[willamette-fcst] Forecast - Thursday, June 11th, 2009
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Thu Jun 11 09:14:16 PDT 2009
Daily Smoke Management Forecast
Oregon Department of Agriculture
Smoke Management Program
Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts.
Thursday, June 11th, 2009 at 9:00am.
Agricultural burning is allowed. Suggested burn times are from now until 7:00pm.
Straw stack burning is allowed, for dry stacks, from now until 7:00pm.
Western North America remains under a split-flow jet stream
pattern this morning, with one branch of stronger winds aloft
diving southeastward, from northern Alaska, into eastern
Montana. Another, southern, branch is cutting across the
Pacific Ocean and sending weak upper-level troughs into the
the west coast of the United States. Daytime heating on
Wednesday helped destabilize the atmosphere, with shower
activity developing, once again, across much of
Oregon...mainly over southern Oregon and from the Cascades
eastward. The showers continued overnight,and southeasterly
flow aloft carried the showers northwestward, into the Willamette
Valley, this morning.
An upper-level trough was centered over extreme southwestern
Oregon this morning and bringing cloudy skies to most of the
state. The main exception was a pronounced area of mostly
clear skies extending from extreme north-central Oregon to
the northeastern tip of Oregon. That region, along with
eastern Washington, was getting a drier northeasterly flow
aloft, in response to the northern branch of the jet stream
cutting into Montana.
Doppler radar showed a line of showers extending northwestward,
from central Oregon near Bend, across the Cascades and into the
central Willamette Valley, to just north of Newport along the coast.
Salem received just under one-tenth of an inch of rain this morning,
but points not far to the north and south of Salem stayed dry. The
heaviest rainfall totals have been over southern Oregon during the
past 24 hours. Over one-quarter of an inch fell from Medford to
Lakeview, with Burns getting over a tenth of an inch.
The mid-morning ODA surface analysis showed onshore flow
across western Oregon, which will keep temperatures near to
slightly below normal again today. It will also keep the
atmosphere stable enough so that showers will not likely
develop into thunderstorms west of the Cascades this
afternoon. Mid-morning temperatures were mostly in the mid
to upper 50s across western Oregon, under cloudy skies.
Light rain was still falling over parts of the central
Willamette Valley, but radar was showing a general decrease
in the shower activity. Temperatures east of the Cascades
ranged from near 50 in Klamath Falls, under cloudy skies, to
the mid 60s, with sunshine, in Hermiston.
With a weak upper-level trough maintaining southeasterly flow
aloft over Oregon today, daytime heating will, once again,
destabilize the air mass enough for some showers to develop...mainly
over southern and eastern Oregon. There may also be a few thunderstorms
from the Cascades eastward. Southeasterly flow aloft could swing some
showers northwestward, into the Willamette Valley, again tonight, much
like the past two nights.
Var 3-6 this morning, W 5-10 this afternoon.
Var 4 this morning, NW 8 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 4200 feet. Ventilation index 34.
Salem\'s high temperature today will be near 70.
Minimum relative humidity will be near 59%.
Salem sunset tonight: 8:59pm; sunrise tomorrow: 5:25am.
Little change in the weather pattern is expected through this weekend
with a series of weak upper-level troughs continuing to bring mostly
cloudy skies to western Oregon with a chance of showers and even a
slight chance of thundershowers. A weak ridge should bring some
drying early next week, but another trough is forecast to renew the
shower threat by mid-week. Onshore flow will hold temperatures to near
or slightly below normal across western Oregon through at least Sunday,
with temperatures warming to near normal Monday and Tuesday.
Tomorrow (12 Jun): Mostly Cloudy. Chance of Showers. Slight Chance of T-Storms. 55/72
Sat (13 Jun): Mostly Cloudy. Chance of Showers. Slight Chance T-Storms. 55/72
Sun (14 Jun): Mostly Cloudy. Slight Chance of Showers. 52/71
Mon (15 Jun): Morning Clouds. Becoming Partly Sunny. 50/74
Tue (16 Jun): Morning Clouds. Becoming Mostly Sunny. 50/75
Wed (17 Jun): Mostly Cloudy. Chance of Showers. 50/70
Thu (18 Jun): Mostly Cloudy. Slight Chance of Showers. 53/70
weather at oda.state.or.us
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