GOES-R ceiling/IFR products for Digital Aviation Services

Part of the this year's Winter Experiment involves the exploration of creating cloud and visibility grids for the Digital Aviation Services effort. This idea stems from the National Weather Service overall goal of consistency in issued products. Essentially, the Aviation Weather Center would create a national grid of C&V guidance in AWIPS-2 GFE utilizing various model data and other tools, which they would then pass down to the WFO level. The regional offices would then tweak or edit these grids for the smaller scale quirks and details specific to their area of responsibility and also use this guidance for the issuance of TAFs.

So, how can GOES-R products be used to support this guidance?

It really comes in the initial stages. The mock C&V desks have been run as a collaborative effort between AWC forecasters and WFO forecasters and yesterday one of the foci was on the east U.S. (domains based on AWC FA domains). As forecasters examined various models in the East, they also took a look at observations, such as the cloud base altitudes and the MVFR probabilities to figure out where areas of interest may be and how the models were performing.

20160223 1430 UTC cloud base altitudes in AWIPS-2 D2D

As was noted in an earlier post yesterday, the cloud base altitudes struggled all day with the presence of higher clouds. For this reason, it was difficult to utilize in the Northeast. Further inland, over the Ohio Valley where high level clouds were significantly thinner, the altitudes were still quite a bit higher than observed conditions at various ground stations. While techniques to retrieve ceilings have improved, the presence of even thin cirrus could still throw off the accuracy of the algorithm, and could possible have done so in this case.

Because of these struggles, forecasters chose to shift their attention to the MVFR probabilities:

20160223 1415 UTC GOES-R MVFR Probabilities in AWIPS-2 D2D

In AWC it has been common practice to use IFR probabilities. Interestingly however, the MVFR has been the chosen product during the experiment. Part of this is the fact that the MVFR is not available in the AWC's N-AWIPS systems. However, new insight regarding the AWIPS-2 display has shown a particular usefulness for the Digital Aviation Services effort.

MVFR probabilities provide a more broad view of where low ceiling conditions current exist, i.e. where the areas of concern will be later in the day. It also provides an observation to compare with various models. In this case forecasters were looking at the mid-Atlantic area. There was a broad area of MVFR conditions extending from South Carolina up through Maryland. With a comparison, it appeared that the models handled this area fairly well. Because of this, it was decided that model guidance for the same area in later forecast periods did not require much tweaking.

20160223 Surface ceiling guidance generated by forecasters for 9Z February 24th

Typically models do tend to handle large areas of low ceiling conditions relatively well. However, areas in which there are small scale weather regimes are not often resolved well at all. It is here where the MVFR probabilities really become useful. The probabilities are known to have high accuracy from previous use by WFO and AWC forecasters. As such there has been much confidence in using it as a situational awareness tool to better hone the guidance during the experiment the past week.