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.

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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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Matthew along the east coast of Florida

October 7th, 2016

GOES-13 Visible (0.63 µm) Imagery, 1230-1337 UTC (Click to enlarge)

Hurricane Matthew is on a path that parallels the coast of Florida, with the center remaining just offshore. GOES-13 Visible imagery from a 1-hour time period this morning, above, shows the continued development of convection around the eyewall and the motion of convective bands inland. GOES-13 Visible images with hourly surface winds and wind gusts (in knots) are shown below. The highest wind gust recorded along the central Florida coast was 107 mph (NWS Melbourne PNS).

GOES-13 Visible (0.63 um) images, with hourly surface winds and gusts in knots [Click to play animation]

GOES-13 Visible (0.63 um) images, with hourly surface winds and gusts in knots [Click to play animation]

A 24-hour animation of morphed Microwave imagery (from this site), below, suggests that an eyewall replacement cycle has completed: the very small eye present at storm’s center at the start of the animation has been replaced by a larger-diameter eye at the end of the animation. Storm strength typically drops during eyewall replacements. Note also that the microwave data shows that the strongest convection remained offshore.

mimic_microwave_24hending1100utc07october

Morphed Microwave Imagery of Matthew showing Strongest Convection, 1200 UTC 06 October to 1100 UTC 07 October 2016 (Click to enlarge)

Infrared imagery from GOES-13, below, also shows the coldest cloud tops to the east of the eye (indicated by the arrow in the image).

GOES-13 Infrared (10.7 µm) Imagery, 1355 UTC. The flashing arrow points to Matthew’s eye (Click to enlarge)

A longer animation of GOES-13 Infrared Window (10.7 um) images with hourly surface winds and wind gusts (in knots) is shown below (MP4 | animated GIF).

GOES-13 Infrared Window (10.7 um) images [Click to play animation]

GOES-13 Infrared Window (10.7 um) images [Click to play animation]

A toggle between Suomi NPP VIIRS Visible (0.64 um) and Infrared Window (11.45 um) images at 1751 UTC is shown below; Matthew was a Category 3 hurricane at that time.

Suomi NPP VIIRS Visible (0.64 um) and Infrared Window (11.45 um) images [Click to enlarge]

Suomi NPP VIIRS Visible (0.64 um) and Infrared Window (11.45 um) images [Click to enlarge]

Hurricane Matthew moves into the Bahamas

October 5th, 2016
morphedmw_matthew_last48hrs_ending5oct_1000

Morphed Microwave Imagery showing the eye of Matthew from 1400 UTC 3 October through 1345 UTC 5 October (Click to enlarge)

The animation of Matthew, above, from morphed microwave imagery (from this site), shows the toll that interaction with the high terrain of Hispaniola and eastern Cuba has had on the storm (causing it to be downgraded from Category 4 to Category 3 intensity). The formerly distinct eye had eroded, although eye re-formation occurs at the end of the animation. Once again, a comparison of microwave vs infrared imagery revealed that the well-defined eye structure was much more apparent using microwave data. Strengthening/Re-organization of Matthew in the near term will be governed by Sea Surface Temperatures (that are warm) and wind shear (shown below, from this site, that is weak).

wg8shr_0900_5october2016

Diagnosed wind shear, 0900 UTC on 5 October 2016 (Click to enlarge)

Total Precipitable Water fields (from this site, using data from here), below, show abundant moisture surrounding Matthew at its present position. There is dry air over the eastern United States landmass, however.

Morphed Total Precipitable water from MIRS, 1300 UTC 4 October – 1200 UTC 5 October (Click to enlarge)

Morphed Total Precipitable water from MIRS, 1300 UTC 4 October – 1200 UTC 5 October (Click to enlarge)

During the morning and afternoon hours, the satellite presentation of Matthew began to slowly improve on GOES-13 Visible (0.63 µm) and Infrared Window (10.7 µm) imagery, below (MP4 | animated GIF), with well-defined convective bursts seen later in the day. Note: the noise seen on the 1645 UTC images was due to solar RFI.

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]

Hurricane Matthew

September 30th, 2016

GOES-13 Visible (0.63 µm) imagery, 1115 UTC on 30 September 2016 [Click to enlarge]

GOES-13 Visible (0.63 µm) imagery, 1115 UTC on 30 September 2016″

Early morning visible imagery over Matthew, above, from GOES-13, shows a circular storm with many overshooting tops and no apparent eye. However, Microwave imagery, below, from GCOM at about 0620 UTC, shows an eye structure beneath the clouds. (Information on AMSR-2 is here; Imagery was produced using Polar2Grid, part of CSPP, the Community Satellite Processing Package). Matthew is forecast to turn north and move over the Greater Antilles, threatening Jamaica, Hispaniola and Cuba from Sunday to early Tuesday. More information is available at the National Hurricane Center website.

GCOM AMRS-2 Brightness Temperatures at 36.5 and 89.0 GHz, 0620 UTC on 30 September 2016 [Click to enlarge]

GCOM AMRS-2 Brightness Temperatures at 36.5 and 89.0 GHz, 0620 UTC on 30 September 2016 [Click to enlarge]”

One benefit of Polar2Grid is that it puts different satellite imagery on the same grid, and therefore an animation of Polar data can be produced. The 10.8 µm window channel animation below has imagery from the AVHRR on METOP-A (1349 UTC) and METOP-B (1441 UTC) (Imagery from NOAA-18 (1030 UTC) was projected onto a different grid). A Visible image toggle using data from METOP-A and METOP-B is here.

10.8 µm brightness temperatures from AVHRR on METOP-A (1349 UTC) and METOP-B (1441 UTC) on 30 September 2016 [Click to enlarge]

10.8 µm brightness temperatures from AVHRR on METOP-A (1349 UTC) and METOP-B (1441 UTC) on 30 September 2016 [Click to enlarge]”


===== Update, 1800 UTC =====
Visible imagery from GOES-13 (below) shows the development of an eye. Matthew continues its motion to the west-southwest in between Colombia and Hispaniola.

GOES-13 Visible 0.63 µm Imagery, 1345-1715 UTC on 30 September 2016 [Click to enlarge]

GOES-13 Visible 0.63 µm Imagery, 1345-1715 UTC on 30 September 2016 [Click to enlarge]”

===== Update, 22 UTC 01 October =====

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

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

According to the NHC, Hurricane Matthew reached Category 5 intensity around 00 UTC on 01 October (public advisorydiscussion). An animation of GOES-13 Infrared Window (10.7 µm) images from 09 UTC on 30 September to 18 UTC on 01 October, above, showed the evolution of cold cloud-top brightness temperatures surrounding the small eye during the period of rapid intensification (SATCON)  on 30 September – 01 October.

Interestingly, the center of what had since been downgraded to a Category 4 Matthew did a circular loop during the daylight hours of 01 October, as seen in a 2-panel comparison of GOES-13 Visible (0.63 µm) and Infrared Window (10.7 µm) images, below.

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]

One important point about the location of Matthew:


It is because of this southerly location that the storm was not adequately sampled within the CONUS scan sector (which was being provided with imagery as often as every 5-7 minutes, since GOES-13 was in Rapid Scan Operations mode) — so imagery of Matthew was only available every 30 minutes from the Northern Hemisphere scan sector. Once GOES-R becomes operational, a full disk scan can be performed as freqently as once every 5 minutes, which would provide much better sampling for an important tropical cyclone such as Matthew.