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Area forecast discussion 
National Weather Service Pendleton or
745 PM PDT Friday Aug 1 2014

Short term...fair amount of thunderstorm activity this afternoon
into the evening. Storms scattered about the forecast area as an
upper level impulse is moving through. Several storms have been
strong with hail and heavy rain. Expect to see a decrease late
tonight as they move off to the northeast and diminish. Another
short wave moves through Saturday. Lots of instability based on
model forecasts and slightly stronger winds aloft. Expect showers
and thunderstorms to develop again. Could see some stronger storms.
Otherwise skies will be partly to mostly cloudy tonight into
Saturday. Temperatures will remain above normal with highs mostly
in the 90s tomorrow. 94


Previous disc... /issued 500 PM PDT Friday Aug 1 2014/

Short term...tonight through Monday...the upper ridge over the
western U.S. Will generally remain in place through Sunday, though
it will slowly shift east. The upper level flow over the Pacific
northwest will remain south-southwesterly through tonight then
become more southwest to westerly Saturday afternoon into Sunday.
Weak disturbances imbedded within the upper flow will continue to
move across the region through Sunday. These disturbance will pull
pieces of subtropical moisture out of Nevada which will result in
isolated to scattered showers and thunderstorms over the area late
today through Saturday evening. Shear and energy may be sufficient
for stray strong storms across portions of central and northeast
Oregon Saturday afternoon and evening. Some drying from the west may
begin to work into the area Saturday evening, but the better drying
looks to occur on Sunday. Will indicate a dry slot around the
Columbia River gorge Saturday evening, while limiting showers/storms
on Sunday to central Oregon east to Grant County and northeast to
The Blues and wallowas. A system currently near the south end of
Baja California California looks to move north through California to southern
Idaho on Monday. This system could push some extra moisture into
south-central and southeast Oregon. Meanwhile west to northwest flow
looks to increase across Washington and north-central Oregon. Thus
expect any showers and thunderstorms Monday afternoon to be in
roughly the same locations as on Sunday, though these showers/storms
could be rather wet. 90

Long term...Monday night through Friday...wrap around moisture
associated with a middle/upper level low pressure system in eastern
Oregon and western Idaho will provide a chance of showers and a
slight chance of thunderstorms Monday evening in central and
northeast Oregon Monday evening. The low remains over the Oregon
portion of forecast area on Tuesday thus keeping a slight chance of
afternoon and evening showers and a slight chance of thunderstorms
Tuesday afternoon/evening in the mountains of central and northeast
Oregon. The southern Blue Mountains as well as the Elkhorn and
Wallowa Mountains will have a slight chance of showers overnight
Wednesday through Wednesday morning by virtue of the low still in
far eastern Oregon. Then Flat Ridge of high pressure takes control
across the Pacific northwest for dry and stable conditions Wednesday
afternoon through Friday night. Polan

Aviation...00z tafs...mfr conditions will prevail for the next 24
hours, except directly underneath a thunderstorm where MVFR due to
reduced visibility in brief heavy rain with small hail may be
possible at kpdt and kalw until sunset this evening. Mostly scattered to
broken high cirrus with scattered middle level clouds with bases near 13000 to
15000 feet above ground level through the period. Since 23z this afternoon isolated to
scattered thunderstorms gave been developing over ridge tops in central
Oregon, the Ochoco Mountains, and in the southern Blue Mountains
south of Heppner. Mean deep layer steering flow in the middle levels is
out of the south near krdm and kbdn and from the southwest over
northeast Oregon. Have dropped -tsra for kbdn and krdm for the
remainder of this afternoon and this evening since visible satellite
imagery loop indicates convective cells over Deschutes County and
northern Klamath County are very weak. Thunderstorms will end at
kpdt by around 02z and then begin by 02z at kalw and end by 04z.
Sustained winds will remain below 15 kts. Winds will gust to 35 kts
late this afternoon and early this evening in the vicinity of

There is some potential for a few strong or marginally severe
thunderstorms in central Oregon Saturday afternoon. However, my
confidence is not high enough at this point to include small hail
and gusty winds of 30-40 kts in tafs for krdm and kbdn, but cannot
rule it out after 22z/02nd Saturday afternoon at kbdn and krdm.

Fire weather...warm and dry conditions continue under a ridge of high
pressure. Thunderstorms can be expected over the region this
afternoon and evening and again on Saturday. The best locations for
scattered thunderstorms is across central...north central and
northeast Oregon as well as the far southeastern Washington zones.
These locations are under a red flag warning in effect through
Saturday. Isolated thunderstorms are possible in the Columbia Basin
later this evening and on Saturday. Storms that develop will be a
mixture of wet and dry with precipitation ranging from a few
hundredths of an inch to around a quarter of an inch. Dmh


Preliminary point temps/pops...
PDT 69 98 65 98 / 20 20 20 10
alw 73 99 70 99 / 20 20 20 10
psc 68 101 65 101 / 20 20 20 10
ykm 68 97 64 96 / 20 20 20 10
hri 68 100 64 100 / 20 20 20 10
eln 64 98 60 99 / 20 20 20 10
rdm 59 93 51 94 / 30 30 30 20
lgd 64 93 59 93 / 30 30 30 20
gcd 65 96 59 96 / 30 30 30 30
dls 70 96 64 96 / 20 20 10 10


PDT watches/warnings/advisories... flag warning until 11 PM PDT Saturday
orz041-049-050-502-503-505>507-509>511. flag warning until 11 PM PDT Saturday waz030.


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