September 4, 2017 - Smoke: High pressure and light easterly/southeasterly winds remain in place, with cloud cover from the tropical moisture again likely to limit afternoon clearing, trapping smoke in the drainages west and northwest of the fire. Outflow winds from thunderstorms, though they can clear smoke, also increase fire activity, and the net impact this morning was very unhealthy to hazardous smoke levels this morning in areas northwest/west of the Railroad fire. Mammoth is also getting more evening smoke.

Fire: Emissions and growth on the South Fork and Empire fire remain relatively modest under the slightly cooler, and more humid conditions created by the tropical moisture overhead. However this moisture and associated instability also led to thunderstorms, the outflow winds of which pushed the Railroad growth to over 3600 acres of new growth. This in turn led to much more smoke in the areas to the west/northwest of the fire. More thunderstorms are forecast for today.

Other: Dense smoke for short periods can aggravate symptoms for sensitive persons without changing 24-hr AQI levels. Note: AQ forecasts below reflect only particulate matter - not ozone.


Source: USDA