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

Thu Nov 18 14:28:23 PST 2010

SMOKE MANAGEMENT FORECAST AND INSTRUCTIONS

SALEM FORESTRY WEATHER CENTER

OREGON DEPARTMENT OF FORESTRY

ISSUED: Thursday, November 18, 2010       2:30 PM      Pete Parsons

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

FRIDAY

The axis of a cold upper-level trough will remain just offshore with a moist and very strong west-southwesterly flow aloft over Oregon.  Impulses dropping southward into the trough will act to maintain a weak surface low-pressure area off the Washington coast.  Circulation around that system will feed ample moisture onshore for scattered showers across all zones, with upslope flow enhancing showers on west-facing mountain slopes.  Cold air aloft will keep the snow level near 2000 feet north and 2500 feet south. Expect good smoke dispersal conditions with south to southwesterly transport winds.

OUTLOOK (SATURDAY-MONDAY)

A fairly strong upper-air disturbance will deepen the offshore trough, with both a surface and upper-air circulation center forecast to strengthen and drift southward, to just off the southern Oregon coast, by Saturday evening.  That will weaken the transport winds, with a drier offshore component likely developing, over the northern zones, by late-afternoon.  Transport winds should remain southwesterly over the southern zones with a better chance of showers.  Snow levels will drop to 1500 feet north and 2000 feet south with fair to good smoke dispersal conditions.

On Sunday, the offshore trough will get forced inland, across northern California, with some rain and snow showers circulating northward over the extreme southern zones.  Meanwhile, a mostly dry northwesterly flow aloft will bring partial clearing to the northern zones with just a slight chance of showers.  Snow levels will drop to near 1000 feet north and 2000-2500 feet south.  Smoke dispersal conditions will remain fair to good with increasing southwesterly transport winds.

By Monday, the flow aloft is forecast to turn northwesterly, in response to a cold upper-level system dropping southward from British Columbia.  The track of this system is still uncertain, so it may not produce much in the way of precipitation.  However, it appears likely that it will usher the coldest air of the season into the region.  Snow levels will drop to near sea-level across the northern zones and to near 1500 feet over the southern zones.  Smoke dispersal conditions should remain fair to good with mostly northwesterly transport winds.

2.  DISPERSION

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

MORNING

Mixing height below 2500 ft early rising to 3500 - 4500 ft by late morning.

Transport wind S at 20 - 34 mph.

Surface wind SE to SSW at 9 - 15 mph.

AFTERNOON

Mixing height rising above 5000 ft.

Transport wind SW at 18 - 32 mph.

Surface wind similar to morning.

EVENING

Mixing height 2300 - 3300 ft.

Transport wind decreases to SSW to WSW at 10 - 20 mph.

Surface wind similar to afternoon.

Zone 605-611 (North Cascades):

MORNING

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

Transport wind S to SW at 12 - 24 mph.

Surface wind SSE to SSW at 8 - 12 mph.

AFTERNOON

Mixing height rising above 5000 ft.

Transport wind SSW to SW at 12 - 24 mph.

Surface wind similar to morning.

EVENING

Mixing height 2300 - 3300 ft.

Transport wind SSE to SSW at 10 - 16 mph.

Surface wind similar to afternoon.

Zone 615-620 (South Coast Range):

MORNING

Mixing height below 2500 ft early rising to 3500 - 4500 ft by late morning.

Transport wind SSW to SW at 13 - 25 mph.

Surface wind SSE to SSW at 8 - 12 mph.

AFTERNOON

Mixing height rising above 5000 ft.

Transport wind SSW to WSW at 10 - 18 mph.

Surface wind SSE to SSW at 4 - 8 mph.

EVENING

Mixing height 2300 - 3300 ft.

Transport wind S to SW at 10 - 16 mph.

Surface wind similar to afternoon.

Zone 616-623 (South Cascades):

MORNING

Mixing height below 2000 ft early rising to 3000 - 4000 ft by late morning.

Transport wind SSW to WSW at 10 - 20 mph.

Surface wind SSE to SSW at 6 - 10 mph.

AFTERNOON

Mixing height rising above 5000 ft.

Transport wind SSW to WSW at 8 - 12 mph.

Surface wind SSW to WSW at 4 - 8 mph.

EVENING

Mixing height 2000 - 3000 ft.

Transport wind similar to afternoon.

Surface wind similar to afternoon.

OUTLOOK:

SATURDAY

Mixing height 2500 to 3500 ft during the morning rising to 4200 to 5000 ft during the afternoon.  Transport wind SSE to SSW at 8 - 12 mph.  Surface wind ESE to S at 4 - 8 mph during the morning becoming light and variable during the afternoon.

SUNDAY

Mixing height 1900 to 2900 ft during the morning rising to 4100 to 5000 ft during the afternoon.  Transport wind light and variable during the morning becoming SW to W at 8 - 14 mph during the afternoon.  Surface wind light and variable.

MONDAY

Mixing height 2200 to 3200 ft during the morning rising to 3900 to 4900 ft during the afternoon.  Transport wind WSW to WNW at 6 - 10 mph during the morning becoming WNW to NW at 8 - 12 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 Friday, November 19, 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

All zones except zone 611

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

Zone 611

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

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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