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

Fri Nov 19 14:27:34 PST 2010

SMOKE MANAGEMENT FORECAST AND INSTRUCTIONS

SALEM FORESTRY WEATHER CENTER

OREGON DEPARTMENT OF FORESTRY

ISSUED: Friday, November 19, 2010       2:30 PM      Pete Parsons

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

SATURDAY

A cold upper-level trough will remain anchored over the region with the trough axis staying just offshore. A fairly strong upper-air disturbance will drop southward, into the parent trough, with a corresponding surface low-pressure center developing off the Washington coast and drifting southeastward during the day.

Showers will circulate onshore with the surface low-pressure center forecast to eventually move inland, near the Oregon/California border, late. That will increase the precipitation across the extreme southern zones.  Transport winds should maintain a southerly component over the southern zones with an increasing offshore flow over the northern zones.  Snow levels will drop to 1500 feet north and 2000 feet south with good smoke dispersal conditions.

OUTLOOK (SUNDAY-TUESDAY)

A cold upper-level trough will remain over the region, on Sunday.  One disturbance will rotate inland early, bringing rain and snow to mainly the most southern zones.  The northern zones will come under the influence of an even colder northwesterly flow aloft.  Smoke dispersal conditions will remain good with increasing south to southwest transport winds.  Another upper-level disturbance is forecast to drop southward, from British Columbia, to just off the Washington and northern Oregon coast late in the day.  That system appears to have enough moisture to bring increasing showers to all zones.  Snow levels will drop to near 1000 feet north and 1500-2000 feet south.

By Monday, the flow aloft is forecast to turn northwesterly, with an even colder upper-level system dropping southward, from British Columbia, into the region.  This system will be accompanied by a surface Arctic cold front, which will usher the coldest air of the season into the region.  The track of this system is still uncertain, but if it has enough moisture to work with, it will bring snow to even the lowest elevations in the northern zones.  Snow levels will drop to near 1500 feet over the southern zones.  Smoke dispersal conditions should remain good.  Transport winds will be mostly westerly but will switch to northerly across the northern-most zones late.

On Tuesday, a very cold and drier northerly flow is forecast, with sub-freezing morning temperatures, and possibly snow-covered ground, across most zones.  Skies will stay partly to mostly cloudy with a slight chance of showers.  The snow level will be at sea-level north and near 1500 feet south.  Cold low-level air will stabilize the air mass, especially north, with light north to east winds.  Smoke dispersal conditions will likely decrease to marginal-to-fair.

2.  DISPERSION

Zone 601, 602, 603 and 612 (North Coast Range):

MORNING

Mixing height below 2500 ft early rising to 3000 - 4000 ft by late morning.

Transport wind ESE to SSE at 8 - 12 mph.

Surface wind light and variable but favors NE and controlled by local terrain.

AFTERNOON

Mixing height 4000 - 5000 ft.

Transport wind shifts to ENE to ESE at 8 - 12 mph.

Surface wind increases to N to NE at 4 - 8 mph.

EVENING

Mixing height 1000 - 2000 ft.

Transport wind NNE to ENE at 6 - 12 mph.

Surface wind NNW to NE at 4 - 8 mph.

Zone 605-611 (North Cascades):

MORNING

Mixing height below 2500 ft early rising to 3000 - 4000 ft by late morning.

Transport wind SE to SSW at 6 - 10 mph.

Surface wind light and variable but favors E and controlled by local terrain.

AFTERNOON

Mixing height rising above 5000 ft.

Transport wind shifts to ENE to ESE at 6 - 10 mph.

Surface wind increases to N to NE at 4 - 8 mph.

EVENING

Mixing height 1000 - 2000 ft.

Transport wind NNE to ENE at 5 - 9 mph.

Surface wind becomes light and variable but favors E and controlled by local terrain.

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

MORNING

Mixing height below 2500 ft early rising to 3000 - 4000 ft by late morning.

Transport wind SE to S at 10 - 18 mph.

Surface wind ESE to S at 4 - 8 mph.

AFTERNOON

Mixing height rising above 5000 ft.

Transport wind decreases to SE to S at 6 - 10 mph.

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

EVENING

Mixing height 1500 - 2500 ft.

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

Surface wind similar to afternoon.

OUTLOOK:

SUNDAY

Mixing height below 1000 ft early rising to 2800 to 3800 ft by late morning rising above 5000 ft during the afternoon.  Transport wind light and variable during the morning becoming SW to W at 12 - 22 mph during the afternoon.  Surface wind light and variable during the morning becoming SSE to SW at 4 - 8 mph during the afternoon.

MONDAY

Mixing height 2200 to 3200 ft during the morning rising above 5000 ft during the afternoon.  Transport wind WSW to WNW at 6 - 10 mph during the morning becoming W to WNW at 15 - 25 mph during the afternoon.  Surface wind light and variable.

TUESDAY

Mixing height below 1000 ft early rising to 2200 to 3200 ft by late morning rising to 2800 to 3800 ft during the afternoon.  Transport wind light and variable.  Surface wind light and variable.

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

These instructions are valid for burning conducted on Saturday, November 20, 2010.

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Coast Range

All Zones

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

Cascades

Zone 605 and 606

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

Zone 607, 608, and 616

Units should be 1000 tons or less, spaced 5 miles apart, and 10 miles from downwind SSRAs.  In zone 616 avoid ignitions north of T24S.  South of T29S higher tonnage is possible.  Call the forecaster.

Zone 609, 610, 611, 617, 620, and 622

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

Zone 623

Use standard guidance matrix. (See section 5 below.)

Siskiyous

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

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

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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