GOES-14 SRSOR 1-minute imagery around SFO

There was some concern yesterday evening that SFO would experience low ceiling issues this morning. With SRSOR 1-minute imagery available in a West Coast domain, we were able to examine the SFO terminal area more closely today.

The challenge with SFO lies in the way in which traffic approaches. With parallel runways, airplanes actually end up taking a turn that has them facing each other for a brief period of time before making the final turn towards the runway. To visualize this, check out the image below in Figure 1 that shows traffic approaching SFO this morning.

Figure 1. 20150812 1438 SRSOR 1-minute visible imagery and ASDI flight tracks into SFO

Note the traffic pattern on the north side of the airport. Flights from the southeast take a turn so that they can land on the western most north-south runway. Simultaneously, flights from out east approach from a northeast direction to eventually land on the other north-south runway. It is easy to imagine the head to head approaches into the airfield.

If visibility becomes restricted in any way, safety rules require flights to either 1) be spread out to allow more room between arrivals or 2) land only on one runway. Both of these options reduce arrival numbers and cause delays. This morning low ceilings began to build in from the north. However, there were also south-southwest winds presents due to a retrograding low that has persisted off the West Coast for the past few days (Figure 2).

Figure 2. 20150812 1200 UTC GOES-W WV and Atmospheric Motion Vectors

1-minute imagery showed the leading edge of the fog approach the SFO area and reach the northern tip of the San Francisco Bay. Shortly after, it began receding due to the persistent south-southwesterly winds and also the daytime heating. Below is a loop of SRSOR 1-minute imagery with ceilings and winds.

20150812 1438 - 1604 UTC SRSOR 1-minute imagery and ceiling/wind observations

Note that the low ceilings stayed just outside the SFO terminal area. This allowed the parallel approaches to continue and no delays were necessary.