[willamette-fcst] Silverton Hills AM Forecast_Pete.doc

[Willamette Valley Field Burning Forecast]

SILVERTON HILLS FIELD BURNING FORECAST

OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE

11:20 AM PDT WED JUL 1, 2015



*** This is a test message.  The information is valid. ***

*** State Fire Marshal Burn-Ban Conditions are likely this afternoon. ***



BURN ADVISORY:



Agricultural burning is not recommended.



Prep burning is not allowed.



WEATHER DISCUSSION:



A strong ridge of high pressure will bring sunshine and very warm temperatures today.  Surface pressure gradients are weakly onshore from Newport to Salem but offshore from Redmond to Salem.  Therefore, surface winds should remain northerly this afternoon. The combination of hot temperatures, low humidity, and wind should put the valley into State Fire Marshal Burn-Ban Conditions later this afternoon.



TODAY'S FORECAST:



Sunny and hot.



Salem's high temperature today will be near 97°F (average is 78°F).

Relative humidity:  Dropping to below 30% around 2 p.m.

Surface winds: N 7-13 mph this morning; N 10-15 mph this afternoon.

Transport winds: N 15 mph.

Mixing height: Rising to 3000 feet by noon and to 4500 feet by 5 p.m.

Salem's sunset tonight: 9:02 p.m.



(Salem Airport data for Tuesday, June 30th: High 95°F; Rainfall: .00")

(Maximum Ventilation Index expected today: 70)



EXTENDED DISCUSSION:



A strong upper-level ridge will remain over the region on Thursday for continued hot and dry weather.  Valley temperatures will approach 100°F.  The flow aloft will turn northwesterly on Friday with weak onshore flow developing and capping afternoon temperatures in the mid-90s.  Little change is expected through the weekend.



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 15 mph.



     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 (ODA) and the Oregon Department of Forestry (ODF).  For

information contact ODA at 503-986-4701.



To add/remove your email address from this list, please go to:



http://listsmart.osl.state.or.us/mailman/listinfo/willamette-fcst



Pete Parsons

ODF Meteorologist
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