Wildfires in Alaska

July 3rd, 2009
GOES-11 visible images

GOES-11 visible images

The 2009 wildfire season roared to life in Alaska on 02 July - 03 July 2009, with a number of very large and very intense fires breaking out across interior portions of the state. A ridge of high pressure was in place over the region, allowing Fairbanks to experience a high temperature above 80º F (27º C) on both days. GOES-11 visible images (above) showed some impressive smoke plumes developing on 02 July, especially from the fire located to the east-southeast of Fort Yukon (station identifier PFYU) — note the pulses of “pyrocumulus” that emanated from this >19,000 acre “Little Black One” fire complex:

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE FAIRBANKS AK
1033 AM AKDT FRI JUL 3 2009

…WILDFIRES BRING SMOKE TO INTERIOR…

THE MAJORITY OF THE SMOKE IS COMING FROM A WILDFIRE KNOW AS LITTLE BLACK ONE. THIS FIRE IS LOCATED NORTHEAST OF CIRCLE IN THE YUKON FLATS. AS OF 230 PM YESTERDAY THIS FIRE WAS OVER 19000 ACRES. CURRENT SATELLITE IMAGERY SHOWS THIS FIRE TO BE CONTINUING TO INCREASE IN AREA.

OTHER SMALLER FIRES ARE ALSO BURNING ACROSS THE AREA. WINDS ARE CURRENTLY BLOWING THE SMOKE FROM NORTHEAST TO SOUTHWEST ON THE FIRES.

The large and dense smoke plume originating east of Fort Yukon continued to drift southwestward overnight, and had moved over the Anchorage area (station identifier PANC) by the morning hours on 03 July.

Also, in spite of the very large satellite viewing angle, another feature that could be followed on the GOES-11 visible imagery was the southwestward movement of fog and stratus from the Arctic Ocean into interior portions of the North Slope region of Alaska after about 06:00 UTC on 03 July. The visibility dropped to less than 1/2 mile at Kuparuk (station identifier PAKU) at 06:00 UTC, with an air temperature at that time of 34º F (+1º C).

GOES-11 3.9 µm shortwave IR images (below) revealed a number of very hot fire pixels (black to red color enhancement) — the hottest pixels in the “Little Black One” fire exhibited an IR brightness temperature of 341.0 K (the saturation temperature of the GOES-11 shortwave IR detectors) at 06:30 UTC. The fire located to the west-northwest of Nenana (station identifier PANN) exhibited IR pixels as hot as 340.0 K at 02:30 UTC. The large area of saturated (red) pixels across the Arctic Slope region at 09:00 UTC was due to sun glint (which also caused the very bright pixels to appear at 09:00 UTC on the visible imagery).

GOES-11 3.9 µm shortwave IR images

GOES-11 3.9 µm shortwave IR images

The GOES-11 Wildfire Automated Biomass Burning Algorithm (ABBA) product (below) analyzed the first fire pixels east of the Fort Yukon region around 19:30 UTC on 02 July.

GOES-11 Wildfire ABBA product

GOES-11 Wildfire ABBA product


Wildfire ABBA legend

Outflow boundary in the Bay of Campeche

July 2nd, 2009
GOES-12 visible images

GOES-12 visible images

GOES-12 visible images (above) revealed the northward propagation of an large convective outflow boundary across the Bay of Campeche (in the far southwestern Gulf of Mexico) on 02 July 2009. A larger-scale GOES-12 visible image (below) showed that at one point this outflow occupied an area approximately the size of the state of Wisconsin!

GOES-12 visible image

GOES-12 visible image

An overpass of the QuikSCAT satellite provided SeaWinds near-surface wind data (below) which showed that there was southeasterly flow across much of the Bay of Campeche region, but the wind speeds increased from about 10-15 knots ahead of the outflow boundary to 15-25 knots behind the outflow boundary (the winds at Buoy 42055 gusted to 21 knots around 12 UTC). The QuikSCAT wind vectors showing speeds of 34-50 knots (yellow to red colors) were not valid, due to rain flags greater than 90%. The air temperature and dew point values barely budged with the passage of this outflow boundary, due in part to the very warm (84º F or 29º C) water temperature.

GOES-12 visible + GOES-12 IR + QuikSCAT winds

GOES-12 visible + GOES-12 IR + QuikSCAT winds

AWIPS images of the Blended Total Precipitable Water (TWP) product (below) suggest that the TPW dropped from about 57 mm (2.24 inches, red color enhancement) to around 46 mm (1.81 inches, yellow color enhancement) in the wake of this outflow boundary.

Blended Total Precipitable Water product

Blended Total Precipitable Water product