Smoke from wildfires in parts of Alberta and Saskatchewan Provinces in Canada made entry into the U.S. recently. The smoke may its way into the Tennessee Valley by the afternoon of June 30th and could easily be seen in the True Color RGB imagery from the VIIRS instrument on board Suomi NPP. The smoke was even evident in the SPoRT Day-Night Band Radiance RGB imagery later that night (Image 2)). While the smoke was well aloft and not necessarily impactful to health, it was still an unusual site for many in the eastern U.S. not used to such phenomena.
The Huntsville office has a long history of using total lightning information from the North Alabama Lightning Mapping Array (NALMA) for warning decision-making. Since 2003, WFO Huntsville has been ingesting and receiving a source density product from NASA SPoRT. However, recently, we decided to begin migrating to Flash Extent Density (FED) data; this is more consistent with the Geostationary Lightning Mapper, more consistent with recent operational research, and easier to convey and understand. Typically we are trying to apply the “two-sigma” lightning jump algorithm suggested by Schultz et al. (2009, 2012).
On June 8, a weak front moved across the Huntsville forecast area, initiating development of strong to severe thunderstorms. An 1800 UTC sounding from Redstone Arsenal indicated a relatively high threat for wet microbursts.
One of the storms moved across extreme southern Jackson and northern DeKalb Counties in northeast Alabama. I was viewing the NALMA FED data and watched as the storm went from less than 10 flashes, to 40 flashes, in three “scans” (from 2214 to 2218 UTC). (Interestingly, despite using SAILS with the KHTX radar, AWIPS-2 matched all three lightning images to a single 0.5-degree radar scan.)
Since we cannot get the formal lightning jump algorithm into AWIPS-2 at this time, forecasters need to do some quick mental math to decide if jumps such as these constitute a real jump. I was certain this did (and later Excel work verified this) so I issued a severe thunderstorm warning, despite the storm being very close to the Georgia state border.
This storm produced structural damage in the Cartersville community near the state line shortly after the warning was issued, tearing the roof off of an apartment complex and downing trees and powerlines. There was not much lead time (there rarely is with these kinds of storms) but this reinforces our past experience with total lightning–and reinforces that lightning may be especially useful during a challenging warm season warning environment.
Intense fires in Canada began releasing large amounts of smoke into the atmosphere on June 6th. Since the initial fires, winds have transported the smoke towards the Upper Midwest. The smoke advancing over the Upper Midwest is evident on the VIIRS True Color image from June 8th (shown below).
Last year, NASA SPoRT developed a near-real time aerosol optical depth (AOD) product that combines observations from polar-orbiting (S-NPP VIIRS and MODIS Aqua and Terra) and geostationary (GOES-15 and MTSAT-2) satellites in an effort to generate a product capable of providing a more complete spatial distribution of AOD across the Pacific Ocean. Although this SPoRT AOD product was originally developed to help support the NOAA-led CalWater 2 field campaign (January-March 2015) with monitoring and tracking long-range transported aerosols across the Pacific Ocean, it can also detect aerosols over the United States. AOD products using observations from only a single satellite sensor often provide a very incomplete picture of AOD since high reflectance from clouds generally mask the aerosol signal. The use of multiple satellite sensors in the SPoRT AOD product helps increase the likelihood of observing a cloud-free region where aerosols are present. Our product has been successfully monitoring and tracking the smoke from the Canadian fires since the initial outbreak on June 6th. A snapshot of the AOD product on June 8th is shown below which is zoomed-in to highlight the very high AOD (red colors indicate AOD >1.0) associated with the smoke plume identified in the VIIRS True Color image. Moderate values of AOD (~0.5) are shown in green while low values (<0.2) are shown in blue and magenta.
The smoke plume has propagated further eastward today to over the Mid-Atlantic region, but is lofted in the atmosphere and has not impacted visibility at the surface.
Following the 10 May 2015 tornado (EF1) near Lake City, IA, SPoRT Disasters team members began to acquire commercial satellite imagery through our partnership with the USGS. Once a request for imagery was made by folks in NWS Central Region, images hosted on USGS’s Hazards Data Distribution System (HDDS) web portal were obtained for processing and distribution to the Des Moines, IA Weather Forecast Office (WFO). Concurrently, teams from the DMX WFO were deployed to assess and survey damaged areas. As survey teams collected information from the field, damage points and polygons were uploaded to the NWS Damage Assessment Toolkit’s (DAT) beta damage editor as early as 12 May 2015.
By 14 May 2015, the Disasters team was able to process and disseminate commercial satellite imagery (in this case SPOT-6 panchromatic) to the DAT application for post-event damage assessment and verification by the office. Ground scarring and swirling (see red inset in the image below) from the tornado were evident as a linear feature moving SW to NE through the image. Once the imagery was delivered, members of the DMX office were able to corroborate their original damage polygon with ground scarring in the imagery. It was in this corroboration that surveyors noted divergence in the two paths, as highlighted by the figure below, and subsequently revised their outputs.
Kevin Skow, one of the surveyor’s from the DMX office who worked the event, provided the Disasters team positive feedback on the usefulness of this imagery with regards to their work, “…the modifications you are seeing in the DAT are a direct result of what we found in the satellite data. A second storm produced wind damage within a few miles of the actual tornado path that same night. The ground survey team thought that this damage might be from the tornado. However, the satellite data showed that the path was further to the NW. The satellite data also helped us fine tune the path north of Lake City. The satellite data has proven once again to be a great asset for our storm surveying operations.”
Even with some latency, this event demonstrates the importance of providing satellite imagery to forecast offices during (and following) severe weather. While satellite imagery cannot replace the work performed during ground surveys, this type of data has the ability to provide yet another source of information for surveyors to utilize during their response efforts.
With an unseasonably strong upper low approaching New Mexico, forecasters at NWS Albuquerque anticipated high elevation snow and widespread rain with relatively high QFP values for the period of 26-27 April 2015. A winter storm watch was issued at 400 am MDT on Saturday, April 25. Snow was forecast for the highest terrain across the northern and central New Mexico, but significant snow accumulations were expected late Sunday, April 26 through early Monday, April 26. Additionally, rain amounts in excess of an inch were expected across the eastern plains.
The GFE storm total snow from mid-day Saturday, April 25 is shown below. The forecast called for the most significant snow accumulations, just over a foot across the highest peaks, to occur over the Sangre de Cristo Mountains (just to the west of Interstate 25) and the higher elevations along the Colorado border north of Raton, NM. The watch was upgraded to a warning at 4am MDT on Sunday, April 26.
Widespread precipitation was reported during the overnight hours, with 3-.6in of rain in the Albuquerque metro area. The position of the closed low early on the morning of Monday, April 27 is shown below. Snow was still being reported at Angel Fire in the Sangre de Cristo Mountains, but the big story by this point was rain across the eastern plains.
Two Snowfall Rate products were received during the overnight hours around 3am MDT (09Z). The date/time stamp was not included on the images – the first shows SFR at 0838Z and the second at 0913Z. Both include metar observations from 09Z. Angel Fire is reporting snow, though in both images the SFR ends just north of the site. Raton is reporting rain and the SFR products both show the eastern edge of snow accumulations ending just to the west of Raton. Based on very high accumulations south of Angel Fire, the SFR product may be underestimating the area of active snow.
As is often the case, radar cover across the north central mountains is limited. The 0.5 reflectivity mosaic below is from 09Z, between the two SFR products above. Angel Fire is marked by the purple circle. Radar returns over the Sangre de Cristo mountains are greater north of Angel Fire. In eastern New Mexico, Tucumcari (blue circle) is reporting rain associated with the strongest radar returns. Rain continued through the daytime hours with numerous rainfall reports of over one inch. In fact, Tucumcari Aiport reported 1.50″ of rain, the 3rd largest 1-day total in April since 1941!
Snow accumulation reports did verify our forecast of over a foot of snow for this late season event. Determining snow records is more difficult since routine snow observations are few. Highest totals were received in the Sangres, with 18 inches observed at Black Lake, just south of Angel Fire. Smaller accumulations were noted over the San Juan and Jemez Mountains, areas which did not have a Winter Storm Warning in effect. The RGS Snow-Cloud product from April 28 shows new snow cover across much of the north central high terrain. Snow over the San Juan and Jemez Mountains (west of the Sangres) likely accumulated prior to the SFR products above.
Low clouds and fog in the N. Gulf and Texas regions caused MVFR/IFR/LIFR conditions over a large area. The VIIRS Nighttime Microphysics RGB shows aqua to gray coloring to represent these features. In the RGB the scene is fairly complex with high and middle clouds (reds, blues, purples, tans …..). The RGB composite uses the traditional 11-3.9um difference (seen below) and combines other channels to better illustrate the low cloud features between the middle/high clouds. The RGB also improves the characterization of the thick, cold cloud tops associated with the cutoff low producing precipitation along the coast and southern states when compared to the simple 11-3.9um. Other “microphysical” RGBs are possible during the day or in a form that can be applied both day and night (i.e. 24hr product).
The MODIS RGB image below captured the dust event in portions of the Intermountain West today, April 14th, as strong winds lifted dust across the drought-stricken region. NWS offices in the region issued high wind warnings and dust storm warnings due to the conditions. Visibilities below one quarter mile in some instances were reported with portions of I 80 closed near Tooele, Utah. The dust is indicated by pinkish colored steaks across portions of Utah and Nevada in the Dust RGB below.
This pic was tweeted by Jed Boal of KSL5 TV in Salt Lake City.
Addendum… I just wanted to update with another image a little later on the 14th to show the evolution of the blowing dust. The area of dust ahead of the frontal boundary was diminishing by about 2030 UTC in Utah, while the large area of dust continued to impact portions of southern Nevada in strong northwesterly flow in the post-frontal airmass (image below).