One of the fascinating aspects of GOES-16 is how much better the resolution is at higher latitudes, near the limb or edge of the footprint. Forecasters at the Ocean Prediction Center (OPC) noted how much easier it is to see the ice sheet (when clouds allow) and even the breaking up of this ice into groups of icebergs!
GOES-16 0.86 um “Veggie” channel depicting sea ice near eastern Canada (New Foundland is in the center of the image). *Preliminary, Non-Operational Data* Click to enlarge.
The 0.86 µm near-infrared “Veggie” channel animation above shows the ice swirling or drifting near Labrador and New Foundland. The 1-km resolution imagery is more resolved around 2 km at this latitude due to the, yet you can see amazing detail in the ice breaking up and moving around. Note: The imagery jump is due to GOES-16 ongoing testing during the beta period.
Aqua MODIS 0.86 um “Veggie” image of the ice “swirls” off the Labrador coast valid on 04/24/17. Click to enlarge
The Aqua MODIS image above shows a more nadir view of the ice swirls east of Labrador on 04/24/17. This image is higher resolution (1 km) than the GOES-16 animation above and provides great details that were not previously available to OPC forecasters.
The Iceberg Analysis from 04/24/17, shows the extent and number of icebergs that are being tracked this spring. According to this CBC News article, “about 450 icebergs near the Grand Banks of Newfoundland, up from 37 a week earlier, according to the U.S. Coast Guard’s International Ice Patrol in New London, Connecticut. Those kinds of numbers are usually not seen until late May or early June. The average for this time of year is about 80.” More than 600 icebergs have been spotted in shipping lanes that made the Titanic unfortunately, famous. A couple photos are included below.
So, we have all probably noticed that it has been cold lately. Well, due to the ample snow cover over much of the U.S. at this time, the baroclinic zone is sharpening over the lower Mississippi and Ohio River Valleys this afternoon with the aid of shortwave energy coming out of a cutoff low located over the Southwest U.S. One of the Ocean Prediction Center forecasters, Tim Collins, noted the strong contrast in temperature on either side of this zone in the RGB Air Mass image from MODIS below.
MODIS RGB Air Mass image of the strong baroclinic zone valid on 03/04/15.
Note the orange and purplish coloring to the north (above) of the moisture plume (cirrus, etc). This delineates the colder, drier air advancing south and east, while to the south (below) of the clouds there is a greenish coloring that denotes warmer mid-tropospheric air associated with a ridge of high pressure aloft over the Gulf of Mexico and Southwest Atlantic.
MODIS Water Vapor image to compliment the RGB Air Mass image valid on 03/04/15.
For contrast, the above image is the ~6.7 um water vapor channel from MODIS. Notice that north of the moisture plume you can see evidence of the lower tropopause and cold air by the relative smoothing noted in the image (lighter blue coloring due to the enhancement). To the south of the moisture plume, you can see the dry air at ~400-500 mb associated with the ridge over the Gulf of Mexico.
This baroclinic zone will continue to sharpen overnight and produce a significant snowstorm for many in the central and eastern US into tomorrow.
From September 20 through September 23, 2014, the Ocean Prediction Center (OPC) was monitoring the development of the season’s first hurricane-force extratropical storm in the East Pacific. Models were suggesting a marginal hurricane-force wind event would unfold well west of the Pacific Northwest, near 140W longitude, north of 40N latitude. OPC is routinely using satellite data to monitor and forecast these strong ocean storms. On this particular event, OPC forecaster James Kells collaborated with Michael Rowland and David Kosier on if and when to pull the trigger on the hurricane-force warning.
GOES-15 6.5 um water vapor animation showing the evolution of the hurricane-force low.
The above animation shows the evolution of the hurricane-force low, with an eye-like feature evident near the end of the loop. By 1200 UTC on the 23rd, it was forecast to develop hurricane force winds (64 knots or greater) just west of Oregon near 140W. During the production of the 1200 UTC OPC Surface Analysis, there was question of whether or not the winds had reached hurricane force intensity. The ASCAT pass from ~0600 UTC showed a large area of 50-55 knot winds in the strong cold advection south of the low center, and the GFS model indicated that the system was still developing. The GFS 0-30m boundary layer winds also indicated a very small area with hurricane force intensity.
Advanced Scatterometers A and B overlaid on GOES-15 Infrared imagery showing storm force winds at ~0600 UTC on 09/23/14.
The 1130 UTC MODIS RGB Air Mass product was timelier, and it showed an area of downward momentum south of the low with the deep purple shading. The corresponding water vapor image was less clear with upper level moisture obscuring the downward motion just beneath it. In addition, there were no surface reports south of the low center as there were no buoys moored nor drifting in that vicinity. Furthermore, most ships were aware of the danger and navigated away from the region neglecting the possibility of a surface report in the area of question.
Aqua MODIS RGB Air Mass image from 1130 UTC on 09/23/14.
A cross-section of the 1200 UTC 09/23/14 GFS model potential temperature and dew point temperature was taken through the low center in order to analyze the depth of the stratospheric intrusion, and also to gauge the magnitude of the downward momentum. It showed a deep stratospheric intrusion to roughly 500 hPa, and it corroborated the strong downward momentum indicated by the imagery. The RGB Air Mass image showed the intensity of the downward momentum through the red/purple coloring and gave a good indication of the stronger winds aloft mixing down toward the surface. The imagery increased confidence with classifying the system as a hurricane force low.
The 1200 UTC 09/23/14 GFS vertical cross-section of potential temperature and dewpoint showing the downward transport of drier air associated with the tropopause fold.
The spatial resolution of infrared (IR) polar imagery (e.g., Suomi NPP VIIRS and MODIS) is currently superior to similar geostationary data over North America (~1km vs 4km). Unfortunately, there are relatively few polar passes a day over the contiguous United States. At best, there would be 2 passes over any one location every 12 hours for each polar satellite. This is one reason why it is challenging to introduce operational forecasters to the advantages in using this imagery.
This will all change over the next year with the National Weather Service’s (NWS) second generation Advanced Weather Interactive Processing System (AWIPS2), and the use of polar imagery will become more and more common within NWS Forecast Offices. This is because AWIPS2 will allow the forecaster to overlay multiple images to create GOES/POES hybrid satellite loops.
In the image below, this capability is shown using IR imagery from GOES-13 (10.7 μm), MODIS (~11.0 μm), and Suomi NPP VIIRS (11.45 μm) between 0615 and 0801 UTC on 28 March 2014 over the Southern Mississippi Valley.
IR imagery from GOES-13 (10.7 μm), MODIS (~11.0 μm), and Suomi NPP VIIRS (11.45 μm) between 0615 and 0801 UTC on 28 March 2014 (click image to enlarge).
When polar imagery is available from MODIS or VIIRS, it is overlaid on the GOES imagery which allows the forecaster to take advantage of the greater spatial resolution of the polar imagery. In the example shown above, there are GOES-13 images at 0615, 0631, and 0645 UTC, followed by a VIIRS image at 0655 UTC, two more GOES-13 images at 0715 and 0731 UTC, a MODIS image at 0740 UTC, and one more GOES-13 image at 0801 UTC. As the forecaster cycles through the images, you can envision how this capability would be beneficial. The increased spatial resolution from MODIS and VIIRS allows important details to be extracted which include the location and strength of updrafts/overshooting tops and the location where new convection is forming on the southwestern flank of the MCS. In addition, when deep convection is present, the parallax (GOES pixels are displaced slightly poleward from their correct position) that occurs with geostationary satellites is magnified and the polar imagery “corrects” the location for the forecaster. To see the full impact of these hybrid images, click on the image for a full resolution version.
AWIPS2 is currently being installed at NWS forecast offices throughout the country. +
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).
For those living from NC up through NYC and parts of New England, last night turned quite windy behind the cold front. The thought was that the highest wind gusts would most likely occur with the squall line (possibly > 50 kts), then more general gusts to 40-45 kts (45-50 mph) behind the front with a rapid pressure rise. Not a bad forecast, but it was the post-frontal wind that wreaked the most havoc with many locations seeing wind gusts from 50-65 mph causing power outages, downed trees, and even some shingles blown off of buildings!
So what happened?! Was it purely pressure gradient force (+ 7 mb per hour behind the front)? Strong low-level jet? Stratospheric intrusion? Maybe a little bit of each.
GOES-Sounder RGB Air Mass product overlaid with METARs that include Temperature, Winds, Gusts, and Sky Coverage.
Although the above animation is grainy due to the ~8-10 km resolution of the sounder, I wanted to focus on the Mid-Atlantic and match up the red-coloring of the stratospheric intrusion with the wind speeds and gusts (12z 03/12/14 – 12z 03/13/14). The highest wind gusts occur as the stratospheric drying is moving into the Mid-Atlantic and are stronger than the winds seen through the mountains and points west (it was quite breezy though). I would speculate that the deep mixing in this dry layer prior to sunset was maintained as it crossed the Allegheny and Blue Ridge Mountains. Could the mountains have helped to maintain the deep vertical circulations that helped to transport the higher winds aloft to the surface? Most of the 60+ gusts occurred from 7-10 pm.
I’ve included some higher resolution MODIS images with the same obs to show off what GOES-R resolutions (2 km) would look like for this case.
MODIS Air Mass product with METARS overlaid valid at 1846 UTC on 03/12/14.
MODIS Air Mass product overlaid with METARs valid at 0235 UTC on 03/13/14.
MODIS Air Mass product overlaid with METARs valid at 0646 UTC on 03/13/14.
MODIS Air Mass product overlaid with METARs valid at 1609 UTC on 03/13/14.
Unfortunately, we didn’t get the best ozone retrievals produced by Dr. Emily Berndt (SPoRT) for this event, but I have included the 06 UTC 03/13/14 retrievals for a proof on concept. Notice the higher ozone moving towards the Mid-Atlantic, further supporting the stratospheric component to the red-coloring on the Air Mass product.
AIRS Total Column Ozone product valid at 06 UTC on 03/13/14. The warmer colors indicate > 250 Dobson Units of ozone, which is considered significant.
Overall, an impressive non-convective wind event that continued offshore (not shown). It may be possible to identify these events using the air mass before the first damaging winds occur. . .
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 will be a short post to update you on some incredible satellite imagery that is assisting forecasters today. Some of it is very new and due to some incredible hard work behind the scenes at CIMSS/SSEC University of Wisconsin-Madison and NASA SPoRT, we have these available for the blogs and some of it in operations at the Hydrometeorological Prediction Center, the Ocean Prediction Center, the NESDIS Satellite Analysis Branch, and the Hurricane Center. Thank you everyone for your help!
Suomi NPP VIIRS Day-Night Band (DNB) composite of Sandy courtesy of CIMSS/SSEC/University of Wisconsin-Madison valid on 10/29/12.
The Suomi NPP VIIRS Day-Night Band image above shows Sandy overnight with a “visible” like image thanks to our full moon. This same full moon is already aiding in the astronomical high tides on top of the storm surge and large fetch. At last report, Atlantic City is completely underwater by a few feet and chunks of boardwalk are destroyed up and down the NJ coastline.
GOES-14 SRSO of Sandy on 10/29/12 with GLD-360 1-min lightning overlaid courtesy of Vaisala. Click on image to animate.
The GOES-14 Super Rapid Scan Operations (SRSO) is running at the NCWCP today to assist the forecasters with 1-min imagery at 1 km resolution. This could help HPC, OPC, and SAB look for structural changes in Sandy as she makes her approach to shore this evening. Note the complete lack of cloud-to-ground lightning in the core of the storm, while you see occasional lightning strikes in the bands hundreds of miles to the east. This is definitely one of the larges storms I’ve seen in my relatively short career!
GOES-Sounder RGB Air Mass product valid at 15z on 10/29/12 courtesy of CIRA and NASA SPoRT.
Last week I started to describe some of the upper-level features that would play a role in moving Sandy towards the East Coast. Today, the red “L” indicates the approximate location of the upper-level low that is cutting off and moving Sandy towards the coast. The black “L” is Sandy and shows the proximity. The red area highlighted shows the dry, stratospheric air on the periphery of Sandy, but notice how there is no sign of that over the hurricane? Sandy has been able to re-attain its more tropical look which has led to significant deepening and increases in wind. This tool has been used at HPC to help with the placement and timing of the features when compared to model solutions.
MODIS RGB Air Mass product valid at 0709z on 10/29/12 which shows a much higher resolution image at ~2 km. Image courtesy of NASA SPoRT.
The MODIS RGB Air Mass product above shows a much higher resolution image of the Sandy-Upper-low interaction. I again show the approximate location of the upper-low with the red “L” and the outlined area is the dry stratospheric air and notice there is more than in the previous image. A full transition to extratropical will occur tonight, but that doesn’t matter anymore as Sandy’s effects are already being felt even in DC and Baltimore.
The AMSR-2 image showing heavy rain in the blue area.
In addition to S-NPP, NOAA JPSS will be providing global data from the new Japanese AMSR-2 sensor to NOAA operational users later next year. AMSR-2 is the follow-on to AMSR-E which is on NASA’s AQUA satellite but failed last year. AMSR-2 will provide many capabilities including instantaneous rainfall rates as it flies over. The figure above is the 89V channel of AMSR-E, the blue area is associated with the heaviest rainfall rates from Sandy. Thank you to Mitch Goldberg from JPSS for providing me with this description! Special thanks to Fuzhong Weng and his team for providing us with this outstanding image.
If you are on the East Coast, be safe! For everyone else, I’m not sure I will be able to post anymore blogs for a while on here. I am leaving the reigns in the hands of Amanda Terborg (Satellite Liaison at the Aviation Weather Center) and Chris Siewert (Satellite Liaison at the Storm Prediction Center) to keep you all updated.
I would also like to give a shout-out to the forecasters at HPC, OPC and NHC along with the satellite analysts at SAB for doing a spectacular job during this historic event. I hope everyone that reads this understands the amount of pressure that is on a forecaster when trying to relay information to the public about the severity of what we are seeing and will see tonight. Thank you!
Growing up on the Jersey shore, I would wonder whether it was ever possible for a hurricane to come in off the ocean and hit NJ head-on. Oh, my naive youth! I guess Sandy is about to show us that anything is possible!
Today’s post is more to show you some of the great tools we are using to help analyze the large-scale pattern interactions with Sandy. Please note that even though the latest NHC forecast philosophy calls for Sandy to become post-tropical (no longer considered a hurricane) about 120 miles off the NJ coastline, there will be winds close to hurricane strength near the NJ coastline, while farther inland hurricane force gusts are certain a good possibility!
GOES-14 visible imagery in super rapid scan operations (SRSO) with 1-min lightning overlaid courtesy of the Vaisala GLD-360.
The animation above (click on the image to open in a larger screen) shows us a special GOES-14 super rapid scan of Hurricane Sandy on 10/27/12 with 1-min lightning overlaid. Notice there is very little lightning and much of it is in the arcing band to the north and east of Sandy’s center. This imagery is being used at HPC and the Ocean Prediction Center (OPC) during this entire event to showcase future capabilities of GOES-R. This helps forecasters monitor convective trends near the core and outer bands as Sandy transitions to a hybrid storm.
For a longer loop, minus the lightning: http://tinyurl.com/955fvvd. Thank you to Timothy Schmidt from NESDIS STAR for providing the animation!
GOES-Sounder RGB Air Mass product with features highlighted valid at 20z on 10/27/12.
The GOES-Sounder RGB Air Mass product above continues the story-line I started a few days ago. The shortwave (upper-level low circled in red) that is responsible to tangling Sandy with the Mid-Atlantic is now diving southeast at a rapid clip. This low (red “L”) will continue east-southeast overnight and you can see the effects of its influence on Sandy by the fanning out of the upper-level clouds to the west-northwest. As this occurs, Sandy (black “L”) will first move north-northeast into tomorrow, before being captured by the aforementioned shortwave. I highlighted in the yellow-circle some obvious dry air (red-shading) in the Sandy’s eastern quadrant. This is indicative of significant drying at upper-levels, most likely associated with a stratospheric intrusion, which has assisted in the hybrid nature of Sandy.
Although not shown today, the blocking in the Atlantic is already causing a significant atmospheric traffic jam. The large ocean storm is still moving southeast and the upper ridge will block any possible escape of Sandy, therefore allowing this highly unusual northwest-west track into either DE or NJ.
The MODIS RGB Air Mass product valid at 1828z on 10/27/12.
The final image today is courtesy of the MODIS instrument on NASA’s AQUA satellite. This version of the RGB Air Mass product is much higher resolution than the GOES-Sounder version, but it is a polar orbiter, therefore you only get a few images a day. Notice the amount of red-shading wrapping around the eastern quadrant of Sandy (yellow-circle). This shows us that the tropical to extratropical transition is underway and with the added energy coming in from the west, we will likely see Sandy deepen further from its current 961 mb pressure. This means the winds could actually increase despite the classification!
Hopefully everyone along the Mid-Atlantic and southern New England have made their preparations. Conditions will go downhill starting tomorrow. Again, the main impacts will be high wind, heavy rainfall, severe coastal flooding (4-8 feet in spots along the Delmarva and NJ), and mountain snows! What a storm!
I will try to update the blog on Sunday morning. Thanks for reading!