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

Thu Apr 21 14:40:49 PDT 2011

SMOKE MANAGEMENT FORECAST AND INSTRUCTIONS

SALEM FORESTRY WEATHER CENTER

OREGON DEPARTMENT OF FORESTRY

ISSUED: Thursday, April 21, 2011       2:30 PM      Pete Parsons

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

FRIDAY

A weak upper-level ridge of high pressure is forecast to bring generally dry and warmer conditions.  After a cold start, partly to mostly sunny skies should warm afternoon surface temperatures close to normal.  The freezing level will only rise to about 6000 feet north and 7000 feet south, so afternoon heating will provide good mixing.  Transport winds will turn offshore.  A very weak disturbance, in a westerly jet stream directed at California, may increase clouds over the extreme southern zones late in the day.
OUTLOOK (SATURDAY-MONDAY)
The upper-level ridge now appears as if it will remain strong enough to bring another generally dry day on Saturday.  However, a weak weather system will move across northern California and bring a slight chance of showers to the southern-most zones.  Mostly sunny skies will help temperatures climb to above normal across the northern zones, but more cloudiness will hold temperatures to near normal across the southern zones.  Daytime mixing will be good.  Look for transport winds to turn back onshore in the afternoon, as the upper-level ridge axis slides east of the region.

As the upper-level ridge continues to weaken and shift eastward, a strengthening westerly jet stream will drive a weak cold front across western Oregon Easter Sunday morning.  Precipitation from this system could locally exceed .25 inches, especially over higher terrain.  The snow level will drop to 4000 feet north and 5000 feet south.  Mixing should be good with increasing southwesterly transport winds.

A stronger cold front is forecast to come onshore Sunday night and early Monday.  This system will bring more significant precipitation to all of western Oregon, with the snow level dropping to 3000 feet north and 4000 feet south.  Mixing should be good with brisk southwesterly surface and transport winds.

2.  DISPERSION

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

MORNING

Mixing height below 1500 ft early rising to 3000 - 4000 ft by late morning.

Transport wind NNE to ENE at 9 - 15 mph.

Surface wind NNE to ENE at 5 - 9 mph.

AFTERNOON

Mixing height rising above 5000 ft.

Transport wind similar to morning.

Surface wind NNE to NE at 8 - 12 mph.

EVENING

Mixing height lowers below 2000 ft after sunset.

Transport wind similar to afternoon.

Surface wind similar to afternoon.

Zone 605-611 (North Cascades):

MORNING

Mixing height below 1500 ft early rising to 3000 - 4000 ft by late morning.

Transport wind NNE to ENE at 5 - 9 mph.

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

AFTERNOON

Mixing height rising above 5000 ft.

Transport wind N to NE at 6 - 12 mph.

Surface wind similar to morning.

EVENING

Mixing height lowers below 2000 ft after sunset.

Transport wind NE to E at 8 - 12 mph.

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

Zone 615-620 (South Coast Range):

MORNING

Mixing height below 1500 ft early rising to 3000 - 4000 ft by late morning.

Transport wind ENE to E at 8 - 12 mph.

Surface wind NE to E at 4 - 8 mph.

AFTERNOON

Mixing height rising above 5000 ft.

Transport wind shifts to N to NE at 4 - 8 mph.

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

EVENING

Mixing height lowers below 1500 ft after sunset.

Transport wind NNW to NE at 4 - 8 mph.

Surface wind similar to afternoon.

Zone 616-623 (South Cascades):

MORNING

Mixing height below 1000 ft early rising to 3000 - 4000 ft by late morning.

Transport wind E to SE at 4 - 8 mph.

Surface wind light and variable and controlled by local terrain.

AFTERNOON

Mixing height rising above 5000 ft.

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

Surface wind similar to morning.

EVENING

Mixing height lowers below 1500 ft after sunset.

Transport wind similar to afternoon.

Surface wind similar to afternoon.

OUTLOOK:

SATURDAY

In the north mixing height below 1000 ft early rising to 1700 to 2700 ft by late morning rising above 5000 ft during the afternoon.  In the south mixing height below 1000 ft early rising to 3000 to 4000 ft by late morning rising above 5000 ft during the afternoon.  Transport wind ESE to SSE at 4 - 8 mph during the morning becoming WSW to NW at 4 - 8 mph during the afternoon.  Surface wind light and variable.

SUNDAY

Mixing height 2100 to 3100 ft during the morning rising above 5000 ft during the afternoon.  Transport wind SSW to SW at 9 - 15 mph.  Surface wind S to SW at 4 - 8 mph during the morning becoming SSW to WSW at 4 - 8 mph during the afternoon.

MONDAY

Mixing height 3800 to 4800 ft during the morning rising above 5000 ft during the afternoon.  Transport wind SSW to SW at 20 - 34 mph.  Surface wind SSW to SW at 12 - 22 mph.

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

These instructions are valid for burning conducted on Friday, April 22, 2011.

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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, 606, 620, and 622

Units should be 500 tons or less, spaced 5 miles apart, and 10 miles from downwind SSRAs.  Higher tonnage is possible south of T20S in Zone 606.  Call the forecaster.

Zone 607, 608, and 616

Units should be 1000 tons or less, spaced 5 miles apart, and 10 miles from downwind SSRAs.  South of T30S in Zone 616 units should be 500 tons or less, spaced 5 miles apart.

Zone 609, 610, 611, 617, and 623

Use standard guidance matrix. (See section 5 below.)  Ensure adequate distance from downwind SSRAs for smoke to dissipate.  South of T30S in Zone 617 units should be 750 tons or less, spaced 5 miles apart.

Siskiyous

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

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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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