WILDFIRE SMOKE
FORECAST
OREGON DEPARTMENT
OF FORESTRY WEATHER OFFICE
1:30 PM PDT MON
JUL 21, 2014
SIGNIFICANT FIRE INFORMATION:
Numerous wildfires in various stages of containment extend
from central to eastern Oregon.
For updated
“Significant Fire” details, visit ODF’s fire blog at http://wildfireoregondeptofforestry.blogspot.com/
or the Northwest Interagency Coordination Center (NWCC) at http://www.nwccweb.us/index.aspx.
A “Significant
Fire Potential” map, for ODF protected lands, is available at (http://nfdrs.smkmgt.com/ODF_Significant_Fire_Potential.png).
AIR QUALITY:
DEQ smoke
monitoring sensors are indicating generally good air quality throughout central
and eastern Oregon at this time.
Statewide air
quality index readings are available at http://www.deq.state.or.us/aqi/index.aspx
SMOKE DISPERSION FORECAST:
Wildfire smoke dispersion depends on the stability
of the atmosphere as well as wind direction and speed. A stable atmosphere
holds smoke to the ground and an unstable atmosphere allows smoke to rise and
dissipate. Smoke is typically mixed to higher altitudes during the afternoon,
when daytime heating destabilizes the air mass. Conversely, smoke tends to
settle near the ground and in drainages during the overnight and early morning
hours.
TODAY:
Upper level low is northwest of Vancouver Island and
slowly moving toward the state. Clouds are moving through the state from the
southwest to northeast. With the heating of the day some thundershowers will
start to develop. Mixing levels will be good this afternoon and keep wildfire
smoke mostly dispersed. Low-level wind flow is mainly light but favoring
southwesterly. This may shift from southwest to west and maybe northwest in some
locations later this afternoon. Wind flow lightens overnight and becomes mainly
influenced by local terrain.
TUESDAY &
WEDNESDAY:
Upper low moves to just off the coast on Tuesday and
inland on Wednesday. This will increase showers and thundershowers and likely
reduce fire activity on most of the active fires. However, new fire starts are
possible, especially over south central Oregon, where less moisture is likely to
occur. Mixing will be mostly good and wind flow mostly S to SW Tuesday then
becoming erratic later Tuesday due to thunderstorm development. Expect SW to W
flow Wednesday as the low starts to move through. With moisture, good mixing and
good wind flow, smoke problems should be minimal.
EXTENDED
OUTLOOK:
Upper low moves to the east and weakens Thursday and
Friday. Flat upper level ridge moves in to dry and warm the air mass. Expect
mixing heights to become quite poor overnight but remain good during the
daytime. Wind flow decreases and turns northwesterly on Thursday, light drainage
flow overnight, and northerly on Friday. Communities to the south or southeast
of fires would likely be most susceptible to impact, although most fires would
likely not have much smoke production.
Current weather
forecasts from the Portland, Medford, and Pendleton National Weather Service
offices are available at: http://www.wrh.noaa.gov/pqr/, http://www.wrh.noaa.gov/mfr/, and http://www.wrh.noaa.gov/pdt/
respectively.
This bulletin is
also available on the web at
ODF Smoke Management Meteorologist