MODIS fog product highlights fires

The daytime MODIS pass over Southeast Texas/Louisiana highlighted an interesting feature.  The 1944z 1/26/2010 fog product pass clearly showed 3 “hot spots” that did not show up in the GOES visible product nor in the  MODIS visible.  An altocumulus deck was developing and expanding northeast throughout the day and across the two northern burn sites.

MODIS fog product 1944z

GOES Visible 1945z

Surface observations from KJAS-Jasper Airport to the west of these plumes.
METAR KJAS 271845Z AUTO 13007KT 10SM OVC095 17/06 A3026 RMK AO2 T01710061
METAR KJAS 271905Z AUTO 12004KT 10SM OVC095 18/06 A3025 RMK AO2 T01750064
METAR KJAS 271925Z AUTO 11005KT 10SM BKN095 18/07 A3024 RMK AO2 T01830068
METAR KJAS 271945Z AUTO 16007KT 120V180 10SM BKN095 19/07 A3023 RMK AO2 T01900070
METAR KJAS 272005Z AUTO 17008KT 10SM OVC085 19/08 A3022 RMK AO2 T01900075

Radar sequence from Fort Polk KPOE 88-d

1915z

1924z

1934z

1944z

1954z

2004z

RUC Sounding at KJAS-Jasper Texas
The RUC sounding indicates the presence of the AC/mid level moisture transport from SW to NE and the mixing layer transport winds.

The plumes can be clearly seen on the radar imagery sequence and in the Modis fog product. Interestingly this is during the day, not a time that the fog product would typically be used. And that the plumes are visible beneath or through a mid level deck may have some uses. Perhaps the plume has extended above the mid level deck but this seems unlikely given the circular nature of the highlighted instead of being stretched downwind to the ENE as the cloud movement would support, and the radar plumes clearly show the low level trajectory northward albeit these images are only the 0.5 degree slices. The 0.5 degree beam height was approximately 4400 ft for the plume to the WNW of the KPOE radar and 1800 ft for plume to the east of the radar.

It would be interesting to find out if others have noted this in other areas or under different cloud regimes.

Kent Prochazka
Forecaster at Houston/Galveston

One thought on “MODIS fog product highlights fires

  1. VERY INTERESTING POST!!! The fog product uses the difference in two thermal channels, one which is more sensitive to fire signatures. I suspect you might be sensing the fire signature through thin clouds….. I will have to investigate this further!

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