Yakima Valley

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Record Report

Statement as of 05:28 PM PDT on September 04, 2015

... Record low temperature set at Redmond or...

a record low temperature of 31 degrees was set at Redmond or today.
This ties the old record of 31 set in 1969.

Public Information Statement

Statement as of 9:30 PM EDT on September 4, 2015
630 PM PDT Fri September 4 2015

... Month in review for northeast Oregon and southeast Washington for
the month of August 2015...

... Continued warmer and drier than average for most locations during
the month of August...

I. Temperature and precipitation overview

August average temperatures were above normal across much of the region
for the calendar month ranging from approximately 0 to 3 degrees above
normal. Most locations saw both maximum and minimum temperatures
average above normal for the month, with maximum temperatures mainly
between 1 to 3 degrees above average, and minimum temperatures between
0.5 to 3 degrees above average. The only exception to this was near
Pendleton and La Grande where the minimum temperature was 0 to 2
degrees below average for the month. Total precipitation was below
normal for most locations, ranging from less than 5 to about 50 percent
of normal. A few locations near the crest of the Washington Cascades
did have above normal precipitation due to a storm system late in the
month. To summarize, conditions were mild and generally dry across much
of the area during the month of August. Several daily and monthly
records were broken throughout the month.

August 2015 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 90.8 +2.9 56.4 +3.1 73.6 +3.0 0.01 -0.21
Kennewick 92.0 +1.7 62.5 +0.8 77.2 +1.2 T -0.22
Walla Walla 90.0 +0.8 64.2 +3.3 77.1 +2.1 0.30 -0.29
The Dalles 90.0 +2.5 62.1 +1.7 76.0 +2.0 0.03 -0.16
Redmond 86.6 +1.0 47.0 +0.8 66.8 +0.9 0.02 -0.51
Pendleton Airport 87.8 -0.2 56.9 -0.3 72.4 -0.2 0.01 -0.32
La Grande 88.6 +3.2 52.2 -1.6 70.4 +0.8 0.27 -0.41

ii. Selected records

The first two days of August featured hot and dry conditions over the
region, with many locations topping 100 degrees for daytime maximum
temperatures. In general temperatures were around 10 degrees above
average for the first two days of the month, and several record high
temperatures were set during this time. For the 3rd through the 9th the
region saw near to below average temperatures with the dry conditions
continuing. The coolest day occurred on the 6th when temperatures were
nearly 10 degrees below average in some locations. The 10th through the
13th of the month saw a brief, but pronounced warm up along with
scattered thunderstorms for parts of the area. Temperatures again
approached or even topped 100 degrees on the 12th in some locations. The
second half of the month saw more active weather with several
significant weather events occurring. These events were mainly wind and
blowing dusts event, with one thunderstorm event as well (see the
significant weather section below for more details). The second half of
the month also featured temperatures that were closer to normal,
generally within 5 degrees of average each day. There were no
significant heatwaves noted during the second half of the month. Also,
the last few days of the month saw the first measurable rainfall in
many locations for quite some time.

The following table lists the weather station, rank of the 1-day record
warmest maximum temperature for August, the record temperature with
date of occurrence, the current all-time record temperature for August,
or the previous record in cases where 2015 is the new record.

City rank August 2015 Max T August Max T record

Ellensburg, WA #1(t) 106 on 8/1 106 on 8/17/2008
Bickleton, WA #1(t) 102 on 8/2 & 8/14 102 on 8/4/1961
Satus Pass, WA #1(t) 102 on 8/1 102 on 8/4/1998
Condon, or #3(t) 102 on 8/1 103 on 8/8/1972*
Monument, or #3(t) 110 on 8/3 115 on 8/1/2009
Long Creek, or #3(t) 101 on 8/1 108 on 8/4/1961
Prosser, WA #4(t) 105 on 8/1 106 on 8/3/2009*
The Dalles, or #5(t) 109 on 8/1 110 on 8/17/1977*

*occurred on multiple previous dates/years

Thus far in 2015 (through August 31st) many locations around the region
have experienced the top 3 number of 100+ degree days. A few locations
have even set a new record for the number of 100+ degrees days through
August 31st. It remains to be seen if any records will stand after the
September is over. Although uncommon, a few additional 100 degree days
have occurred in the past during the first half or so of September. The
weather pattern this September is not particularly favorable for
additional 100+ degree days in our area.

City rank number of 100 degree previous or current
                     days through Aug 31st 2015 record number and year

Yakima, WA #1 24 days 17 days in 1971
Walla Walla, WA #1(t) 17 days 17 days in 1985
Ellensburg, WA #1 18 days 10 days in 2014
Hermiston, or #1 23 days 17 days in 2014
Pasco, WA #1 23 days 18 days in 2014
Bickleton, WA #1 6 days 3 days in 1928
Moro, or #1(t) 8 days 8 days in 1998
Moxee City, WA #1(t) 10 days 10 days in 1971
Prosser, WA #1 19 days 16 days in 1998
Satus Pass, WA #1 6 days 5 days in 2003
Long Creek, or #1(t) 4 days 4 days in 2002
Whitman mission #2 17 days 18 days in 1967
Meacham, or #2(t) 1 days 2 days in 1960
Antelope, or #2 9 days 10 days in 2009
La Grande, or #2 6 days 8 days in 2003
The Dalles, or #3(t) 17 days 21 days in 1996
Sisters, or #3 6 days 7 days in 2003

The mean synoptic pattern for the month of August 2015 was
characterized by an anomalous ridge of high pressure near the Aleutian
Islands & western Gulf of Alaska. There was also a strong ridge over
the Arctic Ocean with an undercutting trough off the north-central
California coast extending westward across the subtropical Pacific and
northward into northwestern Canada. A weaker ridge of high pressure was
also located over the western US, helping to increase the southwesterly
flow into the Pacific northwest. Below is a list of the stations that
set an all-time record warm daily minimum temperature in the month of
August, also listed is the ranks, August 2015 warm minimum temperatures
and the previous warmest August minimum temperature.

City rank August 2015 min T previous or current
                                                   warmest August min T

Ellensburg, WA #1(t) 76 on 8/1 70 on 8/03/2009*
Walla Walla, WA #5(t) 76 on 8/1 78 on 8/10/1984
The Dalles, or #6(t) 75 on 8/3 82 on 8/8/1982
Sisters, or #6(t) 62 on 8/4 68 on 8/8/1982
Long Creek, or #8(t) 62 on 8/3 66 on 8/16/1992
Prosser, WA #8(t) 70 on 8/14 73 on 8/3/1999
Moxee City, WA #10 68 on 8/12 72 on 8/16/2008

A few locations set top 5 warmest average minimum temperatures in
August 2015 as well. The following table lists the location, the rank,
the average August low temperature, and the record warmest average
August low temperature, or the previous record when August 2015 is the
new record.

City rank August 2015 previous or current warmest
                             avg min T August avg min T

Walla Walla, WA #3(t) 64.2 66.5 in 1977
Yakima, WA #4 56.4 58.3 in 1977
Bend, or #4 50.3 50.8 in 2004
Prineville, or #4(t) 49.8 52.4 in 1925
Hermiston, or #5 57.6 59.0 in 2014

Through a combination of the hot start to the month and another warm up
mid-month several locations were able to record their warmest average
Max temperature for the month of August. Listed in The Table below is
the location, rank, average Max temperature for August 2015 and either
the record warmest average Max temperature for the month of August, or
the previous record in cases where August 2015 is the new record.

City rank August 2015 previous or current warmest
                               avg Max T August avg Max T

Ellensburg, WA #4(t) 88.7 90.4 in 2012
Satus Pass, WA #5 86.3 87.5 in 1998
Long Creek, or #6 87.9 89.9 in 1967
Meacham, or #7 81.3 84.0 in 1967

through a combination of the hot start to the month and another warm up
mid-month many locations were able to record their warmest average
temperature for the month of August. Listed in The Table below is the
location, rank, average temperature for August 2015 and either the
record warmest average temperature for the month of August, or the
previous record in cases where August 2015 is the new record.

City rank August 2015 warmest August
                                  avg T avg T
Satus Pass, WA #1(t) 68.2 68.2 in 2004
Yakima, WA #3 73.6 74.2 in 1977
Prosser, WA #4 75.0 76.3 in 2004
Ellensburg, WA #5 72.8 73.9 in 2004
Long Creek, or #5 67.5 68.1 in 2001
Hermiston, or #6 74.0 75.3 in 2014
Bend, or #6 67.3 67.7 in 1986
Prineville, or #7 68.6 71.6 in 1901
Walla Walla, WA #8 77.1 80.1 in 1967
Sisters, or #10 65.3 67.4 in 1977
Moro, or #10 71.0 73.2 in 1967

Precipitation totals were well below normal in most locations which
lead to many top 10 lowest precipitation records and several locations
tied for their driest August on record. Listed below are the locations,
rank, August 2015 precipitation and the lowest recorded precipitation
for August. A (t) means that the record tied with other previous
dates/years. The combination of the hot and dry weather also lead to
several days of fire weather concerns throughout the month.

City rank August 2015 precip lowest August precip

Madras, or #1(t) 0.00 inches 0.00 inches in 2010*
Prineville, or #1(t) 0.00 inches 0.00 inches in 1994*
Prosser, or #1(t) 0.00 inches 0.00 inches in 2012*
Richland, WA #1(t) 0.00 inches 0.00 inches in 2006*
Pelton dam, or #1(t) 0.00 inches 0.00 inches in 2012*
Heppner, or #1(t) 0.00 inches 0.00 inches in 2012*
Pasco, WA #4(t) 0.03 inches 0.01 inches in 2006*
Hermiston, or #5(t) 0.01 inches trace in 2011*
John Day, or #10 0.05 inches 0.00 inches in 1969*

* indicates that this record occurred in other previous years

Iii. Significant weather

There were several significant weather events across the area during
the second half of August. There were three significant wind, blowing
dust and fire weather events, along with one nocturnal thunderstorm

On August 14th a push of cooler marine air moved into the area during
the morning hours. This helped to dramatically increase westerly winds
across most of the area as well. This also created widespread blowing
dust over much of the basin, locally reducing visibility to 1 mile or
less at times. Although this did create hazardous travel conditions the
potential for blowing dust was well forecasted several days in advance.
Fires, such as the Canyon Creek complex, made significant advances and
unfortunately destroyed many homes along with other infrastructure
during this event. Listed below are Sample peak wind gusts, minimum
visibility and minimum relative humidity from the August 14-15th event:

Location peak gust min visibility min humidity

Ellensburg 49 mph 10.00 miles 38%
Yakima 43 mph 1.50 miles 31%
Tri-Cities 48 mph 2.00 miles 24%
Pendleton 45 mph 2.00 miles 31%
The Dalles 38 mph 10.00 miles 29%
Redmond 33 mph 10.00 miles 34%
La Grande 40 mph 1.75 miles 11%
Bend 31 mph 10.00 miles 17%
John Day 45 mph 7.00 miles 8%

Although not as severe as the August 14-15th event, winds again
increased behind a cold front helping to kick-up dust and spread
wildfires on August 20th and 21st. Relative humidity levels were rather
low during this event which acted to exacerbate the fire weather issues
further. Listed below are Sample peak wind gusts, minimum visibility
and minimum relative humidity from the August 20-21st event:

Location peak gust min visibility min humidity

Ellensburg 46 mph 10.00 miles 19%
Yakima 31 mph 10.00 miles 21%
Tri-Cities 29 mph 10.00 miles 17%
Pendleton 36 mph 3.00 miles 4%
The Dalles 41 mph 10.00 miles 17%
Redmond 25 mph 10.00 miles 11%
La Grande 26 mph 10.00 miles 14%
Bend 25 mph 10.00 miles 11%
John Day 29 mph 0.50 miles (smoke) 8%

Elevated instability combined with a weak northward moving disturbance
to initiated evening & overnight thunderstorms on the 24th into the 25th.
The thunderstorms mainly affected parts of Wheeler, Gilliam, Morrow,
Umatilla, Benton, Franklin and Walla Walla counties. They occurred
mainly from 7pm through about 4 am before exiting the area into north-
central Washington. These thunderstorms were very dry producing only a
trace of rain at Hermiston and 0.03 inches at Pasco. Multiple cloud to
ground lightning strikes ignited grass and wild fires across these
areas. For this reason a short fused red flag warning was issued just
prior to the event.

Another strong cold front moved into the area during the morning hours
on August 29th bring much of the same weather conditions to the area as
described above. Winds became gusty and started to pick up loose dust
across the area reducing visibilities. This event featured a bit more
moisture behind the initial cold front, with a least a few locations
seeing their first measurable rainfall in months. Although relative
humidity levels remained higher during this event the strong winds still
represented a significant danger for many ongoing wildfires, with some
fires again spreading. Listed below are Sample peak wind gust, minimum
visibilities, minimum humidity, precipitation amount, coolest high and
low temperatures for the August 29th through the 31st event:

Location peak gust min vis min rh precip coolest coolest
                                                    Max T min T
Ellensburg 39 mph 10.00 mi 30% 0.05 72(8/30) 52(8/31)
Yakima 44 mph 0.13 mi 31% 0.01 78(8/30) 49(8/31)
Tri-Cities 37 mph 2.00 mi 22% trace 78(8/30) 59(8/31)
Pendleton 45 mph 2.00 mi 27% 0.01 73(8/30) 48(8/30)
The Dalles 29 mph 10.00 mi 30% 0.03 76(8/30) 54(8/31)
Redmond 32 mph 8.00 mi 25% 0.01 70(8/30) 35(8/31)
La Grande 36 mph 5.00 mi 22% 0.10 68(8/30) 43(8/30)
Bend 36 mph 7.00 mi 25% trace 66(8/30) 37(8/31)
John Day 45 mph 7.00 mi 16% trace 70(8/30) 46(8/31)

Looking ahead to September the climate prediction center (cpc) is
calling for a better chance to see above normal temperatures in our
area, along with below normal precipitation amount. Please keep in mind
that these forecasts are for the entire month averaged out, and that
daily weather conditions will undoubtedly vary.

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