<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii">
<meta name=Generator content="Microsoft Word 12 (filtered medium)">
<style>
<!--
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:10.0pt;
font-family:"Courier New";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
-->
</style>
<!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang=EN-US link=blue vlink=purple>
<div class=WordSection1>
<p class=MsoNormal>SILVERTON HILLS FIELD BURNING FORECAST<o:p></o:p></p>
<p class=MsoNormal>OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE<o:p></o:p></p>
<p class=MsoNormal>9:00 AM PDT TUE AUG 3 2010<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>BURN ADVISORY:<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal> Agricultural burning burning is not recommended.<o:p></o:p></p>
<p class=MsoNormal> Prep burning is not allowed. <o:p></o:p></p>
<p class=MsoNormal> Propane flaming is allowed from 2:00pm to 5:00pm. <o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal>WEATHER DISCUSSION:<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>A broad upper-level trough remains over the Pacific
Northwest this morning with smaller scale disturbances rotating through it.
One system moved across western Oregon Monday morning and brought scattered
thunderstorms to eastern Oregon Monday afternoon. In its wake, weak ridging
quickly stabilized the atmosphere across western Oregon Monday evening.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Onshore flow increased overnight with visible satellite
imagery showing marine low clouds penetrating into most of the Willamette
Valley this morning. The Salem sounding this morning was similar to Monday
morning with a mixing cap at about 4800 feet. The low-level moisture is a bit
deeper this morning, but the low clouds should give way to sunshine by midday.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Another weak system is over Vancouver Island, British
Columbia this morning and is forecast to drop southward into western Washington
later this afternoon. It may produce a few showers across western Washington
but not likely as far south as western Oregon. Increasing westerly flow aloft
will act to increase the onshore flow this afternoon, which may create an open
burning opportunity.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>TODAY’S FORECAST:<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Morning clouds, then sunny and warm. After reaching 85
degrees on Monday, Salem's high temperature today will be near 84 degrees. The
mixing height will not climb to 3000 feet until about 2 p.m. and likely top out
at around 4800 feet around 5 p.m. A cooling sea breeze will drop the mixing
height to 1500 feet by shortly before sunset. Surface and transport winds will
be NW 3-6 this morning and increase to NW 5-12 this afternoon. Relative
humidity will drop to 50% by 1 p.m. and to near 36% by late this afternoon.
The ventilation index will climb to about 38 late this afternoon.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Silverton area sunset tonight: 8:30 pm <o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal>THREE-HOURLY DATA: <o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal> 11am 2pm 5pm
8pm <o:p></o:p></p>
<p class=MsoNormal> Temperature: 69 78 84
76 <o:p></o:p></p>
<p class=MsoNormal> Relative Humidity: 59% 43% 36%
45% <o:p></o:p></p>
<p class=MsoNormal> Surface Wind Direction: 330 310 300
300 <o:p></o:p></p>
<p class=MsoNormal> Surface Wind Speed: 3 5 6
7 <o:p></o:p></p>
<p class=MsoNormal> Transport Wind Direction: 300 310 300
300 <o:p></o:p></p>
<p class=MsoNormal> Transport Wind Speed: 3 5 8
12 <o:p></o:p></p>
<p class=MsoNormal> Estimated Mixing Height: 2200 3000 4800
1500<o:p></o:p></p>
<p class=MsoNormal> Ventilation Index: 7 15 38
18 <o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal>EXTENDED DISCUSSION:<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Little change to the overall weather pattern is expected
through Friday, with a weak upper-level trough remaining over the Pacific
Northwest. Varying degrees of onshore flow will maintain at least a chance of
open burning each afternoon. The onshore flow may weaken a bit on Wednesday,
and then strengthen again late Thursday and Friday, which could lead to
marginal open burning opportunities. <o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>EXTENDED FORECAST: <o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal>Wednesday: Morning clouds, then mostly sunny. Wind: NNW 5-12
mph. 55/84 <o:p></o:p></p>
<p class=MsoNormal>Thursday: Morning clouds, then mostly sunny. Wind: NW 5-15
mph. 56/83<o:p></o:p></p>
<p class=MsoNormal>Friday: Morning clouds, then sunny. 55/82 <o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal>Notes:<o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal> 1. Mixing height, as used here, is the lowest height
at which the<o:p></o:p></p>
<p class=MsoNormal> potential temperature exceeds the potential
temperature at the<o:p></o:p></p>
<p class=MsoNormal> surface. <o:p></o:p></p>
<p class=MsoNormal> As a practical matter it is the approximate height
to which a <o:p></o:p></p>
<p class=MsoNormal> smoke plume will rise assuming good ignition, dry
fuels, and <o:p></o:p></p>
<p class=MsoNormal> winds less than about 15mph. <o:p></o:p></p>
<p class=MsoNormal> 2. Transport winds are a layer average through the
mixing height, <o:p></o:p></p>
<p class=MsoNormal> weighted slightly toward the winds at the top of
the layer. <o:p></o:p></p>
<p class=MsoNormal> 3. Ventilation Index is the height of the mixing layer
times <o:p></o:p></p>
<p class=MsoNormal> the transport wind speed divided by 1000. <o:p></o:p></p>
<p class=MsoNormal> 4. Surface wind direction is the general expected wind
direction. <o:p></o:p></p>
<p class=MsoNormal> At a specific point surface winds are highly
dependent on local<o:p></o:p></p>
<p class=MsoNormal> terrain conditions.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>This forecast is provided under an agreement between the
Oregon Department of<o:p></o:p></p>
<p class=MsoNormal>Agriculture and the Oregon Department of Forestry. For
information contact ODA at 503-986-4701.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Pete Parsons<o:p></o:p></p>
<p class=MsoNormal>ODF Meteorologist<o:p></o:p></p>
</div>
</body>
</html>