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

[ODF Smoke Management Instructions]

SMOKE MANAGEMENT FORECAST AND INSTRUCTIONS

SALEM FORESTRY WEATHER CENTER

OREGON DEPARTMENT OF FORESTRY



ISSUED: Saturday, November 20, 2010       2:30 PM      Pete Parsons



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



SUNDAY



A cold upper-level trough will remain over the region.  One disturbance will rotate inland early, bringing rain and snow to the most southern zones.  The northern zones will come under the influence of an even colder, but drier, 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 by late in the day.  That system will back the upper-level flow, giving it a more over-water trajectory, and increase the shower activity, from north to south, across western Oregon.  Snow levels will drop even lower Sunday evening, with accumulating snow possible down to 500 feet north and 1500 feet south by Sunday night.


OUTLOOK (MONDAY-WEDNESDAY)

On Monday, an even colder upper-level system will drop southward and renew the shower activity across western Oregon.  This system will be accompanied by a surface Arctic cold front, which will locally enhance precipitation and drop snow levels to the valley floors, as it slowly sags southward across western Oregon Monday afternoon and evening.  The latest computer guidance is supporting accumulating snow in western valleys, as well as higher terrain, before a drier northerly flow aloft tapers off the precipitation, from north to south, Monday night.  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 may turn northerly across the northern 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 clear, from north to south, with a chance of showers south early.  The snow level will stay near sea level north and 1500 feet south.  Cold low-level air will stabilize the air mass, especially north, with light transport winds.  Smoke dispersal conditions will likely deteriorate to only marginal to fair.



Computer models show an upper-level ridge building over the region by Wednesday with a dry and much more stable northerly flow aloft.  That will lead to very cold overnight temperatures, especially in snow-covered areas, and surface-based inversions.  A weak impulse in the northerly flow is forecast to bring some middle and high clouds to the region in the afternoon but will not likely be strong enough to produce any precipitation.  Smoke dispersal conditions will further deteriorate, to poor, in most zones.

2.  DISPERSION



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



MORNING

Mixing height below 1000 ft early rising to 2500 - 3500 ft by late morning.

Transport wind light and variable and controlled by local terrain.

Surface wind light and variable and controlled by local terrain.



AFTERNOON

Mixing height rising above 5000 ft.

Transport wind increases to SW to W at 10 - 20 mph.

Surface wind increases to SSE to SSW at 4 - 8 mph.



EVENING

Mixing height 1500 - 2500 ft.

Transport wind WSW to WNW at 9 - 15 mph.

Surface wind SSW to WSW at 5 - 9 mph.



Zone 605-611 (North Cascades):



MORNING

Mixing height below 1000 ft early rising to 2500 - 3500 ft by late morning.

Transport wind light and variable and controlled by local terrain.

Surface wind light and variable and controlled by local terrain.



AFTERNOON

Mixing height rising above 5000 ft.

Transport wind increases to SW to W at 9 - 15 mph.

Surface wind increases to SSW to WSW at 4 - 8 mph.



EVENING

Mixing height 1500 - 2500 ft.

Transport wind SW to WNW at 6 - 12 mph.

Surface wind SSW to WSW at 4 - 8 mph.



Zone 615-620 (South Coast Range):



MORNING

Mixing height below 1500 ft early rising to 2500 - 3500 ft by late morning.

Transport wind WSW to NW at 4 - 8 mph.

Surface wind light and variable and controlled by local terrain.



AFTERNOON

Mixing height rising above 5000 ft.

Transport wind increases to WSW to WNW at 10 - 22 mph.

Surface wind increases to S to SW at 5 - 9 mph.



EVENING

Mixing height 2000 - 3000 ft.

Transport wind similar to afternoon.

Surface wind shifts to SW to WNW at 6 - 10 mph.



Zone 616-623 (South Cascades):



MORNING

Mixing height below 1500 ft early rising to 2500 - 3500 ft by late morning.

Transport wind WSW to NW at 5 - 9 mph.

Surface wind WSW to WNW at 4 - 8 mph.



AFTERNOON

Mixing height rising above 5000 ft.

Transport wind WSW to WNW at 9 - 15 mph.

Surface wind SSW to WSW at 4 - 8 mph.



EVENING

Mixing height 2000 - 3000 ft.

Transport wind WSW to WNW at 10 - 20 mph.

Surface wind SW to W at 8 - 12 mph.



OUTLOOK:



MONDAY

Mixing height 2900 to 3900 ft during the morning rising above 5000 ft during the afternoon.  Transport wind W to WNW at 13 - 25 mph.  Surface wind SW to W at 6 - 10 mph.



TUESDAY

Mixing height below 1000 ft early rising to 2100 to 3100 ft by late morning rising to 2800 to 3800 ft during the afternoon.  Transport wind light and variable.  Surface wind light and variable.



WEDNESDAY

Mixing height below 1000 ft during the morning rising to 1000 to 2000 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 Sunday, November 21, 2010.

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



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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