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NASA SPoRT has developed a real-time configuration of the NASA Land Information System (LIS) that runs over much of the central and eastern United States at 3-km grid spacing.  The LIS produces several products including a suite of soil moisture products that can be used as a tool for assessing drought and flooding potential.  WFO Raleigh along with WFOs Houston and Huntsville are participating in an assessment of these products during August and September. SPoRT created a couple of training modules (LIS Primer module and LIS Applications Module) to prepare NWS forecasters for this new dataset.

There are four LIS soil moisture products that are made available to WFO Raleigh forecasters in AWIPS-2 and which are available online at http://weather.msfc.nasa.gov/sport/case_studies/lis_SEUS.html for the Southeast and http://weather.msfc.nasa.gov/sport/case_studies/lis_NC.html for North Carolina.  The products include:

  1. Volumetric Soil Moisture (0 to 10cm) [SOIM0-10]
  2. Below Ground Relative Soil Moisture (0 to 10cm) [RSOIM]
  3. Below Ground Relative Soil Moisture (0 to 200cm) [INT-RSOIM]
  4. Below Ground One Week Change in Column Relative Soil Moisture (0 to 200cm) [RSOIMDIFF]

Each week, WFO Raleigh Hydrologist Michael Moneypenny serves as a member of the North Carolina Drought Management Advisory Council (NCDMAC) which provides recommendations to the U.S. Drought Monitor (USDM).  The USDM consists of a consortium of academic and government partners, including the University of Nebraska-Lincoln National Drought Mitigation Center (NDMC) and various other federal and state agencies.

WFO Raleigh started receiving the LIS soil moisture products in July and evaluating the products in August. The products were first used during the weekly NCDMAC collaboration call on Tuesday August 5th.  The LIS data was used to expand the D0 (abnormally dry) category at a sub-county level into portions of Robeson and Scotland Counties. In particular, the 0-200 cm Relative Soil Moisture Weekly Change product was used to show changes in the deep layer soil moisture. In figure 1 below, the upper image was referenced by the NCDMAC during the August 5th collaboration call to recommend expansion of D0 at the sub-county scale in the area circled.

In addition, a more formal demonstration of the full suite of LIS soil moisture products was conducted during the weekly NCDMAC collaboration call on Tuesday August 12th. In figure 1 below, the lower image was used to inspect the short time scale improvement of soil moisture conditions in the areas under D0 drought designation. While the graphic shows marked improvement from significant rainfall, the D0 areas were not modified as lingering 30 and 60 day rainfall deficits in these areas (in addition to crop reports), overshadowed the short term improvement.

The NCDMAC will be examining how best to utilize these products for drought assessment. Preliminary ideas include: 1) how the products can be correlated to the observed well level observations available via the USGS and state networks, and 2) how the SPoRT products can be used to enhance or complement the Standardized Precipitation Index product produced by the NC State Climate office.

Figure 1. The 0-200 cm Relative Soil Moisture Weekly Change products ending at 08/05/2014(top) and 08/12/2014(bottom) are shown above. The U.S. Drought Monitor status is shown in the insert in the lower left with the area of abnormally dry conditions (D0) shown in the yellow shading.

Figure 1. The 0-200 cm Relative Soil Moisture Weekly Change products ending at 08/05/2014(top) and 08/12/2014(bottom) are shown above. The U.S. Drought Monitor status is shown in the insert in the lower left with the area of abnormally dry conditions (D0) shown in the yellow shading.

We have a long history of usage of total lightning data via the North Alabama Lightning Mapping Array (LMA) data here at the National Weather Service office in Huntsville, AL. LMA data began flowing here way back in the spring of 2003.  There have been minor interruptions of data at times, mainly during and shortly after the implementation of AWIPS II, but total lightning data have been an integral, consistent part of operations here for over 10 years.  These data have been used most often for detecting the initiation of electrical activity in developing convection.  This is important because studies show that intra-cloud lightning often precedes cloud-to-ground lightning by about 5 to 10 minutes.  Thus, total lightning data can serve as an early warning signal of the more dangerous cloud-to-ground component.  We’ve also used the data to help identify thunderstorms that may experience rapid intensification, since total lightning activity is directly related to strengthening updrafts.  I’ve even posted about an event in March 2012 where I used the LMA data as supplemental evidence that helped prompt a severe thunderstorm warning.  This past Sunday evening (August 10th) I had the opportunity to use the data in a unique way (at least for me)…to help with a flash flood warning decision.

The first image below is a loop of KHTX WSR-88D 0.5 Reflectivity from this afternoon.  Notice the cell that developed and persisted over northwestern portions of Morgan County.  This cell developed directly along the Tennessee River and over the city of Decatur, AL.

Image 1.  KHTX 0.5 deg reflectivity 1920-2112 UTC 10 August 2014

Image 1. KHTX 0.5 deg reflectivity 1920-2112 UTC 10 August 2014

The cell was producing heavy rainfall, and the other operational forecaster and I were watching it closely.  One-hour rainfall amounts shortly after 2100 UTC were approaching 2 inches according to KHTX and nearby ground stations, which was near flash flood guidance for basins in this area.  Of course, we were also dealing with data latency from these various sources, which is generally anywhere from about 5 to 20 minutes or more depending on the source. In a flash flooding situation, just as any other warning situation, things can evolve quickly and data updates as fast as possible are desired.

Perhaps most concerning however, was the fact that this cell was back-building and showing signs of little movement during the period, while some of this rain was falling over the city of Decatur. True, Decatur is a relatively small city, but still has sufficient urban land cover, and is bordered to the north and east by terrain that slopes gently toward the Tennessee River. So, drainage of water can be slow in the city, especially once adjacent backwaters and wetlands associated with the Tennessee River fill with water. While considering a flash flood warning, I still wanted some idea of the potential longevity of the cell over the Decatur area.  The area could have handled this much rainfall if the cell dissipated and/or moved off as most others were prone to do in the low shear environment that day. However, looking at the LMA data really helped with my decision.  Beginning at approximately 2104 UTC, source (image 2) and flash data (not shown) from the LMA showed the beginning of an enormous increase in total lightning activity with this cell.  Also, the increase was taking place directly over the city of Decatur.

Image 2.  KHTX 0.5 degree reflectivity overlaid with North Alabama LMA source density 2104-2134 UTC 11 August 2014

Image 2. KHTX 0.5 degree reflectivity overlaid with North Alabama LMA source density 2104-2134 UTC 10 August 2014

This trend in total lightning continued over the next several minutes.  With the knowledge that this cell was likely undergoing intensification and moisture-laden updrafts were strengthening directly over the city of Decatur, I decided to issue the flash flood warning, which was officially disseminated at 2115 UTC.  We received the first reports of flash flooding at 2145 UTC.  The next image below shows the location of the warning issuance.

KHTX 0.5 degree reflectivity with Flash Flood Warning polygon (green box) 2117 UTC 10 August 2014

KHTX 0.5 degree reflectivity with Flash Flood Warning polygon (green box) 2117 UTC 10 August 2014

The total lightning data in this case served as a very valuable severe weather application tool.  By providing the warning forecaster with knowledge of the location and likelihood of future deep convection, a flash flood warning was issued in a more timely and effective manner than would have been possible without these data.  When used in conjunction with other information and applied properly, these types of data can help to save lives and property.

The SPoRT program has been collaborating with NOAA’s National Hurricane Center to transition passive microwave products to their operational system; the National Centers for Environmental Prediction Advanced Weather Information Processing system, or NAWIPS.  By viewing a storm in microwave wavelengths versus infrared, forecasters have the ability to observe storm structure that may be obscured by high clouds.  Many times, this ability is used to better determine the center fix on a tropical system.

One of the most recent missions to carry a passive microwave instrument is the joint NASA and Japan Aerospace Exploration Agency Global Precipitation Measurement (GPM) satellite.  The core observatory was launched on February 27, 2014 operational data from GPM’s microwave imager (GMI) was first available on May 29.  SPoRT has incorporated this into the data feed for the National Hurricane Center.  SPoRT is currently working to transition these observations to NAWIPS for the Central Pacific Hurrican Center in Honolulu, Hawaii.

The image below, taken by the National Hurricane Center in NAWIPS shows Hurricane Iselle in the Pacific Ocean several days before it struck the big island of Hawaii.  The image shows an RGB (red, green, blue) color composite of Hurricane Iselle from August 5, 2014 at 11:15 AM Eastern Daylight time.  The image is created by combining the horizontal and vertical polarization observations of the 89 GHz channel.  The resulting combination emphasizes strong convection / deep clouds in bright red.

Additional information on GPM can be found at: www.nasa.gov/gpm.

Hurricane Iselle - GMI

Hurricane Iselle as observed by the Global Precipitation Measurement Microwave Imager (GMI) with the 89 GHz RGB composite on August 5, 2014 at 11:15 AM Eastern Daylight Time.

 

Several SPoRT Land Information System (LIS) soil moisture and temperature fields have been evaluated for operational utility at the Huntsville Weather Forecast Office (WFO) for several years now. In fact, their usage here dates back to early 2011. The data have recently been made available in AWIPS II, in March of this year. Prior to that, we had to rely on imagery of specific variables from the SPoRT website. The data have proved to be useful for drought assessments and in several cases for assessing the potential for areal/river flooding. I’ve pointed out some of these uses in previous blog posts:

  • SPoRT LIS Soil Moisture as a Partial Indicator for Flooding Threat
  • Recent Flooding in the Huntsville Forecast Area and Use of the SPoRT LIS
  • SPoRT Land Information System Soil Moisture Data Continued Use at NWS Huntsville
  • The NASA 1km LIS and Recent Applications for the U.S. Drought Monitor
  • In order to get a broader perspective and to properly introduce some of the LIS soil moisture variables to other WFOs, SPoRT is conducting a more formal assessment with a couple of collaborating WFOs, Raleigh and Houston, in addition to the Huntsville office. The assessment began officially on August 1st, and will run through the end of October. Assessment participants at each office will be filling our surveys pertaining to their use of the data while assessing their utility for various operational situations. To prepare NWS forecasters, SPoRT created a couple of training modules (LIS Primer module, and LIS Applications Module) and made those available prior to the start of the assessment.

    Yesterday, when providing input for the U.S. Drought Monitor, I used the 0-10 cm Volumetric Soil Moisture (image 1) as evidence that the area of D0 (abnormally dry) conditions needed to be expanded northward.

    0-10 cm Volumetric Soil Moisture 12Z 5 August 2014

    0-10 cm Volumetric Soil Moisture 12Z 5 August 2014 (click image for a larger version)

    Notice the patch of brown colors in the center of the image, which is located in north central Alabama. Soil moisture values here were lower than in adjacent areas to the south that already held a D0 designation. With this evidence in hand, I called a field agricultural agent of the Alabama Cooperative Extension Service in Cullman County (which serves this area). The agent affirmed that vegetable crops were beginning to be affected by the recent lack of rainfall and dry soils in the area. So, the decision was made to expand the D0 slightly northward into this area.

    This is just one example of the use of these data. They can help make a more effective drought assessment overall, and the 3 km resolution of the data are a great benefit not available in standard, legacy soil moisture analyses.

    In late April,  NASA SPoRT and the Albuquerque NWS met with scientists at New Mexico Tech to coordinate the integration of the Langmuir Lab lightning mapping array data into our operations.  According to Bill Rison, Paul Krehbiel, and Ron Thomas, New Mexico Tech’s Lightning Mapping Array (LMA) is a 3-dimensional total lightning location system. The system is patterned after the LDAR (Lightning Detection and Ranging) system developed at NASA’s Kennedy Space Center by Carl Lennon, Launa Maier and colleagues. The LMA measures the time of arrival of 60 MHz RF radiation from a lightning discharge at multiple stations, and locates the sources of the radiation to produce a three-dimensional map of total lightning activity.  The time-of-arrival technique for studying lightning was pioneered by Dave Proctor in South Africa.  The NASA SPoRT core project site details that operationally, total lightning data provide several advantages to forecasters.  First, total lightning data often give a 3-5 minute lead time ahead of the first cloud-to-ground lightning strike.  This improves lightning safety for the National Weather Service’s Terminal Aerodrome Forecasts (TAFs) and Airport Weather Warnings (AWWs).  This safety feature also can be used for incident support of special events. In addition, the total lightning data provides information about the spatial extent of lightning that is not available in the traditional cloud-to-ground data (http://weather.msfc.nasa.gov/sport/lma/).  This data may also be used to evaluate the degree of lightning activity within active wildfire smoke plumes.  The image below is an example of an LMA station at Briggsdale, Colorado taken by New Mexico Tech.  These stations are solar-powered and communications are operated via cell technology.

    LMA stations at Briggsdale, Colorado.  Photo available from NM Tech.

    Figure 1.  LMA station at Briggsdale, Colorado. Photo available from NM Tech.

    After the first collaboration between NWS Albuquerque and NM Tech, forecaster Jennifer Palucki met with Harald Edens in June to install the xLMA and Live LMA software onto our office outreach laptop.  The LMA data that forecasters are evaluating at Albuquerque consists of source densities.  The imagery is available as a contour shaded product and describes the overall extent of sources from a particular thunderstorm or complex of thunderstorms.  The Live LMA software provides the actual point source information that make up the densities available in AWIPS.  The forecaster can actually see the structure of the point sources making up a flash on a 1-minute temporal resolution.  Figure 2 below shows the composite radar reflectivity valid at 0200 UTC July 23, 2014 for a complex of thunderstorms developing southward into the Albuquerque Metro Area.  The associated LMA source density product at 0202 UTC in Figure 3 illustrates the structure of the shaded point sources for the lightning flash.  The graphic shown in Figure 4 details the point sources available with the Live LMA software.  The source densities making up the flash during this 1-minute period stretched as far as 30-km from north to south and 20-km from east to west.  The altitude of the main source region was near 10-km.  The data available in AWIPS also allows the forecaster to slice and dice the data by elevation angle.  Forecasters at the Albuquerque NWS will continue evaluating the LMA products through summer 2014 to offer feedback to NASA SPoRT and NM Tech on its operational application.

     

    Figure 2.  Mosaic Composite Reflectivity valid at 0200 UTC July 23, 2014.

    Figure 2. Mosaic Composite Reflectivity valid at 0200 UTC July 23, 2014.

     

    Figure 3.  Langmuir Lab LMA Source Density product valid at 0202 UTC July 23, 2014.

    Figure 3. Langmuir Lab LMA Source Density product valid at 0202 UTC July 23, 2014.

    Figure 4.  Live LMA 1-minute point sources valid at 0202 UTC July 23, 2014.

    Figure 4. Live LMA 1-minute point sources valid at 0202 UTC July 23, 2014.

    It is said that a picture says a thousand words…well in this case let’s just say 434 words, as are contained in this post. Anyway, I’d like to point out six features in this morning’s Nighttime Microphysics RGB.  The image below (MODIS Nighttime Microphysics RGB) showed several features of varying degrees of operational relevance.

    MODIS Nighttime Microphysics RGB with annotations valid 0755 UTC 16 July 2014

    MODIS Nighttime Microphysics RGB with annotations valid 0755 UTC 16 July 2014

     

    A myriad of cloud features can be observed, including fog in the valleys of central Appalachia, deep convective clouds along the Florida coast, patches of thin and thick cirrus over north-central Alabama, and low stratus clouds in Missouri…to name just a few.  Sure, this isn’t an exhaustive list of the potential cloud features to observe, but showcases the ability to contrast effectively between different cloud types.  Of perhaps significant interest is the ability to see the contrasting airmasses displayed across the Southeast region.  Notice the  pinkish colors north and west of the yellow curved line that stretches from central Louisiana to southern Virginia.  This represents a lower relative contribution of blue color, or lesser longwave radiation at the 10.8 µm wavelength, which is indicative of cooler temperatures.  To the south and east of this line, much more blue is apparent, which is thus indicative of warmer temperatures.   Surface observations valid at about the same time have been overlaid with the RGB image to provide temperature data context.  Air and dew point temperatures are around 10 degrees F cooler behind the line/front, but notice that the northerly wind shift is still on the south/east side of the line at such locations as Montgomery, AL and Columbus, GA.  At those locations, dew point temperatures were still 70 and 71 F, respectively, with air temperatures at 72 F.  So, the gradient in temperatures still lingered behind the surface front and is well depicted in the RGB imagery.  This type of information can be valuable to forecasters, as temperature, moisture, and wind characteristics are often complex in the vicinity of surface fronts.  Thus, while wind shifts may be observed initially, as in this case, the imagery shows the location of the temperature gradient much better.

    The importance of this type of imagery is that it offers a much more effective assessment of meteorological phenomena than existing GOES imagery.  The only problem currently is the limitation of available imagery to forecasters, since these are from polar-orbiting platforms (Terra, Aqua, Suomi NPP), and thus provide just a few snapshots per night over a given location.  Nevertheless, the imagery form the VIIRS and MODIS instruments offer added value to existing GOES imagery and serve as valuable teaching and preparatory aids for future GOES-R and JPSS missions.

    I wanted to point out a couple of operational advantages of total lightning data offered by current LMA networks scattered across parts of the CONUS, but also the advantages forthcoming with the GLM in the future GOES-R era.  While viewing the data today in conjunction with radar and NLDN data, two great examples were noticed.  First, let’s consider the situation where a cell becomes electrically active (intracloud lightning), but never produces a cloud-to-ground strike.  The first image below shows KHTX 0.5 reflectivity overlaid with LMA Flash Extent Density.

    Image 1.  KHTX 0.5 reflectivity (dBZ) overlaid with North Alabama LMA Flash Extent Density valid 1735/1736 UTC 25 June 2014

    Image 1. KHTX 0.5 reflectivity (dBZ) overlaid with North Alabama LMA Flash Extent Density (pinkish-white shaded area) valid 1735/1736 UTC 25 June 2014

     

    Notice the small area of lightning detected by the North Alabama LMA in the central part of the image.  This cell never actually produced a ground strike.  So, using NLDN data alone, a forecaster would not have known that this cell was electrically active, and capable of producing lightning/thunder.  True, CG lightning was never observed by the NLDN network, but this is rather rare.

    Next, let’s look at a situation where intra-cloud lightning preceded a CG strike as a cell was approaching an airport location.  Image 2 below, shows a cell that has just become electrically active as it was approaching the Tuscumbia/Muscle Shoals area around 1750 UTC.

    Hi

    Image 2.  KHTX 0.5 reflectivity (dBZ) overlaid with North Alabama LMA Flash Extent Density (pinkish-white shaded area) valid 1749/1750 UTC 25 June 2014

    Notice in the image above that the first lightning detection by the LMA was during the 1749-1750 two-minute interval.  Now, we’ll take a look at an image just a little later, which shows the first incident of cloud to ground lightning as detected by the NLDN.

    Image 1. KHTX 0.5 reflectivity (dBZ) overlaid with North Alabama LMA Flash Extent Density (pinkish-white shaded area) valid 1735/1736 UTC 25 June 2014

    Image 3. KHTX 0.5 reflectivity (dBZ) overlaid with North Alabama LMA Flash Extent Density (pinkish-white shaded area), including CG strike (small cyan line) as indicated by NLDN  valid 1757/1758 UTC 25 June 2014

    The image above (Image 3) shows the first CG strike, indicated by the small cyan line, which was about 7-8 minutes after the first intra-cloud flash.  Notice also that this cell was approaching the Muscle Shoals ASOS to the east, for which the HUN office has airport weather warning responsibilities.  These responsibilities include the issuance of warnings for CG lightning with 5 SM of the airport. So, not only do the total lightning data alert to the presence of lightning when a cell never even produces a CG strike, but intra-cloud flashes will often precede CG strikes.  In fact, research has shown this to be by about 5 to 10 minutes.  Forecasters here at the HUN WFO have been privileged to use these data in operations for over 10 years now.  These and future GLM data will be a boon to operations, allowing for earlier lead times in some warning and forecast situations.

     

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