SMOKE MANAGEMENT FORECAST AND INSTRUCTIONS

SALEM FORESTRY WEATHER CENTER

OREGON DEPARTMENT OF FORESTRY

 

ISSUED: Monday, December 22, 2014       2:35 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 NORTHEAST FORECAST AREA ZONES 637-646

 

SHORT-TERM DISCUSSION

The atmosphere will remains stable overnight and throughout Tuesday, as the upper level ridge builds in strength over the Oregon coast. Surface ridges west of the Cascades will push over the mountains and be strengthened by warming air aloft. 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 Wednesday afternoon, with mixing improving ahead of the cold frontal boundary. Rain showers will sweep across western Oregon Wednesday afternoon and taper off after sunset. The freezing level will drop rapidly after frontal passage, so higher elevations may see wet snow late Christmas Eve.

By Thursday morning, another upper level ridge will begin to build offshore from the Pacific Northwest, stabilizing the atmosphere rapidly. 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. 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 be marginal in the morning, with restricted improvement Friday afternoon. The atmosphere will progressively dry out through Friday evening.

2.  DISPERSION

 

TUESDAY

 

Zone 640, 642, and 644 West of R35E:

Mixing height below 1000 ft during the morning rising to 2000 - 3000 ft during the afternoon lowering below 1000 ft during the evening.

 

Transport wind S to SSW at 15 - 25 mph during the morning.  Transport wind decreases to S to SW at 8 - 12 mph during the afternoon and evening.

 

Surface wind ESE to SSE at 8 - 12 mph during the morning and afternoon.  Surface wind decreases to S to SW at 4 - 8 mph during the evening.

 

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

Mixing height below 1500 ft early rising to 1500 - 2500 ft by late morning.  Afternoon mixing height rises to 3000 - 4000 ft then lowers to 1500 - 2500 ft during the evening.

 

Transport wind SE to S at 8 - 12 mph during the morning and afternoon.  Transport wind increases to SSE to SSW at 14 - 28 mph during the evening.

 

Surface wind ENE to ESE at 5 - 9 mph during the morning and afternoon.  Surface wind increases to ESE to SSE at 9 - 15 mph during the evening.

 

OUTLOOK:

 

WEDNESDAY

In the west mixing height below 1000 ft early rising to 1500 to 2500 ft by late morning and through the afternoon.  In the east mixing height 1000 to 2000 ft throughout the day.  Transport wind S to SSW at 14 - 24 mph during the morning becoming WSW to WNW at 15 - 29 mph during the afternoon.  Surface wind SE to S at 8 - 14 mph during the morning becoming SW to W at 8 - 12 mph during the afternoon.

 

THURSDAY

Mixing height 4200 to 5000 ft during the morning lowering to 3500 to 4500 ft during the afternoon.  Transport wind NW to NNW at 15 - 25 mph.  Surface wind WNW to NW at 8 - 12 mph.

 

FRIDAY

Mixing height 2500 to 3500 ft throughout the day.  Transport wind SSW to WSW at 5 - 9 mph.  Surface wind ESE to SSE 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 Tuesday and Wednesday, December 23 and 24, 2014.

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For Tuesday:

 

Zone 640, 642, and 644 West of R35E:

Unfavorable burning situation due to very poor smoke dispersion.  Delay ignitions until 10 a.m.  Avoid ignitions within 20 miles to the SSE through WSW of SSRAs.  For units that will smolder significantly through the night avoid burning within at least 35 miles to the SSE through W in or near drainages leading to SSRAs.  Recommend against burning units that will smolder significantly overnight.  Complete ignitions by 2 p.m. 

 

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

Unfavorable burning situation due to very poor smoke dispersion.  Delay ignitions until 10 a.m.  Avoid ignitions within 20 miles to the SE through SW of SSRAs.  For units that will smolder significantly through the night avoid burning within at least 35 miles to the E through SW in or near drainages leading to 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 12 miles to the SSE through NNW of SSRAs.  Care needed in selecting units as smoke will likely fumigate along the ground in wind prone areas.  Watch for shifting transport winds.  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