[willamette-fcst] Silverton Hills Forecast - Wed, Jul 07 2010

[Willamette Valley Ag/Burning Forecast]

SILVERTON HILLS FIELD BURNING FORECAST
OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE
9:00 AM PDT WED JUL 07 2010

BURN ADVISORY:

     Agricultural burning is allowed.  Suggested burn times are from 11:00am to 7:00pm.
     Prep burning is not allowed. 
     Propane flaming burning is not allowed.	
									
										
WEATHER DISCUSSION:

     A strong ridge of high pressure will bring near record warm temperatures to the
     Willamette Valley today.  Fields are not ready for burning.

     Salem's high temperature today will be near 98.
     Relative humidity drops to 50% by 8am.  Minimum relative humidity 17%.

     Sunset: 8:55 pm	
							
										
THREE-HOURLY DATA:		

                                 11am     2pm     5pm     8pm			
     Temperature:                 81       93      98      92  			
     Relative Humidity:           33%      22%     17%     21%     			
     Surface Wind Direction:     010      360     360     340 		
     Surface Wind Speed:           7        9      10       9    			
     Transport Wind Direction:    10       30      20      30 
     Transport Wind Speed:        10       13      17      17  
     Estimated Mixing Height:   1500     3500    5000    3000
     Ventilation Index:           15       46      85      51     				
										
EXTENDED DISCUSSION:

     The strong ridge of high pressure will continue to bring near record heat to
     the valley Thursday and Friday with weak onshore flow bring some minor cooling
     over the weekend.

EXTENDED FORECAST:	
     
     Thursday:  Sunny with near record warmth.  Light north winds.  62/100
     Friday:    Sunny and continued hot.  Wind: NW 5-10 mph.  63/96
     Saturday:  Sunny and slightly cooler.  Wind: NW 5-15 mph.  57/87
     Sunday:    Patchy morning clouds.  Sunny and warm.  56/86
     Monday:    Patchy morning clouds.  Sunny and warm.  56/88
     Tuesday:   Morning clouds.  Sunny in the afternoon.  54/84
     Wednesday: Morning clouds.  Sunny in the afternoon.  52/82
										
This forecast is provided under an agreement between the Oregon Department of
Agriculture and the Oregon Department of Forestry.  For information contact ODA
at 503-986-4701.									
										
Notes:									
     1.  Mixing height, as used here, is the lowest height at which the
         potential temperature exceeds the potential temperature at the surface.  
         As a practical matter it is the approximate height to which a 
         smoke plume will rise assuming good ignition, dry fuels, and 
         winds less than about 15mph.								
     2.  Transport winds are a layer average through the mixing height, 
         weighted slightly toward the winds at the top of the layer.								
     3.  Ventilation Index is the height of the mixing layer times 
         the transport wind speed divided by 1000.								
     4.  Surface wind direction is the general expected wind direction.  
         At a specific point surface winds are highly dependent on 
         local terrain conditions.