On the morning early of 04/06/17, TAFB forecasters noted a nice V-pattern to convection at the tail end of a front in the northeast Gulf of Mexico. The increased temporal and spatial resolution of GOES-16 compared to the GOES-13 (east) provided more details on the organization and maintenance of the convective line that would otherwise have been analyzed.
GOES-16 0.64 um “Red” visible animation showing strong convection in the eastern Gulf of Mexico, valid 0900 UTC – 1600 UTC on 04/06/17. *Preliminary, Non-Operational Data* Click to Enlarge
Hugh Cobb (TAFB Branch Chief) noted: “We also looked at the Red VIS Band 2 for this event. The VIS imagery was more striking in that you could see the shadows of the high cirrus cast on the lower cloud deck in the animation and the “beavertail” of of the low clouds feeding into and maintaining the deep convection.”
GOES-16 10.3 um “Clean” infrared animation (same as above), valid from 0900 UTC – 1600 UTC on 04/06/17. *Preliminary, Non-Operational Data* Click to Enlarge
GOES-16 10.3 “Clean” infrared imagery with 5-minute GLD-360 lightning density overlaid, valid 0900 UTC – 1600 UTC on 04/06/17. *Preliminary, Non-Operational Data* Click to Enlarge
Jorge Aguirre-Echevarria (TAFB Forecaster) noted that “the striking cloud/convective signature and associate lightning activity observed that day over the waters of the far southern Gulf of Mexico.” In particular, these events are rather rare at such a low latitude in the TAFB Offshore Zones. The GOES-16 10.3 μm infrared imagery proved to be very helpful in seeing the overshooting tops and the cold cloud canopy temperatures which signified the activity would persist west of Key West, FL.
Strong thunderstorms erupted on the evening of 04/28/17 and continued into the overnight, expanding in coverage and producing prolific lightning in spots. The Weather Prediction Center’s Metwatch Desk was particularly busy issuing multiple Mesoscale Precipitation Discussions (MPD) to stay ahead of the flash flood threat.
WPC MPD #0150 issued by forecaster, Greg Gallina, at 0015 UTC on 04/28/17. Click to enlarge
NWS Forecaster, Greg Gallina, indicated the following:
“GOES-16/EAST WV LOOP SHOWS A RELATIVELY FLAT SHORTWAVE ACROSS NW OH WITH THE TRAILING TROF SW ACROSS CENTRAL IND/IL WITH A MCS TRACKING ACROSS CENTRAL IND. THIS MCS IS AT THE APEX OF SOUTHWESTERLY LOW LEVEL JET/WAA REGIME OVERRUNNING A WARM FRONT THAT EXTENDS FROM LWV…N OF LOU AND S OF CVG. THIS COMPLEX HAS BEEN PRODUCING 1.5-2.5″ RAIN AS IT TRACKED THROUGH WEST CENTRAL IND…AND WILL LIKELY MAINTAIN AS IT CROSSES INTO LOWER FFG VALUES ACROSS SE IND/SW OH IN THE NEXT HOUR OR SO.”
GOES-16 6.9 um “mid-level” water vapor animation valid from 1800 UTC – 2357 UTC on 04/28/17. *Preliminary, Non-Operation Data*Click to enlarge
As Greg mentioned, GOES-16 6.9 μm “mid-level” water vapor imagery shows a relatively flat shortwave aiding in the maintenance of the Mesoscale Convective System (MCS) over Indiana and Ohio, while a stronger shortwave can be seen moving out of Iowa into southeastern Minnesota. What other features can you identify in this animation?
GOES-16 1-minute 0.64 um “Red” visible animation valid from 2130 UTC 04/28/17 to 0059 UTC 04/29/17. *Preliminary, Non-Operational Data*Click to enlarge
The GOES-16 1-minute 0.64 μm “Red” visible animation shows the incredible detail in the cloud top environment (0.5 km resolution) of the aforementioned MCS moving through Indiana and Ohio. Note the persistent overshooting tops and their subsequent gravity waves rippling across the cirrus shield. This is indicative of healthy, organized updrafts which a forecaster can then make a decision on whether the activity will persist, strength, or weaken with time.
GOES-16 1-minute 10.3 um “Clean” infrared animation valid from 2130 UTC 04/28/17 to 0259 UTC 04/29/17. *Preliminary, Non-Operational Data*Click to enlarge
Once again, the 1-minute imagery proves valuable here as the trend of the cold cloud tops can be seen expanding with the MCS, while new convection fires near the Illinois, Kentucky, and Indiana borders. Note the dark pixels indicating very cold overshooting tops. Can you spot the enhanced-V structures down-stream from those towers?
WPC MPD #0151 issued by forecaster, Andrew Orrison, at 0300 UTC on 04/29/17. Click to enlarge
As noted by NWS forecaster, Andrew Orrison:
“EXPERIMENTAL GOES-16 IR IMAGERY CONFIRMS THAT CONVECTIVE INITIATION IS UNDERWAY IN AN ELEVATED FASHION ACROSS AREAS OF SOUTHERN MO…FAR NORTHWEST AR AND PARTS OF EASTERN OK. A STRENGTHENING AND VERY MOIST LOW LEVEL JET COUPLED WITH GRADUALLY IMPROVING RIGHT-ENTRANCE REGION JET DYNAMICS IN VICINITY OF A WELL-DEFINED QUASI-STATIONARY FRONTAL ZONE SHOULD FACILITATE A SW/NE AXIS OF STRONG THUNDERSTORMS WITH INTENSE RAINFALL RATES OVER THE NEXT FEW HOURS.”
GOES-16 CONUS (5-minute) 10.3 um “Clean” infrared imagery with the 5-minute GLD-360 lightning density product overlaid, valid from 2130 UTC 04/28/17 to 0256 UTC 04/29/17. *Preliminary, Non-Operational Data*Click to enlarge
The ongoing MCS in the above GOES-16 10.3 μm “Clean” infrared animation with GLD-360 5-minute lightning density overlaid appears to weaken a bit as new convection farther southwest takes advantage of a stout low-level jet. Notice how the lightning cores are exceeding the color scale that was set by the developers at OPC and NESDIS. Grant it, the color scales are somewhat limited by the GEMPAK software (6.5 bit or 96 colors), yet it’s safe to assume the lightning activity is very intense.
WPC MPD #0154 issued by forecaster, Andrew Orrison, at 0500 UTC on 04/29/17. Click to enlarge
Finally, around 0500 UTC on 04/29/17, Andrew Orrison again referenced GOES-16 in his analysis of the well-defined (new) MCS which developed overnight:
“THE SATELLITE PRESENTATION OF THE CONVECTION IS VERY IMPRESSIVE WITH THE EXPERIMENTAL GOES-16 10.3 MICRON/IR IMAGERY DEPICTING A VERY LARGE AREA OF VERY COLD CONVECTIVE CLOUD TOPS…REACHING NEARLY -80C…WITH NUMEROUS OVERSHOOTING TOPS EMBEDDED WITHIN THE CONVECTIVE MASS. THIS IS INDICATIVE OF VERY STRONG FORCING WHICH IS ENHANCED NOT ONLY IN THE LOW LEVELS GIVEN THE LOW LEVEL JET AND ISENTROPIC ASCENT…BUT ALSO BROADLY DIFFLUENT FLOW ALOFT ASSOCIATED WITH RIGHT-ENTRANCE REGION JET DYNAMICS.”
GOES-16 CONUS (5-minute) 10.3 um “Clean” infrared animation valid from 2202 UTC 04/28/17 to 0857 UTC 04/29/17. *Preliminary, Non-Operational Data*Click to enlarge
As Andrew referenced in his MPD, as the night progressed, the convection along the Midwest through Ohio Valley erupted into an elongated MCS with embedded Mesoscale Convective Vortices (MCVs) that will have to be watched later in the day.
WPC Day 1-3 QPF issued at 2040 UTC on 04/28/17 and valid from 0000 UTC 04/29/17 to 0000 UTC 05/02/17. Click to enlarge
As you can see in the above Quantitative Precipitation Forecasts for Day 1 (top) and Days 1-3 (bottom), this was only the beginning of a prolonged flood threat for the Mid-Mississippi Valley and eventually farther north to western Michigan.
GOES-16 is certainly proving to be useful in operations as the increased temporal and spatial resolutions when compared to GOES-E (13) and GOES-W (15), provides more detail, fluidity, and trend monitoring to assist in the forecast decision-making process. Additional channels, multispectral imagery (RGBs), band-differences, and derived products will be explored throughout 2017, so please stay tuned for more posts!
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.
North American Ice Service Iceberg Analysis for 04/24/17. Click to enlarge
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.
Traffic camera view of contrails from Mesa, AZ, courtesy Arizona Department of Transportation. Full Resolution
Top-Left: Red Band (Ch 2, 0.64 um); Top-Right: Cirrus Band (Ch 4, 1.38 um); Bottom-Right: Snow/Ice Band (Ch 5, 1.61 um); Bottom-Left: Mid-Level Water Vapor (Ch 9, 6.9 um). *Preliminary, Non-Operational Data* Full Resolution
This morning there were a lot of contrails evident on the GOES-16 data. Looking at the VEF 12Z 10 APR 2017 sounding (see below), conditions look good for them – lots of high-level moisture. From this, we expect most of the contrails to be in the 200-300 mb (which is around a cruising altitude of ~30,000 ft).
Of course we can’t see the contrails until the sun comes up in the visible and near-IR bands. However, using the different water vapor bands, we can still see them (the improved resolution helps too!). Using this website to learn about weighting functions, we can get a general idea of the level at which the weighting function for each water vapor channel peaks. Since contrails are typically located high in the troposphere, they will appear similarly visible in all three water vapor channels. In other words, most water vapor absorption for the three water vapor channels (see weighting functions below) takes place below the level at which a typical contrail will be located. The 7.34 um channel will be slightly better than the other two water vapor channels at detecting upper level cloud features such as contrails since it is the least sensitive to water vapor absorption.
GOES-16 ABI for Ch 8 (Upper-Level Water Vapor, 6.2 um)
GOES-16 ABI for Ch 9 (Mid-Level Water Vapor, 6.9 um)
GOES-16 ABI for Ch 10 (Low-Level Water Vapor, 7.3 um)
Once the sun does come up, we can use our other bands. In this loop, I have the Red Band (Ch 2, 0.64 um) in the top-left, the Cirrus Band (Ch 4, 1.38 um) in the top-right, and the Snow/Ice Band (Ch 5, 1.61 um) in the bottom-right. First thing I notice is that the contrails don’t show up the best in the Red Band, the Cirrus band pops them the best. According to the GOES-R ABI Fact Sheet for the Cirrus Band,
The “cirrus” near-infrared band at 1.37 μm will detect very thin cirrus clouds during the day. This band is centered in a strong water vapor absorption spectral region. It does not routinely sense the lower troposphere, where there is substantial water vapor, and thus provides excellent daytime sensitivity to high, very thin cirrus under most circumstances, especially in warm, moist atmospheres.
Thus the high-clouds pop against a muted background of the lower troposphere. If you watch this loop, you can also see the contrails increase in abundance as we progress from 12Z through 1530Z. That is due to the increase in air traffice, which is confirmed with this loop (from Planefinder.net).
“The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. Users bear all responsibility for inspecting the data prior to use and for the manner in which the data are utilized.”
Prescribed burns lit up GOES-16 imagery on April 11 in the eastern half of Kansas. The 2 km 3.9 um IR channel shows an abundance of hotspots across the region during the day. The 0.5 km 0.64 um visible channel reveals widespread smoke. Ozone alerts were issued for parts of Kansas given the increased particulate matter in the air.
“The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. Users bear all responsibility for inspecting the data prior to use and for the manner in which the data are utilized.”
During the overnight hours of March 19-20, 2017, an amplifying upper level shortwave moved off the Mid Atlantic coast and led to the rapid development of a mesoscale oceanic cyclone across the Gulf Stream east and southeast of Cape Hatteras. The upper level feature moved south and southeast along the backside of a deep upper level long wave trough near 68W. The global models including the GFS and ECMWF were not well initialized with the upper level shortwave and consistently, over the previous several model runs, were only indicating a weak trough would develop at the surface. Conversely, the 4km NAM and HRRR were each showing surface low development and significantly higher associated surface winds than shown by the coarser global models. OPC forecasters had been carrying storm warnings across a few offshore zones through 00 UTC March 20, 2017.
Animation of the 20 March 2017 00 UTC 4 km NAM pmsl and surface winds. Yellow boundaries delineate the OPC offshore forecast zones. Click here to open in a new window.
The GOES-16 water vapor imagery, including the 6.9 um mid-level and 6.2 um upper-level, suggested that the mid/upper shortwave was more amplified than initialized by the global models. The feature was also apparent in the GOES-16 7.3 um lower-level water vapor imagery, indicating it may be vertically stacked or at least extend through the lower levels. The three water vapor channels alone indicated there was likely adequate forcing through the upper and mid levels, and even into the lower levels, to support the development of a surface low. However, the low level circulation analyzed in the GOES-16 3.9 um shortwave infrared imagery confirmed the presence of the surface low. In addition, the enhanced baroclinicity the system encountered as it tracked across the Gulf Stream likely played a big role in the storm’s intensification. The sea surface temperature (SST) gradient along the north wall of the Gulf Stream can be seen in the GOES-16 3.9 um shortwave infrared animation.
GOES-16 6.2 um upper-level water vapor animation valid 2102 UTC 19 March 2017 – 0902 UTC 20 March 2017. *Preliminary, Non-Operational Data* Click here to open in a new window.
GOES-16 6.9 um mid-level water vapor animation valid 2102 UTC 19 March 2017 – 0902 UTC 20 March 2017. *Preliminary, Non-Operational Data* Click here to open in a new window.
GOES-16 7.3 um lower-level water vapor animation valid 2102 UTC 19 March 2017 – 0902 UTC 20 March 2017. *Preliminary, Non-Operational Data* Click here to open in a new window.
GOES-16 3.9 um shortwave infrared animation valid 2102 UTC 19 March 2017 – 0902 UTC 20 March 2017. *Preliminary, Non-Operational Data* Click here to open in a new window.
Upon reviewing the GOES-16 imagery and evaluating the most recent model guidance, the overnight OPC forecaster extended the storm warning through the night period, and also expanded the warning to include the outer mid Atlantic offshore waters. The significantly improved temporal and spatial resolution of the GOES-16 imagery, along with the additional water vapor channels, allowed forecasters to better diagnose the strength of the upper level shortwave and also, the presence of the surface low, which then gave forecasters more confidence in amending the warnings. Even as the both the upper level feature and the surface low appear to shear and weaken in the three GOES-16 water vapor channels and 3.9 um shortwave infrared band around 06 UTC, there was a ship which reported gale force winds (35 kt) at 06 UTC well southwest of the surface low.
Thanks for reading!
James Clark (OPC) and Michael Folmer (CICS)
“The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. Users bear all responsibility for inspecting the data prior to use and for the manner in which the data are utilized.”
