Heavy rainfall and high-elevation snowfall in Hawai’i

December 2nd, 2016

GOES-15 Water Vapor (6.5 µm) images, with overlays of GFS model 500 hPa geopotential height [click to play animation]

GOES-15 Water Vapor (6.5 µm) images, with overlays of GFS model 500 hPa geopotential height [click to play animation]

6-hour interval GOES-15 (GOES-West) Water Vapor (6.5 µm) images with overlays of GFS model 500 hPa geopotential height (above) showed middle to upper tropospheric moisture that was being drawn northwestward toward Hawai’i by the circulation of a closed low centered southwest of the state during the 01-02 December 2016 period.

A closer view using 15-minute interval GOES-15 Water Vapor images (below) showed 2 distinct pulses of moisture moving across the eastern portion of the island chain. Due to the prolonged flow of moisture and the variable terrain, Flood Warnings and Winter Storm Warnings were issued for the Big Island of Hawai’i (as shown using RealEarth).

GOES-15 Water Vapor (6.5 µm) images, with hourly surface reports [click to play MP4 animation]

GOES-15 Water Vapor (6.5 µm) images, with hourly surface reports [click to play MP4 animation]

Hourly images of the MIMIC Total Precipitable Water (TPW) product (below) showed the large plume of moisture, which had its roots within the Intertropical Convergence Zone (ITCZ). Maximum TPW values in the vicinity of Hawai’i were in the 50-55 mm (2.0-2.2 inch) range. 24-hour rainfall amounts were as high as 6.27 inches on the island of Hawai’i and 3.67 inches on the island of Kauai.

MIMIC Total Precipitable Water product, with tropical surface analyses [click to play animation]

MIMIC Total Precipitable Water product, with tropical surface analyses [click to play animation]

===== 03 December Update =====

GOES-15 Visible (0.63 µm) images (below) provided glimpses of the snow-covered peaks of Mauna Kea and Mauna Loa (circled in red) on the Big Island of Hawai’i early in the day on 03 December.

GOES-15 Visible (0.63 µm) images, with hourly surface reports [click to play animation]

GOES-15 Visible (0.63 µm) images, with hourly surface reports [click to play animation]

Hurricane Force low in the North Pacific Ocean

November 17th, 2016

GOES-15 Water Vapor (6.5 µm) images, with hourly surface and buoy/ship reports [click to play MP4 animation]

GOES-15 Water Vapor (6.5 µm) images, with hourly surface and buoy/ship reports [click to play MP4 animation]

GOES-15 (GOES-West) Water Vapor (6.5 µm) images (above; also available as a 52 Mbyte animated GIF) showed the development of a Hurricane Force low in the North Pacific Ocean during the 15 November – 17 November 2016 period. Surface analysis charts for this storm, produced by the Ocean Prediction Center, are shown below.

Surface analyses from 12 UTC on 15 November to 12 UTC on 17 November

Surface analyses from 12 UTC on 15 November to 12 UTC on 17 November

Although it was more of an oblique viewing angle, JMA Himawari-8 AHI Water Vapor (6.2 µm, 6,9 µm and 7.3 µm) images (below; also available as a 27 Mbyte animated GIF) provided a nice view of the storm on 15 November as it was intensifying to produce Hurricane Force winds.

JMA Hmawari-8 Water Vapor (6.2 µm, top; 6.9 µm, middle; 7.3 µm, bottom) images [click to play MP4 animation]

JMA Hmawari-8 Water Vapor (6.2 µm, top; 6.9 µm, middle; 7.3 µm, bottom) images [click to play MP4 animation]

Since the ABI instrument on GOES-R is nearly identical to the AHI, there will also be imagery from 3 water vapor bands (6.2 µm, 6.9 µm and 7.3 µm) available once GOES-R becomes operational (as GOES-16) in 2017.

 

3-day transport of airborne Copper River Valley glacial silt/sand over the Gulf of Alaska

October 25th, 2016

GOES-15 Visible (0.63 µm) images, 23 through 25 October 2016, with hourly surface observations [click to play animation]

GOES-15 Visible (0.63 µm) images, 23 through 25 October 2016, with hourly surface observations [click to play animation]

GOES-15 (GOES-West) Visible (0.63 µm) images during the daylight hours on 23, 24 and 25 October 2016 (above) revealed the hazy signature of large amounts of airborne glacial silt and sand from the Copper River Valley being transported southward over the adjacent offshore waters of the Gulf of Alaska. The fine glacial silt and sand particles were being lofted by strong katabatic gap winds being channeled southward down the Copper River Valley — these winds were the result of a strong pressure gradient between arctic high pressure that was moving from the Interior of Alaska to the Yukon Territory of Canada (surface analyses) and a large occluded low centered off the coast of British Columbia and the US Pacific Northwest (24 October visible imagery).

Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images on 24 October 2016 [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images on 24 October 2016 [click to enlarge]

Comparisons between Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images on 24 October (above) and 25 October (below) showed that the small airborne glacial silt/sand particles were very reflective to solar radiation, and exhibited a warmer (darker gray to black enhancement) signature in the Shortwave Infrared images (similar to the warmer signature seen due to spherical water droplets at the tops of supercooled stratiform clouds). On 25 October a large aerosol plume was also emerging from Yakutat Bay, moving southwestward.

Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images on 25 October 2016 [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images on 25 October 2016 [click to enlarge]

Time series of surface observations at Middleton Island in the Gulf of Alaska [click to enlarge]

Time series of surface observations at Middleton Island in the Gulf of Alaska [click to enlarge]

A time series plot of surface observations from Middleton Island (PAMD) in the northern Gulf of Alaska (above) showed that the surface visibility was reduced to 3 miles on 24 October and 5 miles on 25 October as the Copper River plume periodically passed over the island. The ceiling height on 24 October was reported to be as low as 1400 feet as the surface visibility began to decrease. Along the southern coast of Alaska just west of the Copper River Delta, the visibility at Cordova (PACV) dropped to 5 miles with haze reported late in the day on 25 October as the western edge of the plume drifted over that area (below).

Time series of surface observations at Cordova, Alaska [click to enlarge]

Time series of surface observations at Cordova, Alaska [click to enlarge]

A zoom-in of the 2246 UTC Suomi NPP VIIRS true-color Red/Green/Blue (RGB) image on 24 October (using RealEarth) showed the gray to light tan color of the glacial silt/sand plume.

Suomi NPP VIIRS true-color RGB images [click to enlarge]

Suomi NPP VIIRS true-color RGB images [click to enlarge]

Shown below are toggles between Suomi NPP VIIRS true-color RGB and Aerosol Optical Thickness (AOT) images (from the eIDEA site) for 23, 24 and 25 October. Very high values of AOT (in the 0.8 to 1.0 range) were associated with the Copper River plumes.

Suomi NPP VIIRS true-color RGB and Aerosol Optical Depth images for 23 October [click to enlarge]

Suomi NPP VIIRS true-color RGB and Aerosol Optical Depth images for 23 October [click to enlarge]

Suomi NPP VIIRS true-color RGB and Aerosol Optical Thickness images for 24 October [click to enlarge]

Suomi NPP VIIRS true-color RGB and Aerosol Optical Thickness images for 24 October [click to enlarge]

Suomi NPP VIIRS true-color RGB and Aerosol Optical Thickness images for 25 October [click to enlarge]

Suomi NPP VIIRS true-color RGB and Aerosol Optical Thickness images for 25 October [click to enlarge]

A toggle between Terra MODIS Visible (0.64 µm) and Infrared (11-12 µm, commonly referred to as the “split window difference”) Brightness Temperature Difference (BTD) images on 25 October (below) revealed that there was a very subtle Copper River plume signature in the BTD image (note: the default 11-12 µm BTD color enhancement was modified to better highlight the plume in this example).

Terra MODIS Visible (0.64 µm) and Infrared (11.0-12.0 µm) Brightness Temperature Difference images [click to enlarge]

Terra MODIS Visible (0.64 µm) and Infrared (11.0-12.0 µm) Brightness Temperature Difference images [click to enlarge]

In that respect, the MODIS Infrared “split window” BTD images could be used to help locate the Copper River plume during nighttime as well as daytime, as seen in the image comparison below. The ABI instrument on GOES-R will have similar 11 µm and 12 µm Infrared bands, and will have the capability to provide this type of BTD imagery at 5 minute intervals over the entire Full Disk scan.

Nighttime (0706 UTC) and daytime (2031 UTC) Terra MODIS Infrared (11-12 µm) Brightness Temperature Difference images [click to enlarge]

Nighttime (0706 UTC) and daytime (2031 UTC) Terra MODIS Infrared (11-12 µm) Brightness Temperature Difference images [click to enlarge]

Previous cases of similar airborne Copper River plumes have been documented on this blog: Oct 2014 | Nov 2013 | Oct 2012.

Severe Weather in the Pacific Northwest

October 15th, 2016

Window Channel Infrared imagery from COMS-1 (10.8 µm) and GOES-15 (10.7 µm), every 6 hours from 1200 UTC on 7 October through 1800 UTC on 15 October [click to animate]

Infrared Window Channel imagery from COMS-1 (10.8 µm) and GOES-15 (10.7 µm), every 6 hours from 1200 UTC on 7 October through 1800 UTC on 15 October [click to animate]

Strong moisture-laden storms caused abundant precipitation and severe weather over the Pacific Northwest from 13-15 October 2016. The animation above shows two storms making landfall in the Pacific Northwest, one on 13-14 October and a second, on 15 October, which was a storm that originated from the remnants of Typhoon Songda. On 11-12 October, Super Typhoon Songda was recurving, subsequently racing towards the west coast of the United States, and making landfall as a strengthening extratropical cyclone on 15 October. The animation above uses two different satellites (COMS-1 and GOES-15), and includes a seam between the two views because the spectral characteristics of the two infrared window bands are not identical.

Daily precipitation from the Advanced Hydrologic Prediction Center from 13-15 October is shown here, with a weekly total shown below. A large area of precipitation exceeding 6 inches is apparent in the higher terrain.

ahps_7dprecip_15oct_1200

7-day Precipitation Totals ending 1200 UTC on 15 October 2016 (Click to enlarge)

The precipitation amounts were aided by the very moist airmass that accompanied the storms. Total Precipitable Water, shown below, from this site that manipulates data from here, shows the moisture. A larger-scale view that traces the moisture back to the time when Songda first reached typhoon intensity over the West Pacific is available here.

Total Precipitable Water, 12-15 October 2016 [Click to animate]

The strong storm before the one spawned by the remnants of Songda produced an EF2-rated tornado in Manzanita Oregon (YouTube Compilation; SPC Storm Reports; Blog post with damage picture) on 14 October 2016. GOES-15 Visible Imagery, below, shows a storm with overshooting tops moving over northwestern Oregon at the time of the tornado. (GOES-15 was performing a full-disk scan from 15:00-15:26 UTC, so 15-imagery was not available as the tornado moved ashore; the Advanced Baseline Imager on GOES-R will produce CONUS Imagery every 5 minutes in addition to Full-Disk Imagery every 15 minutes). The overshoots are especially apparent in the 1500 and 1530 UTC Images. GOES-13 provided a visible image at about the time of the tornado touchdown, but at a very oblique angle. The cirrus shield of the thunderstorm anvil is apparent, however.

GOES-15 Visible (0.62 µm) imagery, 1445, 1500 and 1530 UTC on 14 October. The Red Square indicates the tornado location [Click to animate]

GOES-15 Infrared Window (10.7 µm) imagery around the time of the severe weather in Oregon, below — which includes locations of SPC storm reports of tornadoes (red) and damaging winds (cyan) — also showed evidence of cold overshooting tops (the coldest clouds tops were around -50º C, yellow enhancement). An infrared image animation showing only the clouds is available here. NOAA-18 flew over the Oregon coast at 1427 UTC, and the AVHRR 12 µm Infrared image showed the parent thunderstorm offshore, upstream of Manzanita (larger-scale view).

GOES-15 Infrared Window (10.7 µm) imagery, 1400-1800 UTC on 14 October [Click to animate]

The Portland, Oregon NWS office issued 10 tornado warnings on 14 October — a record number for a single day.

 

GOES Sounder data can be used to created Derived Product Imagery (DPI) estimates of instability parameters (for example), and many are shown at this site. The GOES-13 Sounder has been offline for about a year after having suffered an anomaly back in November 2015, when the filter wheel became frozen, but the GOES-15 Sounder (and the GOES-14 Sounder) continue to operate. The animation below of GOES-15 Sounder Lifted Index shows values as low as -4ºC upstream of the Oregon Coast for many hours before the tornado; as such, it was a valuable situational awareness tool.

goes_sounder_dpi_14oct2016_1100_1700step

GOES-15 Sounder DPI Estimates of Lifted Index, 1100-1700 UTC on 14 October 2016 (Click to enlarge)

NOAA/CIMSS ProbSevere is a probabilistic estimate that a given thunderstorm will produce severe weather in the next 60 minutes. The animation below shows ProbSevere polygons overlain over radar from 1501 UTC (when the first ProbSevere polygon appeared around the radar cell that ultimately was tornadic) through 1521 UTC. Values from the ProbSevere output are below:

 

TIME PS CAPE SHR MESH GRW GLA FLSHRATE COMMENTS
1501 11% 1048 39.3 0.00 str str 0 fl/min Satellite from 1245/1241
1503 32% 1056 39.7 0.37 str str 0 fl/min Satellite from 1245/1241
1505 32% 1031 39.4 0.37 str str 0 fl/min Satellite from 1245/1241
1507 29% 1013 38.7 0.37 str str 3 fl/min Satellite from 1245/1241
1509 47% 974 37.9 0.62 str str 3 fl/min Satellite from 1245/1241
1511 47% 962 37.6 0.62 str str 3 fl/min Satellite from 1245/1241
1513 32% 745 33.1 0.52 str str 10 fl/min Satellite from 1245/1241
1515 34% 897 35.9 0.52 str str 1 fl/min Satellite from 1245/1241
1517 10% 887 35.7 0.52 N/A N/A 2 fl/min
1519 8% 762 33.6 0.54 N/A N/A 4 fl/min
1521 7% 737 33.1 0.49 N/A N/A 2 fl/min
realearthprobsevere_14october2016_1501_1521anim

NOAA/CIMSS ProbSevere output in RealEarth, 1501-1521 UTC on 14 October 2016 (Click to animate)

The Sounder also has a 9.6 µm “ozone absorption band”, and another example of GOES Sounder DPI is Total Column Ozone, shown below. Immediately evident is the sharp gradient in ozone (yellow to green color enhancement) located just north of the polar jet axis that was rounding the base of a large upper-level low (500 hPa analyses). The GOES-R ABI instrument also has a 9.6 µm band that is sensitive to ozone; however, there are no current plans to produce operationally a similar Total Column Ozone product.

 

GOES-15 Sounder Total Column Ozone DPI [click to animate]

GOES-15 Sounder Total Column Ozone DPI [click to animate]

Suomi NPP Day/Night Band Visible (0.70 µm) Image, 1057 UTC on 14 October 2016, Green Arrow points to Manzanita OR [click to enlarge]

Suomi NPP Day/Night Band Visible (0.70 µm) Image, 1057 UTC on 14 October 2016, Green Arrow points to Manzanita OR [click to enlarge]

Suomi NPP overflew the Pacific Northwest about 4 hours before the severe weather was observed at Manzanita. The Day/Night Visible Image above, courtesy of Jorel Torres at CIRA (Jorel also supplied the NUCAPS Sounding Imagery below), shows a well-developed storm offshore with thunderstorms off the West Coast of the United States (Click here for an image without the Green Arrow). Multiple overshooting tops can be discerned in the imagery.

NUCAPS Soundings are produced from the Cross-Track Infrared Sounder (CrIS, with 1300+ channels of information) and the Advanced Technology Microwave Sounder (ATMS, with 22 channels) that are present on Suomi NPP (in addition to the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument that provides the Day/Night band imagery). The image below shows the location of NUCAPS Soundings — the color coding of the points is such that Green points have passed Quality Control, whereas yellow points denote sounding for which the Infrared Sounding retrieval has failed to converge and Red points denote soundings for which both Infrared and Microwave sounding retrievals have failed to converge).

Suomi NPP Day/Night Band Visible Image, 1057 UTC on 14 October 2016, with NUCAPS Sounding Locations indicated.  The Green Circle shows the location of the Sounding below [click to enlarge]

Suomi NPP Day/Night Band Visible Image, 1057 UTC on 14 October 2016, with NUCAPS Sounding Locations indicated. The Green Circle shows the location of the Sounding below; Refer to the text for the Dot Color meaning [click to enlarge]

NUCAPS Soundings can give valuable information at times other than those associated with radiosonde launches (0000 and 1200 UTC, typically), and over a broad region. The point highlighted above, between the occluded storm and the coast, shows very steep mid-level lapse rates that suggest convective development is likely.

NUCAPS Sounding, location as shown by the Green Circle in the figure above. [click to enlarge]

NUCAPS Sounding, location as shown by the Green Circle in the figure above [click to enlarge]

The imagery below shows soundings a bit farther south, near convection that looks supercellular. The NUCAPS Soundings there suggest very steep mid-level lapse rates.

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