SMOKE MANAGEMENT FORECAST AND INSTRUCTIONS

SALEM FORESTRY WEATHER CENTER

OREGON DEPARTMENT OF FORESTRY

 

ISSUED: Saturday, April 25, 2015       2:35 PM      Tom Jenkins

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Oregon Department of Forestry’s Weather Center will resume 7-days-per-week operations to support the Spring 2015 Prescribed Burning Season on Sunday, April 19th 2015. We have also resumed issuing a daily Smoke Management Forecast and Instructions for the entire state until further notice.

The following days will show progressively deteriorating mixing conditions for prescribed burning operations, but will be favorable to dry and cure fuel. Another storm system predicted for later this week will provide opportunities for increased broadcast burning operations.

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1.  DISCUSSION AND FORECAST FOR NORTHEAST FORECAST AREA ZONES 637-646


SHORT-TERM DISCUSSION

The atmosphere will stabilize rapidly, as an upper-level trough exits the region after sunrise and an upper-level ridge begins to build into Oregon Sunday evening. Onshore flow will weaken and become more northerly, as a surface ridge begins to form near western zones. Mixing conditions will improve after sunrise, but quickly drop after dark as an inversion forms under clearing skies.

EXTENDED DISCUSSION

The upper-level ridge builds and begins to tilt eastward as it moves over the Oregon coast Monday morning. Poor mixing conditions in the morning with light winds will create an inversion in sheltered valleys. Warming air aloft will restrict the amount of mixing in the atmosphere Monday afternoon. The upper-level ridge will shift into the Cascades Monday evening, strengthening the surface ridge in eastern Oregon. Tuesday morning, a stronger inversion will keep mixing levels low, with gradual improvement after sunrise. The surface ridge will slowly drift east into the John Day Basin. The upper-level ridge supporting this feature will shift east towards Idaho Tuesday afternoon. An upper-level trough approaching from the west will begin to destabilize the atmosphere after sunset on Tuesday evening. Wednesday morning, weak onshore flow will develop at the surface and aloft. Mixing conditions will improve quickly, as cooler air aloft moves in from the west. A second upper-level trough will pass northeast across the region Wednesday afternoon, enhancing northerly onshore flow behind it with improved mixing conditions. The atmosphere will remain unstable overnight Wednesday.

2.  DISPERSION

 

SUNDAY

 

Zone 640, 642, and 644 West of R35E:

Mixing height below 1000 ft early rising to 3000 - 4000 ft by late morning.  Afternoon mixing height rises to 4000 - 5000 ft then lowers to 2300 - 3300 ft during the evening.

 

Transport wind light and variable and controlled by local terrain during the morning.  Transport wind increases to W to NW at 6 - 12 mph during the afternoon and increases to W to WNW at 12 - 24 mph during the evening.

 

Surface wind light and variable and controlled by local terrain during the morning.  Surface wind increases to WNW to NNW at 6 - 10 mph during the afternoon and evening.

 

Zone 637, 643, 645, 646, and 644 East of R34E:

Mixing height above 5000 ft during the morning and afternoon.  Mixing height lowers to 2500 - 3500 ft during the evening.

 

Transport wind NW to N at 10 - 20 mph during the morning.  Transport wind decreases to NW to N at 8 - 14 mph during the afternoon and evening.

 

Surface wind NW to NNW at 8 - 12 mph.

 

OUTLOOK:

 

MONDAY

Mixing height below 1000 ft early rising to 2600 to 3600 ft by late morning rising to 3800 to 4800 ft during the afternoon.  Transport wind SE to S at 4 - 8 mph.  Surface wind light and variable during the morning becoming SSE to SSW at 4 - 8 mph during the afternoon.

 

TUESDAY

Mixing height below 1000 ft early rising to 2500 to 3500 ft by late morning rising to 4500 to 5000 ft during the afternoon.  Transport wind SSE to SSW at 15 - 25 mph during the morning becoming SSW to SW at 10 - 20 mph during the afternoon.  Surface wind SE to SSW at 8 - 12 mph during the morning becoming SSW to SW at 9 - 15 mph during the afternoon.

 

WEDNESDAY

Mixing height 3200 to 4200 ft during the morning rising to 4500 to 5000 ft during the afternoon.  Transport wind N to NE at 4 - 8 mph.  Surface wind NW to N at 4 - 8 mph.

 

3.  BURNING INSTRUCTIONS FOR NORTHEAST OREGON ZONES 637-646

    The following considerations should be adhered to in addition to

    the requirements of the Oregon Smoke Management Plan. These

    Instructions are valid for burning conducted on Sunday, April 26, 2015.

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Zone 640, 642, and 644 West of R35E:

Avoid ignitions within 12 miles to the SW through NW of SSRAs.  For units that will smolder significantly through the night avoid burning within at least 20 miles in all directions of SSRAs.  No additional restrictions necessary. 

 

Zone 637, 643, 645, 646, and 644 East of R34E:

Avoid ignitions within 10 miles to the NW through NNE of SSRAs.  For units that will smolder significantly through the night avoid burning within at least 15 miles to the W through NNE in or near drainages leading to SSRAs.  No additional restrictions necessary. 

 

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4.  SPECIAL NOTE:

 

    The smoke management forecaster is available at (503)-

    945-7401. Please call this number and not individual's

    numbers to discuss daily burning.  For large burns (over

    2000 tons) or burns extending over a considerable period,

    please request a special forecast.  Avoid calling before

    8 a.m. and between 2 to 3 p.m.

 

    This forecast is available on the Internet at:

      http://oregon.gov/ODF/FIRE/fire.shtml/#Smoke_Management_Information

 

    Please ensure your units have been planned and accomplished by checking:

      http://oregon.gov/ODF/FIRE/SMP/dailysmoke.shtml