Not that I am fixated on the Sun

Here are the sunset milestones I will be following as we crawl out of winter here in Anchorage.

Sunset after 4 PM:  January 6.
Sunset after 5 PM:  January 30.
Sunset after 6 PM:  February 21.
Daylight Savings Time: March 10.
Sunset after 8 PM:  March 14.
Sunset after 9 PM:  April 6.

I can keep going, but having the sun set after 9 PM is all I need. The sun sets at 11:42 PM on the summer solstice.


Rip Tide

While stationed in Duluth, there was a riptide related death on the lake side of Minnesota Point. It was August 17th, 2003. The lake was abnormally warm, partially due to the strong onshore winds holding the warmer water against the beach. So there was a lot swimmers out in the high waves. This unfortunately created a dangerous rip current situation, and a 21 year old died because of it. Junior Lessard, future Hobey Baker award winner, was also caught in the current. He was rescued by a surfer.

I was on the bay side of the point that day kayaking. I didn’t want anything to do with those big waves, and the bay had calm waters.  I saw the helicopter hovering over the beach from afar, but didn’t connect that it had anything to do with riptides. I thought it was a boat related incident.

Two or three weeks later I snapped a few beach pictures in an attempt to help me understand riptides. No big winds that day, so the pictures aren’t particularly dramatic. This first picture shows the character of the beach. It isn’t straight. There are parts that stick out into the lake (I call them ridges) and the in-between areas that I call troughs.

The lake is shallower over the ridges compared to the troughs. So the waves shoal sooner when going over a ridge (example below).

So the water that flows over the ridge, drains into the adjacent troughs, and flows out back into the lake. This flow is the rip current. Each wave that comes in refills the trough to fuel the current. If you are caught in this current, you will be swept out into the lake with it. Now that you understand this, it makes perfect sense to swim sideways (parallel to the beach) when caught in a current. You swim sideways until you are even with a ridge, away from a trough… then you swim toward shore. The NWS published a page to better explain this.

WRF Weather Modellin’ Cluster

Another computer, another node added to my Basement Super Computer Cluster. I am up to 3 computers in my weather model cluster. Added another 6 core Phenom II to the mess. This computer seems to be unstable, so I should be careful not to overhype this. Your cluster is only as good as your weakest computer. It has been up for 24 hours straight now, so hopes are higher.

What these 6 additional cores have afforded me is to convert my nearly continental US covering model run from 25 km to 20 km grid spacing. I then expanded my 4 km grid spaced “meso” run from covering  just southern Minnesota, to nearly the 5 state area.

Took the opportunity to update the web page. The old page is still up and running, so feel free to use it. Some of you like legacy HTML with 15 year old javascript … I fully understand.

The new pages use OpenLayers and some HTML5/CSS3/Javascript to work their magic. Still not that pretty, but I am an engineer not a designer, so stop complaining.  The course grained run that covers the CONUS can be found here. The finer resolution meso run can be found here. I tried to make these pages work with mobile devices. I succeeded somewhat. They work OK with tablets, not so good with the smaller screens. OpenLayers added pinch and touch natively to their libraries, so that is kind of slick.

The other thing I tinkered with is the Turbulence maps. Some comrades over at Chicago are doing a study and they shipped over some preliminary results. They are comparing speed shear with pilot reported clear air turbulence. The results were quite promising, so I am going to see if I can use it operationally. The Turb 500 mb through the Turb 200 mb charts on the CONUS model run now show speed shear between 50 mb layers. These maps still highlight in thick red contours where the WRF thinks mod-sev Turb will be… so we have that for comparison. As  far as the shading… blue = 25-35 kts shear (lgt-mod turb) | yellow = 35-50 kts shear (mod turb) | red = >50 kt shear (sev turb). It will be interesting to see how this verifies.

14 Years of Radar

Below is a 33 minute video of radar echoes across the continental US over the last 14 years.. The beginning of the video is approximately when the WSR 88D radar network was fully deployed.

At the beginning of the video, I am living in Marquette, Mich. I move to Duluth, MN in October 1998. Then to Shakopee, MN in August of 2006. Where were you living in that span?