Satellite Liaison Blog

GOES-R & JPSS: The Future of Weather Satellites

  • Home
  • About the Blog

S Plains Blowing Dust – 11/14/2020

Posted by Bill Line on 11/22/2020
Posted in: Uncategorized. Leave a comment

A shortwave trough ejecting out of the Great Basin east into the central US plains sent a cold front south through the southern high plains during the afternoon/evening of 11 Nov 2020. Gusty winds developing ahead of and behind the front resulted in widespread blowing dust across the region. Widespread wind gusts in excess of 45 mph were reported, along with visibility reductions generally to around four miles, and in some cases, to near zero. The video below depicts the blowing dust during the afternoon in far east-central Colorado.

https://t.co/jQD6ISHOSD

— DW8525 (@CWCOWX) November 14, 2020

GOES-West water vapor imagery from the previous evening through the day on the 14th reveals the influencing trough as it tracked through the region (Fig 1).

Figure 1: 14 Nov 2020 GOES-West 6.2 um Water Vapor Imagery. Higher Res

Blowing dust already developed during the late morning and early afternoon across northeast Colorado. Lofted dust was captured well in an animation of 500 m visible imagery with a cold 10.3 um IR BT overlay in order to mask out clouds (Fig 2). The 500 m nadir resolution is adequate to pinpoint the source points of the many individual dust plumes, similar to smoke emanating from a wildfire hot spot.

Figure 2: 14 Nov 2020 GOES-East 0.64 um VIS and 10.3 um IR over northeast CO. Higher Res

The lofted dust was also captured during the day in the Day Land Cloud RGB which incorporates the 500 m VIS channel in addition to 0.86 um Veggie band and 1.6 um snow/ice band, allowing it to capture surface/near-surface features well and differentiate ice and water clouds (Fig 3).

Figure 3: 14 Nov 2020 GOES-East Day Land Cloud RGB over northeast CO. Higher Res

GOES-East Geocolor imagery provided perhaps the best depiction of the blowing dust during the daytime (Fig 3b). Further, 1-min imagery was available over the region during the event, allowing for a more detailed characterization to the dust evolution versus the 5-min conus imagery.

Figure 3b: 14 Nov 2020 GOES-East Geocolor over northeast CO. Higher Res

Similar animations capture afternoon blowing dust developing across southern Colorado, including dust collecting along the south-bound cold front as it tracked into the PHs (Fig 4-5).

Figure 4: 14 Nov 2020 GOES-East 0.64 um VIS and 10.3 um IR over southeast CO. Higher Res
Figure 5: 14 Nov 2020 GOES-East Day Land Cloud RGB over southeast CO. Higher Res
Figure 5b: 14 Nov 2020 GOES-East 1-min Geocolor over southeast CO. Higher Res

Dust was similarly lofted across E NM and W TX in dry conditions with strong westerly winds (Fig 6-7).

Figure 6: 14 Nov 2020 GOES-East 0.64 um VIS and 10.3 um IR over western TX. Higher Res
Figure 7: 14 Nov 2020 GOES-East Day Land Cloud RGB over western TX. Higher Res
Figure 7b: 14 Nov 2020 GOES-East 1-min Geocolor over W Texas. Higher Res

A GOES-East Geocolor animation captures the full daytime evolution of blowing dust across the southern High Plains.

Figure 7c: 14 Nov 2020 GOES-East Geocolor over the southern US high plains. Higher Res

While GOES-East visible imagery provided better detection of blowing dust during the afternoon/evening due to increasing forward scattering, GOES-West contributed a better depiction during the morning. Two areas of very active morning blowing dust are shown from the GOES-West perspective: southern Colorado just south of la Junta, and far southwest TX (Fig 8-9).

Figure 8: 14 Nov 2020 GOES-West 0.64 um VIS and 10.3 um IR over southeast CO. Higher Res
Figure 9: 14 Nov 2020 GOES-West 0.64 um VIS and 10.3 um IR over southwest TX. Higher Res

The blowing dust continued after dark (after 2311 UTC) across much of the same region, particularly along and behind the the cold front pushing south out of KS into the PHs. IR only animations also captured the blowing dust evolution. The advantage of the IR-only imagery products is that dust can continue to be diagnosed after dark, in addition to during the day.

The evolution of blowing dust during the day into the night is shown first in the SWD, using a simple linear grayscale color table, with IR Window cold BTs overlaid (Fig 10). This simple display reveals areas of likely blowing dust into the night (dark gray to black), along with cloud top temperature trend information.

Figure 10: 14-15 Nov 2020 GOES-East 10.3 – 12.3 um Split Window Difference over southern Plains. Higher Res

The default AWIPS Dust RGB, which incorporates the SWD along with the Split Cloud Top Phase and IR Window channel, captures the dust (pink) evolution into the night along with cloud top phase information (Fig 11).

Figure 11: 14-15 Nov 2020 GOES-East Default Dust RGB over southern Plains. Higher Res

Tweaks to that RGB, similar to those outlined in this blog post, help to make the lofted dust more easily diagnosable (dark cyan; Fig 12).

Figure 12: 14-15 Nov 2020 GOES-East Modified Dust RGB over southern Plains. Higher Res

Finally, another RGB discussed here allows for dust (bright green) tracking in addition to wildfire hotspot detection (Fig 13). In this case, there did not appear to be any active fires in the region during the time period.

Figure 13: 14-15 Nov 2020 GOES-East Dust-Fire RGB over southern Plains. Higher Res

750 m VIIRS True Color imagery captured the early evolution of the blowing dust from 1930 UTC (SNPP) to 2020 UTC (NOAA-20) across E CO (Fig 14) and W TX (Fig 15).

Figure 14: 14 Nov 2020 VIIRS True Color Imagery over E CO. From NASA Worldview Higher res
Figure 15: 14 Nov 2020 VIIRS True Color Imagery over E NM and W TX. From NASA Worldview Higher res

Finally, an even higher resolution view (10 m) of the blowing dust is captured by the Sentinal-2 mission. These data are only available over a given point every few days, and are not as quickly available to forecasters as the NOAA satellite data, but provide a very high resolution, confirming view after the fact in some cases. The images shared in Figures 16 and 17 show the very early stages of lofted dust (1753 UTC) across southern Wyoming (east of Cheyenne) and southeast Colorado (south of La Junta). The source points of the lofted dust are clearly evident in this imagery.

Figure 16: 14 Nov 2020 Sentinal-2 True Color Imagery over southern WY. From Sentinel Hub EO Browser. Higher res
Figure 17: 14 Nov 2020 Sentinal-2 True Color Imagery over southern CO. From Sentinel Hub EO Browser. Higher res

The following tweets from NWS Amarillo presents photo of the impending blowing dust in the Texas Panhandle, along with a satellite view (GOES Dust RGB) representing the extent of blowing dust and its forecast evolution.

4:33 PM CST, 11/14: A wall of #BlowingDust is moving through the northern #Texas Panhandle. This picture was shared with us from the Perryton Feeders along US Highway 70 south of #Perryton, #Texas. Expect sudden reductions of visibility (as low as 3 miles). #phwx #txwx pic.twitter.com/v3pcltSXtt

— NWS Amarillo (@NWSAmarillo) November 14, 2020

5:30 PM 11/14: #dust is moving through the northern Panhandles and is expected to continue spreading southward over the next couple hours through the blue highlighted area. Visibility could drop to around 3 miles so take it easy out there. #phwx pic.twitter.com/XqWXATK453

— NWS Amarillo (@NWSAmarillo) November 14, 2020

Bill Line, NESDIS and CIRA

Curtis Seaman and Dakota Smith (CIRA)

GOES Imagery Used to Alert Partners of Fire Spread

Posted by Bill Line on 10/23/2020
Posted in: Uncategorized. Leave a comment

A previous blog post documented the explosive growth of the East Troublesome Fire during the day of Oct 21 through the late evening. The fire had spread east to near the Continental Divide, west of Rocky Mountain National Park (RMNP), slowing by late that night.

During the morning of 22 Oct, NWS BOU forecasters monitoring the wildfire hot spot in GOES-East imagery noted an eastward movement of the far eastern portion of the fire, northeast of Grand Lake and west of Estes Park, possibly across the Continental Divide (Fig 1).

Figure 1: 22 Oct 2020 GOES-East Shortwave IR Window Channel imagery. Darker pixels are hotter brightness temperatures. The gray lines indicate contours of 11,000 ft agl elevation, and represent the Continental Divide. The hot spot accelerates east across the Divide late in the animation. Higher res

An image captured by BOU forecasters shows the Fire Radiative Power product in relation to the most recent burn scar shapefile and other local geographic features and towns (Fig 2). Accounting for the surface parallax (from GOES-East, surface features are displaced to the north and west at this location/elevation by several km), fire associated with the easternmost hot spot would actually be situated to the southeast, just east of the Divide and west of Bear Lake in RMNP.

Figure 2: 1306 UTC 22 Oct 2020 GOES-East Fire Power Derived product, burn scar outlines (yellow) from NWS BOU. Higher res

Accounting for surface parallax, BOU believed that the hot spot may have advanced east across the Continental Divide during this period. Based on this development as diagnosed in GOES-East imagery, BOU forecasters alerted (via phone call) RMNP dispatch (and Laminar County) to the possibility that the fire had pushed east across the Divide into western RMNP. They were unaware of fire growth into the park at the time, and would go on to call out fire partners to investigate. Although it took a while to get confirmation, it would be confirmed that the fire had indeed crossed over the Continental Divide.

A cold front would soon push west into the I-25 corridor and eventually to Estes Park, dropping temperatures and raising humidity’s with a light east wind. The moist stable layer may have made it west up to the fire, putting a damper on fire behavior. GOES Natural Color Fire imagery from the early afternoon showed low stratus draped across the eastern Colorado plains, while the wildfire continued to burn hot west of the Divide in the presence of still dry and windy conditions (Fig 3). Also diagnosed in the imagery was a thick smoke plume with pyrocu spreading well east over the stratus deck. The smoke plume masked the hot spot in RMNP for the rest of the afternoon/evening.

Figure 3: 22 Oct 2020 GOES-East 1-min Natural Color Fire RGB. Higher res

During the evening of the 22nd, the glow associated with the fire in western RMNP could be diagnosed in (terrain corrected) VIIRS Day Night Band imagery (Fig 4).

Figure 4: 0903 UTC NOAA-200 VIIRS DNB NCC (left) and topo map (right). Higher res

This is a great example of a forecast office utilizing GOES imagery to provide potentially life saving IDSS to core partners.

Bill Line, NESDIS and CIRA (with input from NWS BOU)

East Troublesome Fire Growth 10/21 – GOES and JPSS Imagery

Posted by Bill Line on 10/22/2020
Posted in: Uncategorized. Leave a comment

The East Troublesome Fire, in Grand County, Colorado near Grand Lake and west of Rocky Mountain National Park, experienced substantial growth during the afternoon/evening of 21 October 2020. Dry environmental and fuel conditions, along with gusty winds, caused the fire to grow from 19,086 acres to 125,602 acres during the 1-day timeframe per Inciweb (see maps below).

GOES-East imagery captured the rapid growth of the associated hot spot signature. Throughout the event, NWS Boulder shared GOES-East imagery of the fire on social media to help inform the public of it’s evolution as it quickly spread east. A couple examples are shown below.

The East Troublesome Fire, in Grand County, has exploded this afternoon in Fire Imagery. Those in mandatory evacuation areas should evacuate immediately!!! #cowx #cofire #EastTroublesomeFire pic.twitter.com/hgGTtsNg8Q

— NWS Boulder (@NWSBoulder) October 21, 2020

[8:57] #EastTroublesomeFire continues to advance towards Grand Lake. IF YOU LIVE IN THIS AREA, EVACUATE IMMEDIATELY!! Fire has been reported as close as Columbine Lake. #cowx #cofire pic.twitter.com/4p3BgFM9JJ

— NWS Boulder (@NWSBoulder) October 22, 2020

VIIRS imagery from the early afternoon captured the wildfire as it began it’s rapid growth (Fig 1). The Fire Radiative Power product provided a high resolution view of the heat associated the fire, highlighting a particularly active zone over the northeast portion of the fire (which would go on to continue to expand east rapidly). The underlay of VIIRS True Color imagery shows the associated smoke plume with pyrocu developing near the hot spot. This imagery is available online from the JSTAR mapper.

Figure 1: 21 Oct 2020 SNPP VIIRS daytime Fire Radiative Power product, True Color imagery. Higher res

The daytime evolution of the wildfire is shown through the GOES-East Natural Color Fire RGB in Figure 2. The rapid growth of the wildfire hot spot is observed to begin after 2000 UTC, with the large smoke plume extending well east. Ashfall was abundant across downstream locations such as Fort Collins and Loveland. Pyrocumulus clouds were also present with the smoke plume. The large burn scar associated with the Cameron Peak Fire, north of Estes Park, is apparent, along with several other smaller burn scars throughout the scene.

Figure 2: 21 Oct 2020 GOES-East Natural Color Fire RGB. Higher res

A VIS-IR-SWIR combo animation extending after sunset highlights the development of the smoke plume, including eventual cooling of pyrocu to as cold as -60C after dark (Fig 3).

Figure 3: 21 Oct 2020 GOES-East VIS, semi-transparent SWIR, semi-transparent IR. Higher res

Long animations of GOES-East SWIR and Fire Temperature RGB show the full evolution of the wildfire hot spot growth on the 21st from Noon through around midnight (Fig 4-5). Steady growth/heating is observed through teh afternoon, before the rapid acceleration east after dark to near the Continental Divide. west of Rocky Mountain National Park.

Figure 4: 21 Oct 2020 GOES-East SWIR. Higher res
Figure 5: 21 Oct 2020 GOES-East Fire Temperature RGB. Higher res

Similar time periods but zoomed out images provide another perspective of the large growth and massive size of the fire (Fig 6-7).

Figure 6: 21 Oct 2020 GOES-East SWIR. Higher res
Figure 7: 21 Oct 2020 GOES-East Fire Temperature RGB. Higher res

The fire becomes so hot in areas that the signal in SWIR channel becomes saturated. This is a situation where the Fire Temperature RGB becomes a little more useful for those wishing to monitor fire heating trends the most active/hottest regions of the wildfire. Figure 8 from 0131 UTC compares SWIR with Fire Temperature RGB, exemplifying the power of the RGB to reveal more detailed temperature information after the SWIR channel becomes saturated. While the SWIR saturates, the Fire Temp RGB shows progressively hotter regions from red to yellow to white through it’s inclusion of the 2.2 um and 1.6 um bands, in addition to the SWIR.

Figure 8: 0131 UTC 22 Oct 2020 GOES-East SWIR (left), Fire Temperature RGB (right).

GOES-West similarly displayed the evolution of the wildfire through the afternoon/evening (Fig 9).

Figure 9: 21 Oct 2020 GOES-West Fire Temperature RGB. Higher res

A couple hours after midnight, SNPP and NOAA-20 VIIRS DNB NCC imagery revealed the glow of the now very large hot spot associated with the East Troublesome Fire, as well as the most active areas (Fig 10). The massive size can be compared with the City of Denver to the east.

Figure 10: 22 Oct 2020 SNPP (top) and NOAA-20 (Bottom) VIIRS DNB NCC. Higher res top, higher res bottom

The VIIRS Fire Radiative Power Product, shown earlier in this post, is also available at night, and shown in Figure 11. Again, the product provides a higher resolution view of the current location of the wildfire, along with the hottest areas.

Figure 11: 22 Oct 2020 SNPP VIIRS nighttime Fire Radiative Power product. Higher res

Bill Line, NESDIS and CIRA

Where is the Hot Spot?

Posted by Bill Line on 10/20/2020
Posted in: Uncategorized. Leave a comment

Wildfires remained active across northern Colorado by 20 Oct 2020. The Cameron Peak Fire, west of Fort Collins, had grown to over 200,000 acres, the largest wildfire in Colorado recorded history.

Viewing GOES-East SWIR imagery over northern Colorado during the morning of Oct 20, a hot spot is barely apparent from the Cameron Peak Fire, just west of Fort Collins (Fig 1-2 top). From the SWIR and other channels, one easily finds that this is due to cloud cover. However, the western US has the benefit of overlapping 5-min (CONUS/PACUS) imagery from GOES-East and GOES-West satellites. Upon viewing GOES-West SWIR imagery, a hot spot associated with the Cameron Peak Fire is readily apparent through the morning (Fig 1-2 bottom).

Figure 1: 20 Oct 2020 GOES-East (top) and GOES-West (bottom) shortwave IR imagery. Higher res
Figure 2: 1611 UTC 20 Oct 2020 GOES-East (top) and GOES-West (bottom) shortwave IR imagery, annotated. Higher res

Viewing Natural Color Fire RGB imagery, the quasi-stationary cloud masking the hot spot in GOES-East imagery is obviously situated to the east of the wildfire in GOES-West imagery, allowing for a clear view of the hot spot (Fig 3-4). This is a good visualization of parallax, and how clouds will appear situated at different locations relative to the surface in reality, and between GOES-East and GOES-West.

Figure 3: 20 Oct 2020 GOES-East (top) and GOES-West (bottom) natural color fire RGB imagery. Higher res
Figure 4: 1611 UTC 20 Oct 2020 GOES-East (top) and GOES-West (bottom) natural color fire RGB, annotated. Higher res

It is important for forecasters in the west to remember that they have two options for 5-min geostationary imagery, and that there are situations where one may provide additional insight over the other.

Bill Line, NESDIS and CIRA

Cameron Peak Fire Oct 14 Growth

Posted by Bill Line on 10/15/2020
Posted in: Uncategorized. Leave a comment

A shortwave trough brought strong, deep westerly winds to northern Colorado and an afternoon cold front on 14 October 2020. Analysis of GOES-East water vapor imagery reveals the shortwave dropping south through MT/WY and then east into the plains (Fig 1). The gusty winds and low RH along with continued dry fuels meant conditions were favorable for the rapid growth and spread of the Cameron Peak Wildfire, which had been burning for months in the mountains just west of Fort Collins.

Figure 1: 14-15 Oct 2020 GOES-East UL Water Vapor Imagery, RAP 500 mb Heights. Higher res

The dangerous fire weather conditions did indeed cause the wildfire to grow considerably during the day, becoming the largest wildfire in Colorado recorded history at over 164,000 acres by early on the 15th, from 135,000 acres early on the 14th. The growth can be visualized in the fire information maps from Inciweb (Fig 2a). Evacuation zones expanded east to just west of Horsetooth Reservoir (Fig 2b).

Figure 2a: Cameron Peak Fire Information Maps from Inciweb from the morning of 10/14 (left) and morning of 10/15 (right). Higher res
Figure 2b: Cameron Peak fire evacuation map on 10/15. Higher res

Both GOES-East and GOES-West satellite imagery captured the evolution of the wildfire hot spot and smoke plume throughout the day. Given the satellite viewing angles and resulting forward scattering, GOES-West VIS provided a clearer view of the smoke plume during the morning, with GOES-East VIS the better option during the afternoon (Fig 3). Given the thick plume, both sensors provided adequate detection.

Figure 3: 14 October 2020 GOES-East (top) and GOES-West (bottom) VIS. Higher res

Focusing on GOES-East, 1-min imagery was available over the wildfire during the day. Early morning Natural Color Fire RGB imagery revealed a lenticular cloud stationary over the fire location around sunrise, dissipating into the morning and revealing the large hot spot (Fig 4).

Figure 4: 14 October 2020 GOES-East 1-min Natural Color Fire RGB during early morning. Higher res

The Natural Color Fire RGB imagery allows one to characterize various aspects of the wildfire given the three components: hot spot (SWIR), smoke plume (VIS), and burn scar (Veggie). While a similar RGB (Day Land Cloud Fires) is available in AWIPS, this particular RGB, which better detects hot spots, is not (though it can be requested). An example scene from this wildfire is annotated in Fig 5.

Figure 5: 1758 UTC 14 October 2020 GOES-East Natural Color Fire RGB annotated. Higher res

Later in the day, the wildfire broke containment and spread rapidly to the east. This expansion is shown in a 2.5 hour period of GOES-East 1-min imagery in the Natural Color Fire RGB (Fig 6).

Figure 6: 14 October 2020 GOES-East 1-min Natural Color Fire RGB during period of rapid fire growth. Higher res

The full daytime evolution of the wildfire in the Natural Color Fire RGB is shown in Figure 7. A similar animation is shown for the Fire Temperature RGB, which can be used to diagnose relative “hot” areas within the broader hot spot of a mature wildfire (Fig 8).

Figure 7: 14 October 2020 GOES-East 5-min Natural Color Fire RGB during full day. Higher res
Figure 8: 14 October 2020 GOES-East 5-min Fire Temperature RGB during full day. Higher res

The smoke was present at the surface across Fort Collins from the morning through the early afternoon. However, a surface backdoor cold front pushed west into the I-25 corridor by mid-afternoon, clearing the near-surface smoke and dramatically improving air quality. The smoke plume remained aloft, however, as was shown in Fig 9, confirming the low-level nature of the cold front. IR-Window imagery with a grayscale color table captures the southwest evolution of the cold front and it’s minimal influence on the smoke plume aloft as observed by from satellite.

Figure 9: 14 October 2020 GOES-East 5-min IR-Window, SWIR (for very hot BTs). Higher res

NOAA-20 VIIRS True Color Imagery and Active Fires Product around 2000 UTC (tail end of rapid spread east) provided a detailed view of both the smoke plume as well as the active fire burn area (Fig 10).

Figure 10: 14 October 2020 NOAA-20 VIIRS True Color Imagery, Active Fires product. From NASA Worldview. Higher res

The natural color fire RGB can also be applied to VIIRS imagery (Fig 11). By using I-band imagery, the product becomes much more detailed given the 375 m spatial resolution. In this case, there were three VIIRS images available within a ~1.5 hour period from SNPP and NOAA-20, allowing for an analysis of the fire growth during that period. Note missing hot spot data within the larger hot spot due to band I4 (swir) pixel saturation. Land surface features such as wildfires are much easier to analyze in time in VIIRS imagery since the implementation of Terrain Correction for VIIRS EDR’s.

Figure 11: 14 October 2020 VIIRS Natural Color Fire RGB. Higher Res

That evening, NOAA-20 VIIRS Day Night Band captured the glow associated with the Cameron Peak Fire, in addition to that from nearby city lights (Fig 13).

Figure 12: 15 October 2020 NOAA-20 VIIRS Day Night Band Near Constant Contrast. Higher res

Some photography of the fire smoke plume from Oct 14 follows:

Absolutely unbelievable smoke from the #CameronPeakFire!

Look at the dark contrast between Loveland and Fort Collins. 🙏🏾 Prayers up for the firefighters and the residents impacted by it. pic.twitter.com/R9N9OgqG4s

— Colorado Drone & Media (@Colorado_Drone) October 14, 2020

Timelapse of #CameronPeakFire from my back porch around 1:30pm today (Oct 14) using 400mm telephoto. Looking from west Loveland towards NW toward Masonville area. @CReppWx @jimbcbs4 #SonyAlpha pic.twitter.com/07tGgWXnJS

— NOCO kuva (@NocoKuva) October 14, 2020

@nexton9news @9NEWS a time lapse from loveland before we were evacuated #cameronpeakfire #cameronpeak pic.twitter.com/3XjbYUhJRj

— tabatha nuckols (@TabathaNuckols) October 15, 2020

Bill Line, NESDIS/CIRA

Southern Plains Haboob

Posted by Bill Line on 10/14/2020
Posted in: Uncategorized. Leave a comment

Very dry antecedent conditions and the passage of a cold front with strong post-frontal winds resulted in the development of a haboob and blowing dust across the southern plains during the evening of 11-12 Oct 2020. Images and videos from across the region captured the haboob as it progressed south and east across CO into KS/OK/TX during the evening.

Current view 5 miles south of Granada #cowx ⁦@NWSPueblo⁩ ⁦@BrianBledsoe⁩ pic.twitter.com/Q1ICsH3AGn

— Christi Stulp (@ChristiStulp) October 11, 2020

That's an organized dust storm out by Wild Horse, Colorado today. #Haboob #9wx 📷: Mark Werts #COwx pic.twitter.com/YLurjwKIxA

— Cory Reppenhagen (@CReppWx) October 11, 2020

Haboob moving toward Dodge City! Wond gusts 60-65 mph behind this cold front. #kswx pic.twitter.com/kiuEhViEhG

— Mike Umscheid (@mikeumsc) October 12, 2020

One-minute GOES-East imagery captured the early evolution of the haboob along the cold front as it progressed south across southeast Colorado during the final hours of sunlight (Fig 1 and 2). The examples provide a comparison between a feature-relative and fixed region animations.

Figure 1: 11 Oct 2020 GOES-East 1-min VIS, feature-following zoom. Higher res
Figure 2: 11 Oct 2020 GOES-East 1-min VIS. Higher res

Given the presence of patchy cloud cover atop the blowing dust, RGB imagery could be used to more easily differentiate/confirm areas of blowing dust (Fig 3 and 4).

Figure 3: 11 Oct 2020 GOES-East 1-min Day Cloud Phase Distinction RGB imagery. Areas of blowing dust appear as light blue/cyan. Higher res
Figure 4: 11 Oct 2020 GOES-East 1-min Dust-Fire RGB imagery. Areas of blowing dust appear as relatively brighter green. Higher res

Ten-min GOES-East imagery covering a broader region and longer period over the southern plains captured the full evolution of the cold front/haboob and region of blowing dust. IR window imagery with a custom grayscale colortable and range of -55C to 45C clearly highlights the temperature contrast ahead and behind the cold front (Fig 5).

Figure 5: 11-12 Oct 2020 GOES-East 10-min IR Window imagery. Higher res

Dust-Fire RGB imagery highlights areas of blowing dust, wildfire hot spots, and intense smoke plumes in the strong southwest flow ahead of the front, in addition to the cold front itself (Fig 6).

Figure 6: 11-12 Oct 2020 GOES-East 10-min Dust-Fire RGB imagery. Higher res

The following morning, a bore was diagnosed in visible imagery following passage of the cold front across southeast Texas (Fig 7).

Figure 7: 12 Oct 2020 GOES-East 5-min VIS imagery. Higher res

Bill Line, NESDIS/CIRA

Washington Smoke and Dust – 07 Sep 2020

Posted by Bill Line on 09/10/2020
Posted in: Uncategorized. 2 Comments


A long-lasting upper level ridge over the western US gave way to a relatively potent upper level trough on 07-08 Sep 2020, resulting in active weather across much of the western US. Over the Pacific Northwest, the system sent a cold front through the region resulting in very dry conditions with gusty winds during the day on the 7th. These conditions helped support the spread of large and fast moving wildfires, as well as widespread blowing dust emanating from freshly plowed fields. As a result, NWS Spokane, WA issued Wind Advisories, a Red Flag Warning and Blowing Dust Advisory for the area.

GOES-West 3.9 um shortwave IR imagery with a simple linear grayscale colortable captures the initial development and following rapid evolution of the wildfires well (Fig 1), while visible imagery reveals widespread opaqueness across the region (Fig 2). The visible texture and (warm) brightness temperature of the atmospheric aerosols (along with presence of wildfires) leads one to surmise that it is either smoke and/or lofted dust.

Figure 1: 07 Sep 2020 GOES-West SWIR. Higher res
Figure 2: 07 Sep 2020 GOES-West VIS. Higher res

Combining the SWIR and VIS, it is revealed that some of the aerosols are anchored to hot spot locations, and are therefore likely smoke plumes, while others are originating from open fields with no hot spots, and are suspected regions of blowing dust (Fig 3).

Figure 3: 07 Sep 2020 GOES-West VIS and SWIR. Higher res

When we view the SWD (with SWIR hotspots overlay), a reliable method for capturing lofted dust given sensitivity of the 10.3 um band, much of the opaque region (smoke and dust) provides a signal typical of lofted dust (neg 10-12 um diff; dark gray to black in this example; Fig 4). There is typically little-to-no signal for smoke in this difference.

Figure 4: 07 Sep 2020 GOES-West SWD and SWIR. Higher res

As a result, the Fire Dust RGB, that combines IRW, SWIR, and SWD to capture hot spots and dust plumes, shows a similar signal between the lofted dust and active smoke plumes (Fig 5).

Figure 5: 07 Sep 2020 GOES-West Fire Dust RGB. Higher res

Viewing other wildfires in the west (Fig 6), there is a similar SWD signal for some of the most impressive smoke plumes that developed later in the day from the large/very active wildfires (Fig 7). Early day smoke across the area that is composed of much smaller particulates has a very weak to no signal in the SWD. The SWD signal apparent in the very active smoke plumes is likely associated with larger smoke particles (ash) being lofted high into the plume by the strong updraft generated by the wildfire. In the Washington case, the SWD signal is likely a brew of dust mixing with smoke and lofted ash.

Figure 6: 07 Sep 2020 GOES-West VIS and SWIR. Higher res
Figure 7: 07 Sep 2020 GOES-West SWD and SWIR. Higher res

Back to Washington, an alternate and IR-only RGB that replaces the IRW (from the Fire Dust RGB) with the Cloud Top Phase difference appears to do a slightly better job at differentiating lofted dust (cyan) from the intense/active smoke plumes (bright green) due to absorption differences between the two channels from dust (small and uniformly shaped particles) to smoke/ash (varying sized particles; Fig 8).

Figure 8: 07 Sep 2020 GOES-West Fire Ash Dust RGB. Higher res

A zoomed out view of the same RGB over the whole western US during the day and following evening continues to separate the impressive smoke plumes from the blowing dust (Fig 9).

Figure 9: 07-08 Sep 2020 GOES-West Fire Ash Dust RGB. Higher res

Combining the VIS, SWIR and 0.86 um veggie band into a Fire Day RGB discussed in previous blog posts, the lofted smoke and dust become more obvious, and one can diagnose a slight difference between the most probable dust regions (greener cyan) and smoke plumes (bluer cyan), in addition to the hot spots (Fig 10). NWS Blowing Dust Warning polygons are overlaid on the imagery.

Figure 10: 07 Sep 2020 GOES-West Fire Day RGB. Higher res

GOES-West Geocolor Imagery also captures the smoke and dust well, with slight differences between the two aerosols discernible (Fig 11). GOES-East Geocolor also captures the plumes, particularly later in the day as forward scattering increases toward that satellite (Fig 12).

Figure 11: 07 Sep 2020 GOES-West Geocolor. Higher res
Figure 12: 07 Sep 2020 GOES-East Geocolor. Higher res

SNPP and NOAA-20 VIIRS Day Night Band NCC imagery captured the glow of the wildfires across Washington (Fig 13). The first few images in the animation are from the 6th, and show the scene (day and night) prior to fire ignition. During the overnight hours early on the 7th, the first large fire developed and was apparent in the series of VIIRS passes. The following day, the initial fire grows and others ignite, with smoke obvious in the imagery. During the overnight hours early on the 8th, the wildfires had grown considerably, and were depicted in the VIIRS DNB imagery. In particular, the perimeter of the wildfires, along with the most active areas, are captured well in the DNB imagery.

Figure 13: 06-08 SNPP and NOAA-20 VIIRS Day Night Band Near Constant Contrast Imagery. Higher res

Many images and video depicting the degree of visibility reduction by dust and smoke were shared on social media, some of which are included below.

Eastern Washington a jumbled mess of smoke and a dust storm amid widespread 40-45 mph winds. This video is from I-90 west of Moses Lake by Ashlee Winlow #wawx pic.twitter.com/myuIlcTvvZ

— Scott Sistek (@ScottSKOMO) September 7, 2020

This is from a friend stuck in the traffic. AVOID THE AREA! https://t.co/rOZLCk50PB pic.twitter.com/pxteSDV4lk

— Kaitlin Knapp (@Kaitlin_Knapp1) September 7, 2020

Bill Line, NESDIS and CIRA

Hurricane Laura 2020

Posted by Bill Line on 08/28/2020
Posted in: Uncategorized. Leave a comment

Hurricane Laura became a named tropical system in the Caribbean at 1500 UTC 21 Aug 2020, and a Hurricane at 1500 UTC 25 August 2020. According to the NHC very early on 27 Aug, “Laura made landfall near Cameron, Louisiana, around 0600 UTC (1 am CDT) with maximum sustained winds of 130 kt, which is near the high end of category 4 status.” The following post includes a collection of GOES ABI imagery captured during the evolution of Laura.

The full evolution of Laura as a named storm through the day after landfall (21-27 Aug) is shown in Figures 1-3 as hourly GOES-East animations. Figure 1 includes 10.3 um IR window channel imagery, while Figure 2 transitions between 10.3 um IR window channel imagery during the night, and VIS-IR Sandwich imagery during the day. Figure 3 characterizes lightning activity during the life of the storm, utilizing GOES-East Flash Extent Density (note, only 5-min GLM FED was used).

Figure 1: 21-27 August 2020 GOES-East hourly IR. Higher Res
Figure 2: 21-27 August 2020 GOES-East hourly IR and VIS-IR Sandwich Combo. Higher Res
Figure 3: 21-27 August 2020 GOES-East hourly IR, GLM FED. Higher Res

A water vapor animation with RAP 500 mb wind and height analyses captures the influencing large scale features during the long trek of Laura. Notably, a broad ridge over the western Atlantic early in the period expands west into the southeast US and eastern GoM throughout the animation, helping to steer Laura west of the track of the preceding Marco, into the western GoM (Fig 4).

Figure 4: 21-27 August 2020 GOES-East hourly UL Water Vapor Imagery, RAP 500 mb height, wind analysis. Higher Res

A feature relative GOES-East VIS animation during the full day of the 25th depicts the strengthening of Laura from a Tropical Storm to a Hurricane (Fig 5).

Figure 5: 25 August 2020 GOES-East 5-min VIS. Higher Res

Zooming out for the same period, Laura is seen advancing into the central Gulf of Mexico, while remnants of Marco accelerates west along the Louisiana Gulf Coast (Fig 6).

Figure 6: 25 August 2020 GOES-East 5-min VIS. Higher Res

A mesoscale sector was available over Laura during it’s evolution, providing forecasters with valuable 1-min-updating imagery. The final 70 minutes of visible imagery on the 25th capture increasing thunderstorm activity around the center of circulation (Fig 7). One-minute imagery eases diagnosis of a center of circulation in tropical systems, particularly in unorganized storm systems. The evolution of individual convective updrafts associated with the tropical system are also more efficiently tracked in space and time using the high temporal resolution, low latency imagery.

Figure 7: 25 August 2020 GOES-East 1-min VIS. Higher Res

During the overnight hours of the 25h-26th, Laura continued to strengthen, with an eye becoming apparent by the early morning of the 26th per GOES-East IR imagery (Fig 8).

Figure 8: 25-26 August 2020 GOES-East 5-min IR. Higher Res

Sunrise over Laura on the 26th revealed a much better organized hurricane with a developing eye, albeit still contaminated with some cloud debris (Fig 9).

Figure 9: 26 August 2020 GOES-East 1-min VIS. Higher Res

A zoomed out view of the full mesoscale sector shows the massive storm approaching the coast (Fig 10). The IR-VIS sandwich combo imagery combines the high spatial detail of the VIS with the quantitative BT information from the IR.

Figure 10: 26 August 2020 GOES-East 1-min VIS-IR Sandwich Combo. Higher Res

By the late morning of the 26th, the eye had cleared considerably, and low and upper level vorticies could be diagnosed in the 1-min VIS with convective activity still becoming organized within the eyewall (Fig 11).

Figure 11: 26 August 2020 GOES-East 1-min VIS. Higher Res

During the afternoon, eye clearing had completed, convective activity became more consistent within the eyewall, and a healthy major hurricane was apparent (Fig 12).

Figure 12: 26 August 2020 GOES-East 1-min VIS. Higher Res

A clear eye and healthy eyewall were still apparent in 1-min visible imagery as sun set on the storm during the early evening of the 26th, jsut several hours prior to landfall (Fig 13).

Figure 13: 26 August 2020 GOES-East 1-min VIS. Higher Res

The full development of the impressive storm during the day of the 26th is diagnosed in GOES-East visible imagery (Fig 14).

Figure 14: 26 August 2020 GOES-East 5-min VIS. Higher Res

GOES-West provided a unique perspective of the hurricane on the 26th given the much larger viewing zenith angle compared to that of GOES-East (Fig 15).

Figure 15: 26 August 2020 GOES-West 10-min VIS. Higher Res

Landfall of Hurricane Laura in southwest Louisiana was displayed in GOES-East IR imagery during the overnight hours. Imagery shows the large eye remaining intact well inland, before filling in by early morning (Fig 16).

Figure 16: 26-27 August 2020 GOES-East 5-min IR. Higher Res

Figure 17 provides a zoomed in look at 2-min IR imagery during landfall, including surface obs.

Figure 17: 27 August 2020 GOES-East 2-min IR, surface obs. Higher res

GOES-East visible imagery after sunrise on the 27th shows the massive storm and lack of clear eye (Fig 18). The weakening tropical system filled most of the 1000 x 1000 km mesoscale sector.

Figure 18: 27 August 2020 GOES-East 1-min VIS. Higher Res

Finally, Day Cloud Phase Distinction RGB imagery from the 27th shows convective activity and upper level clouds (reds and yellows) becoming detached from the low level circulation (cyan/blue clouds; Fig 19).

Figure 19: 27 August 2020 GOES-East 5-min Day Cloud Phase Distinction RGB Imagery. Higher res

Bill Line, NESDIS

10 August 2020 Derecho

Posted by Bill Line on 08/11/2020
Posted in: Uncategorized. 2 Comments

A long-lived line of severe thunderstorms resulted in a broad swath of damaging winds across the Midwest on 10 August 2020. There were hundreds of severe wind reports associated with this derecho, including dozens in excess of 75 mph (significant severe). GOES-East captured the evolution of the complex from initial thunderstorm development over Nebraska through convective decay over Ohio.

A long, 10-min IR animation captured the full evolution of the thunderstorm complex, from 0611 UTC with initial development of thunderstorms over Nebraska, through 0201 UTC with weakening over Ohio/Indiana (Fig 1). Persistent cold cloud tops of <60C were analyzed along the leading edge of the MCS and in association with the severe storms, with cloud tops as cold as -80C sampled in the GOES imagery. NWS convective warning polygons and Local Storm Reports are shown as an overlay on the imagery.

Figure 1: 10 August 2020 GOES-East 10-min IR, NWS convective warning polygons, LSRs. Higher res

Corresponding GLM Flash Extent Density imagery is shown in Figure 2, and is used to infer the locations of strongest updrafts, and updraft trends, within the broader complex. Periodic long flashes are also observed extending into the thunderstorm anvils, representing a lightning threat well away from the strong thunderstorms.

Figure 2: 10 August 2020 GOES-East 10-min IR and GLM FED, NWS convective warning polygons, LSRs. Higher res

Corresponding MRMS composite reflectivity is shown in Figure 3 for comparison, and aligns with the regions of notable/persistent GLM activity and coldest cloud tops.

Figure 3: 10 August 2020 GOES-East 10-min IR, MRMS Composite Reflectivity, NWS convective warning polygons, LSRs. Higher res

GOES-East VIS-IR Sandwich image combo (every 5-minutes) is shown as feature following zoom for the during the daytime of the 10th, following the derecho (Fig 4). The evolution of features within the thunderstorm line is made more apparent in the feature relative animation. The combination of texture in the VIS and brightness temperature information in the IR allows for easy diagnosis cloud top health and trends, including that of overshooting tops, gravity waves, overall texture, and above anvil cirrus plumes. Toward the end of the animation, cloud tops begin to warm, and texture becomes less abundant, indicating weakening convection.

Figure 4: 10 August 2020 GOES-East 5-min VIS-IR sandwich combo. Higher res

GOES-East mesoscale sectors were available over the region, providing 1-min imagery for forecasters (Fig 5 and 6). The high temporal resolution, low latency imagery allows forecasters to more effectively track individual updraft trends in real-time vs the 5-min imagery.

Figure 5: 10 August 2020 GOES-East 1-min VIS, NWS convective warning polygons, LSRs as derecho advances across eastern Iowa. Higher res
Figure 6: 10 August 2020 GOES-East 1-min VIS as derecho advances across Chicago. Higher res

A long (5-hour) 1-min VIS-GLMFED Sandwich animation covers a period of some of the most intense thunderstorm wind gusts, and connects visual texture trends with lightning trends (Fig 7).

Figure 7: 10 August 2020 GOES-East 1-min VIS-GLM FED Sandwich. Higher res

Bill Line, NESDIS/STAR

VIIRS Terrain Correction

Posted by Bill Line on 08/06/2020
Posted in: Uncategorized. 2 Comments

On 28 July 2020, a new “Terrain Correction” was applied to SNPP and NOAA-20 VIIRS Imagery EDR geolocation thanks to work done by the VIIRS EDR Imagery Team. The terrain correction software provides consistent navigation of a given surface pixel, no matter the elevation or position within a swath. Prior to the change, high elevation pixels would appear to shift location within a scene from swath to swath as a result of their changing position within the swath relative to nadir. Examples of the change are shown below. The message from NESDIS:

First we analyze a scene over WA/OR, with the high elevation Cascade Mountain Range flanked by lower elevations to the west and east (Fig 1). Two daytime swaths of NOAA-20 VIIRS contained the scene on 27 July 2020, at 1937 UTC (western part of swath) and 2119 UTC (eastern part of swath). I1 band (0.64 um VIS) EDR imagery appears to depict a shift in the mountain range from west to east from the 1937 UTC swath to the 2119 UTC swath, while the position of low elevation areas within the scene remain relatively static.

Figure 1: 1937 UTC and 2119 UTC 27 July 2020 NOAA-20 VIIRS I1 visible imagery. Higher res

Now viewing the same scene/imagery but on 31 July 2020, with terrain correction applied, there is very little (if any) shift in terrain (Fig 2).

Figure 2: 1958 UTC and 2140 UTC 31 July 2020 NOAA-20 VIIRS I1 visible imagery. Higher res

A similar daytime example is shown using SNPP VIIRS I1 band imagery over south-central Alaska (Fig 3). On 14 July 2020, the position of the mountains within the scene appear to shift dramatically from 2119 UTC to 2301, while the adjacent lower elevations experience no shift at all.

Figure 3: 2119 UTC and 2301 UTC 14 July 2020 Suomi-NPP VIIRS I1 visible imagery. Higher res

The same scene on 04 August, following the terrain correction, experiences very minimal shift of the mountains from swath to swath (Fig 4).

Figure 4: 2127 UTC and 2304 UTC 04 August 2020 Suomi-NPP VIIRS I1 visible imagery. Higher res

Another example is applied to the VIIRS Day Night Band Near Constant Contrast EDR product at night (Fig 5). The first example, from 16 June 2020, is centered over northern Arizona and the active Mangum wildfire. Much of the scene is at an elevation between 4500 ft and 8000 ft, with the wildfire around 7500 ft. From 0837 UTC to 1014 UTC, illumination associated with the wildfire, and nearby towns, appear to shift from west to east.

Figure 5: 0837 UTC and 1014 UTC 16 June 2020 Suomi-NPP DNB NCC. Higher res

Now viewing a similar scene over western Colorado from the late night of 04 August, after the terrain correction (Fig 6). The scene also contains a wildfire, and similar elevation range as previous. As we compare swaths, however, the light associated with the high elevation wildfire and nearby towns remain stationary.

Figure 6: 0759 UTC and 0935 UTC 05 August 2020 Suomi-NPP DNB NCC. Higher res

Bill Line, NESDIS/STAR

Posts navigation

← Older Entries
Newer Entries →
  • Follow Blog via Email

    Enter your email address to follow this blog and receive notifications of new posts by email.

    Join 2,179 other subscribers

  • RSS Satellite Liaison Blog

    • Colorado Shallow Cold Air
    • RGB Applications: Anticipating Convective Initiation Using the Nighttime Microphysics RGB
    • Widespread Dense Blowing Dust Plume – 15 Jan 2021
    • Southern High Plains Early Day Blowing Dust – 14 Jan 2021
    • Use of GOES Imagery During Oklahoma Fog Event
    • 12/23/2020 Blowing Dust and Blowing Snow
    • Argentina Thunderstorms and Blowing Dust
    • Mid-Dec Northeast Snow
    • Mid-Dec 2020 NM/TX Blowing Dust Events
    • Overnight Fire Growth in Southern California
  • Recent Posts

    • Colorado Shallow Cold Air
    • RGB Applications: Anticipating Convective Initiation Using the Nighttime Microphysics RGB
    • Widespread Dense Blowing Dust Plume – 15 Jan 2021
    • Southern High Plains Early Day Blowing Dust – 14 Jan 2021
    • Use of GOES Imagery During Oklahoma Fog Event
  • February 2021
    S M T W T F S
     123456
    78910111213
    14151617181920
    21222324252627
    28  
    « Jan    
  • Keyword Search

  • Archives

    • February 2021 (1)
    • January 2021 (4)
    • December 2020 (5)
    • November 2020 (1)
    • October 2020 (5)
    • September 2020 (1)
    • August 2020 (4)
    • June 2020 (4)
    • May 2020 (4)
    • April 2020 (8)
    • March 2020 (9)
    • February 2020 (6)
    • January 2020 (4)
    • December 2019 (3)
    • November 2019 (1)
    • October 2019 (5)
    • September 2019 (2)
    • August 2019 (5)
    • July 2019 (2)
    • June 2019 (1)
    • May 2019 (5)
    • April 2019 (7)
    • March 2019 (4)
    • February 2019 (4)
    • January 2019 (3)
    • December 2018 (2)
    • November 2018 (7)
    • October 2018 (3)
    • September 2018 (3)
    • August 2018 (1)
    • July 2018 (8)
    • June 2018 (5)
    • May 2018 (4)
    • April 2018 (5)
    • March 2018 (7)
    • February 2018 (5)
    • January 2018 (4)
    • December 2017 (4)
    • November 2017 (7)
    • October 2017 (9)
    • September 2017 (6)
    • August 2017 (12)
    • July 2017 (5)
    • June 2017 (9)
    • May 2017 (8)
    • April 2017 (17)
    • March 2017 (20)
    • October 2016 (1)
    • August 2016 (1)
    • July 2016 (1)
    • May 2016 (1)
    • March 2016 (2)
    • February 2016 (1)
    • October 2015 (1)
    • August 2015 (1)
    • July 2015 (1)
    • April 2015 (3)
    • March 2015 (3)
    • February 2015 (1)
    • December 2014 (1)
    • October 2014 (1)
    • September 2014 (3)
    • August 2014 (4)
    • July 2014 (1)
    • June 2014 (4)
    • May 2014 (9)
    • April 2014 (5)
    • March 2014 (3)
    • February 2014 (1)
    • January 2014 (1)
    • December 2013 (1)
    • November 2013 (1)
    • October 2013 (1)
    • June 2013 (2)
    • May 2013 (3)
    • April 2013 (1)
    • March 2013 (1)
    • February 2013 (2)
    • January 2013 (1)
    • December 2012 (1)
    • November 2012 (4)
    • October 2012 (10)
    • September 2012 (2)
    • August 2012 (1)
  • Categories

    • ABI
    • AirMass RGB
    • AIRS
    • Arctic
    • Aviation
    • AWC
    • Cloud Heights
    • Convection
    • CTC
    • Day-Night Band
    • Derived Stability Indices
    • Dust
    • Fires
    • Flash Flooding
    • G16-CH02_0.64_VIS-Red
    • G16-CH03_0.86_NIR-Veggie
    • G16-CH04_1.37_NIR-Cirrus
    • G16-CH05_1.6_NIR-SnowIce
    • G16-CH07_3.9_SWIR
    • G16-CH08_6.2_WV-Upper-Level
    • G16-CH09_6.9_WV-Mid-Level
    • G16-CH10_7.3_WV-Low-Level
    • G16-CH11_8.4_IR-SO2
    • G16-CH13_10.3_IR-Clean
    • G16-CH14_11.2_IR-Legacy
    • Heavy Rain
    • Himawari
    • Hurricane-Force Storms
    • Hurricanes
    • HWT
    • Ice
    • JPSS
    • Lightning
    • Microwave
    • MODIS
    • MTSAT-2
    • NearCast
    • News
    • NHC
    • OMPS
    • OPC
    • Overshooting Top Detection
    • ProbSevere
    • QPE
    • R2O/O2R
    • Rapid Intensification
    • RGB
    • Satellite Analysis Branch
    • Smoke
    • SPC
    • Split Window Difference
    • SRSOR
    • Super Rapid Scan
    • TAFB
    • Tornado
    • TPW
    • Tropical
    • Tropics
    • Uncategorized
    • VIIRS
    • Volcano
    • Water Vapor
    • Winter Weather
    • WPC
Powered by WordPress.com.
Satellite Liaison Blog
Proudly powered by WordPress Theme: Parament.