[willamette-fcst] Silverton Hills Midday Forecast_doug.doc

[Willamette Valley Field Burning Forecast]

SILVERTON HILLS FIELD BURNING FORECAST

OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE

12:00 PM PDT TUES. JUL 16, 2013



BURN ADVISORY:



Agricultural burning is not recommended today.

Prep burning is not recommended today.



WEATHER DISCUSSION:



Abundant mid-level moisture is moving in from the south today over the area, bringing some scattered light showers through the afternoon to the valley. No significant rain is expected, and cooler surface conditions will prevail due to the cloud cover. Partly to mostly cloudy conditions will predominate through the day. Any marine surge later in the day into this evening is likely to be weak. Transport winds are likely to be weak but generally from the north later today.



The upper trough off the coast remains in place for the next several days, but with more southwesterly flow skies will return to mostly sunny on Wednesday and warmer conditions.





TODAY'S FORECAST:



Partly cloudy with a few light showers through the afternoon.



Salem's high temperature today will be in the middle 80s.

Relative humidity:  Will drop to 35-40% by 5 p.m.

Surface winds:  N 3-7 mph through the afternoon; NW 5-10 mph this evening.

Transport winds: Generally N 5-10 mph

Mixing height: Rising to near 3000 feet this afternoon.

Salem's sunset tonight: 8:55 p.m.



(Salem Airport data for Monday, July 15th: High 89°F; Rainfall .00")

(Maximum Ventilation index expected today: 25)



EXTENDED DISCUSSION:



Upper ridging will persist through the week and even strengthen late in the week, with the trough off the coast moving westward slowly. Expect mostly sunny conditions and very warm temperatures with maximums in the middle to upper 80s.





The National Weather Service's digital forecast is available at:

http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text



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 (ft) times

         the transport wind speed (mph) 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.



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.



Doug Wesley

ODF Meteorologist

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://omls.oregon.gov/pipermail/willamette-fcst/attachments/20130716/300cfa9e/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Silverton Hills Midday Forecast_doug.doc
Type: application/msword
Size: 31232 bytes
Desc: Silverton Hills Midday Forecast_doug.doc
URL: <https://omls.oregon.gov/pipermail/willamette-fcst/attachments/20130716/300cfa9e/attachment.doc>