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viirsntmicro_obs_20170208

The Nighttime Microphysics RGB Imagery, provided by S-NPP VIIRS in above image, efficiently highlights the low cloud and fog areas in aqua to dull gray, to allow forecasters to better see where hazards exist to transportation (aviation, public, or marine).  This VIIRS image also provides forecasters with a look at the new geostationary capabilities that will be available soon with GOES-16 ABI.  This Nighttime Microphysics RGB Imagery was originally created by EUMETSAT around 2006, transitioned by NASA/SPoRT to forecasters within the NOAA Satellite Proving Ground over the last 5 years, and recently adopted by GOES-16 as one of the many RGB products that will be available to better utilize the ABI three fold increase in the number of bands over the current GOES imager. Currently, the Nighttime Microphysics RGB Imagery from VIIRS as well as several AVHRR and MODIS instruments is regularly used by forecasters in operations, which has allowed them to gain experience in preparation for this new capability from GOES-16.

On February 8, 2017 Dense Fog Advisories were in place across the Gulf Coast and parts of the Southeast (see image below) and there have been many similar events in the region for this winter.

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Near 1000 UTC (~4:00am CST) large areas of low ceilings and visibility were occurring in the advisory regions, as seen in the first image of the post.  In the images below, take a look at how the Nighttime Microphysics RGB Imagery (this time from NOAA-19/AVHRR) compares to using a single longwave infrared channel in the split scene of the Gulf Coast region and then compare this with the same scene where only the Nighttime Microphysics  RGB Imagery is shown.  Note that the fog and clear areas can look similar in the infrared image and that the fog itself is a bit warmer than the ground areas in Texas. For help interpreting these types of images, NASA/SPoRT has RGB Quick Guides available at  https://weather.msfc.nasa.gov/sport/training/ .

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A methane explosion occurred last Friday, January 20, in rural northwest Alabama (story from WAFF-TV).  NWS Huntsville provided decision support services to the incident, which posed significant risks to emergency personnel.  The active pattern last weekend created additional concerns, since several rounds of rain and thunderstorms were forecast to move across the area (though fortunately the significant severe weather from that weekend remained well to the south).

One such event arrived Saturday morning as stratiform rain pushed back into the area. Forecasters noted that there were indications of cloud-to-ground lightning from the National Lightning Detection Network along the leading edge of the rainfall, so we leveraged flash extent density data from the North Alabama Lightning Mapping Array to investigate further.  Strangely, when loaded as an image in AWIPS-2, this showed little.

It took some time to discover why.  The flash rates were so low (1 flash per ‘scan’) that the FED image interpolation was smoothing the data below what the color curve could visualize.  After the interpolation was turned off or the color curve edited again, the flashes were much more apparent, as seen in the following GIF loop from AWIPS.

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A loop of Multi-Radar/Multi-Sensor radar imagery from 1144 UTC to 1222 UTC, 21 January 2017, with flash extent density data from the North Alabama Lightning Mapping Array overlaid in white.  The methane incident is denoted by the yellow dot in northwest Alabama, and a 10-mile range ring is indicated by the yellow circle.

Adding the full flash extent density information from the NALMA helped the forecasters to visualize the lightning threat beyond what was otherwise available in AWIPS.  This helped when it came time to brief emergency personnel on the approaching threat.

This event also helps to reinforce the potential utility of the Geostationary Lightning Mapper (GLM) aboard GOES-16 as it becomes available this spring.  However, forecasters will have to visualize the GLM data wisely.  It will likely more important to view low flash rates for an IDSS or safety mindset, versus higher flash rate changes for severe weather.  Even with total lightning, context is everything.

The state of California has been suffering from a multi-year drought that has severely depleted water resources and reservoir levels. Recent winters have failed to produce precipitation and mountain snows to replenish the losses during the dry summers. However, the situation has rapidly changed this winter, particularly in the past week when multiple atmospheric rivers have impacted the state.

An atmospheric river is a concentrated channel of deep moisture that is transported from the tropical Pacific Oceanic regions to the West Coast of the United States.  These events are often associated with prodigious amounts of rainfall and mountain snows that lead to flooding, mudslides, and avalanches.  We have seen such events this past week impact California, especially the central and northern parts of the state.  CIRA’s total precipitable water product in Figures 1a and 1b depict two separate atmospheric rivers impinging on central California from 8 and 10 January 2017, respectively. The first wave transported a plume of tropical moisture from the south-southwest, which led to massive rainfall and high snow levels.  The second atmospheric river on the 10th was less directly connected to the tropics (coming in from the west-southwest), but nonetheless exhibited a well-focused transport of high moisture content.  Widespread flooding and mountain avalanches have resulted from these moisture plumes as the impacted California, as well as dramatic replenishment of reservoirs.

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Figure 1.  CIRA total precipitable water product (inches) valid at (a) 2100 UTC 8 Jan 2017, and (b) 2100 UTC 10 Jan 2017.

 

SPoRT’s real-time instantiation of the Land Information System (aka “SPoRT-LIS”) has nicely depicted the substantial replenishment of the moisture content in the soils over California.  The SPoRT-LIS is an observations-driven, ~3-km resolution run of the Noah land surface model that consists of a 33-year climatology spanning 1981-2013, and real-time output at hourly intervals sent to select NOAA/NWS partnering forecast offices.  The one-year change in the SPoRT-LIS total column soil moisture at 1200 UTC 11 January (Fig. 2) shows large increases over most of California, particularly in the higher terrain (given by blue and purple shading).  [At the same time, annual degradation in soil moisture can be seen across the central and eastern U.S.]  Interestingly, a substantial portion of California’s annual soil moisture increases has occurred in just the past week (Fig. 3; SPoRT-LIS total column soil moisture change over the past week).  One can certainly see the important role that atmospheric rivers play in being “drought busters”!

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Figure 2.  One-year change in the SPoRT-LIS total column relative soil moisture, valid 1200 UTC 11 January 2017.

 

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Figure 3.  One-week change in the SPoRT-LIS total column relative soil moisture, valid 1200 UTC 11 January 2017.

 

A map of the SPoRT-LIS daily soil moisture percentiles from 11 January highlight the very wet anomaly over California relative to the 33-year soil moisture climatology (Fig. 4; similar to the pattern of annual soil moisture change from Fig. 2).  Blue shading denotes greater than or equal to the 98th percentile, thus indicating unusually wet soils on the tail end of the historical distribution.

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Figure 4.  SPoRT-LIS total column relative soil moisture percentile from 11 January 2017.

 

Finally, SPoRT is acquiring and assimilating in real time the Soil Moisture Active Passive (SMAP) Level 2 (L2) retrievals produced by NASA/JPL into an experimental version of the SPoRT-LIS.  SPoRT is a SMAP Early Adopter and has a funded project to conduct soil moisture data assimilation experiments with LIS and evaluate impacts on land surface and numerical weather prediction models.  Figure 5 shows SMAP L2 retrievals of the evening overpasses from ~0000 UTC 11 January.  Panel (a) is the 36-km resolution radiometer product, while panel (b) shows the enhanced-resolution product, obtained from the SMAP radiometer by using Backus-Gilbert optimal interpolation techniques to provide data on a finer (9 km) grid.  The enhanced-resolution product provides much more detail of the wet soils in California, while retaining the same overall regional patterns as the original 36-km retrieval.  Given the loss of the active radar component of the SMAP mission, SPoRT plans to assimilate both the 36-km and 9-km products separately, and compare results on model accuracy.

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Figure 5. SMAP Level 2 soil moisture retrievals for the evening overpasses from ~0000 UTC 11 January 2017; (a) 36-km resolution product; (b) enhanced 9-km resolution product.

Herein is an example of the Tracking Meteogram Tool, which was developed by NASA SPoRT, being used to track and create a time series plot of the total lightning associated with a thunderstorm at the National Weather Service forecast office in New Braunfels, TX (Austin/San Antonio – EWX). The information gleaned by the time series plot from the tracking meteogram tool assisted in the warning decision making process.

For full disclosure, I have a background in total lightning and its operational uses in severe weather operations. My Master’s thesis at the University of Alabama in Huntsville was on the utility of total lightning and the lightning jump to assist in the quasi-linear convective system (QLCS) tornado warning decision process. Also, as a CIMMS research associate at the NWS Warning Decision Training Division, I developed a four-part series on best practices for using total lightning to assist in storm interrogation for various convective modes and severe hazards. I have been an intern at the NWS forecast office in New Braunfels, TX since May 2016.

On the evening of November 1st, 2016, there were isolated thunderstorms in the forecast across the Interstate 35 corridor between San Antonio and Austin, but severe weather of any sort was not anticipated across our area. The Storm Prediction Center convective outlook highlighted the eastern half of our CWA for possible thunderstorms, but did not have even a marginal risk area outlined.

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Storm Prediction Center (SPC) Convective Outlook product issued at 1z on November 2nd, 2016 (8 pm CDT on November 1st, 2016).

On this particular shift, I was working the public service desk, while my colleague Nick Hampshire, a lead forecaster at EWX, was working the short-term forecast desk. Given my background in total lightning, I typically overlay the one minute 5 km by 5 km Earth Networks Total Lightning Detection Network (ENTLN) total lightning product on top of reflectivity for situational awareness purposes. Isolated showers and thunderstorms began initiating across the region around 6-7 pm that evening. These showers and storms were, as expected, fairly mundane and short lived, only producing light to moderate rainfall before the updraft was cut off and the storm dissipated. When the showers did manage to produce lightning, the lightning frequency was low and short lived.

Around 7:40 pm, a shower initiated east of Seguin, moving northward toward the cities of San Marcos and Austin. By the time it reached San Marcos around 8:20 pm, the shower began producing lightning. As the storm progressed northward toward the city of Austin, the total lightning flash rates continued to increase. To monitor the time series trend of the total flash rate, I used the Tracking Meteogram Tool and configured it to display the sum of the values, thereby plotting all the lightning being produced by the storm at any one time. I noticed a steady increase in the lightning flash rate that coincided with and even slightly preceded the strengthening of the storm as determined by radar signatures. A quick interrogation using radar and the standard environmental package from LAPS of the storm at around 8:51 pm showed 50+ dBZ echoes up to beyond the -30 degree Celsius level (~30,000 feet).

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4-panel display of reflectivity at different tilts from KEWX radar at 8:51 pm CDT on November 1st, 2016 (0151 UTC on November 2nd, 2016).

The total flash rate at this time was 46 flashes per minute, and the flash rate had increased from 34 flashes per minute at 8:47 pm to a local maximum of 47 flashes per minute at 8:52 pm. Given the radar signatures as well as the rapid increasing trend in total flash rate, Mr. Hampshire and I decided that a Significant Weather Advisory was warranted. In the text product, we mentioned pea to nickel sized hail associated with this storm. The SPS was issued around 8:52 pm. We received a few reports of pea sized hail in southwest Austin on social media shortly after 9 pm (2z).

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1 minute ENTLN total lightning 5 km grid with tracking meteogram tool (left) and time series plot of total lightning for the storm of interest from 0133 UTC (8:33 pm CDT) to 0204 UTC (9:04 pm CDT) on November 2nd, 2016 (November 1st, 2016) 

 

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Radar loop from KEWX from 0054 UTC (7:54 pm CDT) to 0210 UTC (9:10 pm CDT) on November 2nd, 2016 (November 1st, 2016)

This case demonstrated the value of total lightning and the tracking meteogram tool. Given the forecast and the atmospheric environment, severe weather was not anticipated. However, it was the large, rapid increase in total lightning that initially prompted my attention to this storm and caused me to delve further into interrogating the severe potential. Had I not had the total lightning information available to me, the Significant Weather Advisory almost certainly would have come out later and perhaps not at all. Granted, this storm did not meet severe criteria, but not having any product issued for pea sized hail when hail of any size was not in the forecast would not have been an ideal situation, and the value added from the total lightning was still noteworthy.

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Tweet posted from the NWS Austin/San Antonio twitter account shortly after the storm had passed through Austin, dropping pea sized hail.

 

November 19th has been eagerly anticipated by the meteorological community as it is the launch of the next-generation GOES-R satellite.  The satellite will carry a suite of space weather instruments as well as two Earth observing sensors.  The Advanced Baseline Imager (ABI) will provide three times more channels to view the Earth, four times greater spatial resolution, and 5 times faster coverage.  The ABI will provide new means to monitor atmospheric phenomena.  Additionally, GOES-R will carry the first ever lightning observation sensor on a geostationary platform; the Geostationary Lightning Mapper (GLM).  Numerous organizations, including NASA SPoRT, have been supporting the GOES-R Proving Ground for many years to aid the operational community in preparing for the new capabilities of GOES-R.

Specifically, NASA SPoRT has been formally involved with the Proving Ground since 2009, although much of our work prior to this point has provided relevant information with respect to GOES-R.  SPoRT has been primarily involved in two activities.  The first has been the assessment of and training for multi-spectral imagery, often called red-green-blue (RGB) composites.  The RGB composites are used to combine multiple single channels into a single image in order to help emphasize phenomena that forecasters wish to monitor.  This can range from air mass microphysics to atmospheric dust.  This work has leveraged work by Europe’s EUMETSAT organization who first developed several of these RGB composites for their Meteosat Second Generation satellite.  SPoRT has worked with NASA’s MODIS instruments from Aqua and Terra as well as the JPSS VIIRS instrument to create the respective RGBs from polar orbiting instruments.  These snapshot demonstrations provided forecasters local examples of RGB composites to allow them to investigate these products prior to GOES-R’s launch.  SPoRT has also coordinated with other product developers to help transition their early development work to National Weather Service forecasters.  This included the University of Alabama in Huntsville’s GOES-R convective initiation product and the NESDIS quantitative precipitation product.

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MODIS Dust RGB demonstrating a future capability of the GOES-R ABI. Dust (magenta) can be seen approaching Las Vegas, Nevada.

In additional to the ABI work, SPoRT has been integral to supporting total lightning (intra-cloud and cloud-to-ground) observations in operational applications.  This dates back to 2003 with the first transition of experimental ground-based lightning mapping arrays that evolved into the pseudo-geostationary lightning mapper (PGLM) product in 2009 to provide operational training for the GLM.  Since then, SPoRT has developed the GLM plug-in for the National Weather Service’s AWIPS system, has personnel serving as the National Weather Service liaison for the GLM, and have developed foundational training that is being provided to every forecaster in the National Weather Service.

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Sample of the pseudo-geostationary lightning mapper demonstration product in AWIPS being used for training on the Geostationary Lightning Mapper.

SPoRT will continue to be actively engaged in GOES-R applications post launch.  This will take the form of developing an applications library, or short 3-5 focused case examples, for both the ABI RGBs and the GLM.  SPoRT will also participate in the formal applications training for RGBs and GLM that will be released to the National Weather Service.  Lastly, SPoRT will be leading an operational assessment of the GLM with National Weather Service forecasters and associated emergency managers.

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GOES-R launching on November 19, 2016!

…And GOES-R is off!

Today, the GOES-R satellite launched from Kennedy Space Center at approximately 642 EST!  As a forecaster, I am very excited about the flow of data and imagery that will be available to us in the near future.  Congratulation to all those who have invested so much time and energy into this project.

The GOES-R satellite launches aboard an Atlas-V Rocket at Kennedy Space Center, approx 642 pm EST.

The GOES-R satellite launches aboard an Atlas-V Rocket at Kennedy Space Center, approx 642 pm EST.

SPoRT would like to thank our collaborators who have worked with us to develop forecasting and other applications for this mission during recent years. And we look forward to continued collaborative projects in the future!

A number of fires have erupted in recent weeks due in part to the drought gripping parts of the Southeast U.S.  Especially hard hit are areas in and around the southern Appalachians, extending into central portions of Alabama and Georgia, where D3 (Extreme) to D4 (Exceptional) drought conditions exist, per the latest U.S. Drought Monitor (Image 1).

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Image 1. U.S. Drought Monitor for 8 November 2016. Notice the large area of D3-D4 drought gripping parts of the Southeast.

Recently, the fires and some smoke were captured well in Shortwave IR (Image 2) and Day-Night Band imagery (Image 3) produced by the VIIRS instrument onboard the Suomi NPP satellite.

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Image 2. Fires appear as small black dots in the Shortwave IR (~3.7 um) imagery taken at 0734 UTC 15 Nov 2016.

 

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Image 3. In this Day-Night Band Radiance RGB, the fires (center of white circles) appear similar to city lights, however smoke plumes are evident with some of the stronger and heavier smoke-producing fires (red ovals), 0734 UTC 15 Nov 2016

Since boundary layer winds tend to shift direction at night with the loss of deep mixing, the Day-Night Band image can be used by forecasters to detect how smoke plumes change direction at night and may help with forecasts of smoke impacts.