Suomi NPP VIIRS 11.45 µm IR + 0.7 µm Day/Night Band images

A comparison of AWIPS images of 375-meter resolution (projected onto a 1-km AWIPS grid) Suomi NPP VIIRS 11.45 µm IR channel data with the corresponding 0.7 µm VIIRS Day/Night Band (above) showed a large Mesocale Convective System (MCS) with an expansive cold cloud shield (exihibiting IR brightness temperatures as cold as -84 C) over parts of North Dakota and South Dakota at 08:43 UTC (3:43 AM local time) on 06 July 2012. A number of well-defined cloud-top gravity waves could also be seen propagating northward and northeastward outward away from the core of the storm. There was a damaging wind report at 09:03 UTC in south-central North Dakota:  SW WIND GUST OF 68 MPH AT 403 AM CDT...AND N WIND GUST OF 68 MPH AT 408 AM CDT. Illumination from a full moon made convective overshooting tops and some of these cloud-top gravity waves easy to see on the Day/Night Band image.

About 2 hours later, these cloud-top gravity waves wee more difficult to identify on a 1-km resolution POES AVHRR 10.8 µm IR image (below) at 10.32 UTC (5:32 AM local time), although a few could still be seen in eastern North Dakota, western Minnesota and southern Manitoba. There was a wind gust to 51 knots (59 mph) reported at 10:40 UTC in southeastern North Dakota.

POES AVHRR 10.8 µm IR channel image + METAR surface reports and severe wind reports

As the MCS began to dissipate around sunrise, a vivid display of transverse banding cirrus filaments could be seen on 1-km resolution GOES-13 0.63 µm visible channel images (below; click image to play animation) forming along the southern periphery of the storm over eastern South Dakota, southern Minnesota, and far northern Iowa. This transverse banding is a satellite signature of potential high-altitude turbulence — and there was one pilot report of moderate turbulence at 38,00 feet in eastern South Dakota.

GOES-13 0.63 µm visible channel images (click image to play animation)

View only this post Read Less

Suomi NPP VIIRS 0.7 µm Day/Night Band image + 3.74 µm shortwave IR image

A comparison of AWIPS images of the Suomi NPP VIIRS 0.7 µm Day/Night Band (DNB) with the corresponding 3.74 µm shortwave IR data (above) showed a large arc-shaped layer of dense smoke aloft over much of central South Dakota at 09:21 UTC (4:21 AM local time) on 04 July 2012, along with a number of shortwave IR “hot spots” (black to yellow to red color enhancement) and brightly-glowing DNB signatures from active wildfires that were burning in southeastern Montana and eastern Wyoming. Since the Moon was in the full phase, it provided good illumination of the various cloud features across the region.

The following afternoon, the dense smoke feature was still very evident over eastern South Dakota into western Minnesota on Terra and Aqua MODIS true-color Red/Green/Blue (RGB) images from the SSEC MODIS Direct Broadcast site (below). Other areas of smoke were seen in the vicinity of the fires in Montana and Wyoming. High aerosol concentrations were also indicated by the Suomi NPP Ozone Mapper Profiler Suite.

MODIS true-color Red/Green/Blue (RGB) images

View only this post Read Less

Suomi NPP 11.45 µm IR, 0.7 µm Day/Night Band, and 3.74 µm shortwave IR images

A comparison of AWIPS images of Suomi NPP VIIRS 11.45 µm IR, 0.7 µm Day/Night Band, and 3.74 µm shortwave IR data (above) showed (1) a pair of strong thunderstorms over the Montana/North Dakota/South Dakota border region, with cold cloud top IR brightness temperatures and excellent illumination of the overshooting tops and other cloud features due to the full phase of the moon, and (2) a few wildfires that were burning, with the largest ones being located in southeastern Montana and northeastern Wyoming. The wildfires exhibited “hot spots” (black to yellow to red color enhancement) on the shortwave IR image, and also appeared very bright on the Day/Night Band image due to the large areas of flames.

METAR surface reports plotted on the VIIRS IR image (below) revealed that Buffalo, South Dakota (station identifier K2WX) had a wind gust of 48 knots (55 mph). Hail of 2.0 inches in diameter was reported from this storm 25 minutes earlier at 09:15 UTC.

Suomi NPP VIIRS 11.45 µm IR image + METAR surface reports

A comparison of the 275-meter resolution (projected onto a 1-km AWIPS grid) Suomi NPP VIIRS 11.45 µm IR image with the corresponding 4-km resolution GOES-13 10.7 µm IR image (below) demonstrates (1) the obvious advantage of higher spatial resolution, with better details seen in the storm top structure; the coldest cloud top IR brightness temperature on the VIIRS image was -77 C, compared to -63 C on the GOES image, and (2) the significant geo-location displacement of the GOES-13 image features, due to the problem of parallax with such a large satellite viewing angle (which is about 60 degrees for this region from the GOES-13 satellite).

Suomi NPP VIIRS 11.45 µm IR image + GOES-13 10.7 µm IR image

View only this post Read Less

POES AVHRR 10.8 µm IR channel image + cumulative SPC storm reports

An AWIPS image of 1-km resolution POES AVHRR 10.8 µm IR channel data with overlays of cumulative SPC storm reports (above) showed a strong mesoscale convective system (MCS) as it was moving southeastward across northern Indiana at 18:23 UTC or 12:23 PM local time on 29 June 2012 — this MCS evolved into a long-lived progressive derecho event, producing a broad swath of wind damage across the Ohio River Valley and into the Mid-Atlantic states (SPC storm reports). A peak wind gust of 91 mph was recorded at Fort Wayne, Indiana, with hail as large as 3.0 inches in diameter falling near Danville, Illinois. At least 12 fatalities have been attributed to this derecho.

Two ingredients helping to fuel the development and upscale growth of this derecho event were convergence/lift along a quasi-stationary frontal boundary, and rich moisture pooled along and just south of the frontal boundary. 10-km resolution GOES-13 sounder Total Precipitable Water (TPW) derived product imagery (below; click image to play animation) showed TPW values in the 50 to 65 mm (2.0 to 2.4 inch) range.

GOES-13 sounder Total Precipitable Water derived product imgery (click image to play animation)

================================

GOES-13 sounder Lifted Index derived product imagery (click image to play animation)

There was also extreme instability present along and just south of this frontal boundary, as seen on GOES-13 sounder derived product images of Lifted Index or LI (above; click image to play animation) and Convective Available Potential Energy or CAPE (below; click image to play animation). AWIPS cursor sampling of these instability products showed widespread LI values of -14.8º C, and CAPE values of 6000 J per kg (denoted by the lighter purple color enhancements on each sounder product).

GOES-13 sounder Convective Available Potential Energy (CAPE) derived product (click image to play animation)

Clear sky single-field-of-view (SFOV) GOES-13 sounder temperature and moisture profiles within this axis of extreme instability (below) showed an LI value of -16.8º C at Point A in far eastern Illinois at 16 UTC. Note that the locations of some of these available GOES sounder temperature/moisture profiles were situated between the standard rawinsonde sites of Lincoln, Illinois (KILX) and Wilmington, Ohio (KILN) — this demonstrates the potential value of using GOES sounder data in regions (or at times of the day) between conventional rawinsonde launches.

GOES-13 sounder vertical profiles of temperature and dew point

3 comparisons of 1-km resolution POES AVHRR and MODIS visible channel and IR channel imagery with plots of cloud-to-ground lightning strikes (below) depicted the storm structure at 18:18 UTC, 19:17 UTC, and 19:48 UTC. Thunderstorms on the 19:48 UTC POES AVHRR image exhibited a minimum cloud top IR brightness temperature of -90 C.

POES AVHRR 0.86 µm visible, 12.0 µm IR, and cloud-to-ground lightning strikes

MODIS 0.65 µm visible, 11.0 µm IR, and cloud-to-ground lightning strikes data

POES AVHRR 0.86 µm visible, 12.0 µm IR, and cloud-to-ground lightning data

4-km resolution GOES-13 10.7 µm IR channel images with overlays of SPC storm reports (below) showed the southeastward progression of the MCS and the attendant hail and damaging winds reports. The GOES-13 IR images also exhibited unusually cold IR brightness temperatures, at times as low as -81º C (at 20:45 UTC).

GOES-13 10.7 µm IR images + SPC storm reports (click image to play animation)

During the following overnight hours, the core of the derecho continued to move southeastward across West Virginia, Virginia, and eventually to the East Coast and the adjacent offshore waters of the Atlantic Ocean. In addition to creating a widespread swath of damaging winds at the surface, the MCS was also responsible for a number of reports of high-altitude turbulence, as seen on 4-km resolution GOES-13 10.7 µm IR images with overlays of pilot reports of turbulence (below; click image to play animation). Severe turbulence was reported over or near the periphery of the storm at 01:00 UTC, 02:16 UTC, and 02:45 UTC.

GOES-13 10.7 µm IR channel images + Pilot reports of turbulence (click image to play animation)

Better storm-top structure can be seen on a sequence of 1-km resolution POES AVHRR 12.0 µm and MODIS 11.0 µm IR images (below), including a very detailed view of the transverse banding that formed along the northern edge of the dissipating MCS.

POES AVHRR 12.0 µm IR + MODIS 11.0 µm IR images

An overlay of 1-hour cloud-to-ground lightning strikes (ending at 07:00 UTC) on the Suomi NPP VIIRS 11.45 µm IR channel image at 07:14 UTC (below) showed a decreasing amount of lightning activity as the parent MCS began to slowly dissipate as it moved out over the waters of the western Atlantic Ocean. The corresponding 07:14 UTC VIIRS 0.7 µm Day/Night Band image did manage to reveal a few bright white pixels resulting from cloud-top illumination by clusters of lightning.

Suomi NPP VIIRS 11.45 µm IR image + VIIRS 0.7 µm Day/Night Band image

The strong surface winds downed a large number of trees and powerlines, causing widespread power outages that affected over 3 million people. One area especially hard-hit was West Virginia and adjacent portions of Virginia and Ohio, where a before/after comparison of Suomi NPP VIIRS 0.7 µm Day/Night Band (DNB) images around 07 UTC (4 AM local time) on 29 June and 30 June (below; courtesy of Jordan Gerth, CIMSS) revealed the large areas of darkness (lack of city lights) on 30 June after the derecho had moved through. The large dark areas seen on the DNB images over Pennsylvania on 29 June (VIIRS IR image) and Ohio/Michigan on 30 June (VIIRS IR image) were due to strong thunderstorms obscuring the view of the city lights below.

Suomi NPP VIIRS 0.7 µm Day/Night Band images on 29 June and 30 June

UPDATE: GOES-13 10.7 µm IR channel images of the entire derecho event (below; also available as a QuickTime movie). The GOES-13 satellite had been placed into Rapid Scan Operations (RSO). providing images as frequently as every 5-10 minutes during much of the life cycle of the storm.

GOES-13 10.7 µm IR channel images (click image to play animation)

In addition, a McIDAS-V combination of GOES-13 10.7 µm IR images and CAPE derived from overpasses of the Suomi NPP CrIS and the Aqua AIRS instruments (below; image courtesy of Joleen Feltz) showed that the derecho was moving toward pockets of instability that were in place along the trough axis that was oriented from southwest to northeast along the East Coast. Plotted in yellow are the surface wind gusts of 80 mph or greater associated with the derecho.

GOES-13 IR + CAPE from Suomi NPP CrIS and Aqua AIRS

View only this post Read Less