Daily Archives: October 18, 2012

Fog Over Florida

GOES-R IFR Probabilities (from GOES-14 and GOES-13) (upper left), Thickness of lowest liquid water cloud (upper right), Brightness temperature difference product from AVHRR (lower left), Brightness temperature difference product from GOES-East (lower right)

Light winds allowed for the development of radiation fog over Florida early in the morning of Oct 18th, 2012, and the GOES-R IFR Probability fields matched the development of the fog, with probabilities increasing over the course of the night as IFR conditions became more and more widespread.  The GOES-R IFR Probability product fuses satellite data with Rapid Refresh model output (as well as ancillary data such as SSTs and surface emissivity).

An interesting aspect of this case is the development of a mid-level cloud deck — visible in the AVHRR brightness temperature difference field at 1031 UTC (and in the GOES-R cloud thickness product as well, from GOES) over the north-central part of the Florida Peninsula.  A still image of the 10.7 micron field, below, plainly shows this mid-level feature.  This region of mid-level clouds correlates well with a slight drop in the GOES-R IFR probabilities.

GOES-14 10.7 micron imagery, 1101 UTC.

The Thickness of the lowest liquid cloud layer, upper right, can be correlated with fog dissipation time.  The last image before twilight conditions, at 1115/1132 UTC, shows thicknesses peaking around 1000 ft.  This corresponds to a dissipation time of at most 4 hours.  Indeed, a visible image at 1415 UTC show that the fog has largely dissipated.  The visibility at KJAX increases to 3 statute miles at 1419 UTC.

GOES-14 visible imagery at 1415 UTC on 18 October 2012