Summer 2013 Highlights

The summer months of June - August across eastern Oklahoma and northwest Arkansas were on average slight cooler and drier for Tulsa, OK and Fayetteville, AR, while Fort Smith, AR was slightly warmer and wetter than normal.  Above normal rainfall helped to alleviate the drought conditions across the region, and even led to flooding across several counties and on some area rivers.  Many daily high and low temperature records were broken, however, even with the excessive rainfall, no daily precipitation records were set during the summer months.  An active severe weather season set up during June and July, with several rounds of thunderstorms bringing large hail and damaging winds, along with a 2 tornadoes.  The strongest system was the derecho that affected much of eastern Oklahoma and northwest Arkansas during the evening of July 23, bringing very strong winds and widespread wind damage to the area.

Temperatures . . .

The following line graphs depict the mean temperature for the months of June - August (in blue) along with the expected mean temperature (in red) for Tulsa, OK, Fort Smith, AR and Fayetteville, AR.  The mean temperatures were taken from 1980 - 2010.

The summer months of 2013 started out cooler than normal, with the first week of June slightly below normal.  By mid-June, however, temperatures warmed, leaving the month as a whole slightly warmer than normal at Tulsa, Fort Smith, and Fayetteville.  Conditions cooled again during early and late July, leaving the month on average slightly cooler than normal at all three sites.  August temperatures remained near normal for much of the month, except for a 4 to 5 day stretch in the middle of the month where temperatures were between 7-11 degrees below normal.  This mid-month cool down was enough to trend the monthly averages slightly below normal for the month at Tulsa and Fayetteville, while Forth Smith remained normal for the month.

Precipitation . . .

The following bar graphs depict the mean precipitation for the months of June - August (in blue) along with the expected mean precipitation (in red) for Tulsa, OK, Fort Smith, AR and Fayetteville, AR.  The mean precipitation amounts were taken from 1980 - 2010.

Well below normal precipitation amounts fell over northeast Oklahoma and northwest Arkansas during the month of June, while above normal precipitation fell over southeast Oklahoma and western Arkansas.  This is displayed in the bar graphs above, with Tulsa and Fayetteville receiving only 1.69" (normal is 4.72") and 1.37" (normal is 4.98") of rainfall, while Fort Smith received 6.10" (normal is 4.28") during the month.  July brought closer to normal amounts of rain, with Tulsa receiving 1.57" above normal precipitation, and Fort Smith receiving slightly above normal amounts (+0.65") and Fayetteville receiving slightly below normal amounts (-0.68").  August was again near normal for rainfall, with Fort Smith receiving 1.25" above normal precipitation, and Tulsa receiving normal amounts (-0.02") and Fayetteville receiving slightly below normal amounts (-0.42").

Drought Progression . . .

The following chart depicts the amount of precipitation that fell leading up to, and during the summer months of 2013, and how that impacted the current drought across the area.  The first image is the amount of rainfall that fell during the month (observed precipitation).  The second image is the percentage of expected rainfall that fell during the month (percent of normal).  The third image is the state of drought near the end of that month (drought progression).

	Observed Preciptation	Percent of Normal	Drought Progression
May 2013			May 28, 2013
June 2013			June 25, 2013
July 2013			July 30, 2013
August 2013			August 27, 2013

At the end of spring 2013, northeastern Oklahoma was still experiencing drought conditions, with much of the area along and northwest of Highway 44 experiencing between D0 - D2 drought conditions (D2 - Severe).  D0 (Abnormally Dry) and D1 (Moderate) drought persisted across northeast Oklahoma during the month of June, as below normal precipitation occurred over much of the area.  Above normal precipitation fell over northeast Oklahoma during the month of July, bringing an end to most of the drought, however, below normal rainfall over northwest Arkansas created D0 - D1 drought conditions in that portion of the forecast area.  Near normal rainfall over much of eastern Oklahoma and northwest Arkansas during August helped to alleviate the remaining D1 drought, but a few small areas of D0 remained heading into September.

Averages and Records . . .

Below are tables for Tulsa, OK, Fort Smith, AR and Fayetteville, AR with their monthly averages and records for temperatures and precipitation for the summer months of June - August, along with the summer seasonal average.  Below the tables are the daily temperature and precipitation records set this summer season.

Tulsa:

* June 3, tied the lowest minimum temperature record of 52 degrees (other records from 1922 and 1946).

* No daily precipitation records were set during the summer season in Tulsa.

Fort Smith:

* June 28, tied the highest minimum temperature record of 80 degrees (other record from 1945).

* July 26, set a new lowest maximum temperature record of 76 degrees (old record was 80 degrees from 2004).

* July 26, set a new lowest average temperature record of 72.5 degrees (old record was 73.0 degrees from 1911).

* August 16, set a new lowest maximum temperature record of 79 degrees (old record was 80 degrees from 1942 and 1992).

* No daily precipitation records were set during the summer season in Fort Smith.

Fayetteville:

* June 21, set a new highest minimum temperature record of 74 degrees (old record was 73 degrees from 1964 and 1998).

* June 21, set a new highest average temperature record of 82.0 degrees (old record was 81.5 degrees from 1964 and 1974).

* June 30, set a new lowest maximum temperature record of 78 degrees (old record was 79 degrees from 1981, 1995, and 2004).

* June 30, tied the lowest average temperature record of 67.0 degrees (other record from 1950).

* July 1, tied the lowest minimum temperature record of 55 degrees (other record from 1976).

* July 2, set a new lowest minimum temperature record of 51 degrees (old record was 57 degrees from 1951, 1959, and 1985).

* July 3, set a new lowest minimum temperature record of 51 degrees (old record was 53 degrees from 1959).

* No daily precipitation records were set during the summer season in Fayetteville.

How does this summer compare to the summers of 2011 and 2012?

Everyone remembers how hot the summer months of 2011 and 2012 were.  Here are some numbers to show just how much hotter those years were compared to this past summer.

Tulsa:

Fort Smith:

Fayetteville:

Weather Highlights . . .

Here are a few of the more significant events of the summer season 2013, including severe weather, heavy rain, and flooding.

June:

June 1 Heavy Rain and Flooding Event Photo Credit: HPC	June 16-17 Severe Weather Event Photo Credit: NWS Tulsa	June 27 Heat Burst Event Photo Credit: OK Mesonet

Heavy rain fell during the end of May and beginning of June, leading to flooding issues across portions of the forecast area, mainly within Okfuskee, Okmulgee, and McIntosh Counties.  Major street flooding was reported in Henryetta, with roads closed, and cars and building inundated with water.  Over 4 inches of rain fell during a 24-hour period ending the morning of June 1st in Okemah, Eufaula, Stigler, and Whitefield.  More information about the severe weather of late May and early June 2013 can be found here.  During the late afternoon hours on June 16th, and into the early morning hours of June 17th, severe thunderstorms tracked across eastern Oklahoma and into western Arkansas.  The severe storms brought strong damaging winds, large hail, and heavy flooding rains to the area.  Reports of downed trees and power poles were relayed to the National Weather Service, along with flooded roadways and large hail.  The end of June brought a short lived heat wave between June 26-28th, with temperatures reaching into the upper 90s and lower 100s across much of the forecast area.  During the late evening hours on June 27th, a heat burst was recorded at the Foraker Mesonet site in northern Osage County.  A heat burst is when air descends toward the surface, warming quickly as it falls.  The temperature in Foraker warmed from about 75° to 90° in about 30 minutes.  More information about heat bursts can be found here.

July:

July 10 Heat Event Photo Credit: OK Mesonet	July 20-22 Heavy Rain and Flooding Event Photo Credit: Bigheart Times	July 23-24 Severe Weather Event Photo Credit: NWS Tulsa

July started out cool, with below normal temperatures setting a few new record low temperatures in Fayetteville.  By July 9th, temperatures had warmed into the mid-90s to 100 degrees across the forecast area.  The following day, on July 10th, the highest temperatures of the summer were hit, with highs reaching 102° in Tulsa, 104° in Fort Smith, and 99° in Fayetteville.  A heat advisory was issued for the entire forecast area, and an excessive heat warning was issued for Tulsa County.  The heat wave broke on July 13th, when an upper level low pressure system moved into the region.  Several days of showers and thunderstorms started during the middle of the month, followed by heavy rainfall over northeast Oklahoma between July 21st and July 22nd.  Two day rainfall totals included 8.80" in Barnsdall (Osage Co), 6.79" in Avant (Osage Co), 5.63" in Foraker (Osage Co), 5.09" in Miami (Ottawa Co), 4.17" in Lenapah (Nowata Co), 3.83" in Vinita (Craig Co), and 3.69" in Ramona (Washington Co).  This caused significant flooding to occur across the area, including near Barnsdall in Osage County (pictured above).  On the afternoon of July 23rd, severe thunderstorms developed over southern Kansas, and tracked southeast into the area.  These storms produced strong winds, large hail, heavy flooding rains, and one EF-1 tornado (Wagoner, OK) across portions of eastern Oklahoma and western Arkansas.  The system will be remembered best for its intense winds and wind damage.  Winds in excess of 70 mph where recorded at several locations, including 71 mph at the Tulsa Mesonet, 73 mph at the Burbank Mesonet, 76 mph at the Tulsa International Airport, and 91 mph at a Tulsa home weather station near 37th & Nogales.  The 76 mph reading from the Tulsa International Airport was the strongest wind gust ever recorded there.  More information about the severe weather on July 23rd - July 24th can be found here.

August:

Aug 7-9 Severe Weather Event Photo Credit: HPC	Aug 12-14 Heavy Rain and Flooding Event Photo Credit: Channel 6 News	Late August Heat Wave Event Photo Credit: NWS Tulsa

The first half of August was cooler and wetter than normal, with two heavy rainfall events bringing severe weather and flooding to portions of the forecast area.  The first system moved across northeast Oklahoma and northwest Arkansas during the early morning hours on August 8th.  Several reports of damaging winds were reported, along with very heavy rain and flooding.  24-hour rainfall amounts included 6.61" in Garfield (Benton Co), 6.44" in Bella Vista (Benton Co), 4.88" in Jay (Delaware Co), 4.23" in Kansas (Delaware Co), and 3.20" in Vinita (Craig Co).  Flash flooding was reported in Benton, Delaware, Washington, Ottawa, Carroll, and Craig Counties.  A second round of heavy rain occurred a few days later, between August 12th and August 14th, when another band of heavy rain fall across eastern Oklahoma and western Arkansas.  The heaviest rain occurred across Creek, Okmulgee, Muskogee, and McIntosh counties where between 3 and 4 inches of rain were common.  Flooding was reported in McIntosh and Washington counties where several days of rain caused many roadways to become impassable including one in Dewey, Oklahoma (pictured above).  While the first half of August was cool and wet, a dome of high pressure set up over the region for the second half of the month, putting an end to the excessive rainfall and raising temperatures well into the 90s and even 100s.  The last day of the month was the hottest, with Tulsa reaching 102°, Fort Smith reaching 101°, and Fayetteville reaching 98°.

Fall 2013 Forecast . . .

Below is a chart with the Climate Prediction Center's forecast for both temperatures and precipitation for the next three months (October - December), along with the Seasonal Drought Outlook for the fall months through December 31.  For temperatures (left), there is an increased chance of above normal temperatures for portions of the Oklahoma panhandle and southwest Oklahoma, however, eastern Oklahoma and northwest Arkansas display the "EQ" or equal chances rating.  This means that there are no indications that the temperatures during this period will be either above or below normal, thus, normal, below normal, and above normal temperatures are all equally likely.  For precipitation (center), again eastern Oklahoma and northwest Arkansas show an equal chance rating.  This means that there are no indications that the precipitation amounts will be either above or below normal, thus, normal precipitation, below normal, and above normal are all equally likely.  The third image depicts the drought outlook for the nation.  Mush of western and southern Oklahoma is colored brown, indicating that drought conditions currently affecting the region are expected to persist or intensify.  Most of eastern Oklahoma and northwest Arkansas are listed in the "no drought posted or predicted" indicating this area is not under a D1 or greater drought, and is not expected to develop drought conditions.

Fall 2013 Temperature Outlook	Fall 2013 Precipitation Outlook	Fall 2013 Drought Outlook

Updated: November 17, 2013