[ODF_Private_Forests] Termination of Prescribed Burn Suspension on Wednesday

[WEEKS Kevin]

ODF Private Forests News:

The statewide suspension on prescribed burning is lifted effective Wednesday morning. Additional information about changing conditions is included in this message from ODF meteorology manager Jim Trost.

Kevin Weeks
ODF Agency Affairs / Private Forests Division
(503) 945-7427

________________________________
From: TROST Jim
Sent: Tuesday, January 20, 2009 1:02 PM


The blanket, statewide suspension of prescribed forestland burning is terminated effective Wednesday morning, Jan 21.  However, conditions remain marginal and any burning that is planned must be coordinated with the smoke management meteorologist (503-945-7401) prior to ignition.  Until conditions improve, consider only those units with a critical need to be burned and only those that are well away from SSRAs.

Conditions are far from ideal and burning will still need to be very carefully controlled.  Here is Jim Little's analysis of what we can expect for the next few days:

For the past several days the Pacific Northwest has felt the effects of a major and persistent ridge of high pressure in the upper atmosphere. This has brought dry weather and warm temperatures to much of Oregon. The exception has been valley locations which have remained cold due to low level temperature inversions. The atmosphere has been very stable and smoke dispersion conditions have been generally poor over the state.

The upper level ridge axis is now over eastern Idaho and beginning to weaken. An upper level trough of low pressure is now located about 400 miles west of the Oregon coastline. Smoke dispersal conditions will improve slowly as this feature continues to move eastward. However, computer models indicate that it is splitting into at least three upper systems. The stronger portions will move to the north and south of Oregon while the weaker center portion will slowly push into the northern part of the state.

Unfortunately this will likely not be strong enough to scour out the cold air in many western valley locations and in the Columbia Basin. For that, we are now waiting for a stronger upper trough to drop down from the northwest over the weekend.

Bottom line: Slowly improving smoke dispersal conditions the rest of this week, with significantly better conditions over the weekend. We will be lifting the state-wide ban on forestry burning on Wednesday. However, we will only approve burns on an individual basis. Complex wind flow patterns associated with the splitting trough, and continued surface-based inversions mean approvals will be limited. Feel free to speak with the forecaster regarding specific locations, but locations below about 2500 feet or near SSRA's are not likely to be approved.


Jim Trost
Meteorology Manager
Oregon Dept of Forestry
2600 State St, Salem, OR 97310
(503)945-7448

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