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

The GOES-16 Land Surface Temperature product (above, courtesy of Jordan Gerth, CIMSS) revealed a dramatic increase in the land surface temperature (or surface “skin temperature”) following the onset of easterly/northeasterly Santa Ana winds in Southern California’s Ventura County during the overnight and early morning hours of 24 October 2017. Between 06-14 UTC (11 PM-7 AM local time), the surface air temperature increased from 66-91ºF at Oxnard (KOXR), 75-90ºF at Point Mugu (KNTD) and 77-91ºF at Camarillo (KCMA). Surface wind gusts of 32 mph were recorded at Camarillo during this period, although 64 mph was reported at South Mountain (elevation 2350 feet)..

A warming trend in that same area was also evident in the MODIS Land Surface Temperature product (below), during the time between the Terra (0539 UTC) and Aqua (0951 UTC) overpasses — LST values ranged from the low 60s F (lighter shades of yellow) to the upper 80s and low 90s F (darker shades of red) in the higher elevations.

A similar warming signature was seen over Ventura County on GOES-16 Shortwave Infrared (3.9 µm) images (below) — although an even more pronounced Santa Ana wind warming signal was evident farther to the southeast over Orange County (where winds gusted as high as 69 mph); note how the warmer orange-enhanced infrared brightness temperatures surged southwestward toward the coast.

A number of record high temperatures resulted from this Santa Ana wind event:

Final record highs for today across SW CA. Some record highs will be possible on Wed as well. #LAHeat #LAWeather #cawx #SoCal pic.twitter.com/gwalGarQmL

— NWS Los Angeles (@NWSLosAngeles) October 25, 2017

In fact, the highest temperature in the Lower 48 states that day was 108ºF at Miramar Naval Air Station and San Luis Obispo, California.

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A plot of the Advanced Dvorak Technique for Typhoon Lan (above) showed that the tropical cyclone underwent a period of rapid intensification during the 00-12 UTC period on 20 October 2017.

A 24-hour animation of Himawari-8 rapid-scan (2.5 minute interval) Infrared Window (10.4 µm) images (below) revealed the development of a very large eye during the 20 October/06 UTC to 21 October/06 UTC period.

A nighttime comparison of Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1700 UTC or 2:00 AM kocal time (below; courtesy of William Straka, CIMSS/SSEC) provided a good visualization of the “stadium effect” — an eye that was more narrow at the surface, with a larger diameter at higher altitudes. A packet of mesospheric airglow waves (reference) was also evident on the Day/Night Band image, propagating south-southeastward away from the eye.

A 2-panel comparison of Himawari-8 Visible (0.64 µm) and Infrared Window (11.45 µm) images (below) showed the eye of Lan after it attained Super Typhoon status at 18 UTC on 20 October. Mesovortices could  be seen within the eye on the rapid-scan images.

A large amount of moisture was associated with this tropical cyclone, as depicted by hourly images of the MIMIC Total Precipitable Water product (below) — note the large area with TPW values of 70 mm or greater (light violet color enhancement).

A TPW value of 72.5 mm (2.87 inches) was derived from the Minamidaitojima, Japan rawinsonde data at 12 UTC on 21 October (below). Minamidaitojima is the largest island in the Daito Islands group southeast of Okinawa, Japan  — this station was just to the northeast of Lan around 12 UTC.

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

Stratus and Fog formed over the valleys of Kentucky (and in surrounding states) early on 18 October 2017 (It was there on 17 October as well). When was the fog first obvious from Satellite imagery? It very much depends on the spatial resolution of the Satellite viewing the scene. The Brightness Temperature Difference field (10.3 µm – 3.9 µm) from GOES-16, shown above, can be used to identify regions of stratus clouds that are made up of water droplets. Carefully examine the animation; the time when fog is definitively present over valleys of eastern Kentucky (around 84º W Longitude) is around 0327 UTC.

GOES-16 has 2-km resolution (at the sub-satellite point — 89.5º W Longitude during GOES-16 Check-out); this is superior to GOES-13’s nominal 4-km resolution at the subpoint (75º West Longitude). The GOES-13 Brightness Temperature Difference Field (10.7 µm – 3.9 µm) at 0330 UTC shows no distinct indication of Fog/Stratus over eastern Kentucky. A series of animations of the GOES-13 Brightness Temperature Difference field, from 0215-0345 UTC, from 0415-0500, from 0545-0700 and from 0700-0815 suggest GOES-13 identified the region of fog about 4 hours after GOES-16, at 0730 UTC.

The GOES-13 vs. GOES-16 toggle below, from 0700 UTC on 18 October 2017, shows how the resolution improvement with GOES-16 facilitates earlier detection of fog and stratus as it develops overnight.

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After reaching Category 3 intensity over the eastern Atlantic Ocean on 14 October, Hurricane Ophelia (storm track) rapidly underwent transition to an extratropical storm which eventually spread high winds across much of Ireland and the United Kingdom on 16 October 2017. EUMETSAT Meteosat-10 upper-level Water Vapor (6.25 µm) (above) and lower-level Water Vapor (7.35 µm) images (below) revealed the familiar “scorpion tail” signature of a sting jet (reference). Hourly wind gusts (in knots) from primary reporting stations are plotted in red.

Two sites with notable wind gusts were Cork, Ireland (67 knots at 0930 UTC) and Valley, UK (70 knots at 1500 UT), shown below. In fact, a wind gust of 103 knots (119 mph or 191 km/hour) was reported at the Fastnet Rock Lighthouse off the southwest coast of Ireland.

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In a toggle between Terra MODIS (overpass time around 1159 UTC) and Aqua MODIS (overpass time around 1345 UTC) true-color Red-Green-Blue (RGB) imagery (above), a somewhat hazy appearance was seen over the Irish Sea on the Terra MODIS image. This was due to an airborne plume of sand from the Sahara Desert (UK Met Office story).

In fact, blowing sand was observed about 3 hours later at Isle of Man, from 1520-1620 UTC — during that time period their surface winds gusted to 68 knots (78 mph), and surface visibility was reduced to 2.2 miles (below).

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