GOES-17 IFR Probability fields are now being created for Alaska

October 15th, 2020 |

GOES-17 IFR Probability fields over Anchorage AK and surroundings, 0200 – 1300 UTC on 15 October 2020 (Click to animate)

CIMSS is now producing IFR Probability fields (and Low IFR Probability, Marginal VFR Probability, and Cloud Thickness fields) using GOES-17 data.  (Recall that GOES-16 IFR Probability fields  are now produced by NOAA/NESDIS and are distributed via the Satellite Broadcast Network (SBN) to National Weather Service Forecast Offices.  GOES-16, however, does not view Alaska).  GOES-17 fields will presently be available via an LDM pull.  NOAA/NESDIS will likely start processing the fields in 2021.

The animation above shows IFR Probability fields today over the Anchorage region.  The animation is preceded by a view of the topographic features, and IFR conditions on 15 October seem centered on topographic features.

GOES-17 can view the North Slope of Alaska.  This location is quite far from the GOES-17 sub-satellite point, so resolution is degraded from the nadir 2-km views. However, regions of likely IFR conditions are easily tracked (Again, the animation is preceded by topography), with a large region between the Arctic Ocean and the high terrain of the Brooks Range.

GOES-17 IFR Probability fields over northern Alaska, 0200 -1300 UTC, 15 October 2020 (Click to animate)


GOES-17 views of Alaska southeast, below show probabilities of low clouds and reduced visibility. As over other regions of Alaska today, highest probabilities are over high terrain. GOES-17 IFR Probability for the PACUS domain is available at this website. Work is ongoing to insert IFR Probability (from GOES-16 and GOES-17) into Real Earth.

GOES-17 IFR Probability fields over Alaska Southeast, 0200 -1400 UTC, 15 October 2020 (Click to animate)

GOES-17 fields contain artifacts in the form of horizontal stripes that can be traced to the poorly-functioning Loop Heat Pipe on GOES-17.  GOES-17 is now in a reduced-scanning mode between 0600 and 1200 UTC to enhance the ability of the satellite to shed excess heat:  fewer Mesoscale sectors are scanned, full disk sectors are not as frequent (every 15 minutes instead of every 10), and the ‘PACUS’ sector is not scanned.  This scanning strategy will continue through the end of October.

The Forecast Decision Training Division has a Quick Guide on IFR Probability fields here.  A 20-minute YouTube video explaining the product is here.