Advected LPW product in identifying circulations in the vertical

On the evening of 21 February 2017, a well defined mid-level circulation moved into the San Francisco Bay region.  This circulation was responsible for a region of convection in the vicinity, mostly showers but a few thunderstorms with some low-level rotation.

The mid-level circulation can be readily identified in the 700-500 mb layer of the CIRA advected layer precipitable water (LPW) product (lower left panel) :


The circulation also shows up, to a lesser extent, in the 850 – 700 mb layer (upper right panel).

A loop of the product is shown here:

This product consists of moisture information from microwave sensors on various polar orbiting satellites, which is then advected by a model for a very short-term forecast.  Mid-level circulations that are sufficiently large enough to be resolved can be readily observed, and also indicate where they are in the vertical, providing information about the depth of the circulation.

This product is new, building on the previous product termed the layered precipitable water product which 1) made use of lower resolution data (i.e., more blocky) and 2) did not include advection from a model.  A loop of the LPW product for this case:

still shows the mid-level circulation, but not nearly as well due to the more coarse resolution of the data (and perhaps due to advection not being included also).

Posted in Coastal Effects, Convection, Satellites | Leave a comment

7-8 February 2017, New Orleans Power Outage

After a series of tornadoes ripped through southeastern Louisiana and southern Mississippi on 7 February 2017, a power outage occurred in eastern New Orleans affecting 10,000 plus people. Below is a screenshot of the affected areas: the red lines imply the power lines are off. Additionally, there are a different colored triangles on the map: the blue, yellow and red colors show 1-50, 51-250, and 251-1000 customers that were affected, respectively, and out of power.


Figure 1: Shows the areas in New Orleans affected by the power outage caused by the tornadoes that occurred on 7 February 2017.

To verify these power outages, one can use the Day/Night Band (DNB) that utilizes a sun/moon reflectance model that illuminates atmospheric features, senses emitted lights and monitors clouds during the night-time. Figure 2  shows the city of New Orleans before the power outage on 7 February 2017 at 0807Z and Figure 3 shows the magnitude of the power outages in Eastern New Orleans at 0749Z. Refer to the red circle in both images.


Figure 2: A DNB image of the city of New Orleans before the power outage occurred. The red circle is the area of interest to compare to Figure 3. The moon percent visibility and the moon elevation angle are also provided in the top-right hand corner, implying that the moon is above the horizon during this time period.


Figure 3: A DNB image of the city of New Orleans after the power outage occurred. The red circle is the area of interest to compare to Figure 2. Approximately 10,000 plus people were affected by the power outage.

A supplemental animation can be seen here.

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