G16-CH07_3.9_SWIR

Monitoring the Remnants of Ian from GOES-16

Posted by Kevin Thiel (CIWRO) on 10/03/2022
Posted in: G16-CH07_3.9_SWIR, G16-CH13_10.3_IR-Clean, Nighttime Microphysics RGB, SPC. Leave a comment

On Saturday October 1st the remnants of Hurricane Ian were moving northward through the Mid-Atlantic region, after making a second U.S. landfall the previous day in South Carolina. Overnight, the SPC was monitoring the final stages of Ian’s extra-tropical transition with a marginal threat for severe weather in the coastal North Carolina/Virginia region.

One forecaster on shift that night was monitoring the remnants from the perspective of GOES-16, and noted how various ABI products could be used to examine cloud layers and types in this dynamic environment.

CH7 shortwave and CH13/15 longwave IR shows mainly the cooler cloud tops associated with high-level clouds. Low-level clouds can be inferred by the warmer temps (CH7) or weaker grey features in CH13/15. However, the NtM [Nighttime Microphysics] RGB composite satellite data neatly contrasts colder, high-level clouds (western PA westward and in a warm conveyer belt over the Atlantic) from the lower but cool clouds (North Carolina into Virginia) and the very low, warm clouds (southeast Pennsylvania into New Jersey and Delaware). Though buoyancy is scant and severe is not expected in this area, the NtM RGB composite’s ability to contrast cloud types in this event demonstrates potential to identify important cloud features related to severe weather.

SPC Forecaster Comment

When overlaid with the RAP mesoanalysis field at 500 mb, the Channel-13 (Clean Longwave IR) and Channel-7 (Shortwave IR) bands from the ABI reveal the higher, cooler cloud tops north of the low into Pennsylvania. The warm conveyor belt over the Atlantic coast can be seen in the 500 mb RAP mesoanalysis with enhanced southerly winds east of low, and from the ABI infrared imagery with a lack of high clouds due to upper level subsidence.

Channel 13 (clean longwave IR) imagery of Ian’s remnants from the perspective of GOES-16. Overlaid with 500 mb RAP mesoanalysis data.
Channel 7(shortwave IR) imagery of Ian’s remnants from the perspective of GOES-16. Overlaid with 500 mb RAP mesoanalysis data.

While these bands individually can be used to point out these features, the forecaster notes that the Nighttime Microphysics RGB allows them to more readily identify and monitor these cloud features from the tropical cyclone remnants at night. This is driven by the RGB’s ability to combine information from multiple ABI bands (7, 13, and 15) to provide qualitative information for forecasters regarding cloud types and heights.

Nighttime Microphysics RGB imagery of Ian’s remnants from the perspective of GOES-16. Overlaid with 500 mb RAP mesoanalysis data.

Kevin Thiel, OU CIWRO

Prescribed Burns in Kansas

Posted by Bill Line on 04/11/2017
Posted in: ABI, Fires, G16-CH07_3.9_SWIR, Smoke, Uncategorized. Tagged: , , , , . Leave a comment

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.

KS_fire_anno

GOES-16 3.9 um IR (hottest temps) overlaid on 0.64 um VIS. Full resolution: https://satelliteliaisonblog.files.wordpress.com/2017/04/ks_fire_anno.gif

– Bill Line, NWS

“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.”

Atlantic Mesoscale Oceanic Low in late March 2017

Posted by Michael Folmer on 04/11/2017
Posted in: ABI, G16-CH07_3.9_SWIR, G16-CH08_6.2_WV-Upper-Level, G16-CH09_6.9_WV-Mid-Level, G16-CH10_7.3_WV-Low-Level, OPC, Uncategorized, Water Vapor Imagery. Tagged: , , , , . 4 Comments

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.

500mb_OPC_analysis

500 mb analysis valid 00 UTC 20 March 2017 issued by the Ocean Prediction Center.  Click here to open in a new window.

NAM_4km_slpwsp_201703

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.

G16_6p2_Hatteras_201703

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.

G16_6p9_Hatteras_201703

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.

G16_7p3_Hatteras_201703

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.

G16_3p9_Hatteras_201703

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.”