Wildfire in Oregon, June 20 to 30, 2018

Area Forecast Discussion
National Weather Service Pendleton OR
221 PM PDT Wed Jun 20 2018

...MARGINAL RISK OF SEVERE THUNDERSTORMS THROUGH THIS EVENING...

.SHORT TERM...Tonight through Saturday...A shortwave is moving
onshore northern CA early this afternoon. Ahead of this feature,
initial showers/thunderstorms have developed across southern
sections of central OR. Coverage and intensity of storms will
increase through the afternoon as peak heating is reached. High
resolution models continue to show the thunderstorms forming into a
complex early this evening, moving northward late evening/overnight.
Will use the highest PoPs across central OR and the associated
highlands, with less coverage further north through the evening with
some increase in coverage overnight as the shortwave moves gradually
to the east. With sufficient deep layer shear through at least
early this evening, strong to locally severe storms will be
possible with gusty winds and hail the main threats. Thunderstorm
coverage will decrease some overnight, but at least a slight chance
of storms will linger with residual instability. Lows tonight will
be unseasonably warm, especially north of central OR, with lower
elevation lows in the mid 60s to around 70.

The shortwave will continue to move east Thursday, exiting the
area Thursday night. PoPs will remain quite high from the Blue
Mountain foothills eastward with likely PoPs through Thursday
afternoon. With some instability, chances of thunderstorms will
continue. With the greatest shear to the east, do not expect
strong/severe storms Thursday. Areas to the west will experience a
slight chance of residual showers early, ending by afternoon.
Residual activity in the evening across the eastern mountains will
end by the overnight as shortwave ridging/drier NW flow enters
the region. Dry conditions will prevail Friday and Saturday under
NW flow. In the wake of the system, windy conditions will prevail
on Friday/Friday evening with some local gusts approaching
advisory criteria. Above normal temperatures Thursday will cool
slightly Friday and Saturday.

.LONG TERM...Saturday night through Wednesday...Saturday night an
upper trough will be departing the area while an upper ridge
builds along the coast. Do not expect any precipitation Saturday
Night except perhaps in eastern Wallowa county in the early
evening but have gone with dry forecast. Sunday will see the ridge
move overhead for a dry and warm day with highs in the 80s and
lower 90s. The ridge will move off to the east Sunday night as a
trough moves to the coast. The trough will move east gradually and
come ashore Monday night and then through the area Tuesday. Most
of the energy and moisture with the trough will remain up in
British Columbia so our area should remain dry. The trough will
bring breezy west to northwest winds of 10 to 20 mph Monday in the
late afternoon and evening. After the trough departs on Tuesday
models have some timing differences but it appears that a westerly
flow will be over the area on Tuesday night followed by a weak
trough that arrives Wednesday. All models continue fair and dry
weather Tuesday night and Wednesday. After the warm day on Sunday,
temperatures will drop back to the mid 70s to mid 80s Monday and
then to the mid 70s to lower 80s with mid 60s to mid 70s in the
mountains on Tuesday and Wednesday.

&&

.AVIATION...Previous discussion...18Z TAFs...VFR conditions will
prevail into this afternoon. Scattered to numerous thunderstorms
will develop across central OR, affecting KRDM/KBDN around 23Z, with
gusty winds, hail and brief periods of heavy rain possible until
about 03-04Z. Further north, thunderstorm coverage will be more
isolated to scattered, affecting KDLS and KYKM from 02Z-06Z and
KALW, KPSC and KPDT from 06Z-11Z. Areas of MVFR will be possible in
the heavier showers and stronger thunderstorms. However, activity
will decrease in coverage and intensity after 06Z-09Z. Winds outside
of thunderstorms will remain 12 kts or less through this evening,
with some increase overnight. KDLS will increase to 15 to 20 kts
with gusts to 25 kts after 16Z tomorrow morning.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  65  85  58  84 /  40  60  10   0
ALW  67  88  60  87 /  30  60  10   0
PSC  69  90  61  89 /  30  40  10   0
YKM  67  88  58  85 /  30  10   0   0
HRI  70  90  61  88 /  40  40  10   0
ELN  65  84  57  80 /  30  10   0   0
RDM  54  84  49  83 /  70  10   0   0
LGD  58  79  51  81 /  60  60  10   0
GCD  56  81  51  82 /  70  30  10   0
DLS  67  83  61  81 /  50  10   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
&&

80/83

Special Weather Statement
National Weather Service Pendleton OR
238 PM PDT WED JUN 20 2018

ORZ509-202230-
East Slopes of the Oregon Cascades OR-
238 PM PDT WED JUN 20 2018

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN DESCHUTES COUNTY
UNTIL 330 PM PDT...

At 237 PM PDT, Doppler radar was tracking a strong thunderstorm 13
miles west of Deschutes River Woods, or 15 miles west of Bend, moving
north at 15 mph.

Dime size hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Sisters and Black Butte Ranch.

LAT...LON 4441 12179 4440 12142 4430 12143 4425 12149
      4422 12148 4418 12145 4398 12149 4398 12174
TIME...MOT...LOC 2137Z 181DEG 15KT 4406 12162