Gap flow in the Strait of Juan de Fuca

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.

On the morning of 18 July 2017, low-level clouds moved eastward through the Strait of Juan de Fuca.  This can be seen in the GOES-16 Nighttime Microphysics RGB product:

Recall in this RGB product, low clouds are depicted in the aqua color (before sunrise), which is moving eastward.  After sunrise, there is a reflected component to the 3.9 micron band, therefore its recommended to only make use of this product at night.  After sunrise we may make use of the visible imagery:

Note the speed of the eastward moving low-level clouds appears to be faster than other low-level clouds in the region.  This is due to gap flow through the Strait of Juan de Fuca, a well known topic of research.

One method to make for a smooth transition in your loop between nighttime and daytime is to make use of the image combination in AWIPS and make use of visible imagery for the daylight hours.  Here is a different example of gap flow through the Strait of Juan de Fuca that makes use of the fog product at night:

Like the nighttime microphysics product, this product also makes use of the 3.9 micron band.  Once sunlight is introduced with any product that involves the 3.9 micron band, it may change the interpretation of the product which is why it is recommended for nighttime use only.  In this loop, the visible imagery becomes clear after sunrise but we still see a bit of the fog product which you may adjust with the alpha setting in your color table editor on AWIPS.

Posted in Ceilings, Fog, Visibility | Leave a comment

Tropical Activity in the East Pacific

It is that time of year again! The time of year where tropical storms, hurricanes initiate and permeate through the Atlantic and the East Pacific Oceans. Currently, a few to note are tropical depression Greg, Tropical Storm Irwin and Hurricane Hilary. A screenshot of the National Hurricane Center’s  (NHC) ‘Active Storm’ Map showing the relative locations of the storms is seen below as of 26 July 2017.


You can check out the CIRA GeoColor product loop of the tropical activity via the new RAMMB/CIRA Slider, a user interface where users can see and analyze satellite products over the entire globe. The loop is from 26 July 2017 between 14-17Z.

According to NHC, it is important to note that Hilary is a Category 2 Hurricane with maximum sustained winds of 105 mph and is forecast to move west/northwest at 13 mph as of 9AM MDT, 26 July 2017.

Here is the latest visible image of Hurricane Hilary seen below via MODIS and AVHRR at 1 kilometer resolution via the CIRA ‘TC Real Time’ website. MODIS and AVHRR are instruments on-board a few polar-orbiting satellites such as the NOAA-18 satellite.


Furthermore, what is fascinating is some of the model output such as the GFS and ECMWF models have Tropical Storm Irwin and Hurricane Hilary experiencing a Fujiwhara Effect in the next few days: where both storms rotate relatively close to one another (counter-clockwise, where both storms are approximately less than 900 miles apart from each other). According to the models in this particular case, Tropical Storm Irwin will become engulfed into Hurricane Hilary in the later days. We will see what happens! Check out the GFS model run animation of this phenomena, initialized at 12Z, 26 July 2017 via the Tropical Tidbits website below. (1)

Posted in MODIS, NWP Models (NCEP), POES, Satellites, Tropical Cyclones | Leave a comment

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.

Posted in Miscellaneous | Comments Off on California (Alamo Fire)

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.

Posted in Monsoon | Comments Off on Onset of southwest monsoon as depicted by the CIRA advected LPW product