In ForeFlight Mobile 9.0 we’ve added a high resolution surface wind analysis to the list of map layers you can display through the SiriusXM satellite weather broadcast. This new product includes both windspeed and direction presented as wind barbs similar to the winds aloft layer. Tapping on any wind barb will show the specific details.
Two surface wind layers?
Yes, there will be two surface wind layers when connected to the SXAR1. The layer you have been using in prior releases and the one you can view when connected to the Internet is strictly based on surface observations from the various weather reporting stations around the world (typically airports). This depicts the actual wind reported in the routine observation (METAR) or special observation (SPECI). The surface wind layer is depicted at weather stations as colored wind barbs; at this point in time the wind markers shown include the gust factor.
The new surface wind analysis layer is not observed data from weather stations, but instead is generated by a forecast model, and therefore, completely automated. It’s only available when connected to the SXAR1 and shows an analysis of the prevailing wind at 10 meters above the surface; it does not include the gust factor. Unlike the observed data that is updated when new observations are taken, the surface wind analysis is updated once every hour. When refreshed, this will provide wind data that will be valid at the top of the previous hour.
The primary value of this new layer is to show low level circulations at the synoptic scale level. This will point out high (clockwise) and low pressure (counter-clockwise) circulations as well as lines of convergence in the vicinity of strong frontal boundaries. This is difficult to see with the coarse network of observing sites throughout the U.S. But with the high resolution surface wind barb analysis, these circulations and convergence zones show up nicely.