Intense Eastern Pacific / Gulf of Alaska storm

April 2nd, 2012 |
GOES-15 6.5 µm water vapor channel images (click image to play animation)

GOES-15 6.5 µm water vapor channel images (click image to play animation)

McIDAS images of 4-km resolution GOES-15 6.5 µm water vapor channel data (above; click image to play animation) displayed the development of a classic “dry swirl” water vapor signature indicating the transition to an occluded cyclone during the 01 April – 02 April 2012 time period. The Ocean Prediction Center was forecasting large areas of hurricane force winds associated with this storm (00 UTC | 06 UTC | 12 UTC).

A sequence of AWIPS images of 1-km resolution MODIS 11.0 µm and POES AVHRR 12.0 µm IR channel data (below) showed a variery of small-scale banding structures during various stages of development of the storm.

MODIS 11.0 µm + POES AVHRR 12.0 µm IR channel images

MODIS 11.0 µm + POES AVHRR 12.0 µm IR channel images

The approach of a strong Potential Vorticity (PV) anomaly helped the storm to intensify rapidly, with with CRAS model fields indicating the tropopause (taken to be the pressure level of the PV1.5 surface) lowering to around the 900 millibar level by 06 UTC on 02 April (below).

GOES-15 6.5 µm water vapor images + CRAS model PV1.5 pressure

Although the storm was near the edge of the GOES-15 sounder scan, an image of the GOES-15 sounder Total Column Ozone product (below) showed that the PV anomaly was situated along a strong ozone gradient (which is often the case).

GOES-15 6.5 µm water vapor image + GOES-15 sounder Total Column Ozone product (with overlays of CRAS model PV1.5 pressure)

GOES-15 6.5 µm water vapor image + GOES-15 sounder Total Column Ozone product (with overlays of CRAS model PV1.5 pressure)

The MIMIC Total Precipitable Water (TPW) product (below) showed the storm tapped an area of moisture that was situated north of the Hawaiian Islands, eventually stretching this moisture into a thin filament along the storm’s cold frontal boundary.

MIMIC Total Precipitable Water product (click image to play animation)

MIMIC Total Precipitable Water product (click image to play animation)

Later in the day, an overpass of a EUMETSAT MetOp satellite provided ASCAT ocean surface winds over the large occluded storm as it was moving slowly off the coast of British Columbia, Canada. A comparison of 1-km resolution MODIS 0.65 µm visible channel and MODIS 11.0 µm IR channel images with an overlay of ASCAT wind vectors is shown below.

MODIS 0.65 µm visible channel and 11.0 µm IR channel images + MetOp ASCAT scatterometer surface winds

MODIS 0.65 µm visible channel and 11.0 µm IR channel images + MetOp ASCAT scatterometer surface winds

GOES-15 is operational once again

March 23rd, 2012 |
GOES-13 + GOES-15 6.5 µm water vapor channel images (with surface analyses and buoy reports)

GOES-13 + GOES-15 6.5 µm water vapor channel images (with surface analyses and buoy reports)

GOES-15 was restored to operational status mid-day on 23 March 2012 (after a satellite outage that began after 20:30 UTC on 21 March). Using AWIPS, a sequence of  GOES-13 6.5 µm water vapor channel images early in the day, followed by the return of GOES-15 6.5 µm water vapor channel images (above) showed the dramatic improvement in the appearance of features associated with a large mid-latitude cyclone over the East Pacific Ocean. This cyclone was producing Storm Force winds over the open waters of the Pacific, as well as Gale Force winds off the coasts of California and Oregon.

McIDAS images of GOES-15 0.63 µm visible channel data (below) portrayed the large size of this storm system.

GOES-15 0.63 µm visible channel images (click image to play animation)

GOES-15 0.63 µm visible channel images (click image to play animation)

Shown below is an HD-format version of an animation of GOES-15 0.63 µm visible channel images (courtesy of Tim Schmit, NOAA/ASPB/CIMSS).

GOES-15 0.63 µm visible channel imsage (click image to play animation)

GOES-15 0.63 µm visible channel imsage (click image to play animation)

Warm water temperatures in the Great Lakes

March 21st, 2012 |
MODIS Sea Surface Temperature product

MODIS Sea Surface Temperature product

On 20 March 2012, the Milwaukee/Sullivan NWS forecast office posted a story about possible record warm water temperatures in southern Lake Michigan. Then, on 21 March 2012, the Lake Erie water temperature measured at Buffalo, New York was 39º F, which tied for the warmest water temperature ever measured there during the month of March (Lake Erie water temperature records).

An AWIPS image of the MODIS Sea Surface Temperature (SST) product (above) showed that there were a number of pockets of warm SST values in the 50s F (green to yellow color enhancement) within Lakes Michigan, Huron, Erie, and Ontario, with only a few isolated SST values in the 30s F (darker blue color enhancement) in each of those lakes.

Upwelling of cold water along the eastern shore of Lake Michigan

September 7th, 2011 |
Comparison of 8-day average MODIS SST (left) and 07 September MODIS SST (right)

Comparison of 8-day average MODIS SST (left) and 07 September MODIS SST (right)

 

A comparison of the MODIS 8-day average Sea Surface Temperature (SST) ending on 06 September 2011 (above, left) with the MODIS SST product on 07 September 2011 (above, right) revealed a dramatic cooling of the near-shore waters just off the east coastline of Lake Michigan. Persistent strong northerly daytime winds (gusting in the 20-30 mph range) induced an upwelling of colder water from below the surface, with 07 September values as cold as 6.8ºC (44ºF) at one location (Latitude/Longitude 43.63 North/81.96 West) — compared to the previous 8-day average SST of 22.8ºC (73ºF) at that same location. Unfortunately, the MODIS Cloud Mask that is applied to the SST product mistakenly identifies the strongest SST gradient as a cloud, and blanks out the SST product along the far western fringe of the ribbon of colder water.

AWIPS images of MODIS 0.65 µm visible channel and 11.0 µm IR channel data (below) showed greater detail in the ribbon of colder waters, with a series of eddies forming along the northern edge of the feature. Since no Cloud Mask is applied to the IR image, the full westward extent of the cold water feature can be seen.

 

MODIS 0.65 µm visible channel and 11.0 µm IR channel images

MODIS 0.65 µm visible channel and 11.0 µm IR channel images

 

A sequence of four MODIS 11.0 µm IR images (below) shows the evolution of the eddy features along the western edge of the cold water. Note that the land surfaces exhibit cool IR brightness temperatures (blue to cyan color enhancement) on the first 2 night-time images (03:10 UTC and 07:21 UTC, or 10:10 pm and 2:21 am local time), but on the 2 daytime images (16:45 UTC and 18:27 UTC, or 11:45 am and 1:27 pm local time) urban areas and regions with less dense vegetation heat up and exhibit much warmer IR brightness temperatures (orange to red color enhancement). However, the Lake Michigan IR brightness temperatures generally remain constant during this time period.

MODIS 11.0 µm IR images

MODIS 11.0 µm IR images

 

CIMSS participation in GOES-R Proving Ground activities includes making a variety of MODIS images and products available for National Weather Service offices to add to their local AWIPS workstations. Currently there are 49 NWS offices receiving MODIS imagery and products from CIMSS. In addition, the VISIT training lesson “MODIS Products in AWIPS” is available to help users understand these products and their applications to weather analysis and forecasting.