Using the GOES-R Cloud Top Cooling Rate product (applied to GOES-13 data), the Storm Prediction Center issued a Mesoscale Discussion (above) highlighting the risk of strong thunderstorms producing hail and/or strong wind gusts over parts of the Georgia/South Carolina border region on 17 September 2014. According to the SPC storm reports, there was hail up to 1.0 inch in diameter in addition to some tree and power line damage in southern South Carolina. AWIPS II image combinations of the Cloud Top Cooling (CTC) rate product (colors) and the GOES-13 10.7 µm IR channel gray-scale images (below; click image to play animation) showed that CTC rate values for the storm north of Augusta, Georgia (KAGS) at 19:00 UTC were as high as -16º C per 15 minutes; at 19:15 UTC, the CTC rate value for that storm was as high as -39º C per 15 minutes. The first Severe Thunderstorm Warning for this storm was later issued at 19:34 UTC.
Using the GOES-R Cloud Top Cooling Rate product (applied to GOES-13 data), the Storm Prediction Center issued a Mesoscale Discussion (above) highlighting the risk of strong thunderstorms producing hail and/or strong wind gusts over parts of the Georgia/South Carolina border region on 17 September 2014. According to the SPC storm reports, there was hail up to 1.0 inch in diameter in addition to some tree and power line damage in southern South Carolina.
AWIPS II image combinations of the Cloud Top Cooling (CTC) rate product (colors) and the GOES-13 10.7 µm IR channel gray-scale images (below; click image to play animation) showed that CTC rate values for the storm north of Augusta, Georgia (KAGS) at 19:00 UTC were as high as -16º C per 15 minutes; at 19:15 UTC, the CTC rate value for that storm was as high as -39º C per 15 minutes. The first Severe Thunderstorm Warning for this storm was later issued at 19:34 UTC.GOES-13 10.7 µm IR channel images (below; click image to play animation) showed the rapidly cooling cloud-top IR brightness temperatures associated with these thunderstorms as they moved southeastward and intensified: the coldest value for the aforementioned thunderstorm was -40º C at 19:00 UTC, dropping to -62º C by 20:45 UTC.
A time series plot of the Advanced Dvorak Technique (ADT) intensity estimate for Hurricane Odile (above) showed that the tropical cyclone went through a period of rapid intensification on 14 September 2014, reaching Category 4 on the Saffir-Simpson hurricane scale as it moved northwestward toward the southern tip of Baja California (Odile track map).
McIDAS images of GOES-15 10.7 µm IR channel data covering the 13-15 September period (below; click image to play animated GIF; also available as an MP4 movie file) showed Odile from the period of rapid intensification on the 14th to landfall on the 15th. Odile made landfall near Cabo San Lucas around 04:45 UTC on 15 September, with an estimated intensity of 110 knots — this ties with Hurricane Olivia (1967) as the strongest hurricane to make landfall in Baja California Sur during the modern satellite era.
Several hours prior to landfall, a comparison of GOES-15 10.7 µm IR and DMSP SSMIS 85 GHz microwave images from the CIMSS Tropical Cyclones site (below) indicated that Odile had a large outer eyewall at that particular point in time.
Even after several hours of traversing the rugged terrain of the Baja California peninsula, Odile continued to maintain hurricane intensity; the faint signature of an eye could still be seen on AWIPS II images of Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR channel data at 22:34 UTC on 15 September (below).]]>
McIDAS images of 4-km resolution GOES-15 10.7 µm IR channel data (above; click image to play animation; also available as an MP4 movie file) showed the merger of two large mesoscale convective systems (MCS) which produced an all-time record maximum calendar day precipitation amount of 3.29 inches at Phoenix Sky Harbor Airport (PHX) on 08 September 2014. Some locations in the Phoenix area received in excess of 5 inches of rainfall (NWS Phoenix event summary).
An AWIPS-II image of 375-meter resolution Suomi NPP VIIRS 11.45 µm IR channel data (below) showed the MCS pair at 09:07 UTC or 3:07 AM local time — this was prior to the merger, and the southeastern storm exhibited a minimum cloud-top IR brightness temperature of -84º C (purple color enhancement), which was much colder than the -71º C seen with the northwestern storm. At the onset of the heavy thunderstorms at PHX, southerly to southeasterly winds — likely outflow from the southeastern MCS — gusted as high as 31 knots (36 mph) and visibility was reduced to 0.8 mile (surface reports: text | graph).
As the circulation of former-Hurricane Norbert continued to spin over the Pacific Ocean west of Baja California, deep tropical moisture kept working its way farther inland — GOES sounder Total Precipitable Water (TPW) values in excess of 50-60 mm (2.0 to 2.4 inches) were eventually seen across the southwestern half of Arizona (below; click image to play animation).
The Blended Total Precipitable Water product (below; click image to play animation) also showed values of 50-60 mm working their way into southwestern Arizona during the 06-08 September period.
The Percent of Normal TPW product (below; click image to play animation) indicated that these TPW values were in excess of 200% of normal (yellow color enhancement) over large portions of the Desert Southwest. On the morning of 08 September, the TPW value of 2.03 inches derived from rawinsonde data at Tucson, Arizona set a record high for the month of September at that location.]]>
After being started by lightning on 11 August, the Happy Camp Fire Complex (Inciweb) continued to burn in far northern California on 03 September 2014. McIDAS images of GOES-15 (GOES-West) 0.63 µm visible channel data (above; click image to play animation) initially revealed the smoke which had settled into the area valleys during the previous night, and then showed a new smoke plume which drifted southwestward off the coast, then turned to the left and moved southward along the adjacent nearshore waters. The smoke moved over Arcata/Eureka airport (KACV), at one point reducing the surface visibility to 6 miles.
As the fie continued to burn into the following night, an AWIPS II image of Suomi NPP VIIRS 3.74 shortwave IR channel data at 10:21 UTC (3:21 AM local time) showed the cluster of fire hot spots (black to yellow to red pixels), while the corresponding VIIRS 0.7 µm Day/Night Band image showed that the bright glow of the fire complex was as large and as intense as that from many of the larger cities in the region.]]>
The NASA Global Hawk aircraft are once again being used to study tropical cyclones during the 2014 season. As part of CIMSS participation in GOES-R Proving Ground activities, a Global Hawk flight path tool was developed to display important parameters such as ACHA Cloud Top Height, Tropical Overshooting Tops, and lightning (above; click image to play animation). Global Hawk pilots use this product to navigate the aircraft around locations of potential turbulence.
To support the Global Hawk investigation of Tropical Storm Dolly on 02 September 2014, the GOES-13 satellite was placed into Rapid Scan Operations (RSO) mode to provide images at 5-7 minute intervals. GOES-13 0.63 µm visible channel images (above; click to play animation) and 10.7 µm IR channel images (below; click to play animation) are shown which cover the 3-hour period of the Global Hawk flight segment shown above. There is evidence of overshooting tops seen in the visible imagery, with cloud-top IR brightness temperatures of -80º C and colder (purple color enhancement).]]>
Tropical Storm Dolly has formed in the western Gulf of Mexico. The Suomi NPP VIIRS Day Night Band imagery, above, shows the exposed low-level swirl of the storm (then still a tropical depression). North-northwesterly shear (shown here, from this site) means the deep convection (shown below) is displaced to the east of south of the the low-level circulation (click here for a toggle between the Day Night Band and the 11.45µm imagery). Cloud-top IR brightness temperatures from VIIRS were as cold as -87º C. ASCAT winds from 0230 UTC show a region of tropical storm-force winds associated with convection east and north of the circulation center.
Early-morning visible imagery from GOES-13, below, shows the large area of convection over the southern Gulf. The NHC-reported positions of the storm at 0900 UTC and 1500 UTC (22.6º N, 94.8º W and 23.4º N, 96.5º, respectively) are indicated by the red boxes on the images. Strong convection just south of the surface circulation developed at sunrise, obscuring the low-level swirl. That strong convection is especially apparent in the GOES-13 10.7 imagery, at bottom. GOES IR Brightness Temperatures were as cold as -84º C in the animation. (For more on Dolly from the National Hurricane Center, see this link).]]>
It is rather rare to have no named tropical cyclones anywhere on the globe on the first day of September, but that was the case on 01 September 2014. A sequence of hourly global composite IR images from the SSEC RealEarth web map server (Animated GIF | MP4 movie file | YouTube video) showed the void of tropical activity — until Tropical Depression 5 formed late in the day in the Gulf of Mexico. This feature later became Tropical Storm Dolly early on 02 September.]]>
The CIMSS Saharan Air Layer (SAL) product (above; click image to play animation) showed a large pocket of SAL (yellow to red color enhancement) drifting westward over the far western Atlantic Ocean and toward the Gulf of Mexico on 28 August 2014.
On GOES-13 0.63 µm visible channel images (below; click image to play animation), the hazy signature of the SAL dust could be seen surging westward, not far to the south of Category 1 intensity Hurricane Cristobal.
The SAL also exhibited a warm/dry signature (yellow to orange color enhancement) on the corresponding GOES-13 6.5 µm water vapor channel images (below; click image to play animation).
At 17:16 UTC, a Suomi NPP VIIRS true-color Red/Green/Blue (RGB) image from the SSEC RealEarth web map server (below) showed that Hurricane Cristobal had developed an eye formation.
A comparison of AWIPS-2 images of Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR channel data (below) revealed that the coldest cloud-top IR brightness temperatures (-77º C, lighter gray color enhancement) were located within convection just southwest and southeast of the eye.]]>
GOES-13 is currently in Autumn Eclipse Season, when the Earth-Satellite-Sun geometry means that solar energy can reach the satellite sensors directly. NOAA NESDIS has software to mitigate the effects of Stray Light in the Sensor Processing System (SPS) that transforms the raw GOES Imager data to navigated and calibrated (GVAR) data. However, earlier this month, the SPS at Wallops inadvertently omitted the Stray Light Correction. The animation above, from 16-27 August, shows how Stray Light intruded into the 3.9 µm imagery on the GOES-13 Imager; on 25 August the Stray Light Correction was turned back on, and the final two images show no major Stray Light effects over the satellite view (Stray Light is still recorded in outer space). The animation above is for 5:15 UTC, when Stray Light affected the eastern part of the full disk scan. At 4:45 UTC, Stray Light affected the western part of the disk, and at 05:00 UTC, the central part of the disk.
Click here for more about the Stray Light Correction.]]>
Some locations in northeastern Montana received up to 7-8 inches of rainfall over a 5-day period (NWS Glasgow rainfall map), which led to flooding in many areas. A comparison of before (12 August) and after (26 August) 250-meter resolution MODIS false-color Red/Green/Blue (RGB) images from the SSEC MODIS Today site (above) showed the areal extent of flooding (cyan to darker blue areas on the 26 August image). The RGB images use MODIS bands 7/2/1 to help highlight the areas of of floodwater.
The maps below show the total observed rainfall, the departure from normal, and the percent of normal for the 7-day period ending on 26 August.]]>