Drought Information Statement
Issued by NWS Tulsa, OK

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2
AXUS74 KTSA 202001

Drought Information Statement
National Weather Service TULSA OK
301 PM CDT Fri Apr 20 2018

...Moderate to Severe Drought continues across a portion of
northeast Oklahoma...


Rainfall continues to be well below normal northwest of the
Interstate 44 corridor, and moderate to severe drought persists in
that area. The data provided in this statement will focus on the
D1-D2 area. No drought or abnormally dry conditions were present
in northwest Arkansas.

According to the U.S. Drought Monitor (USDM) valid April 19,
2018, Severe (D2) Drought conditions covered portions of Osage and
Pawnee Counties in northeast Oklahoma.

Moderate (D1) Drought conditions were present in portions of
Osage, Pawnee, Washington, and Nowata Counties in Eastern

Abnormally Dry (D0) but not in drought conditions remained over
parts of Creek, Pawnee, Osage, Tulsa, Washington, Rogers, Nowata,
and Craig Counties in northeast Oklahoma.

The USDM is a collaborative effort between several government and
academic partners. It is a weekly national product issued on
Thursday morning using data collected through the previous Tuesday
morning, so it does not consider precipitation which has fallen
after the data cut-off time.

There are five levels of intensity depicted on the USDM. The USDM
levels are the following: D0 - Abnormally Dry (not in drought but
showing dryness) D1 - Moderate Drought D2 - Severe Drought D3 -
Extreme Drought D4 - Exceptional Drought

The local Drought Information Statement is issued by the NWS
office in Tulsa when needed to supplement the national USDM
product. Local statements may be issued monthly during times when
the USDM indicates severe drought conditions or as local
conditions warrant.

Summary of Impacts...

State and Local Actions:
The Oklahoma Governor declared a State of Emergency due to
ongoing wildfires and critical fire weather conditions. This
declaration is in effect for 52 Oklahoma Counties, including
Creek, Okfuskee, Okmulgee, Osage, and Pawnee Counties. The
Oklahoma State Climate Office (Oklahoma Climatological Survey,
OCS) hosts recorded briefings focused on the current conditions,
impacts, and outlooks for drought conditions across the Southern
Plains. Updated drought briefings are available at

Soil Moisture Impact:
The OCS daily averaged fractional water index for April 19, 2018
shows values of 0.4 to 0.8 (where 1.0 is saturated and 0.0 is
completely dry) at 2 and 4 inches below ground across the drought
area. Further down at 24 inches below ground, the values were 0.9
to 1.0.

As of April 20, 2018, the Arkansas-Red Basin River Forecast
Center (ABRFC) gridded soil moisture indicates that the upper
zone, which responds to short term rainfall, is 10 percent to
around 30 percent full across the drought area. This represents
slight to moderate agriculturally dry conditions for the area.
These values corresponds from around 30 to 70 percent of normal
across the area. The lower zone was 20 to greater than 40 percent
full in the drought area, which represents slight hydrologically
dry to neutral conditions. These lower zone anomalies were 30 to
70 percent of normal.

The Climate Prediction Center (CPC) calculated soil moisture
anomaly analysis as of April 19, 2018 showed soil moisture was
80-100 mm (3.1-3.9 inches) below normal across the drought area in
northeast Oklahoma.

Fire Impacts:
A burn ban was in effect for Osage and Pawnee Counties of April
20, 2018. Fires have been active across the drought area over the
past month, with frequent high fire weather days.

There are concerns of red imported fire ant infestations due to
hay being donated from restricted areas to help with livestock
affected by the drought and wildfires.

Climate Summary...

Thunderstorms affected the area on April 13, 2018, bringing
isolated 0.10 to around 0.75 inches of rain to a small portion of
Pawnee, Osage, Washington, and Nowata Counties. No additional rain
has occurred since then.

In the last 30 days, 0.25 to around 1.5 inches of rain has fallen
in the D0-D2 area of northeast Oklahoma. This is only 10 to 50
percent of the normal rainfall expected for this time of year.

According to OCS, for the last 30 days ending April 19, 2018,
northeast Oklahoma ranks as the 32nd driest period since records
began in 1921. North central Oklahoma ranks as the 13th driest.
Since the beginning of the Water Year (October 1, 2017), northeast
Oklahoma ranks as the 42nd driest and north central Oklahoma
ranks as the 4th driest.

Precipitation/Temperature Outlook...

Widespread rainfall is expected to begin tonight and continue
through Saturday night. 1 to 2 inches of rain is expected from
this storm system. There will be another chance for some rain
Tuesday night. Below normal temperatures are expected across the
area over the next 7 days.

The CPC 8-14 Day Outlook calls for an increased chance for above
normal temperatures and near normal rainfall across all of
eastern Oklahoma and northwest Arkansas.

Beyond this period, the CPC outlook for May 2018 (issued April
19, 2018) indicates an enhanced chance for above normal
temperatures and an equal chance for above, near, and below median
rainfall across all of eastern Oklahoma and northwest Arkansas.

Hydrologic Summary And Outlook...

According to the U.S. Army Corps of Engineers (COE), a couple of
reservoirs in and near the drought area of northeast Oklahoma were
operating below their normal conservation pool levels as of April
20, 2018: Kaw Lake 86 percent and Birch Lake 94 percent.

According to the U.S. Geological Survey (USGS), the 7-day average
streamflow as of April 19, 2018 was below (10th-24th percentile)
normal for the following rivers: Black Bear Creek at Pawnee, Bird
Creek at Avant, and the Verdigris River near Lenapah. Rivers much
below (less than 10th percentile) normal included Caney River
above Coon Creek at Bartlesville and Caney River near Ramona.

Next Issuance Date...

This product will be updated on May 18, 2018 or sooner if
significant changes in drought conditions occur.

Related Websites...

U.S. Drought Portal

U.S. Drought Monitor

National Weather Service Tulsa

Arkansas-Red Basin River Forecast Center

Oklahoma Climatological Survey Drought Tools

Arkansas Forestry Commission

Oklahoma Forestry Commission

U.S. Army Corps of Engineers Tulsa District

U.S. Geological Survey Realtime Data

Climate Prediction Center


The U.S. Drought Monitor is a collaborative effort between
several government and academic partners including the NWS, the
National Climatic Data Center, the USDA, state and regional
climatologists, and the National Drought Mitigation Center.
Information for this statement has been gathered from NWS and FAA
observation sites, the Oklahoma Climatological Survey, the USACE
and the USGS.

Questions or Comments...

If you have any questions or comments about this drought
information statement, please contact,

National Weather Service Tulsa
10159 E. 11th St. Suite 300
Tulsa Oklahoma 74128
Phone:   918-838-7838
Email:   sr-tsa.webmaster@noaa.gov


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.