Wet streaks in soil moisture observed in west Texas…

This morning I observed some rather odd looking streaks in the 10.3 µm imagery in western portions of Texas.  Sampling the 10.3 µm data revealed alternating areas of relative warm/cool skin surface temperatures in the cloud free conditions in the area on the upstream side of departing deep convection.  The temperature difference in the skin temperatures were around 5 C at this time.  The 10.3 µm image below was taken from appox. 1357 UTC this morning (3 May 2018).

Image 1.  10.3 um imagery from GOES-16, 1357 UTC 3 May 2018

Arguably, the streaks of lower temperature values showed up better in the 3.9 µm imagery.  Notice the streaks or alternating bands of yellow/orange colors in portions of west Texas.

Image 2.  3.9 um imagery from GOES-16, 1357 UTC 3 May 2018

Realizing these temperature differences were likely due to the recent convective rainfall, I looked up the SPoRT LIS 0-10 cm volumetric soil moisture data, which corresponded nearly perfectly with the streaks of relative lower temperature values (Image 3).  So indeed, this was due to the recent heavy, convective rainfall across the area.

Image 3.  SPoRT LIS 0-10 cm Volumetric Soil Moisture, 15 UTC 3 May 2018

 

Dust RGB Imagery and NASA’s CALIPSO/CALIOP

Dust RGB Imagery and NASA’s CALIPSO/CALIOP

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Dust RGB via GOES-16 from 1732-2232 UTC on 12 April 2018 over the U.S. Southwest

SPoRT used the MODIS and VIIRS imagers (on NASA’s Aqua & Terra satellites, and NOAA’s S-NPP satellite, respectively) within the NOAA’s Satellite Proving Ground to assess the value of a “Dust RGB Imagery” product for potential use with GOES-R (now GOES-16).  The Dust RGB proved useful on 13 April 2018 (animation above) where many dust plumes developed in the U.S. Southwest and Mexico.  Forecasters were able to monitor dust plume initiation and issue advisories and warnings.  In addition, several plumes continued to have impacts after sunset, and the Dust RGB, which uses only IR window channels (see Dust RGB Quick Guide), was able to continue monitoring the event at night while the visible imagery was no longer valuable.  Some advisories were extended beyond their original expiration time.  NASA SPoRT is using the NASA CALIPSO satellite and associated CALIOP lidar on board to validate and categorize dust signatures seen in the RGB and examine quantitative aspects like plume height and thickness.  The image below shows an event from 3 April 2018 where forecasters from the NWS Albuquerque WFO and CWSU evaluated the Dust RGB impact to operations as part of SPoRT’s assessment activities, and the CALIOP lidar backscatter captured the dust plume over west Texas.  From CALIOP the dust plume appears to be about 2 km thick in most locations, but the most concentrated region reached a height of about 3 km above ground.

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Dust RGB via GOES-16 (upper) over the CONUS and lidar backscatter via CALIOP (on NASA’s CALIPSO satellite) for 2007 UTC on 3 April 2018.  Annotations in yellow point out the dust plume and clouds along the path of CALIOP shown by white arrow/text.

Monitoring Hurricane Harvey with the Geostationary Lightning Mapper (GLM)

Figure 1, below, shows a single image from the attached movie showing the Geostationary Lightning Mapper observations for Hurricane Harvey.

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Figure 1:  Example image from the attached movie from 0700 UTC on August 25, 2017 while Harvey is a Category 2 hurricane.  The image shows the 11.2 micron infrared imagery in grey scale (background) and the GLM group density (shaded) accumulated over 15 minutes.

The link to the animation below monitors Harvey from 1400 UTC on August 23, 2017 while it was still a remnant system coming off the Yucatan Peninsula through the initial landfall and heavy precipitation across Texas at 2345 UTC on August 27, 2017.  The animation shows the ABI 11.2 micron infrared imagery (using a greyscale color curve to emphasize GLM) as well as the GLM 8 km group density (using the SPoRT color curve tested at the Hazardous Weather Testbed and being prepared as the default, operational curve).  Given the length of time covered by the animation, the data are shown at 15 minute intervals.  Specifics on Harvey (i.e., maximum winds and minimum pressure) are from the National Hurricane Center’s product archive for this storm.  The link is for an mp4 movie and is approximately 62 MB in size.

[62 MB]  Hurricane Harvey mp4 link.

Several still images are shown below highlighting interesting features.

One feature is the distribution of the total lightning observations throughout the tropical cyclone and the magnitude of the lightning density.  Generally, the total lightning is not distributed throughout the entire storm, but concentrated in bands and sometimes in the eye wall, as seen in Figure 1.  Figure 1 can be compared to the early stages when Harvey was upgraded to a Tropical Storm (Figure 2), but also later where many times there is no lightning in the eye wall (Figure 3). Also, please note that the accumulations are for 15 minutes versus 1 or 2 minutes shown in severe weather cases.

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Figure 2:  This is the same as Figure 1, but for Tropical Storm Harvey at 0415 UTC on August 24, 2017.  

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Figure 3:  This is the same as Figure 1, but at 0815 UTC on August 25, 2017.  This is highlighting the distribution of total lightning is mainly in the convective bands and note in the eye wall.

Figure 4 shows Harvey as it makes landfall as a Category 4 hurricane.  Here, GLM group density values are on par with the outer convective bands as the eye wall makes landfall.

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Figure 4:  Same as Figure 1, but at 0215 UTC on August 26, 2017.  This image highlights the GLM group density observations in Hurricane Harvey’s eye wall as it makes landfall.

Lastly, after the initial landfall, Figure 5 shows a large increase in the magnitude and spatial area of the GLM group densities in the outer convective band as some of the catastrophic rain impacts the Houston, Texas region.

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Figure 5:  Same as Figure 1, but at 0245 UTC on August 27, 2017.  This image highlights the increased GLM group density magnitude and spatial extent during part of the catastrophic rains that impacted Houston, Texas.

NOTE:  NOAA’s GOES-16 satellite has not been declared operational and its data are preliminary and undergoing testing. Users receiving these data through any dissemination means  (including, but not limited to, PDA and GRB) assume all risk related to their use of GOES-16 data and NOAA disclaims any and all warranties, whether express or implied, including (without limitation) any implied warranties of merchantability or fitness for a particular purpose.

GOES-16 ABI and GOES-R CI aid IDSS over the weekend

Once again, NWS Huntsville provided impact-based decision support services (IDSS) for the Panoply Arts Festival in downtown Huntsville.  Since it occurs in late April every year, Panoply has a long history of coping with challenging weather conditions, and NWS Huntsville has staffed the event every year to help with those challenges.  This year was no exception.

 

Saturday was a summer-like day, with the main forecast challenge being convective initiation from a field of cumulus clouds.  The UAH-developed GOES-R Convective Initiation algorithm output was helpful with this process as it correctly forecast low probabilities for much of the day.

 

We also decided to look at GOES-16 ABI data to see if it added any value.  In addition to monitoring the low (7.3um) and mid-level (6.9um) water vapor channels on a larger scale, the Red Visible (0.64 micron) was most beneficial.  A mesoscale domain sector was in place over the region at the time, enabling forecasters to easily look for growing cumulus clouds (though there were not many of these).  (Apologies for the quick and small screen captures!)

GOES-16 ABI 0.64um imagery – valid 29 April 2017 1950 UTC

During the mid-afternoon, forecasters staffing the emergency operations center noticed an interesting trend in the visible imagery: areas to the south that were shrouded by thicker cirrus were seeing clearly-suppressed cumulus development, and the cumulus clouds were developing again once the cirrus had passed by. This almost created a “moving shadow” effect.

GOES-16 ABI 0.64um imagery – valid 29 April 2017 2013 UTC

GOES-16 ABI 0.64um imagery – valid 29 April 2017 2029 UTC

The forecasters were able to use this to determine that convective initiation–and thus impacts to Panoply and downtown Huntsville–were very unlikely, since the cirrus clouds were moving into the area.
There is a great deal of promise for IDSS using the new GOES-16 data, particularly once the Geostationary Lightning Mapper begins flowing on a preliminary basis.
Note The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. Users bear all responsibility for inspecting the data prior to use and for the manner in which the data are utilized.
Dust RGB analyzes “dryline” for 3/23/17

Dust RGB analyzes “dryline” for 3/23/17

 

The Dust RGB, originally from EUMETSAT and a capability of GOES-R/ABI, can be helpful in identifying features other than dust, including drylines. A dryline represents a sharp boundary at the surface between a dry air mass and moist air mass where there is a sudden change in dew point temperatures. In this event from 3/23/17, a dryline in eastern New Mexico and west Texas is distinguishable via the Dust RGB imagery animation from GOES-16 (Fig. 1), while a large dust plume (magenta) is impacting areas further west. Note that the visible imagery (Fig. 2) shows clouds forming along the dryline, but these clouds drift downwind toward the northeast as they mature, away from the dryline itself, making it difficult to monitor the dryline position.  However, the dryline position can easily be seen via the color difference of the Dust RGB across the boundary of dry and moist air, and in fact, the dryline appears fairly stationary or moves in a slight westward direction, opposite of the cloud motion.  In situ observations (Fig. 3) are a primary tool for monitoring the dryline location, but the advantage of satellite imagery is an increased spatial and temporal resolution for forecasters.

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Figure 1. GOES-16 Dust RGB valid from 2022 to 2322 UTC, on 23 March 2017 centered on extreme western Texas.  Dryline seen in color difference of cloud-free area in eastern New Mexico and west Texas while dust plume is in magenta shades.

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Figure 2. GOES-16 Visible (0.64u) channel valid from 2027 to 2322 UTC on 23 March 2017 as in Figure 1.

For the above and subsequent images/animations: NOAA’s GOES-16 satellite has not been declared operational and its data are preliminary and undergoing testing. Users receiving these data through any dissemination means  (including, but not limited to, PDA and GRB) assume all risk related to their use of GOES-16 data and NOAA disclaims any and all warranties, whether express or implied, including (without limitation) any implied warranties of merchantability or fitness for a particular purpose.

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Figure 3. METAR station plot of surface observations at 2143 UTC on 23 March 2017 centered over New Mexico.

The ability to identify drylines using the Dust RGB gives the forecaster the capability to analyze these boundaries in ways not seen before. In the Dust RGB (Fig. 4), the surface area on the dry side is seen as a purple color (i.e. increased red contribution), and the moist side appears more blue (i.e. less red). This dryline can be noted more easily than in visible imagery (Fig. 5) due to the sensitivity of the 12.3 micron channel used in the 12.3 – 10.35 micron difference within the Dust RGB red component.  The 12.3 micron channel goes from warmer to cooler brightness temperatures with changes in density from very dry to very moist air. The blue contribution is consistent on each side of the line because the surface temperature, and hence the 10.35 micron channel, does not change much from either side of the dryline. There is limited ability to identify drylines using high resolution visible imagery, as seen in the Midland WFO Graphicast (Fig. 6) where cumulus clouds are documented forming along the dryline. Unfortunately, visible imagery is only useable during daylight hours and a user is dependent on cloud features along the dryline in order to analyze its position. However, aside from the obvious value of the color difference in cloud free areas to depict the dryline, the Dust RGB, is viable both during daytime and nighttime hours.

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GOES-16 Advanced Baseline Imager Data Observes Severe Weather Event on Day 1!

Today marks the first day that the beta-mode Advanced Baseline Imager (ABI) data have been made available from GOES-16.  NASA SPoRT is obtaining the ABI data via the GOES Rebroadcast (GRB) data transmission system receiver located at the NASA Marshall Space Flight Center in Huntsville, Alabama.

Mother Nature provided some active weather through the Tennessee River Valley today as SPoRT team members worked to produce imagery from the receiver.  Below is a one hour animation of ABI data from 1817 to 1917 UTC updating every 5 minutes.  This shows Band 2 visible 0.64 µm imagery at a resolution of 0.5 km.  The imagery shows the line of storms as it entered northern Alabama.

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GOES-16 ABI 0.64 um visible imagery from 1817 to 1917 UTC on 1 March 2017.  These data come from the GOES Rebroadcast (GRB) data transmission system receiver located at the NASA Marshall Space Flight Center in Huntsville, Alabama. (Full resolution)

Please note, the GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. Users bear all responsibility for inspecting the data prior to use and for the manner in which the data are utilized.

For comparison, the following figure below shows the same ABI 0.64 µm imagery at 2006 UTC (0.5 km) side-by-side with the existing GOES-13 visible data at 2007 UTC (1 km).  Notice the impressive detail observed with the higher resolution GOES-16 imagery!

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Comparison of GOES-16 ABI 0.64 um (left, 2006 UTC – 0.5 km) and the GOES-13 Imager (right, 2007 UTC – 1 km) on 1 March 2017.  The yellow circle highlights an overshooting top in Jackson County, Alabama.  These data come from the GOES Rebroadcast (GRB) data transmission system receiver and the GVAR receiver, both located at the NASA Marshall Space Flight Center in Huntsville, Alabama. (Full resolution)

Please note, the GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. Users bear all responsibility for inspecting the data prior to use and for the manner in which the data are utilized.

NUCAPS Soundings and Hurricane Matthew

CrIS/ATMS soundings processed through the NOAA Unique Combine Processing System (NUCAPS) are available in AWIPS.  SPoRT is working with the Joint Polar Satellite System (JPSS) Proving Ground to testbed the utility of NUCAPS soundings to anticipate hurricane tropical to extratropical transition.  Although satellite derived soundings are “smoother” than radiosondes they can provide valuable information about the depth of moist or dry layers in data sparse regions. Forecasters can anticipate extratropical transition by identifying the dry slot and upstream potential vorticity anomalies on satellite imagery that may interact with a storm while also considering many other factors that lead to extratropical transition.  Although Hurricane Matthew is not expected to undergo extratropical transition for quite a few days, the NUCAPS Soundings can be used to diagnose the temperature and moisture characteristics surrounding the hurricane as highlighted below.

GOES-13 water vapor imagery shows dry upper levels west of Hurricane Matthew and abundant moisture surrounding the system (Fig. 1).  Since water vapor imagery can only detect moisture characteristics in the mid-to upper- levels of the atmosphere, the NUCAPS soundings (green dots on Fig. 1) can be analyzed to provide more information about the vertical extent of the dry air and whether it is in close proximity to the hurricane in the mid- to lower- levels.

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Fig. 1. 5 October 2016 1830 UTC GOES-13 water vapor imagery and 1811 UTC NUCAPS Soundings. Green dots represent point and click soundings. Blue numbers label location of example soundings highlighted below.

Scroll down through the example Soundings to compare the changes in moisture conditions west of Hurricane Matthew. Soundings 1 and 2 (Fig. 2 and 3), taken in a region of dry air as identified by the orange color enhancement on the water vapor imagery, confirm a dry column throughout the depth of the atmosphere. Sounding 3 (Fig. 4) shows the drying is not as intense in the upper-levels and mid-level drying extends down to about 600 mb. Sounding 4 and 5 (Fig. 5 and 6) show upper level conditions are more moist closer to the hurricane, as expected from the water vapor imagery. While Sounding 4 (Fig. 5) shows moist conditions throughout the atmospheric column, Sounding 5 (Fig. 6) does show mid-level dry air is present.  Previous analysis of Sandy 2012 and Arthur 2014 showed the same signature (e. g., similar to Sounding 5) became more abundant surrounding the systems as upper-level dry air intruded.  Currently, there are very few soundings with this signature surrounding Hurricane Matthew.  The NUCAPS soundings confirm dry atmospheric conditions are well west of the system and there is very little mid- to low- level dry air in the proximity of the system.  This preliminary example is presented but as Hurricane Matthew continues to evolve NUCAPS Soundings and SPoRT Ozone Products will be analyzed to discern the utility for anticipating dry air intrusion and associated hurricane tropical to extratropical transition.

Sounding 1

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Fig. 2. 5 October 2016 1811 UTC NUCAPS Sounding at Location 1.

 

Sounding 2

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Fig. 3. 5 October 2016 1811 UTC NUCAPS Sounding at Location 2.

Sounding 3

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Fig. 4. 5 October 2016 1811 UTC NUCAPS Sounding at Location 3.

Sounding 4

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Fig. 5. 5 October 2016 1811 UTC NUCAPS Sounding at Location 4.

Sounding 5

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Fig. 6. 5 October 2016 1811 UTC NUCAPS Sounding at Location 5.