<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>
<!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* 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 WED SEP 15, 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 allowed from 12:00pm to 2:00pm with a
50 acre limit. <o:p></o:p></p>
<p class=MsoNormal> Propane flaming is allowed from 12:00pm to 2:00pm. <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 weak cold front about 200 miles offshore has already
spread clouds across most of Washington and the western half of Oregon. Radar
is picking up some light rain offshore, but there were no reports of rain
inland as of mid-morning. The surface map shows weak pressure gradients across
western Oregon this morning with light winds in the Willamette Valley.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Clouds should lower and thicken today with increasing
south-southwesterly winds. The morning sounding showed fairly warm air aloft,
and mixing heights will be slow to rise today due to the cloud-cover. There
could be a brief window of opportunity for open burning this afternoon, if the
approaching light rain holds off until this evening. Transport winds may be
too southerly early in the afternoon and become too strong for good plume
development later in the afternoon.<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>Mostly cloudy. A chance of rain in the afternoon with rain
likely this evening. After reaching 80 degrees on Tuesday, cloudy skies will
hold the high temperature to near 75 degrees this afternoon. The mixing height
will climb to near 3000 feet about noon and likely top out between 3000 and
4000 feet in the mid-afternoon, then drop below 3000 feet by 5 p.m. Relative
humidity will drop to near 50% this afternoon with the ventilation index
climbing to around 42.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Silverton area sunset tonight: 7:17pm <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: 68 74 74
65 <o:p></o:p></p>
<p class=MsoNormal> Relative Humidity: 65% 51% 51%
73% <o:p></o:p></p>
<p class=MsoNormal> Surface Wind Direction: 170 190 210
190 <o:p></o:p></p>
<p class=MsoNormal> Surface Wind Speed: 6 6 8
5 <o:p></o:p></p>
<p class=MsoNormal> Transport Wind Direction: 190 200 230
200 <o:p></o:p></p>
<p class=MsoNormal> Transport Wind Speed: 10 12 15
10 <o:p></o:p></p>
<p class=MsoNormal> Estimated Mixing Height: 2000 3500 2500
1000<o:p></o:p></p>
<p class=MsoNormal> Ventilation Index: 20 42 38
10<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>A transitory ridge will bring a break from the rain on
Thursday with another weather system slated to come onshore by Friday afternoon.
Wet weather is forecast this weekend and perhaps into early next week.
However, there does appear to be an opportunity for some drying of fields
around the middle of next week.<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> Thursday: Mostly cloudy. Chance of rain. High near
75. <o:p></o:p></p>
<p class=MsoNormal> Friday: Rain likely by the afternoon. High near 72. <o:p></o:p></p>
<p class=MsoNormal> Saturday: Rain likely. High near 70. <o:p></o:p></p>
<p class=MsoNormal> Sunday: Mostly cloudy. Chance of rain. High near 70.
<o:p></o:p></p>
<p class=MsoNormal> Monday: A chance of showers. High near 73. <o:p></o:p></p>
<p class=MsoNormal> Tuesday: Partly sunny. Slight chance of showers. High
near 76.<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>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p>
</div>
</body>
</html>