Drought Information Statement
Issued by NWS Tucson, AZ

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000
AXUS75 KTWC 231905
DGTTWC
AZC003-009-011-019-021-023-190000-

Drought Information Statement
National Weather Service Tucson Arizona
1205 PM MST Mon April 23 2018

...Extreme drought conditions across northern Graham, northern
Greenlee, southeast Pima, southwest Cochise and all of Santa Cruz
counties...

...Severe drought conditions across the rest of southeast Arizona...

Synopsis...

Well above normal temperatures and much below normal precipitation
has prevailed across southeast Arizona since the latter part of the
2017 Monsoon.  Drought conditions have slowly deteriorated over the
past 6-8 months with further deterioration expected until the
monsoon arrives.

Summary of Impacts...

Soil Moisture Conditions.
Soil moisture levels have begun to be rapidly depleted after the
rain that we did receive in the latter half of February.  The top 10
cm of soil has basically reached the point where there is no
moisture available for plant growth and deeper soil moisture
availability is diminishing fairly quickly.  The vast majority of
southeast Arizona has drier deep (0-200 cm) soil moisture levels
than one year ago, an already dry period that experienced active to
extreme fire behavior.

Fire Impacts.
Other than significant precipitation received in February, the long
time period of dry weather and the generally much warmer than
average temperatures experienced through the winter have brought
fuel moisture conditions to critical levels.  Live fuel moisture
levels are near or at all time dryness levels for this point in the
fire season across southeast Arizona.  The current values are
comparable to those typically observed during the second week of
June when much of the vegetation has long been dormant and dried
out.

The larger dead fuels (heavy brush to small logs) are also
critically dry and currently near or drier than historical maximum
dryness levels for late April.  For the brush sized fuels, these
values are actually drier than levels normally found at the driest
point in fire season in mid June.

Based on these fuel conditions and where there is fuel available,
fire behavior can be expected very active to possibly extreme during
the heat of the day and/or during high wind events.

Climate Summary...

Station           Since Oct 1   %%%%   |  Since Jan 1   %%%%
                     2017      normal  |     2018      normal
Tucson airport       2.57"       49%   |     1.98"       71%
Picacho Peak         1.88"       31%   |     1.67"       46%
Nogales              3.14"       45%   |     2.22"       73%
Douglas airport      1.87"       41%   |     1.04"       51%
Sierra Vista         2.76"       55%   |     2.17"       83%
Tombstone            2.50"       45%   |     1.76"       62%
Willcox              3.18"       52%   |     2.95"       97%
Safford              2.01"       37%   |     1.69"       64%
Ajo                  1.31"       32%   |     0.91"       36%
Organ Pipe NM        0.91"       17%   |     0.38"       12%

Precipitation/Temperature Outlook...

The latest seasonal forecast for southeast Arizona, issued by the
Climate Prediction Center, calls enhanced probabilities of above
normal temperatures for May, June and July time period. On the
rainfall side, there are equal chances for either below normal,
normal or above normal.

Hydrologic Summary and Outlook...

Rain and snow events were limited this winter season, causing
mountain snowpack to be well below the seasonal average.  Due to the
low snow totals in the mountains, current runoff outlooks for the
2018 runoff season are remaining very low.  Below is a table of the
current most probable (50th percentile) runoff forecast for April-
May 2018 at select locations in the Gila River Basin:

River                                    Percent Runoff
San Francisco River at Clifton                14%
Gila River at Head of Safford Valley          31%
San Carlos Reservoir at Coolidge Dam           3%

Next Issuance Data...

This product will be updated on May 18th, or sooner if conditions
significantly change.

&&

Related websites...

Additional information on current drought conditions may be found at
the following web addresses:

U.S. Drought Monitor...http://www.drought.unl.edu/DM
NOAA Drought Page...http://www.drought.noaa.gov
NWS Precipitation Analysis Page...http://water.weather.gov
Climate Prediction Center...http://www.cpc.ncep.noaa.gov
Western Region Climate Center...http://www.wrcc.dri.edu
Arizona Department of Water Resources...http://www.azwater.gov/AZDWR
Arizona State Climatologist...http://azclimate.asu.edu
NWS Tucson...https://www.weather.gov/tucson
Additional River information...
NWS...http://ahps2.wrh.noaa.gov/AHPS2/index.php?wfo=twc
USGS...http://waterdata.usgs.gov/AZ/NWIS/current?type=flow

Acknowledgements...

Data for this statement was compiled from a number of different
federal, state and local agencies. The drought monitor is a multi-
agency effort involving the NOAA National Weather Service and
National Centers for Environmental Information (NCEI), the USDA,
state and regional climate center climatologists and the National
Drought Mitigation Center.

Questions or comments...

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

National Weather Service
540 North Park Avenue, Suite 304
Tucson, Arizona 85719
Phone: 520-670-6526
Email: w-twc.webmaster@noaa.gov

$$

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