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

Fri Oct 8 14:33:45 PDT 2010

SMOKE MANAGEMENT FORECAST AND INSTRUCTIONS

SALEM FORESTRY WEATHER CENTER

OREGON DEPARTMENT OF FORESTRY

ISSUED: Friday, October 8, 2010       2:30 PM      Pete Parsons

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

SATURDAY

The jet stream is transitioning to a more autumn-like pattern.  A developing westerly flow aloft pushed a very weak cold front across Washington and the northern half of western Oregon on Friday.  That system was primarily a cloud-maker with only spotty light rainfall. However, it did cool the air aloft and increase the transport winds enough to improve ventilation conditions.

A stronger system, with some entrained tropical moisture, will approach the coastline early Saturday.  The bulk of the rainfall is forecast to stay north of Oregon, but some rain is likely across the northern half of the region Saturday morning, with a chance of light rain south.

The cold front is forecast to stall and push north, as a warm front, Saturday afternoon and night.  That will likely result in a considerable contrast in rainfall, from northwest to southeast, across western Oregon.  The north coastal range will see the most rain, perhaps 1-2 inches, while the southern Cascades could stay dry.

Increasing southerly transport winds will aid ventilation, but warming aloft and cloud-cover will suppress afternoon mixing heights, especially north and west.  Smoke dispersal conditions will be fair in the north and good in the south.

OUTLOOK (SUNDAY-TUESDAY)

Rain will increase, from west to east, across the entire region Sunday, as the final cold front in this series of Pacific storms comes onshore.  Brisk southwesterly transport winds will veer to northwesterly, in the wake of the cold front, Sunday afternoon.  There will not be much post-frontal shower activity Sunday evening, because the air aloft will stay fairly mild.  The snow level should stay above 7000 feet.

Clearing skies should lead to strong surfaced-based inversions by Monday morning with recent rains possibly leading to valley fog formation.  The flow aloft is forecast to dry out and turn northwesterly on Monday.  Transport winds will turn northerly across the northern zones and northeasterly across the southern zones.  That will aid in the drying of the low-level air mass and should help to clear fog from most valley locations in the afternoon.  Even with some sunshine, mixing heights will be suppressed by subsidence aloft, associated with the building ridge of high pressure, so smoke dispersal conditions will be marginal at best.

Strong surface-based inversions are likely again Tuesday morning, as the upper-level ridge moves directly over Oregon.  Areas of morning valley fog and low clouds are likely, with afternoon clearing. Low mixing heights and light offshore transport winds will likely make for poor ventilation conditions.

2.  DISPERSION

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

MORNING

Mixing height 2000 - 3000 ft.

Transport wind SSE to SSW at 15 - 25 mph.

Surface wind SE to S at 8 - 12 mph.

AFTERNOON

Mixing height 2800 - 3800 ft.

Transport wind SSW at 18 - 32 mph.

Surface wind similar to morning.

EVENING

Mixing height 2000 - 3000 ft.

Transport wind SSW to SW at 15 - 25 mph.

Surface wind similar to afternoon.

Zone 615-620 (South Coast Range):

MORNING

Mixing height 2000 - 3000 ft.

Transport wind SSE to SSW at 12 - 22 mph.

Surface wind SE to SSW at 6 - 12 mph.

AFTERNOON

Mixing height 2700 - 3700 ft.

Transport wind S to SW at 12 - 24 mph.

Surface wind SSE to SW at 6 - 10 mph.

EVENING

Mixing height 1500 - 2500 ft.

Transport wind SSW to SW at 10 - 20 mph.

Surface wind similar to afternoon.

Zone 616-623 (South Cascades):

MORNING

Mixing height 2000 - 3000 ft.

Transport wind S to SW at 10 - 18 mph.

Surface wind SSE to SW at 6 - 10 mph.

AFTERNOON

Mixing height 3000 - 4000 ft.

Transport wind SSW to WSW at 8 - 12 mph.

Surface wind SSW to WSW at 4 - 8 mph.

EVENING

Mixing height 1000 - 2000 ft.

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

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

OUTLOOK:

SUNDAY

In the north mixing height 2100 to 3100 ft during the morning rising to 4000 to 5000 ft during the afternoon.  In the south mixing height 1300 to 2300 ft during the morning rising to 4000 to 5000 ft during the afternoon.  Transport wind SSW to WSW at 10 - 18 mph during the morning becoming NW to NNW at 10 - 18 mph during the afternoon.  Surface wind S to SW at 4 - 8 mph during the morning becoming WNW to NNW at 6 - 10 mph during the afternoon.

MONDAY

Mixing height below 1000 ft early rising to 1600 to 2600 ft by late morning rising to 2600 to 3600 ft during the afternoon.  Transport wind N to NE at 4 - 8 mph.  Surface wind light and variable during the morning becoming NNW to NE at 4 - 8 mph during the afternoon.

TUESDAY

Mixing height below 1000 ft early rising to 1000 to 1600 ft by late morning rising to 1700 to 2700 ft during the afternoon.  Transport wind light and variable during the morning becoming NE to E at 4 - 8 mph during the afternoon.  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, October 9, 2010.

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Coast Range

Zone 601 and 612

Units should be 1000 tons or less, spaced 10 miles apart, and 12 miles from downwind SSRAs.  North of Tillamook in Zone 601, use standard guidance matrix. (See section 5 below.)

Zone 602 and 603

Units should be 500 tons or less, spaced 10 miles apart, and 12 miles from downwind SSRAs.  North of T3N in Zone 602, use standard guidance matrix. (See section 5 below.)  Units may be 750 tons or less, spaced 10 miles apart, south of the Siuslaw River in Zone 603.

Zone 615 and 616 west of R8W

Units should be 1500 tons or less, spaced 10 miles apart, and 12 miles from downwind SSRAs.  Higher tonnage is possible south of T29S in Zone 616.  Call the forecaster.

Zone 616 east of R9W

Units should be 750 tons or less, spaced 10 miles apart, and 12 miles from downwind SSRAs.  Higher tonnage is possible south of T29S.  Call the forecaster.

Zone 618, 619, and 620

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

Cascades

All zones except zone 611

Use standard guidance matrix. (See section 5 below.)  Ensure adequate distance from downwind SSRAs for smoke to dissipate.  Avoid ignitions north of T24S in Zone 616.

Zone 611

Units should be 750 tons or less, spaced 10 miles apart, and 12 miles from downwind SSRAs.

Siskiyous

Units should be 750 tons or less, spaced 10 miles apart, and 12 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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