[willamette-fcst] Forecast - Wednesday, April 14th, 2010

[Willamette Valley Ag/Burning Forecast]

Daily Smoke Management Forecast




Oregon Department of Agriculture
Smoke Management Program
Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts.

     This daily Willamette Valley Agricultural Weather Forecast will become a seasonal product,
     as of Friday April 16th. The last broadcast and email of this forecast will be Thursday,
     April 15th. It will return as the \"Willamette Valley Field Burning Weather Forecast,\"
     issued daily via email and broadcast on WPOZ 585, beginning Thursday July 1st.

Issued: 
     Wednesday, April 14th, 2010 at 12:00pm.

Burn Advisory:
     Recommended burn times for agricultural burning are from now until 6:00pm.
     Stack burning is not allowed.

Weather Discussion:
     Clearing skies and light winds allowed temperatures to locally drop to the freezing mark
     in the Willamette Valley early this morning.  Hillsboro dipped to 31 degrees and
     McMinnville fell to 32.  Salem bottomed out at 33 degrees, while Eugene dipped to 34.

     An upper-level trough was parked just off the west coast at midday with a south-southeasterly
     flow aloft over Oregon.  Two distinct circulation centers were rotating around in the trough.
     The one of immediate concern, near the northern California coast, is spreading considerable
     clouds over southwestern Oregon and helping convective cloud formation over the southern
     and central Oregon Cascades. Skies were mostly sunny over the remainder of the state.     

     Doppler radar continued to show light showers over the extreme southwestern corner of the
     state with a few showers developing over the southern Cascades and over south-central Oregon.  
     The ODA surface analysis showed high pressure over Washington and weak low pressure over
     south-central Oregon...resuling in light north-northeasterly winds across western Oregon. 
     Under mostly sunny skies, midday temperatures had recovered into the low to mid 50s along
     the coast and in the Willamette Valley.  Sections of southwestern Oregon, where skies were
     cloudy, were only in the upper 40s.

     The upper-level disturbance currently affecting extreme southwestern Oregon will slowly
     migrate northward this afternoon.  Clouds will increase, from south to north, across the
     state.  Sunshine ahead of the system should warm Willamette Valley temperatures to around
     60 degrees.  The daytime heating, combined with cool air aloft, with make the atmosphere
     increasingly unstable this afternoon and evening.  Showers will likely develop over the
     southern and central Cascades with the possibility of some thundershowers.

     Showers should spread into the southern Willamette Valley late this afternoon and northward,
     across the remainder of western Oregon, this evening and tonight.  There is a slight chance
     that the atmosphere could be unstable enough for an evening valley thunderstorm.  Rainfall
     totals will likely vary significantly, with some areas picking up only a few hundredths of
     an inch and others getting more than one-quarter of an inch. Showers will taper off, from
     south to north, overnight, with mostly cloudy skies keeping minimums in the 40s.

Surface Winds:
     NNE 5-12 this afternoon.
Transport Winds:
     NNE 12 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 4000 feet.  Ventilation index 48.
High Temperature:
     Salem\'s high temperature today will be near 61.
Humidities:
     Minimum relative humidity will be near 47%.
Sunrise/Sunset:
     Salem sunset tonight: 7:56pm; sunrise tomorrow: 6:27am.

Extended Outlook:
     We will likely see a break from the showers after Thursday morning with the next upper-level
     disturbance forecast to rotate through the region Friday afternoon. The entire system is
     forecast to weaken and come onshore Saturday, but there may not be much shower activity
     associated with it by that time.

     It still appears that Sunday will be the nicest day of the next week, with highs possibly
     climbing into the low 70s.  The long-range models continue to show a strong cold front
     coming onshore by Monday afternoon...followed by a cool trough on Tuesday. Some drying
     and warming is forecast for the middle of next week, but more systems are slated to make
     their way onshore late next week.

Tomorrow (15 Apr):  Chance AM Shower North.  Mostly Sunny.  Snow Level 5000 Feet.  41/64

Fri (16 Apr):  Mostly Cloudy.  Chance of Showers.  Snow Level 6000 Feet.  43/63

Sat (17 Apr):  Partly Cloudy.  Slight Chance of Showers. Snow Level 6-7000 Feet. 45/66

Sun (18 Apr):  Partly Cloudy and Warm.  46/72

Mon (19 Apr):  Rain Likely Developing. Cooler. Snow Level Dropping to 4-5000 Feet.  44/62

Tue (20 Apr):  Showers Likely...Decreasing Late.  Snow Level 4000 Feet.  41/57

Wed (21 Apr):  Partly Cloudy.  Slight Chance of Showers.  42/61

ODA Meteorologist
weather at oda.state.or.us