Fall 2013 Highlights

Temperatures . . .

The following line graphs depict the mean temperature for the months of September - November (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 fall months of 2013 started out slightly warmer than normal, with average temperatures running between 3 - 5 degrees above normal for September.  Daily average temperatures were about 10 degrees above normal at all three sites between September 8 - 12 and September 18 - 19.  Temperatures cooled to near normal conditions during the month of October, with all three sites monthly average temperatures within 1 degree of normal.  November continued the cooling trend, with average monthly readings running between 2 - 3 degrees colder than normal.  One particular cold snap occurred between November 23 - 27, when daily average temperatures dropped to 10 - 20 degrees below normal.

Precipitation . . .

The following bar graphs depict the mean precipitation for the months of September - November (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.

The fall season started out dry, with all three sites receiving below normal amounts of precipitation during the month of September (Tulsa -1.76", Fort Smith -2.55", Fayetteville -1.16").  Most of the rainfall for the month occurred during two periods of the month: September 19 - 20, and on September 28.  Precipitation increased across the forecast area during the month of October, bringing near normal amounts to Tulsa (-0.41") and Fort Smith (-0.14"), and above normal amounts to Fayetteville (+1.22").  Drier than normal conditions returned for late fall, with below normal precipitation falling during November for Tulsa (-0.90"), and with Fort Smith (-2.04") and Fayetteville (-1.99") receiving less than half the expected amounts.

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

Snow occurred only during the month November this past fall, with Trace amounts recorded in Fort Smith and Fayetteville between November 24 - 26.  No snow was recorded in Tulsa this fall, which is -0.7" below normal.

Drought Progression . . .

The following chart depicts the amount of precipitation that fell leading up to, and during the fall 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
August 2013			August 27, 2013
September 2013			September 24, 2013
October 2013			October 29, 2013
November 2013			November 26, 2013

At the end of summer 2013, a few small areas of drought remained across portions of eastern Oklahoma and northwest Arkansas.  One area of D-0 drought extended from Mayes County east into Washington County, while another D-0/D-1 area of drought remained within far southeast Oklahoma in Pushmataha and Choctaw Counties.  Below normal amounts of rain during the month of September caused to drought to expand across the area, especially over southeast Oklahoma, where the D-0/D-1 drought intensified to D-3 drought in southern Choctaw County.  Near normal rainfall during October served to lessen the drought across the area, leaving only small areas of D-0 drought scattered throughout the region, and a small amount of D-1 drought in Choctaw County.  Below normal precipitation again occurred across much of eastern Oklahoma and northwest Arkansas in November, however the drought conditions remained slight, with only a small area of D-0 drought in northeast Oklahoma, and the D-0/D-1 drought continuing in Choctaw County.

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 fall months of September - November, along with the fall seasonal average.  Below the tables are the daily temperature and precipitation records set this fall season.

Tulsa:

* October 4, set a new highest minimum temperature record of 73 degrees (old record was 71 degrees from 2007).

* No daily precipitation records were set during the fall season in Tulsa, OK.

* No daily snowfall records were set during the fall season in Tulsa, OK.

Fort Smith:

* November 17, set a new highest maximum temperature record of 82 degrees (old record was 81 degrees from 1952 and 1958).

* November 24, set a new lowest maximum temperature record of 33 degrees (old record was 34 degrees from 1938).

* No daily precipitation records were set during the fall season in Fort Smith, AR.

* No daily snowfall records were set during the fall season in Fort Smith, AR.

Fayetteville:

* September 8, tied the highest maximum temperature record of 95 degrees (other record from 1955).

* September 9, tied the highest maximum temperature record of 95 degrees (other records from 1980 and 1985).

* September 10, set a new highest maximum temperature record of 95 degrees (old record was 93 degrees from 1963).

* No daily precipitation records were set during the fall season in Fayetteville, AR.

* No daily snowfall records were set during the fall season in Fayetteville, AR.

Weather Highlights . . .

Here are a few of the more significant events of the fall season 2013, including severe weather, winter weather, heavy rain, drought, and extreme cold.

September:

September Drought and Heat Wave Photo Credit: NWS Tulsa	September 19 Severe Weather Photo Credit: NWS Tulsa	September 28 Heavy Rainfall Photo Credit: NWS Tulsa

The first part of September was very dry, with above normal temperatures due to a large area of high pressure that developed over the west central part of the nation (pictured above left).  All three climate sites (Tulsa, OK, Fort Smith, AR, and Fayetteville, AR) received well below normal precipitation during this time frame, creating slight drought conditions across the area.  Rainfall amounts between Sept 1 - Sept 15 ranged from 0.00" in Tulsa, OK, 0.14" in Fort Smith, AR, and 0.39" in Fayetteville.  A strong cold front pushed into the region on September 19th (pictured above center), bringing cooler temperatures, along with showers and thunderstorms to eastern Oklahoma and northwest Arkansas.  During the afternoon hours, a few of the storms became severe, and brought hail and damaging winds to some locations.  A few reports of downed trees were relayed to the National Weather Service, including two from the Midtown and Utica Square areas.  Another cold front push through the region on September 28th (pictured above right), and brought some much needed rainfall to the area.  Tulsa, OK received 1.25", Fort Smith, AR received 0.57", and Fayetteville, AR received 0.82".

October:

October 4 - 5 Thunderstorm and Heavy Rainfall Photo Credit: NWS Tulsa	Mid October Below Normal Temperatures Photo Credit: NWS Tulsa	October 29 - 31 Heavy Rainfall Photo Credit: NWS Tulsa

The first few days of October were warmer than normal, with temperatures in the mid to upper 80s.  Late in the evening on October 4, and into the morning hours of October 5, a strong cold front moved into the eastern Oklahoma and northwest Arkansas, triggering showers and thunderstorms across the area (pictured above left).  Heavy rainfall was reported, with the Tulsa, OK area receiving 1.08" of rain, the Fort Smith, AR area receiving 1.03", and the Fayetteville, AR area receiving 2.60" of rain.  The middle to latter portion of October was cooler than normal due to several concurrent cold fronts passing over the region (pictured above center).  Daily high temperatures between October 16 - October 25 ranged from 5 to 15 degrees below normal.  Toward the end of the month, another round of rain showers brought and extended period of wet weather to the region (pictured above right).  Between October 29 - October 31 the Tulsa, OK area received 1.13", the Fort Smith, AR area received 0.67", and the Fayetteville, AR area received 0.83".  Luckily, the precipitation ended before Halloween night, allowing any Trick-Or-Treaters to attend their annual quest for candy.

November:

November 5 - 6 Heavy Rainfall Photo Credit: NWS Tulsa	November 12 - 13 Extreme Cold Photo Credit: NWS Tulsa	November 23 - 26 Winter Weather Photo Credit: Channel 6 News

During the first week of November, a slow moving cold front moved across the area, bringing a long period of rainfall to eastern Oklahoma and northwest Arkansas (pictured above left).  Between November 4 - 6 the Tulsa, OK area received 1.27" of rain, the Fort Smith, AR area received 1.27" of rain, and the Fayetteville, AR area received 0.59" of rain.  A very strong cold front pushed into the region on November 11, dropping temperatures between 20 and 30 degrees.  Temperatures went from being several degrees above normal on November 11, to 15 degrees below normal on November 13.  Low temperatures November 12 - 13 ranged from the middle teens to the middle 20s (pictured above center).  Several rounds of freezing drizzle and freezing rain occurred between November 23 - 26, forming a light glaze on elevated surfaces and many area roadways.  Numerous car accidents were reported across the area due to the slick conditions, including one on the Will Rogers Turnpike near Tulsa, OK on November 25 (pictured above right).

Winter 2013-2014 Forecast . . .

Below is a chart with the Climate Prediction Center's forecast for both temperatures and precipitation for the next three months (December - February), along with the Seasonal Drought Outlook for the late fall and winter months through February 28.  For temperatures (left), there is an increased chance (40%) of above normal temperatures across much of eastern Oklahoma and western Arkansas.  This does not mean that there will not be any cold periods during this time frame, but that the temperatures averaged over the entire winter season has a 40% chance of being slightly warmer than average.  For precipitation (center), all of eastern Oklahoma and northwest Arkansas show an "equal chances" 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 through the end of February.  All of our forecast area (eastern Oklahoma and northwest Arkansas) is 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.

Winter 2013-2014 Temperature Outlook	Winter 2013-2014 Precipitation Outlook	Winter 2013-2014 Drought Outlook

Updated: January 19, 2014