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Archive for the ‘Training’ Category

The Albuquerque NWS recently began receiving an updated NESDIS snowfall rate (SFR) product from NASA SPoRT. We were anxious to see how the updated product performed during our most recent winter storm. A fast moving upper level trough and associated Pacific Front blasted into western New Mexico on the afternoon of Saturday, December 13. The upper low deepened and closed off over New Mexico with wrap around snow impacting northeast New Mexico through mid-day Sunday, December 14.  Ahead of the system, temperatures were very warm with Albuquerque reporting a high of 61 and Santa Fe reporting a high of 57 on Saturday.  The RGB snow-cloud product from 2045Z on Sunday depicts snow cover following the event. Four areas in the state were impacted – the western high terrain, the San Juan and Sangre de Cristo Mountains (mainly west slopes) in north central New Mexico, and extreme northeastern corner of New Mexico. Four yellow ovals mark areas to be discussed in this blog entry. Strong westerly, downslope flow on the backside of this storm system resulted in the snow-free region along the eastern slopes between Taos and Raton.
SnowCloud121414_2045Z

In the loop below, the 0.5 reflectivity mosaic and surface observations show the surface front moving into western New Mexico (left most oval in the snow-cloud product) during the period from 1942Z to 2318Z. In the first image, the winds have shifted to the northwest in Farmington (FMN) and rain is reported as temperatures are too warm to support snow. Note that throughout the loop the Farmington area, especially west and north of the site, there are no radar returns. The Four Corners area has poor to no radar coverage and it is an area where we hope the SFR product will help us. Snow was reported at Gallup (GUP) by 2030Z.

0.5 Reflectivity 1942Z to 2318Z

The SFR product was limited during this initial period, with only one swath covering New Mexico at 2034Z (shown below). This image (obtained from the SPoRT product page) shows that snow is detected in northeast Utah and northwest Colorado, but not in northwest New Mexico.  The Gallup area ended up with about one inch of snow while higher terrain south of Gallup reported two to three inches. While only rain was reported at the Farmington ASOS, the snow-cloud product shows some snow just to the east of Farmington where reports of one-half to an inch of snow was reported.

SPoRT_SFR_121314_2034Z

The next SFR product with coverage over New Mexico had a timestamp of 0338Z (14 December 2014), and is compared to the composite reflectivity image of 0336Z in the image below. Reflectivity is strongest just west and northwest of the Albuquerque ASOS (ABQ), which is reporting rain. The cold front however was moving quickly from west to east toward the ABQ metro area. The strong reflectivity returns to the northwest of Albuqurque are actually bright banding as rain began changing over to snow. The dual polarization hydrometeor classification algorithm showed the rain/snow line shifting quickly eastward. Fifteen minutes prior to this image, rain transition to snow was reported in Rio Rancho, just northwest of Albuquerque. The higher terrain just east of Albuquerque, the Sandia and Manzano Mountains, did receive snow accumulations of two to four inches and the SFR product highlights that area with light rates (blue) of about .02 inches/hour. The Santa Fe area (SAF) is not reporting snow at this time, but is highlighted with the max values of SFR, though snow reports in the Santa Fe area were generally less than 2 inches.  Recall that afternoon temperature were quite warm, making it difficult for snow to accumulate. The SFR product also depicts rates up to .05 inches/hour over the Sangre de Cristo mountains north and east of Santa Fe, where accumulations of 4 to 8 inches were reported. Interestingly, the SFR product is estimating precipitation around Santa Fe when the radar reflectivity pattern and observation do not indicate rain or snow. A portion of this area to the immediate northeast and east of ABQ is beam-blocked by the Sandia Mountains (yellow oval southwest of SAF).

mosaic_Comp_Ref_20141214_0336_SFR_0338Z

A similar comparison is shown for 13 hours later, or around 1655Z on December 15. (Another image was available around 08Z, but is not discussed in the post.)  Note that the SFR product depicts accumulating snow, albeit light, from eastern Taos through all but extreme southern Colfax County. Two stations (KAXX and KRTN) are reporting snow, but radar composite reflectivities do not extend over either location. Snow did accumulate at KAXX, but not at Raton (KRTN) where temperatures hovered right above freezing.

mosaic_Comp_Ref_20141214_1642_SFR_1645Z

Snow that is evident in extreme northeast New Mexico occurred after mainly 16Z and was associated with persistent wrap around precipitation (a SFR product was not available). The SFR product was not used in near real time for this event but was re-examined only a short time thereafter. However, the product did validate that we will indeed be able to complement radar void coverage areas in an operational forecast environment using polar-orbiting satellite imagery. This example will also serve to highlight potential product applications, advantages, and disadvantages for forecaster training prior to the upcoming NESDIS evaluation period.

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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.

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Last year, NASA SPoRT submitted a proposal to collaborate with the Operations Proving Ground in Kansas City, Missouri.  The effort is focused on evaluating the Meteogram Moving Trace Tool developed by the Meteorological Development Laboratory (MDL) with support from NASA SPoRT to include total lightning.  One of the top requests from forecasters has been to create a time series plot of total lightning in real-time.  SPoRT first began to develop the total lightning tracking tool for use in AWIPS II to use with total lightning observations from the ground-based lightning mapping arrays.  The effort has now expanded to SPoRT coordinating with MDL’s meteogram tool for AWIPS II.  The advantage of the MDL tool is that it can create time series trends for multiple data sets beyond total lightning (e.g., radar, satellite, models).

This week, the Operations Proving Ground has brought together forecasters, developers, and trainers from multiple organizations to evaluate the use of this tool in several scenarios.  The opportunity for face-to-face discussions, training, and evaluation has been invaluable for the MDL and SPoRT developers to assess how the tool may be used in operations and to fix bugs that are found.  The face-to-face nature has allowed for bugs or requests for new features to be addressed throughout the day and to test the fixes the following day.  The week long evaluation facilitated by the Operations Proving Ground will lead to several improvements to the meteogram trace tool in preparation for its deployment in AWIPS II later this year.

Forecasters evaluating the meteogram trace tool at the Operations Proving Ground in Kansas City, Missouri.

Forecasters evaluating the meteogram trace tool at the Operations Proving Ground in Kansas City, Missouri.

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A strong cold frontal boundary that surged south across the high plains of Colorado, New Mexico, Oklahoma and Texas April 29, 2014 was forecast to produce widespread strong winds and blowing dust.   The presence of cloud cover is a key limitation of observing important surface features from satellite imagery.  The following series of imagery illustrates how the availability of the Dust RGB composite product can improve analysis of dust through clouds even when compared with other high resolution satellite imagery.  The 500-meter Visible valid at 2026 UTC over west Texas shows exceptional detail of the cloud field over the area however based on surface observations it is difficult to see verify any dust.  The 1-km True Color image valid at the same time also shows various cloud structures as well as the background appearance of the land surface.  Again, it is still difficult to discern any dust in the imagery.  Finally, the Dust RGB at 2026 UTC details precisely where the location of the main dust field exists beneath the cloud cover.  Source regions are even visible over southeastern Colorado.  A sharp boundary along the southern extent is also evident over the Permian Basin.  This area of dust surged west into eastern NM through the morning of the 30th and even produced visibility reductions in the Rio Grande Valley around Albuquerque.

MODIS-VIIRS 500-meter visible image valid at 2026 UTC April 29, 2014.

MODIS-VIIRS 500-meter visible image valid at 2026 UTC April 29, 2014.

MODIS-VIIRS 1-km True Color image valid 2026UTC April 29, 2014.

MODIS-VIIRS 1-km True Color image valid 2026UTC April 29, 2014.

MODIS-VIIRS 1-km Dust RGB image valid 2026UTC April 29, 2014.

MODIS-VIIRS 1-km Dust RGB image valid 2026UTC April 29, 2014.

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SPoRT is planning an assessment of Total Lightning products with several existing and new collaborators from WFOs, CWSUs, and National Centers, ranging in locations from southern Florida to New Mexico and Colorado.  From May 15 – July 15, 2014 operational forecasters will evaluate the application of total lightning to support severe storm, public safety, and aviation weather warning responsibilities.  To prepare, SPoRT is holding tele-training sessions with collaborators during the week of April 21 and has provided users several training modules as well as a Total Lightning Quick Guide.  These can be found via SPoRT’s Training Page and on the NOAA LMS.  Experience with total lightning data will prepare users for the GOES-R GLM as well as provide feedback from operations to researchers regarding the types of products users desire.

Total lightning (left) in a source density product form and radar reflectivity near the mixed phase level.  Higher values of total lightning correspond to regions where strong updrafts result in numerous particle collisions and charge separation.

Total lightning (left) in a source density product form and radar reflectivity near the mixed phase level. Higher values of total lightning correspond to regions where strong updrafts result in numerous particle collisions and charge separation. This image is from the NASA/SPoRT Quick Guide Training.

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Radar_1103UTC_03Mar2014

SFR_1107UTC_03Mar2014

During the weekend of Mar 02-03 2014, several weather features moved northeast across the area. The precipitation started out as rain across West Virginia with some freezing rain, sleet and snow across portions of southeast Ohio. Colder air began to filter into the region and as it did, the precipitation changed from rain to freezing rain to sleet and finally to snow. By 603 AM, the precipitation had turned to snow across all of West Virginia, but for portions of the extreme southeast counties.

I have attached two images from around 6 AM on Mar 3rd. The first image showed the radar data from KRLX at 603 am while the second image was the 607 am SFR product and 6 AM surface observations. When comparing these images, the “best” SFR signal for heavy snow was located along a line where the precipitation transitioned from freezing rain to snow. The heaviest signal in the SFR images was actually located over Mingo County where a total of 8 inches of snow was reported from the storm.

Freezing rain was falling across portions of extreme southeast West Virginia. Bluefield WV (KBLF) is located southeast of the “SFR” heaviest snow signal in an area where the SFR product is not showing anything. The SFR product did a great job across that area as the 6 AM KBLF observation indicated freezing rain was falling at that time.

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SPoRT continues to work with select NWS WFOs in evaluating the NESDIS SFR product.

One thing to take into consideration when using data from “whisk-broom” instruments on polar-orbiting satellites, such as the Advanced Microwave Sounding Unit (AMSU) used to generate the SFR product, is that data at the edge of the swath (i.e. limb) may provide misleading or erroneous observations. As the instrument scans farther from nadir, it is looking through more of the atmosphere, creating both a bigger observation field of view (i.e., larger pixel) and having the signal attenuated by more atmospheric constituents (e.g., in-cloud and falling snow).  As a result, when interpreting the SFR product, it is important to look for the extent of the swath (outlined in gray in the product in AWIPS) to determine whether the observed SFR is going to be limited by these limb effects.

Let’s take a look at an example over the NY Tri-State area for the post Super Bowl snow event.  In the first image, from Metop-A valid at 1458 UTC, there is a large area of snowfall across the area.  The heaviest SFRs appear to be around 1.2-1.5 in/hr (when multiplying the liquid equivalent by 10) across central and southern New Jersey.  However, an hour later (see second image from Metop-B valid at 1554 UTC), the shape of the heaviest SFR has expanded north and west and there are now readings over 2.0 +in/hr.  Other areas that had a SFR of less than 0.5 in/hr in the 1458 UTC image, appear to have a SFR of around 1.0 in/hr just an hour later, which is a large jump in intensity.

While it is certainly possible that the snow evolved and intensified in less than an hour, it is more likely that instrument limb effects are likely to blame for the larger SFRs in the second image.  Make sure to check that swath edge when using polar-orbiting satellite data!

NESDIS SFR Product from 1458 UTC on 3 February 2014 showing snow detected near nadir for Metop-A

NESDIS SFR Product from 1458 UTC on 3 February 2014 showing snow detected near nadir for Metop-A.

NESDIS SFR Product from 1554 UTC on 3 February 2014 depicting what are likely erroneous higher intensity SFR values along the swath edge from Metop-B.

NESDIS SFR Product from 1554 UTC on 3 February 2014 depicting what are likely erroneous higher intensity SFR values along the swath edge from Metop-B.

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