SMOKE MANAGEMENT FORECAST AND INSTRUCTIONS

SALEM FORESTRY WEATHER CENTER

OREGON DEPARTMENT OF FORESTRY

 

ISSUED: Monday, December 22, 2014       2:40 PM      Tom Jenkins
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This will be the final smoke management instruction for 2014, and is valid for Tuesday, December 23rd and Wednesday, December 24th. ODF Smoke Management will be closed on December 25th and December 26th and will re-open on Monday, December 29th, 2014.

For smoke management guidance and burning clearance, call the forecaster Mondays through Fridays 7:30am-5:00pm. The smoke management instruction will resume when burning operations increase in Spring 2015 or sooner as required.

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1.  DISCUSSION AND FORECAST FOR SOUTH CENTRAL OREGON ZONES 624 AND 625

 

SHORT-TERM DISCUSSION

The atmosphere will remains stable overnight and throughout Tuesday, as the upper level ridge builds in strength over the Oregon coast. The surface ridges will be enhanced by warming air aloft, shifting into the Cascades before mid-day. Winds will start out light & variable, influenced primarily by terrain, but shift to offshore flow Tuesday afternoon. Mixing conditions will start out poor, with little to no improvement in the afternoon hours. Offshore flow will persist after dark, as the upper level ridge passes east of the Cascades and an upper level trough approaches from the Gulf of Alaska.

EXTENDED DISCUSSION

Christmas Eve is primed to be a favorable burning day before the holiday weekend. The atmosphere will become unstable as an upper level trough approaches early Wednesday, following the jet stream southeast across Oregon. It will form a surface frontal system, with the warm front extending across northern zones before sunrise. Winds will shift to onshore flow by mid-day, with mixing improving ahead of the cold frontal boundary. Rain showers will sweep across western Oregon Wednesday evening. The freezing level will drop rapidly behind the cold front, producing a wintry mix that will persist into late Christmas Eve.

By Thursday morning, another upper level ridge will begin to build offshore from the Pacific Northwest, stabilizing the atmosphere progressively. Wintry mix will taper off early Christmas morning as mixing in the atmosphere diminishes. Surface ridges will form by sunrise near the Oregon coast, creating steady onshore flow that will weaken as the ridges move onshore Christmas Day. Mixing conditions will start good, maintained due to the advancing high pressure Thursday afternoon. Mixing conditions will deteriorate rapidly after sunset, however. The upper level ridge will continue to build overnight, slowing its approach towards North America. This will strengthen the surface ridges and cause them become trapped on the western side of the Cascades Friday morning. Winds will become light & variable, influenced primarily by local terrain. Mixing conditions will remain poor all day under very stable conditions, and the atmosphere will progressively dry out through Friday evening.

2.  DISPERSION

 

TUESDAY

 

Mixing height below 1000 ft early rising to 1000 - 1700 ft by late morning.  Afternoon mixing height rises to 1000 - 2000 ft then lowers below 1000 ft during the evening.

 

Transport wind light and variable and controlled by local terrain.  Transport wind increases to SE to S at 4 - 8 mph during the evening.

 

Surface wind light and variable and controlled by local terrain.

 

OUTLOOK:

 

WEDNESDAY

Mixing height below 1000 ft early rising to 1000 - 2000 ft by late morning and through the afternoon.  Transport wind SSW to WSW at 8 - 14 mph.  Surface wind S to SW at 4 - 8 mph during the morning becoming WNW to NW at 8 - 12 mph during the afternoon.

 

THURSDAY

Mixing height 4000 - 5000 ft during the morning lowering to 3000 - 4000 ft during the afternoon.  Transport wind NW to NNW at 10 - 20 mph during the morning becoming NW to N at 8 - 12 mph during the afternoon.  Surface wind WNW to NNW at 8 - 12 mph.

 

FRIDAY

Mixing height below 1000 ft early rising to 1000 - 1700 ft by late morning rising to 1500 - 2500 ft during the afternoon.  Transport wind E to ESE at 8 - 12 mph.  Surface wind ENE to ESE at 4 - 8 mph.

 

3.  BURNING INSTRUCTIONS FOR ZONES 624 AND 625 INCLUDING THE WALKER

    RANGE PORTION OF ZONE 624

This instruction is valid for burning conducted on Tuesday and Wednesday, December 23 and 24, 2014.

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For Tuesday:

 

Unfavorable burning situation due to very poor smoke dispersion.  Delay ignitions until 12 p.m.  Avoid ignitions within 20 miles in all directions of SSRAs.  For units that will smolder significantly through the night avoid burning within at least 35 miles in all directions of SSRAs.  Recommend against burning units that will smolder significantly overnight.  Complete ignitions by 2 p.m. 

 

For Wednesday:

 

Delay ignitions until 10 a.m.  Avoid ignitions within 15 miles to the SSW through NNW of SSRAs.  Watch for shifting transport winds. 

 

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4.  SPECIAL NOTE:

 

    The smoke management forecaster is available at (503)

    945-7401.  The smoke management forecaster is available

    to discuss specific burns.  The duty forecaster phone

    number is (503) 945-7401. Please call this number and

    not individual's numbers to discuss daily burning. Please

    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