California (Alamo Fire)

The state of California had sufficient moisture over the winter where the Sierra Nevada Mountains tabulated record amounts of snowfall. However, as we have transitioned into the summer months of 2017, fires have been initiated in the southern and southwestern parts of California.

One fire to note is the Alamo Fire which is located just east of Santa Maria, California. For users that are not familiar with the area, Santa Maria is located approximately 170 miles northwest of Los Angeles.

As of 11 July 2017, the cause of the fire is still unknown and the fire has burned more than 28,000 acres. On a positive note, 45% of the fire has been contained so far.

Below is an animation of the Alamo Fire from 6-10 July 2017 via the Day/Night Band (DNB), that utilizes a sun/moon reflectance model that illuminates atmospheric features, senses emitted lights and assists with cloud monitoring during the nighttime. This is also a perfect time to check out DNB imagery since the moon just passed the full moon stage of the lunar cycle.  In the animation, the moon percent visibility and moon elevation angle are also provided. Click the image below and the animation will begin.


Also, here is an additional link using the CIRA RAMMB Slider which shows the Alamo Fire on 8 July 2017 via the GeoColor Product.

For further updates on the Alamo Fire keep tabs with the ‘Cal Fire’ state webpage.

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Onset of southwest monsoon as depicted by the CIRA advected LPW product

Between the first and second week of July, moisture associated with the southwest monsoon surged into the Mojave dessert.  Prior to the arrival of this airmass, very hot temperatures and low dewpoint temperatures existed throughout the southwest.  After the arrival of this airmass, temperatures were not quite as high, and dewpoint temperatures were considerably higher.  The CIRA advected layer precipitable water product at 01Z on 5 July 2017 was representative of before the arrival of this moist airmass across the southwest:


For example, in the 850-700 mb layer (upper right panel) the blue colors represent a much drier airmass in southern California and Arizona, with a moist airmass just south of the Mexico border (in the green shades).

Soon afterwards, we see in this animation the advection of moisture from Mexico into the southwest US:

this more moist airmass at mid/upper levels goes around the strong 500 mb ridge to bring mid/upper level moisture into much of the intermountain west.  The greater moisture introduces better chances for rain, particularly for regions that had been very hot and dry.

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Advantage of 1-minute imagery for the evolution of rapidly evolving low clouds

The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing.  Users bear all responsibility for inspecting the data prior to use and for the manner in which the data are utilized.

We begin by looking at the GOES-16 visible (0.64 micron) loop on the morning of 11 July 2017 at 5 minute temporal resolution:

Notice the low-level clouds in southern Georgia extending northeastward towards coastal South Carolina that appear to flicker since they are rapidly evolving.

The GOES-16 IR (10.35 micron) loop shows a similar evolution:

A portion of this scene was captured by the mesoscale sector so that we may view the imagery at 1 minute temporal resolution:

Rather than the flickering effect we saw at 5 minute temporal resolution, we instead see rather rapid evolution of clouds developing / dissipating much more smoothly.

The environment is characterized by very light winds throughout the troposphere, along with high relative humidity through much of the low to mid levels:



How deep do these clouds extend in the vertical?  We can help answer this question by looking at the 3 GOES-16 water vapor bands (at 5 minute temporal resolution), and we will also include the Air Mass RGB product:

The rapidly evolving low-level clouds are evident in the low-level water vapor band (7.34 micron).  At 6.9 microns (mid-level water vapor band) we still see some of those features, but not as clearly.  Note that we do see numerous gravity waves, which may be playing a role in the rapidly evolving low-level clouds.  As expected, the low-level clouds do not appear in the 6.19 micron (upper-level water vapor band), however gravity waves are still observed.

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Undular bore in the Split Window Difference Product

The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing.  Users bear all responsibility for inspecting the data prior to use and for the manner in which the data are utilized.

By Louie Grasso and Dan Lindsey

On the morning of 30 June 2017, an undular bore is observed in north Texas.  The clouds associated with the undular bore can be seen on the GOES-16 visible (0.64 micron) band.  The GOES-16 Split Window Difference (10.3 – 12.3 micron) product adds additional information.  The undular bore is observed to exist further west of where clouds associated with the undular bore (in clear skies) are located.  We observe this feature in the split window difference due to local maxima in water vapor depth along the “crests” of the undular bore.


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