Well, we are winding down the GOES-14 Super Rapid Scan Operations for GOES-R (SRSOR) for 2014 and we have seen three interesting tropical cyclone cases (Lowell, Marie, Cristobal), each unique in their own way. Hurricane Cristobal has more or less maintained intensity over the last two days and the lightning bursts have been very interesting to observe using the 2-min imagery overlaid on the SRSOR imagery. Today’s lightning activity, similar to yesterday, featured intermittent activity in the large band to the east and southeast of the hurricane. Meanwhile, additional thunderstorms developed near a pseudo-warm front feature to the northeast of the storm. I have included the OPC West Atlantic Surface Analysis for reference:
OPC West Atlantic Surface Analysis valid at 18z on 08/27/14.
Another interesting feature is the lightning bursting near the center of Cristobal, especially at the very end of the animation. A strong overshooting top is observed in the visible imagery and there is a quick uptick in concentrated lightning activity associated with that cell. A possible supercell? I think it’s possible and a sign that Cristobal is still entraining some dry air into the core. What other features can you identify?
GOES-14 SRSOR visible imagery with Vaisala GLD-360 2-min lightning density overlaid in 2-min increments. Animation is courtesy of James Kells (OPC). Click on the animation to expand in a separate window.
It’s a shame that we will not have additional SRSOR data this year, but Mother Nature has put on quite the show and it’s incredible how we can utilize our technology in new, inventive ways to assist forecasters.
As a reminder, GOES-R will launch in early 2016 and will contain a Geostationary Lightning Mapper (GLM) which will help in observing intracloud lightning as well as cloud-to-ground lightning.
For more information on the GOES-14 SRSOR, please visit: http://cimss.ssec.wisc.edu/goes/srsor2014/GOES-14_SRSOR.html
Another day of GOES-14 Super Rapid Scan Operations for GOES-R. . .another hurricane. Now, I know. . .Hurricane Cristobal is not a very photogenic hurricane, but during the course of the day, the storm has shown signs of better organization. One very noticeable feature has been the increase of lightning in the large, elongated band in the eastern quadrant. Over the last couple of hours, there has been a marked increase in lightning near the center of Cristobal. Could this be dry air intrusion? A sign of intensification? I’ll let you be the judge. The lightning data here is from the Vaisala GLD-360 lightning strikes, but is displayed as a 2-minute density product which was developed collaboratively among the Ocean Prediction Center (OPC), the National Environmental Satellite, Data, and Information Service (NESDIS) Center for Satellite Applications and Research (STAR), and the Cooperative Institute of Climate and Satellites (CICS) at the University of Maryland. The 2-min lightning density is time matched with the SRSOR in 2-min increments for a smooth (ish) animation.
GOES-14 SRSOR (feeds courtesy of CIRA and CIMSS) with Vaisala GLD-360 2-min lightning density overlaid. Thanks to James Kells (OPC) for creating the animation. Click on image to expand in another window.
While I have your attention, thanks to some quick work by Christopher Juckins and Frances Achorn of OPC, we now have a public, real-time version of the 30-min lightning density product overlaid on GOES-13 infrared imagery. Feel free to bookmark these pages for future use:
Much of the GOES-14 super rapid scan operations for GOES-R (SRSOR) has been spectacular, but maybe I’m biased. . .this morning’s sunrise of Hurricane Marie was spectacular! I overlaid the GLD-360 lightning feed on top of the 1-minute imagery (1 to 1) and noticed some interesting observations. For one, it was evident that the eye was slowly clouding over which was unfortunate. Also. . .all of the lightning activity (what little existed) was well to the northeast, closer to land. My question here. . .does this mean there was no lightning in Marie, such as intracloud? This is where the Geostationary Lightning Mapper (GLM) will be a very useful tool in the future. It is important to note that Marie was in a rather steady-state this morning, with a possible eyewall replacement cycle on the way. . .so this may account for no lightning strikes in the eyewall.
GOES-14 SRSOR with Vaisala GLD-360 lightning strikes overlaid. Special thanks to James Kells (OPC) for helping with this animation. (Click on animation to expand in another window)
This was one of those storms that people will talk about for years, especially those that were directly affected by it. It all started with three separate shortwaves that all phased together once off the Mid-Atlantic coast, far enough offshore to limit any direct effects save for some unusual late season snow and gusty winds the next day. The highest impact area included Cape Cod, Nantucket, Nova Scotia, and New Foundland. I’m sure any ships that were in the vicinity were not happy with this situation!
GOES-Sounder RGB Air Mass animation valid 03/24/14-03/26/14.
The evolution of the nor’easter can be seen in the GOES Sounder RGB Air Mass animation above. A southern stream system originating in the Gulf of Mexico moved east of Florida while two other shortwaves dropped southeast out of Canada. All of the pieces combined near the North Carolina coastline, but the explosive deepening took place as the combined system moved northeast away from the Mid-Atlantic. There appears to be a few stratospheric intrusions, but the most impressive intrusion occurs with the final shortwave as noted by the dark oranges and reds that appear at the end of the day on 03/25. When models are forecasting a phasing situation, this product can be quite useful in identifying the features and observing the stratospheric drying seemingly “bleed” from one shortwave to the other.
MODIS RGB Air Mass product valid at 1540 UTC on 03/26/14.
MODIS RGB Air Mass product with ASCAT winds overlaid valid at 1540 UTC on 03/26/14.
The two MODIS RGB Air Mass products above show the nor’easter near peak intensity. Notice how distinct the gradient between oranges and greens is in this image, almost as though you can see the upper portion of the frontogenesis, well behind the actual front. The intensity of the stratospheric intrusion is quite evident by the dark pinks near the center of the cyclone. The second image shows the wind field overlaid from ASCATB. Notice the large area of hurricane force winds (red wind barbs) near the bent-back front, in the comma-head of the cyclone. This area of wind affected parts of Southeast Massachusetts, including Nantucket where winds gusted from 60-85 mph. Nantucket recorded a wind gust of 82 mph and about 10″ of snow. Meanwhile, Nova Scotia bore the brunt of this beast with wind gusts of 129 mph at the Bay of Fundy and 115 mph in Wreckhouse. Waves were equally impressive with altimeter readings between 40-50 ft and a buoy report of 52.5 ft.
GOES-13 Infrared imagery with the GLD-360 30-minute lightning density product overlaid.
Another interesting aspect of this storm was the two distinct areas of thunderstorms that erupted. I overlaid the OPC and TAFB offshore zones for reference. Notice well east of the Bahamas there are possible supercell thunderstorms associated with the southern shortwave energy. Meanwhile, as the strong northern stream shortwaves exit the NC coastline, two areas of thunderstorms developed with the easternmost storm exhibiting supercell characteristics. Although the lightning was not as intense with this northern area, I would speculate that the storms were associated with very strong wind gusts due to the dry air associated with the stratospheric intrusion.
VIIRS Visible image valid at 1719 UTC on 03/26/14.
VIIRS Visible image with the 18 UTC OPC surface analysis overlaid.
I’ll finish this entry with two VIIRS Visible images above showing the majestic beauty of this nor’easter. The 18 UTC OPC surface analysis depicts the storm at a maximum intensity of 955 mb, after a 45 mb drop in 24 hours! This qualifies as one of the most explosive cyclones on record. Another tidbit. . .this was the strongest storm in this part of the Atlantic since Hurricane Sandy (2012).
Well, it’s February and it’s the East Pacific off of California, so the short answer is no. But. . .what an amazing structure, right? We haven’t seen anything this good looking in the tropical Atlantic in years! But I digress. . .
MODIS RGB Air Mass product valid at 0621 UTC on 02/28/14. The blue lines are the boundaries of OPC (north), TAFB (south), and Hawaii (west)
MODIS RGB Air Mass product valid at 1032 UTC on 02/28/14.
The first image was collected four hours before the second image and you can see how the center of the intense storm developed an “eye-like” feature (images courtesy of NASA SPoRT). Notice the distribution of the pinks and reds in both images as well. That is dry, stratospheric air filling the center of the strong upper-level low (~300-500 mb). The second area shows an additional area of pink approaching the southern California coast. This area is associated with strong instability that has led to rare California thunderstorms.
So, how do we know if there is stratospheric air?
AIRS Total Column Ozone product valid at 2200 UTC on 02/27/14.
AIRS Ozone Anomaly Product valid at 2200 UTC on 02/27/14.
The first image above is the AIRS Total Column Ozone product developed at NASA SPoRT. The color bar on the left is not correct. The main idea is that the warmer (cooler) the colors, the more (less) ozone is in the atmospheric column. The green colors indicate ozone levels above 200 Dobson Units (ozone unit of measurement) with the magenta areas indicating ~500 Dobson Units. The second image shows the AIRS Ozone Anomaly product with the first level of blue indicating 125% of normal, while the yellow region indicates >200% of normal ozone at that latitude and geographic location. Stratospheric air is associated with high levels of ozone and potential vorticity which can help identify the strength of the upper-level low. These images show the connection of this ozone pocket with the “reservoir” of ozone located in the northern latitudes at this time of year.
AIRS Total Column Ozone Product valid at 1000 UTC on 02/28/14.
AIRS Ozone Anomaly valid at 1000 UTC on 02/28/14.
As the upper-low cut off and became stacked over the surface low (~971 mb), you can see how the high concentration of ozone becomes more focused over the storm. Once again, the magenta coloring indicates ozone levels >500 Dobson Units. The anomalies are more incredible with a large area of >200% of normal directly west of southern California.
I will continue to work with forecasters at OPC, TAFB, SAB, and WPC on discovering ways to use these products in conjunction with the RGB Air Mass products to gauge storm strength and look for signals upstream of developing tropopause folds and stratospheric intrusions.
GOES-15 Visible imagery with the GLD-360 30-minute lightning density product overlaid.
The ozone isn’t the only impressive part of this storm. Notice the occasional bursts of lightning within the spiral bands of the parent storm. Although not completely unusual, this is a great indicator of how much energy is available to this storm.
GOES-Sounder RGB Air Mass product with GLD-360 lightning strikes overlaid.
I put together a longer animation of the GOES-Sounder RGB Air Mass product with the GLD-360 lightning strikes overlaid. Note the first system that came ashore in California earlier this week, then moved over the four-corners regions with plenty of lightning, especially for this time of year. The current storm is seen lurking offshore with more lightning developing in a band of thunderstorms that moved from Los Angeles to just north of San Diego. This system will be responsible for the next bought of winter weather for the Midwest to the Mid-Atlantic next week.
Thanks for reading and as always, feel free to contact me with questions and feedback!
This is just a quick post to show how dynamic our Mid-Atlantic to New England snowstorm was this past week. While areas from Virginia up through Massachusetts saw a high snow-to-liquid ratio snowfall due to very cold temperatures, the Gulf Stream saw thunderstorms ignite as all that upper-level energy and strong temperature gradients (air and ocean) interacted. There were two waves, the first one produced more discrete cells in the northern OPC offshore zones and appears to have been initiated by a small shortwave embedded in the southwest flow. The second area of convection was ignited by the strong shortwave that exited the NC coast. There was even a brief period of low-topped convection near the low center as it went through the central zones. These storms were then followed by strong winds as the front raced east.
The animation below (click on the image to enlarge) shows the GLD-360 lightning density product overlaid on GOES-13 Infrared imagery during the systems transition from land to ocean.
GLD-360 Lightning Density (30-minute accumulation) overlaid on GOES-13 Infrared imagery.
During the past 24 hours, we have had the special privilege to ingest 1-min satellite data from GOES-14 as part of a Super Rapid Scan Operations for GOES-R (SRSOR) demonstration. The emphasis has been on the thunderstorm complexes that developed over the Upper Midwest on Wednesday afternoon and moved towards the Mid-Atlantic. I have put together two animations below with two different lightning product overlaid to shows the difference between cloud-to-ground strikes and cloud-to-ground density plots.
GOES-14 SRSOR overlaid with the GLD-360 cloud-to-ground lightning strikes (click on image to animate).
GOES-14 SRSOR overlaid with the 2-min GLD-360 Lightning Density (click on image to animate).
Notice how the lightning density provides more information on the intensity of the updrafts, while that signal gets flooded out by all the pluses and minuses in the previous image. Although having the SRSOR is a special, temporary privilege, GOES-R will allow for this as part of a regular routine. When you couple high resolution (temporal and spatial) satellite imagery with the high temporal resolution of lightning data, forecasters will be able to gain an edge on severe weather forecasting. This could assist in earlier warnings and less false alarms in the future.
I will try to post more examples of today’s severe weather tomorrow.
Well, that didn’t take long. . .a week ago we were enduring the wrath of tornadoes through the Plains and Midwest and this week the tropics, not wanting to be out-done, decided to chip in. Tropical Storm Andrea formed late yesterday and has decided to make an early visit to Florida.
I wanted to continue the theme of showing off the capabilities of the Overshooting Top Detection and Lightning Density products that forecasters at the Satellite Proving Ground for Marine, Precipitation, and Hazardous Weather Applications are evaluating. Andrea has put on an interesting show today as you’ll see below.
The Overshooting Top Magnitude Product overlaid on GOES-14 Infrared imagery valid on 06/06/13 (click on image to animate).
The Overshooting Top (OT) Magnitude product (developed by Kris Bedka – SSAI) has been getting quite a workout today over the Gulf and near-shore waters of Florida. Many of the OTs have exhibited a 9-15 degree difference between the OT and the cirrus shield. One OT from early in the loop nearly exceeds the scale I set for the product! Notice how most of the strong OT signatures are seen over water with very few over land in this case. Although wind is expected with a tropical cyclone, these OTs may indicate localized areas of enhanced wind gusts that mariners would have to be made of aware of, even being far from Andrea’s center.
The experimental GLD-360 Lightning Density product overlaid on GOES-14 Infrared imagery valid on 06/06/13 (click on image to animate).
The new experimental GLD-360 Lightning Density product has been very revealing today as it helps to contrast the difference between lighting activity associated with a tropical system and activity associated with continental thunderstorms. Notice how the lighting activity with Andrea starts out relatively quiet, but increases as a squall line develops northwest of Cuba and the Keys. Even so, the lightning activity is not overly impressive as this is 30-minutes of binned lighting strokes. The thunderstorms near the center of Andrea are practically absent of lightning during this entire animation. Meanwhile, the thunderstorms over Louisiana and Texas show very intense lightning activity near the end of the loop.
Pop quiz: why the contrast?
Finally, my email was greeted by some beautiful imagery of Andrea from overnight courtesy of William Straka III from CIMSS at the University of Wisconsin. I have included a couple of these images below for your enjoyment.
Andrea as seen on from the Day-Night Band from VIIRS on the Suomi-NPP satellite valid at 0726 UTC on 06/06/13.
This image from the Day-Night Band on VIIRS is very cool as you are seeing the cloud pattern associated with Andrea with very low amounts of atmospheric light known as “air glow”. The bright spots on the Florida peninsula are the city lights. It’s amazing that even with minimal light, you can still get a feel for the vertical dimensions of the clouds.
Enhanced Infrared imagery from the Suomi-NPP satellite valid at 0726 UTC on 06/06/13.
This enhanced infrared image (375 m resolution) from VIIRS of Andrea says it all!
The last two weeks have featured some rather remarkable weather that has ranged from morning lows around freezing, high temperatures soaring way above 100, and unfortunately, some deadly tornadoes. As part of the Satellite Proving Ground at the NOAA Center for Weather and Climate Prediction (NCWCP), we are currently demonstrating some products that will help with diagnosing and forecasting convection. The Overshooting Top Detection (OTD) is the first product that forecasters are evaluating and in the next few months, we will introduce a new lightning density product (see earlier post on the first spring MCC) that utilizes the Vaisala GLD-360 lightning feed to create a density plot of lightning strikes.
As many of you know, the evening of 05/15 brought some very severe weather to the Dallas-Fort Worth metro with at least one EF-4 and one EF-3 tornado in the southwest suburbs. These storms were part of a larger scale system that was rotating through Oklahoma and the two products mentioned above provided some very interesting and useful information about these storms.
GOES-13 Infrared satellite image with the Overshooting Top Magnitude product overlaid valid at 0102 UTC on 5/16/13.
The image above was taken approximately four minutes before the first report of this eventual EF-4 tornado touched down in Granbury, TX. The Overshooting Top Magnitude product adds more information to the overshooting top (OT) associated with this supercell thunderstorm than just the fact that it exists. The OT is approximately 9-11 degrees Celcius colder than the surrounding cirrus of the anvil. This could indicate the potential for large hail and in this case, a precursor to the tornado. Typically, the severe weather occurs between 5-30 minutes after the time of the OT detection.
2 km Mosaic Base Reflective Radar valid at 0104 UTC on 05/16/13.
This radar image compliments the satellite image above and is valid approximately 2 minutes before the tornado report was received. The two supercells highlighted are the tornado producing storms west-northwest of Fort Worth, TX. The southernmost supercell is responsible for the OT seen in the satellite image. Although I cannot say with absolute confidence that the OT Magnitude product would have given a strong indication of a potential EF-4 tornado, it did provide information on the most intense updrafts associated with these storms.
n GOES-13 Infrared satellite imagery with the Vaisala GLD-360 Lightning Density product overlaid valid at 0115 UTC on 05/16/13.
The new Vaisala GLD-360 Lightning Density product that has been developed as a coordinated effort with the Ocean Prediction Center (OPC), NESDIS STAR, and the Cooperative Institute for Climate and Satellites (CICS) did a great job of showing the highest concentration of cloud-to-ground (CG) lightning strikes associated with the thunderstorms about 9 minutes after the tornado report was received. Notice how the two lightning cores are as distinct in this image as the radar image above! This algorithm takes all of the individual CGs (positive and negative) and bins them into 2-minute, 15-minute, and 30-minute lightning density plots. The above image is a 30-minute accumulation of CGs, scaled. The purpose of this product is to simulate the capabilities of the upcoming Geostationary Lightning Mapper (GLM) that will be on GOES-R and is a compliment to the Pseudo-GLM product that is being developed and provided by NASA SPoRT and the University of Alabama-Huntsville.
GOES-13 Infrared satellite image with the Overshooting Top Magnitude product overlaid valid at 0232 UTC on 05/16/13.
Another interesting caveat of this severe weather event was this unusually strong OT Magnitude signal observed at 0232 UTC. The OT Magnitude exceeded the scale I created for the product with an OT that was greater than 18 C colder than the surrounding cirrus anvil! I’m sure there was significant hail in this area at this time!
*I created animations of the above mentioned products for this event which you can access at the bottom of this post. Just click on the images and the animation should run on a separate window.*
A Supercell Thunderstorm over the Gulf Stream?!
In the early morning hours of 05/16, another supercell formed nearly 1800 miles to the east-northeast over the Gulf Stream, east of the Mid-Atlantic. As a thunderstorm crossed the north wall of the Gulf Stream, it quickly intensified around 08 UTC into a supercell as it moved east over very warm waters. Although not a threat to anyone, the storm was located over shipping lanes and there was a ship located just northeast of the storm during maximum intensity. As you look at the images below, I want you to think about this question: If you observe similar structures and similar lightning patterns to the TX case, and have no radar, is it possible that this supercell was producing large hail, torrential rainfall, microbursts, or even a large waterspout?
GOES-13 Infrared satellite image with the Overshooting Top Magnitude product overlaid valid at 0802 UTC on 05/16/13.
The image above shows the OT Magnitude product indicating an OT that is approximately 16-17 C colder than the surrounding cirrus! This is very intense for a maritime thunderstorm and indicates this storm most likely exhibited a supercell structure. One of the OPC forecasters noted that this is the most intense thunderstorm he has witnessed over the Atlantic offshore zones in a long time.
GOES-13 Infrared satellite imagery with the Vaisala GLD-360 Lightning Density product overlaid valid at 0815 UTC on 05/16/13.
Once again, the GLD-360 Lightning Density product shows a very intense core of CG lightning strikes co-located with the OT indicated above. It actually appears the lightning was more intense in this supercell than what was observed over TX a few hours earlier.
One of the OPC forecasters had this to say about using these product for his operations:
“I used the overshooting cooling product to help determine the intensity of the supercell, whether [it] was exhibiting a weakening or strengthening trend. In the afternoon I used the overshooting cooling product to support adding higher winds in thunderstorms to the offshore forecast in developing convection over this same offshore zone. The product also validated the very high lightning density data seen with these thunderstorms.”
Once again, I have created animations of this event below for your convenience. Think about the question above when you look at the animations and I encourage you to leave comments or questions as this could lead to interesting discussion. I think these two events provide an interesting comparison and it might be feasible to use these products for maritime convection to warn recreational boaters, military ships, and cargo vessels of potential severe maritime convection. The OPC and Tropical Analysis and Forecast Branch (TAFB) will continue to evaluate these products through the summer as part of the GOES-R Proving Ground activities.
GOES-13 Infrared and OT Magnitude animation valid on 05/16/13. (Click on the image to animate)
2 km Mosaic Base Reflective Radar animation valid on 05/16/13. (Click on image to animate)
GOES-13 Infrared and Vaisala GLD-360 Lightning Density product animation valid on 05/16/13. (Click on image to animate)
GOES-13 Infrared and OT Magnitude product animation valid on 05/16/13. (Click image to animate)
GOES-13 Infrared and Vaisala GLD-360 Lightning Density product animation valid on 05/16/13. (Click on image to animate)
The Satellite Proving Ground at the NOAA Center for Weather and Climate Prediction (NCWCP) and the National Hurricane Center (NHC), has begun the next round of GOES-R proxy product demonstrations. The 2013 theme is on convective products that include the NSSL WRF and NAM simulated satellite imagery, the overshooting top detection, lightning density product, and convective initiation. The first wave of products will focus on the first two products, but I am testing and archiving the new lightning density product that has been developed by a collaborative effort with the Ocean Prediction Center (OPC), the Cooperative Institute for Climate and Satellites (CICS), and NESDIS STAR using the Vaisala GLD-360 lightning feed at the NCWCP.
GLD-360 Lightning Density product overlaid on GOES-13 infrared imagery valid on 04/03/2013.
After a cold end to winter and a very slow start to spring, thunderstorm season started with a bang the last few days. In particular, a cluster of thunderstorms developed over southeast TX on Tuesday night and proceeded to drop substantial hail (~3.5″ diameter) in Galveston County. The image above shows the lightning density product with the most intense convective cell that produced the large hail. Notice how the color scale does not go high enough to emphasize the intense amount of lightning (cloud-to-ground) with that cell.
GLD-360 Lightning Density animation of the 04/03/2013 MCC evolution.
The entire event is highlighted in the above animation (30-minute bins to match the 30-minute GOES-13 infrared imagery) as the clusters of thunderstorms over TX transfer energy to the Gulf of Mexico. As this new cluster of thunderstorms intensifies, it meets the qualifications to be designated a mesoscale convective complex (MCC) and even included a mid-level mesoscale convective vortex (MCV) that traveled just south of the northern Gulf coast. A wake low formed near the MS/AL coastlines and produced winds that exceeded 50-60 mph in spots. While this was going on, notice how intense (dense) the lightning activity is in the southern portion of the MCC as the complex continually evolves.
GLD-360 Lightning Density 2-minute increment animation of the renegade supercell on 04/03/2013.
Finally, a renegade, elevated supercell thunderstorm formed over old Mexico and paralleled/straddled the Rio Grande River to a point just west of Brownsville. I created the above animation with a 2-minute increment to showcase the short-term evolution of this supercell. . .using lightning!!!
I expect to show off more lightning density cases as we move through severe weather season into hurricane season. One major advantage to having this product in operations at the NCWCP and NHC is that forecasters will be able to monitor the relative strength of convection over maritime and mountainous regions that lack convectional radar coverage. This product coupled with the OTD product (a separate post in the making) will continue to assist forecasters in the Proving Ground!