed the gradual ventilation of smoke from the Payette River valley as the temperature inversion eroded and mixing via winds increased.

GOES-14 Visible (0.63 um) images, with plots of hourly surface reports [click to play MP4 animation]

GOES-14 Visible (0.63 um) images, with plots of hourly surface reports [click to play MP4 animation]

Flooding in Louisiana

August 12th, 2016

Morphed MIRS observations of total precipitable water (TPW), 1500 UTC 11 August - 2100 UTC 12 August [click to play animation]

Morphed MIRS observations of total precipitable water (TPW), 1500 UTC 11 August – 2100 UTC 12 August [click to play animation]

Persistent convection in an atmosphere rich in moisture has led to life-threatening flooding over many Parishes in southern Louisiana. The animation above, taken from images at this site that morphs MIRS estimates of Total Precipitable Water (with values valid over both land and water) shows values around three inches over much of southeastern Louisiana. These TPW values agree with in situ observations such as the radiosonde from New Orleans at 1200 UTC on 12 August, where 2.70″ was observed. 24-hour rainfall totals ending at 1200 UTC on 12 August (Link) show a widespread region of more than 6″; raingauge observations of 6-hour totals at 1200 and 1800 UTC, below, show that the rain continued into the day on 12 August.

GOES-14 Visible (0.62 µm) images, with METAR observations of 6-hour precipitation, 1200 and 1800 UTC on 12 August 2016 [click to enlarge]

GOES-14 Visible (0.62 µm) images, with METAR observations of 6-hour precipitation, 1200 and 1800 UTC on 12 August 2016 [click to enlarge]

The flood-producing thunderstorms were very slow-moving, as evidenced in the animation of Infrared Window (10.7 µm) images from GOES-14, below (GOES-14 is in SRSO-R mode this month). Very little motion occurs in the two hours of this loop (using images at 5-minute time steps).

GOES-14 Infrared Window (10.7 µm) Imagery, 1625-1830 UTC on 12 August 2016 [click to play animation]

GOES-14 Infrared Window (10.7 µm) Imagery, 1625-1830 UTC on 12 August 2016 [click to play animation]

The entire sequence of 1-minute interval GOES-14 Infrared Window (10.7 µm) images from 0001-2358 UTC on 12 August is shown below.

GOES-14 Infrared Window (10.7 µm) images, with surface weather symbols plotted in yellow [click to play MP4 animation]

GOES-14 Infrared Window (10.7 µm) images, with surface weather symbols plotted in yellow [click to play MP4 animation]

This event is also discussed at the Satellite Liaison Blog, where the focus is on 1-minute visible imagery from GOES-14 and 1-minute lightning data.

===== 13 August Update =====

GOES-14 Infrared Window (10.7 µm) images, with hourly surface weather symbols plotted in yellow [click to play MP4 animation]

GOES-14 Infrared Window (10.7 µm) images, with hourly surface weather symbols plotted in yellow [click to play MP4 animation]

The heavy rainfall continued into 13 August, with storm total accumulations exceeding 31 inches in Louisiana (WPC storm summary). The entire sequence of 1-minute interval GOES-14 Infrared Window (10.7 µm) images spanning the period 1115 UTC on 11 August to 2159 UTC on 13 August, above, shows the development of multiple clusters of slow-moving thunderstorms, some of which exhibited cloud-top IR brightness temperatures of -80ºC or colder (violet color enhancement).