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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Hurricane Nicole

October 13th, 2016

Track of Nicole, from 12 UTC on 04 October to 12 UTC on 13 October [click to enlarge]

Track of Nicole, from 12 UTC on 04 October to 12 UTC on 13 October [click to enlarge]

From its inception as a highly-sheared Tropical Storm on 04 October, Nicole moved in an erratic path with small intensity fluctuations for 8 days (above); then a period of intensification began on 12 October, with the storm reaching Category 4 intensity southwest of Bermuda at 03 UTC on 13 October. With ample illumination from the Moon (which was in the Waxing Gibbous phase, at 90% of full) Nicole exhibited a well-defined eye on Suomi NPP VIIRS Day/Night Band (0.7 µm) imagery at 0615 UTC, with cold cloud-top temperatures surrounding the eye on the corresponding VIIRS Infrared Window (11.45 µm) image (below).

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

As Nicole approached Bermuda, increasing deep-layer wind shear began to impact the storm and weaken it to a Category 3 — and DMSP-17 Microwave (85 GHz) data showed that the eye had become open to the south (below).

DMSP-17 SSMIS Microwave (85 GHz) and GOES-13 Infrared Window (10.7 µm) images [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) and GOES-13 Infrared Window (10.7 µm) images [click to enlarge]

The passage of Nicole over Bermuda is shown on GOES-13 Visible (0.63 µm) and Infrared Window (10.7 µm) images spanning the period 1037-1555 UTC (below).

GOES-13 Visible (0.63 µm) and Infrared Window (10.7 µm) images [click to play animation]

GOES-13 Visible (0.63 µm) and Infrared Window (10.7 µm) images [click to play animation]

As the eye of Nicole passed over Bermuda around 13 UTC, the staff at the Bermuda Weather Service were able to successfully launch a rawinsonde balloon, which reported data as high as the 202 hPa pressure level or 12.2 km altitude — much higher than their previous launch attempts at 06 and 12 UTC (below). The Total Precipitable Water (TPW) value derived from that 15 UTC sounding was 72.5 mm or 2.85 inches, which was in general agreement with that displayed by the MIMIC TPW product. Note that the eye of Nicole did not appear to be directly over Bermuda on the 1300 UTC GOES-13 images — this is due to a combination of parallax and the fact that the eye had a significant southwest-to-northeast tilt with height.

Bermuda rawinsonde reports from 00, 06, 12 and 15 UTC on 13 October [click to enlarge]

Bermuda rawinsonde reports from 00, 06, 12 and 15 UTC on 13 October [click to enlarge]

A sequence of Infrared images from POES and Metop AVHRR (12.0 µm) and Terra MODIS (11.0 µm) during the period 1016 to 1513 UTC is shown below.

POES and Metop AVHRR, and Terra MODIS infrared images [click to enlarge]

POES and Metop AVHRR, and Terra MODIS infrared images [click to enlarge]

Hurricane Matthew: heavy rainfall and flooding across the Southeast and Mid-Atlantic US

October 9th, 2016

MIMIC Total Precipitable Water product, from 06 October/04 UTC to 08 October/16 UTC [click to play MP4 animation]

MIMIC Total Precipitable Water product, from 06 October/04 UTC to 08 October/16 UTC [click to play MP4 animation]

Copious amounts of moisture associated with Hurricane Matthew resulted in heavy rainfall (map | text list) and widespread flooding across the Southeast and Mid-Atlantic US during the 07 October to 09 October 2016 period. Hourly images of the MIMIC Total Precipitable Water (TPW) product (above; also available as a 22 Mbyte animated GIF) showed the high TPW values that spread from Florida to the Mid-Atlantic states; all-time record high TPW values were measured via rawinsonde at Jacksonville, Florida and Charleston, South Carolina, with a record high value for the month of October at Newport/Cape Hatteras, North Carolina (Tweet). For more details, see the Weather Underground blog.

Track of Matthew, from 28 September at 12 UTC to 09 October at 18 UTC

Track of Matthew, from 28 September at 12 UTC to 09 October at 18 UTC

Matthew set numerous records for intensity, longevity, and landfall (summary) — an animation of hourly GOES-13 Water Vapor (6.5 µm) images covering the 11-day period from 12 UTC on 28 September to 12 UTC on 09 October is shown below (also available as a large 113 Mbyte animated GIF). The CIMSS Tropical Cyclones site posted GOES-13 Visible (0.63 µm) animations from the individual days of 03 October, 04 October, 05 October, 06 October, 07 October, and 08 October.

GOES-13 Water Vapor (6.5 µm) images [click to play MP4 animation]

GOES-13 Water Vapor (6.5 µm) images [click to play MP4 animation]

The combination of high winds and flooding led to widespread power outages, with over 2 million homes and businesses without power. A comparison of nighttime Suomi NPP VIIRS Day/Night Band (0.7 µm) images from 28 September (before Mattthew arrived) and 09/10 October (after the passage of Matthew) showed a notable reduction in the glow of city lights in areas with no power (below; images courtesy of William Straka, SSEC). Note that the presence of patchy clouds on all 3 images tended to diffuse or even obscure the appearance of city lights below, depending on the thickness of the cloud layer(s).

Suomi NPP VIIRS Day/Night Band (0.7 µm) images on 28 September, 09 October and 10 October [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) images on 28 September, 09 October and 10 October [click to enlarge]

As clouds cleared in the wake of Hurricane Matthew on 09 October, a Suomi NPP VIIRS true-color Red/Green/Blue (RGB) image at 1859 UTC, viewed using RealEarth (below), revealed patterns of turbidity in the offshore waters of the Atlantic Ocean from Florida to North Carolina; this increased turbidity was a result of high amounts of particles suspended in the water due to a combination of mixing from prolonged high winds and runoff from inland flooding.

Suomi NPP VIIRS true-color image [click to enlarge]

Suomi NPP VIIRS true-color image [click to enlarge]

About 8 hours later, a Terra MODIS Sea Surface Temperature (SST) product image at 0243 UTC on 10 October (below) showed a large eddy of warm Gulf Stream water (with a maximum SST value of 85.2º F, darker red color enhancement) surrounding a pocket of cooler water (with a minimum SST value of 78.5º F, darker blue color enhancement) off the coast of South Carolina.

Terra MODIS Sea Surface Temperature product [click to enlarge]

Terra MODIS Sea Surface Temperature product [click to enlarge]

The VIIRS Instrument on Suomi NPP provides data that are used in a River Flood Product (discussed previously on this blog). The product uses three reflective bands (I01, I02, and I03 at 0.64 µm, 0.86 µm and 1.61 µm, respectively) and the infrared window band I05 at 11.45 µm. The image below (courtesy of Sanmei Li at George Mason University) identifies many flooded regions over North Carolina. In particular, the flooding near Goldsboro and Lumberton is identified.

snppviirs_floodmap_south_north_carolina_usa_11oct_2016_18_17

JPSS River Flood product produced with Suomi NPP data, 1817 UTC on 11 October 2016 (Click to enlarge)

A sequence of 1 pre-Matthew (06 September) and 3 post-Matthew (09, 10 and 12 October) Terra/Aqua MODIS false-color RGB images from the SSEC MODIS Today site (below) also helped to highlight areas of flooding (darker shades of blue, especially notable along river valleys) that resulted from the heavy rainfall.

Terra and Aqua MODIS false-color images, from 06 September and 09, 10 and 12 October 2016 [click to enlarge]

Terra and Aqua MODIS false-color images, from 06 September and 09, 10 and 12 October 2016 [click to enlarge]

Hurricane Matthew makes landfall in western Haiti, then eastern Cuba

October 4th, 2016

GOES-13 Visible (0.63 µm) Imagery, 1045-1245 UTC on 4 October 2016 (Click to enlarge)

Hurricane Matthew has made landfall in western Haiti. The rocking animation (click here for a straight animation) above shows the cloud-filled eye of the storm crossing the Tiburon Peninsula. The storm’s center is forecast to remain largely over water as it moves through the Windward Passage between Cuba and Hispaniola.

A closer look using a 2-panel comparison of GOES-13 Visible (0.63  µm) and Infrared Window (10.7 µm) images, below, shows the deteriorating satellite presentation following interaction with the topography of the islands. The GOES-13 satellite was in Rapid Scan Operations (RSO) mode, providing images as frequently as every 5-7 minutes.

GOES-13 0.63 µm Visible (left) and 10.7 µm Infrared Window (right) images [Click to play animation]

GOES-13 0.63 µm Visible (left) and 10.7 µm Infrared Window (right) images [Click to play animation]

NOAA-18 overflew the region around 1130 UTC while the eye was on land, and the toggle below shows Visible (0.64 µm) and Infrared Window Channel (10.8 µm) imagery from 1130 UTC. The cloud-filled eye is distinct in the infrared image at that time, but a sequence of POES AVHRR Infrared (12.0 µm) images showed the rapid deterioration shortly after landfall (as was seen in the GOES-13 images above).

NOAA-18 AVHRR Visible (0.64 µm) and Infrared (10.8 µm) Imagery, 1130 UTC on 4 October 2016 (Click to enlarge)

A toggle between 1215 UTC GOES-13 Infrared Window (10.7 µm) and 1217 UTC DMSP-18 SSMIS Microwave (85 GHz) images from the CIMSS Tropical Cyclones site, below, revealed that a well-defined eye was still evident in the microwave data.

GOES-13 Infrared Window (10.7 µm) and DMSP-18 SSMIS Microwave (85 GHz) images [Click to enlarge]

GOES-13 Infrared Window (10.7 µm) and DMSP-18 SSMIS Microwave (85 GHz) images [Click to enlarge]

Aqua overflew Matthew shortly after 1800 UTC on 4 October, and the toggle below shows the 1-km visible (0.65 µm) and the 1-km ‘Cirrus Channel’ (1.38 µm). The Cirrus Channel detects radiation at a wavelength where very strong absorption by water vapor is occurring; only high clouds are detected with this channel, and the toggle between the Cirrus Channel and the Visible nicely outlines the cirrus canopy of the storm. The Advanced Baseline Imager (ABI) on GOES-R also includes a Cirrus Channel.

Aqua MODIS Visible (0.65 µm) and

Aqua MODIS Visible (0.65 µm) and “Cirrus Channel” (1.38 µm) at 1832 UTC on 4 October 2016 [Click to enlarge]

Meanwhile, to the northeast of Matthew, in the tropical Atlantic, Tropical Storm Nicole has formed. The animation of visible imagery from GOES-13, below, shows a sheared storm; the low-level circulation is west of the deepest convection. It’s unlikely that Nicole will intensify much under such sheared conditions. Cirrus outflow from Matthew is evident at the south and west of Nicole.

GOES-13 Visible (0.63 um) images [click to play animation]

GOES-13 Visible (0.63 um) images [click to play animation]

ASCAT on METOP-A sampled both storms in its morning overpass over the western Atlantic, as shown below. The maximum scatterometer-derived wind speeds were 60 knots with Matthew and 40 knots for Julia.

GOES-13 Visible (0.63 µm) image, with Metop-AASCAT winds [Click to enlarge]

GOES-13 Visible (0.63 µm) image, with Metop-AASCAT winds [Click to enlarge]

Late in the day on 04 October, Category 4 Hurricane Mathew made a second landfall along the far eastern tip of Cuba. As seen in the image toggle below, in spite of a ragged appearance on GOES-13  Infrared Window (10.7 µm) imagery, a distinct eye was still seen using DMSP-18 SSMIS Microwave (85 GHz) data.

GOES-13 Infrared Window (10.7 µm) and DMSP-18 SSMIS Microwave (85 GHz) images [Click to enlarge]

GOES-13 Infrared Window (10.7 µm) and DMSP-18 SSMIS Microwave (85 GHz) images [Click to enlarge]