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Issued by NWS Pendleton, OR

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NOUS46 KPDT 190354


...Month In Review for Northeast Oregon and Southeast Washington for
the month of August 2016...

...August was warmer and much drier than average across the region...

I.  Temperature and Precipitation Overview

August temperatures were near to slightly above average over much of
the region for the calendar month, ranging from approximately 0 to 3
degrees above average. The exception to this was near John Day, where
temperatures ended the month about 2 degrees below average. Most
locations saw warmer maximum temperatures compared to average, ranging
from about 1 to 4 degrees above average for the month. Overnight lows
were closer to average, ranging from about 1 degree below average to 3
degrees above average.

Total monthly precipitation was generally well below average for the
month. In fact, most locations had less than 25 percent of normal
precipitation in August. A few mountainous locations in the
northern Blue Mountains and in Wallowa County were closer to 50 percent
of average precipitation. These very low precipitation totals allowed
many locations to set or tie record minimum precipitation totals for
the month.

August 2016 Data and Departure From Normal For Selected Cities:

                Max   Dep   Min   Dep   Ave   Dep   Pcpn   Dep
                Temp  Norm  Temp  Norm  Temp  Norm  Totl   Norm

Yakima          91.0  +4.2  54.6  +2.8  72.8  +3.5  Trace -0.26
Kennewick       90.7  +1.4  61.8  +1.0  76.3  +1.3  0.00  -0.18
Walla Walla     90.2  +2.1  60.4   0.0  74.7  +0.5  0.16  -0.41
The Dalles      90.6  +3.3  59.6  +0.1  75.1  +1.7  0.00  -0.23
Redmond         87.5  +2.7  45.5  +0.3  66.5  +1.5  0.02  -0.48
Pendleton       88.3  +1.5  55.7  -1.1  72.0  +0.2  0.07  -0.31
La Grande       88.1  +2.4  51.6  -0.7  69.9  +0.9  0.16  -0.69

II.  Selected Records

The first ten days of August started off mainly cooler than average,
with two storms systems moving through the area. These weather systems
brought windy conditions and even a few showers and thunderstorms. The
middle ten days of the month featured much hotter and drier weather.
Most locations had high temperatures in the mid-90s to lower 100s
during this time period. Finally, the last ten days of the month had
breezy, and somewhat cooler weather conditions. The windy conditions
made for several critical fire weather days during this time period.
Read more details on these weather events in the significant weather
section below.

The mean synoptic pattern for the month of August 2016 was
characterized by a large ridge of high pressure extending across the
Gulf of Alaska and much of the northeastern Pacific. The Pacific
Northwest was on the eastern flank of this ridge, with a north to
northwest flow dominating our weather pattern through the month. There
was a weak area of below average heights over the southwest US and also
south of the Aleutians. This overall pattern kept temperatures near
average for our area through the month, with well below average
precipitation amounts for many locations.

During the second half of August a heat wave affected the area, and
several locations set daily record high maximum temperatures. Although
these temperatures were hot, they were not unprecedented enough to make
it in the top ten highs for the month. Listed below are the location,
new daily record high, and the previous daily record high.

City              New Record Max T    Previous Max T Record

Easton, WA        91 on 8/19(T)       91 on 8/19/2012
Satus Pass, WA    97 on 8/19          95 on 8/19/1977
Ellensburg, WA    93 on 8/29          93 on 8/29/1949
Sunriver, OR      92 on 8/22          89 on 8/22/2003
Pasco, WA        100 on 8/21(T)      100 on 8/21/2005

Overnight low temperatures were rather cool at times through the month,
which allowed four locations to set top 10 records. Listed below are
the location, rank, August 2016 average minimum temperature and the
current or previous record coolest average minimum temperature in

City             Rank     August 2016    Coolest Avg
                          Avg Min T      Aug Min T

John Day, OR      #8      44.8           42.4 in 1959
Pasco, WA         #8      55.4           52.9 in 2002
Hermiston, OR     #8      54.8           52.4 in 2002
Meacham, OR       #9      38.9           34.5 in 2002

With the large upper level ridge of high pressure building over the
region during the middle of the month, average high temperatures of the
month were elevated. This weather pattern lead to daytime highs
reaching the top 10 warmest on record for several locations. Listed
below are the location, rank, August 2016 average maximum temperature
and the warmest, average August maximum temperature on record.

City             Rank    Aug 2016     Current August
                         Avg Max T    Avg Max T Record

Hermiston, OR    #6      91.6         92.0 in 2012
Easton, WA       #7      77.0         79.9 in 1933
Ellensburg, WA   #8      88.6         90.4 in 2012
Yakima, WA       #8(T)   91.0         93.0 in 1967
Pasco, WA        #9(T)   91.3         93.4 in 1998
Sisters, OR      #10     86.9         91.5 in 1977

Accordingly a few locations experienced a top 10 warmest August on
record. Listed below are the location, rank, August 2016 average
monthly temperatures and the current warmest August average temperature
on record:

City             Rank    Aug 2016     Warmest August
                         Avg T         Avg T Record

Easton, WA       #8      62.6          66.3 in 2014
Yakima, WA       #8      72.8          74.2 in 1977
Ellensburg, WA   #9      72.0          73.9 in 2004

Only one main storm system moved through our area during the month
bringing any showers or thunderstorms. The rest of the weather systems
moving through generally lacked any precipitation...instead bringing
cooler temperatures and windy conditions. This allowed many locations
to set records for a top 10 driest August on record. Listed below are
the locations, rank, August 2016 monthly precipitation total, and the
current or previous August minimum monthly precipitation record:

City              Rank    August 2016       Current or Previous Aug
                          Precip Total     Min Monthly Precip Record

The Dalles, OR   #1(T)    0.00 Inches      0.00 Inches in 1998 (3X)
Antelope, OR     #1(T)    0.00 Inches      0.00 Inches in 2012 (10X)
Bend, OR         #1(T)    0.00 Inches      0.00 Inches in 2015 (10X)
Goldendale, WA   #1(T)    0.00 Inches      0.00 Inches in 2012 (10X)
Kennewick, WA    #1(T)    0.00 Inches      0.00 Inches in 2016 (10X)
Moxee City, WA   #1(T)    0.00 Inches      0.00 Inches in 2012 (9X)
Ellensburg, WA   #2       Trace            0.00 Inches in 1955 (1X)
Yakima, WA       #2(T)    Trace            0.00 Inches in 1955 (1X)
Pasco, WA        #6       0.04 Inches      0.01 Inches in 2006 (3X)
Dayville, OR     #7(T)    0.02 Inches      0.00 Inches in 2012 (2X)
Long Creek, OR   #7(T)    Trace            0.00 Inches in 2012 (6X)
Hermiston, OR    #8(T)    0.05 Inches      Trace       in 2011 (4X)
Easton, WA       #9       0.36 Inches      0.02 Inches in 2012 (1X)

*(nX) is the number of times the record lowest precipitation value has
been achieved at a given location*

III. Significant Weather

There were several significant weather events across the area during
the month of August including rain showers, thunderstorms, a heat wave,
and fire weather days:

On August 2nd, a deep upper level low pressure system moved directly over
eastern Washington and Oregon. This upper level low brought clouds,
windy conditions and much cooler weather to the region.

Listed below are some sample rain amount, peak wind gusts and the
coolest temperature from around the region during this event:

Location         Peak Wind Gust    Coolest Temp

Pendleton, OR       49 MPH          59 Degrees
Meacham, OR         21 MPH          39 Degrees
Redmond, OR         33 MPH          43 Degrees
Pasco, WA           40 MPH          56 Degrees
Walla Walla, WA     36 MPH          60 Degrees
Yakima, WA          40 MPH          53 Degrees
Hermiston, OR       49 MPH          60 Degrees
Ellensburg, WA      44 MPH          56 Degrees
The Dalles, OR      37 MPH          61 Degrees
Easton, WA          NA MPH          52 Degrees

A storm system moved through the area during the August 5th through the
8th time period. This weather system brought showers and even
thunderstorms to the region. However, no severe weather was reported.
Listed below are the locations, 4 day precipitation totals, and whether
or not thunder was reported at a given location:

Location          4 Day Precip      Thunder?

Pendleton, OR        0.07 Inches      Yes
Meacham, OR          0.18 Inches      No
Redmond, OR          0.02 Inches      Yes
Pasco, WA            0.04 Inches      No
Walla Walla, WA      0.16 Inches      Yes
Yakima, WA           Trace            No
Hermiston, OR        0.05 Inches      No
Ellensburg, WA       Trace            No
The Dalles, OR       0.00 Inches      No
Easton, WA           0.02 Inches      Yes

A ridge of high pressure then built over the area from August 12th
through the 18th, brining drier and hotter conditions. Many lower
elevation locations reported peak temperatures in the upper 90s to
around 100 degrees during this period. See below for peak temperature
reports from around the region:

Location              Peak Temperature

Pendleton, OR         98 Degrees
Meacham, OR           87 Degrees
Redmond, OR           97 Degrees
Pasco, WA            100 Degrees
Walla Walla, WA       98 Degrees
Yakima, WA           100 Degrees
Hermiston, OR        101 Degrees
Ellensburg, WA        99 Degrees
The Dalles, OR       103 Degrees
Dayville, OR         101 Degrees
Bend, OR              92 Degrees
Heppner, OR           94 Degrees
La Grande, OR         96 Degrees
Madras, OR            94 Degrees

Then, two separate storm systems moved into the area, first on August
21st and again on the 27th. Conditions were very hot and dry on the 21st,
with extremely low relative humidity reported across the region.
Humidity values were slightly higher on the 27th, but winds remained
gusty. Several wildfires spread across the area in the dangerous fire
weather conditions. Listed below are the location, peak wind gust, and
lowest humidity value reported during these two events:

Location         Peak Wind     Lowest Humidity

Pendleton, OR     43 MPH       6 Percent
Meacham, OR       20 MPH       8 Percent
Redmond, OR       30 MPH       4 Percent
Pasco, WA         29 MPH      13 Percent
Walla Walla, WA   36 MPH       6 Percent
Yakima, WA        36 MPH       9 Percent
Hermiston, OR     40 MPH       8 Percent
Ellensburg, WA    48 MPH      20 Percent
The Dalles, OR    43 MPH      22 Percent
John Day, OR      23 MPH       7 Percent

The latest drought monitor shows some minor degradation in the drought
conditions, with all of Oregon and Washington now back in the D0, or
abnormally dry category. Much of Eastern Oregon is now back in the D1,
or moderate drought category. A small portion of Northeast Oregon is
now experiencing a D2, or severe drought. The monthly drought outlook
for September from CPC indicates drought persisting across eastern
Oregon, with drought development likely across north-central Oregon

Currently, cooler than average sea surface temperatures were observed
in the Nino 3 and 3.4 regions. Nino 1+2 continues to have warmer than
average sea surface temperatures. The La Nina watch has now been
cancelled. ENSO neutral conditions are slightly favored through the
upcoming winter months. This probability of La Nina development is now
lower than last month`s update, around 40 percent through the winter

Looking ahead to the rest of September the Climate Prediction
Center(CPC) is calling for most of the Inland Pacific Northwest to have
a 33 to 39 percent chance for above average temperatures in the month
of September. This higher probability for warmth extends across the
entire western United States and western Alaska. Some of the highest
chances for above average temperatures in September are present over
Nevada and across the Northeast US.

Much of eastern Washington and Oregon have greater chances for below
normal precipitation totals during September, with east-central Oregon
having a greater than 40 percent chance of below average precipitation
during September. Higher probabilities for above average precipitation
totals in September are present in the upper Midwest and along the
immediate East Coast, from Florida north to Maine. Please remember that
these are probabilities of averages, and that the day-to-day weather
will still vary for the month.


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