The corresponding 4-km resolution GOES-15 Infrared (10.7 µm) images (below) revealed that cloud-top IR brightness temperatures quickly cooled from -23º C at 2130 UTC to -42º C at 2200 UTC.There was a 30-minute gap in GOES-15 coverage from 2100 to 2130 UTC (due to a full disk scan), but a comparison of 1-km resolution NOAA-19 AVHRR Visible (0.63 µm) and Infrared (10.8 µm) caught the very early growth of the tornado-producing storm at 2115 UTC (below). The cloud-top IR brightness temperatures were as cold as -23º C at that time, indicating a high probability that cloud glaciation had begun. A timely overpass of the Suomi NPP satellite allowed a comparison of 375-meter resolution VIIRS Visible (0.64 µm) and Infrared (11.45 µm) images during the time that the tornado was srill on the ground (below). Once again, the strong slant of the storms due to increasing wind speeds aloft allowed the western/southwestern sides of the thunderstorm clouds to be brightly illuminated on the visible image. The coldest cloud-top IR brightness temperature was -51º C (yellow color enhancement), which was just shy of the -53º C tropopause temperature reported on the Oakland rawinsonde report at 12 UTC. A VIIRS true-color image of the storm visualized using RealEarth is shown below. The actual satellite overpass time was around 2151 UTC. GOES-15 sounder Lifted Index (LI) derived product images (below) showed the pockets of post-frontal instability over central California — LI values less than -4 C were seen (yellow color enhancement).
The Storm Prediction Center has revised its criteria for initiating GOES Rapid Scan Operations (RSO) calls. Previously, RSO was automatically activated when a Moderate Risk (MDT) appeared in the SPC Day 1 Convective Outlook. On October 1st that was changed per a September email from SPC:
Starting October 1, the SPC Lead Forecaster will contact the NCO/SDM to request GOES RSO whenever a Day 1 Convective Outlook includes an ENH Risk area. Data from the first six months of 2015 suggests SPC would request RSO on approximately 10-20 more days compared to the current MDT Risk criterion. Activating RSO on a more frequent basis using the ENH Risk criterion would improve NWS forecaster situational awareness on convectively active days and help prepare users for much higher temporal frequency GOES-R data.
An Enhanced Risk was issued on 11 November 2015 as a strong extratropical cyclone was developing over the midsection of the country. The image above shows the GOES-13 Water vapor imagery from 1145 UTC on 11 November. A strong jet extends from the southwestern United States northeastward. On the previous day (10 November, at 12 UTC) Albuquerque reported 135-knot winds at 300 hPa (and no winds at all at 200 hPa as the balloon was lost to the tracker); at 00 UTC on 11 November, winds were 162 knots just above the 250 hPa level. Strong veering, indicating warm advection, is apparent over the mid-Mississippi River Valley. Low-level warm advection is forecast to increase as the extratropical cyclone intensifies.
Update: GOES-East began RSO at 1545 UTC on 11 November 2015 — a few image animations are shown below.Of particular interest on 6.5 µm water vapor imagery, above, was the tightly-wrapped signature of the middle-tropospheric vorticity center moving northeastward along the Kansas/Nebraska border. The 10.7 µm Infrared images, above, showed the development of thunderstorms across Iowa which exhibited cloud-top IR brightness temperatures in the -50 to -60º C range (yellow to red color enhancement). Hail, damaging winds, and tornadoes were produced by these areas of deep convection (SPC storm reports). 3.9 µm Shortwave Infrared images, above, displayed numerous “hot spots” (black to yellow to red color enhancement) due to fire activity in parts of northeastern Oklahoma and southeastern Kansas. Finally, 0.63 µm Visible channel images, above, showed the hazy signature of smoke plumes from these Kansas/Oklahoma fires (along with a separate plume of blowing dust). In addition, as clouds cleared along the western edge of the storm, swaths of fresh snow cover could be seen over portions of Wyoming, Colorado, South Dakota, Nebraska, and Kansas. As much as 12.5 inches of snow was reported in northeastern Colorado, with wind gusts of 75 mph creating blizzard conditions.
Multi-day YouTube animations showing the formation of Patricia are available here (0.63 µm visible imagery from GOES-13) and here (10.7 µm infrared imagery from GOES-13). The multi-day location of Patricia’s 850 hPa relative vorticity signature (derived from satellite atmospheric motion vector data) can be seen here.
A plot of the Advanced Dvorak Technique intensity estimate (below) showed the rate of rapid intensification on 22-23 October. At one point Patricia’s central pressure deepened 100 hPa in 24 hours, and 73 hPa in 12 hours, making it the fastest-intensifying tropical cyclone on record in the Western Hemisphere.GOES-15 Visible (0.63 µm) images (below; also available as an MP4 animation) revealed the small “pinhole” eye of Patricia during rapid intensification on 22 October. As Patricia was rapidly intensifying from a Category 1 to Category 5 intensity, the tropical cyclone was moving over a region of high Ocean Heat Content (below), and Sea Surface Temperature values were as high as 31º C.
A comparison of Suomi NPP VIIRS Infrared (11.45 µm) and Day/Night Band (0.7 µm) images at 0741 UTC on 23 October is shown below (courtesy of William Straka, SSEC). With ample illumination from the Moon (which was in the Waxing Gibbous phase, at 78% of Full), the “visible image at night” capability of the Day/Night Band provided a detailed view of cloud-top gravity waves surrounding the eye.
A later VIIRS Infrared (11.45 µm) image at 0920 UTC is shown below.
A comparison of GOES-15 (GOES-West) and GOES-13 (GOES-East) Visible (0.63 µm) images (below) showed the eye of Patricia from sunrise on 23 October until landfall along the west coast of Mexico around 2315 UTC. A mesonet station at the Chamela-Cuixmala Biosphere Reserve (located approximately 10 miles northwest of the eye landfall position) reported maximum sustained winds of 185 mph at 2350 UTC, with a peak wind gust of 210.9 mph at 2310 UTC.MIMIC morphed microwave imagery (below) showed the development and motion of the very compact eye during the 22-23 October period. There was also a signature of the formation of a secondary outer eyewall, suggesting that an eyewall replacement cycle was underway as Patricia was approaching the west coast of Mexico. View a 23 October weather briefing held at CIMSS to discuss Hurricane Patricia here.
===== 25 October Update =====
Following the landfall of Patricia late in the day on 23 October, and increase in offshore sediment could be seen in Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images (from the RealEarth web map server) on 24 and 25 October (below), a result of runoff from heavy rains inland.
A plot of the Advanced Dvorak Technique (ADT) intensity estimate for Hurricane Olaf (above) showed that the storm went through a period of rapid intensification during the 19-20 October 2015 period, reaching Category 4 strength. The National Hurricane Center noted that Olaf became the 6th major hurricane in the eastern North Pacific during the 2015 season, and that this was is the farthest south (9.9º N latitude) that a major hurricane had formed in that ocean basin since reliable records began in 1971 (discussion archive: NHC | CPHC).
4-km resolution GOES-15 (GOES-West) 10.7 µm Infrared channel images during the period of rapid intensification (below) revealed that cloud-top IR brightness temperatures were quite cold (in the -80º to -90º C range, violet colors) early in the day on 19 October, but then warmed a bit into the -70º to -80º C range (black to white shades) on 20 October as the eye became more well-defined.A 375-meter resolution Suomi NPP VIIRS Infrared (11.45 µm) image at 10:23 UTC on 20 October (below) hinted at the presence of mesovortices within the eye of Hurricane Olaf.