SMI West (Smoke Management Instructions) Western Oregon Smoke Management Instructions

Sat Apr 30 14:30:49 PDT 2011

SMOKE MANAGEMENT FORECAST AND INSTRUCTIONS

SALEM FORESTRY WEATHER CENTER

OREGON DEPARTMENT OF FORESTRY

ISSUED: Saturday, April 30, 2011       2:30 PM      Pete Parsons

1.  DISCUSSION AND FORECAST FOR THE WESTERN OREGON AREA FORECAST ZONES 601-623

SUNDAY

A drying northwesterly flow aloft will help to clear skies, in the wake of an unseasonably cold upper-level trough.  That will make for a very cold morning, with areas of valley frost.  A transitory upper-level ridge is forecast to move onshore, during the day, with continued warming and drying of the air mass.  The freezing level will jump to 9000 feet north and 10,000 feet south.

A surface thermal trough is forecast to build northward, into southwestern Oregon, and help high temperatures recover to above normal.  Offshore flow, especially early in the day, will combine with ample sunshine to aid in the drying of fuels, with fair to good afternoon mixing.  The surface thermal trough is forecast to shift eastward enough for a return to onshore flow, across the southern-most zones, late in the afternoon.  Winds will likely go light and variable across the northern zones in the afternoon.  The burning instructions reflect transport winds turning light and variable across most zones by early afternoon.

OUTLOOK (MONDAY-WEDNESDAY)
The upper-level ridge is forecast to progress east of the state by Monday with an increasing westerly flow aloft directing a cold front onshore in the morning.  Transport winds will likely turn onshore across the northern zones early in the morning, which will limit burning opportunities in the coast range.  The latest guidance is more impressive with rainfall amounts and coverage from this system.  Some northern areas will likely see more than .10 inches, with light rain or a few showers possibly reaching the southern zones.  Cooling aloft should maintain fair to good mixing Monday.  Southwesterly transport winds will become more west to northwesterly, in the wake of the cold front, during the afternoon.  High temperatures will be slightly below normal north and near normal south.  Snow levels will drop to around 3500 feet north and 5500 feet south late.

An upper-level trough will push east of the state Tuesday.  A drying northwesterly flow aloft will begin to clear skies, with a few lingering showers possible north.  The freezing level will rise to near 7000 feet north and 10,000 feet south by evening.  Even with increasing sunshine, locally brisk north to northwesterly winds will hold temperatures near to slightly below normal. Warming aloft and cool surface temperatures will likely suppress mixing slightly, especially south, with fair to good afternoon mixing.

Another weak and transitory upper-level ridge is forecast to move onshore by Wednesday afternoon, bringing mostly sunny and warmer conditions.  Temperatures will recover to near normal north and to above normal south.  Northerly transport winds may turn slightly offshore, as a surface thermal trough attempts to build northward into southwestern Oregon.  The freezing level will lift to about 9000 feet north and to over 10,000 feet south.  Warming aloft may suppress mixing heights slightly, but warmer surface temperatures should make for fair to good afternoon mixing.

The upper-air pattern is forecast to remain progressive, with long-range computer models differing on the strength of a weaker weather system forecast to come onshore late Thursday and Friday. That system may bring light rain or showers to the northern zones.  A stronger weather system is forecast to bring back cool and damp conditions next weekend.

2.  DISPERSION

Zone 601-612 (North Coast Range and Cascades):

MORNING

Mixing height below 500 ft early rising to 2500 - 3500 ft by late morning.

Transport wind NE to E at 4 - 8 mph.

Surface wind NNE to ENE at 4 - 8 mph.

AFTERNOON

Mixing height rising to 4000 - 5000 ft.

Transport wind becomes light and variable and controlled by local terrain.

Surface wind becomes light and variable and controlled by local terrain.

EVENING

Mixing height 1000 - 2000 ft.

Transport wind similar to afternoon.

Surface wind similar to afternoon.

Zone 615-623 (South Coast Range and Cascades):

MORNING

Mixing height below 1200 ft early rising to 3000 - 4000 ft by late morning.

Transport wind E to SE at 6 - 10 mph.

Surface wind ENE to ESE at 4 - 8 mph.

AFTERNOON

Mixing height rising above 5000 ft.

Transport wind becomes light and variable and controlled by local terrain.

Surface wind becomes light and variable and controlled by local terrain.

EVENING

Mixing height 1000 - 2000 ft.

Transport wind similar to afternoon.

Surface wind similar to afternoon.

OUTLOOK:

MONDAY

Mixing height 2400 to 3400 ft during the morning rising above 5000 ft during the afternoon.  Transport wind SSW to SW at 10 - 22 mph during the morning becoming W to WNW at 10 - 22 mph during the afternoon.  Surface wind S to SW at 5 - 9 mph during the morning becoming W to NW at 8 - 14 mph during the afternoon.

TUESDAY

Mixing height below 1000 ft early rising to 2400 to 3400 ft by late morning rising to 3800 to 4800 ft during the afternoon.  Transport wind NNW to NNE at 6 - 12 mph.  Surface wind NW to NNE at 5 - 9 mph.

WEDNESDAY

Mixing height below 1000 ft early rising to 2000 to 3000 ft by late morning rising to 4000 to 5000 ft during the afternoon.  Transport wind NE to ENE at 8 - 14 mph.  Surface wind N to NE at 5 - 9 mph during the morning becoming NNW to NNE at 9 - 15 mph during the afternoon.

3.  BURNING INSTRUCTIONS FOR ALL ZONES IN THE WESTERN OREGON AREA

These instructions are valid for burning conducted on Sunday, May 1, 2011.

=================================================================

Coast Range

Zone 601 and 612

Units should be 750 tons or less, spaced 8 miles apart, and 10 miles from downwind SSRAs.

Zone 602 and 603

Units should be 500 tons or less, spaced 8 miles apart, and 10 miles from downwind SSRAs.

Zone 615 and 618

Use standard guidance matrix. (See section 5 below.)  Avoid burning directly upwind of the North Bend/Coos Bay SSRA.

Zone 616 west of R8W

Units should be 1500 tons or less, spaced 5 miles apart, and 10 miles from downwind SSRAs.  Higher tonnage is possible south of T29S.  Call the forecaster.

Zone 616 east of R9W

Units should be 1000 tons or less, spaced 5 miles apart, and 10 miles from downwind SSRAs.  Higher tonnage is possible south of T29S.  Call the forecaster.

Zone 619

Units should be 2000 tons or less, spaced 5 miles apart, and 10 miles from downwind SSRAs.

Zone 620

Units should be 500 tons or less, spaced 5 miles apart, and 10 miles from downwind SSRAs.

Cascades

Zone 605, 606, 620, and 622

Units should be 500 tons or less, spaced 5 miles apart, and 10 miles from downwind SSRAs.

Zone 607, 608, 609, 617, and 623

Use standard guidance matrix. (See section 5 below.)  Ensure adequate distance from downwind SSRAs for smoke to dissipate.

Zone 610 and 611

Units should be 1500 tons or less, spaced 5 miles apart, and 10 miles from downwind SSRAs.

Zone 616

Units should be 1000 tons or less, spaced 5 miles apart, and 10 miles from downwind SSRAs.

Siskiyous

Units should be 1000 tons or less, spaced 5 miles apart, and 10 miles from downwind SSRAs.

==============================================================

4.  SPECIAL NOTE:

    Call the smoke management duty forecaster at (503) 945-7401 to

    discuss burning.  Please do not call individual's numbers to

    discuss daily burning.  If the forecaster is not available,

    leave a message and he will return your call as soon as possible.

    Avoid calling between 2 to 2:30 p.m.

    The forecast is available on the Internet at:

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

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

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

5.  STANDARD GUIDANCE MATRIX:

  * Greater than 5000 ft mixing height:  No burning within 5 miles of

    downwind SSRA.  Maximum 100 tons per mile from downwind SSRA.

    Example:  500 ton maximum allowed if burned 5 miles from downwind SSRA.

  * 3000 - 5000 ft mixing height:  No burning within 10 miles of

    downwind SSRA.  Maximum 75 tons per mile from downwind SSRA.

    Example:  750 ton maximum allowed if burned 10 miles from downwind SSRA.

  * Less than 3000 ft mixing height:  No burning within 15 miles of

    downwind SSRA.  Maximum 50 tons per mile from downwind SSRA.

    Example:  750 ton maximum allowed if burned 15 miles from downwind SSRA.

  * All exceptions must be coordinated with the duty forecaster

    prior to ignition.

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