Drought Information Statement
Issued by NWS Phoenix, AZ

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AXUS75 KPSR 290235
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Drought Information Statement
National Weather Service Phoenix AZ
735 PM MST Fri Dec 28 2018

...Light Rain Continues Local Drought Relief in December...

Synopsis...

After a favorable weather pattern yielded several heavy rainfall
events across much of the Southwest United States during the first
half of October, conditions became much drier in November with only
localized rainfall across the region. However, a couple beneficial
localized rains in western Arizona and SE California in December
have helped drought conditions again. The fall and early winter
rains have helped both short term rangeland and streamflow through
much of the region. Soil moisture profiles and fire weather
conditions also correspondingly improved. The seasonably cooler fall
weather has allowed these impact groups to stabilize despite limited
rain or snow. Greater improvements to longer term water resources
will still require adequate winter rain and snow given the prolonged
regional drought.

Some drought improvements were noted in SE California over the past
month with little improvement in Arizona. Moderate Drought and
Abnormally Dry conditions were occurring over much of central and
southern Arizona while Moderate to Severe Drought persists across
west central Arizona, as well as much of southeast California.

The tropical Pacific is currently transitioning to an El Nino
episode; and confidence is now high that this El Nino will peak
during the middle of winter and persist into the spring. This
episode should only reach a weak category, but could briefly touch
into the moderate category. While many other factors contribute to
the atmospheric pattern, there could be a slight tilting of odds
towards wetter conditions later this year into early next year.


Summary of Impacts...

Extensive October rainfall aided in rangeland and pasture conditions
though more expansive recovery was hindered by the longer term
drought and extremely dry soils. Reports around the region indicate
stock ponds are beginning to refill. In the beginning of December,
49% of the area is still rated as poor or very poor. This compares
to 44% of the area at this time last year, but only slightly better
than the 55% one month ago.

The wet weather during the beginning of October and cooler late fall
and early winter weather has dampened much of any fire weather
threat. 100-hour dead fuel moisture values have maintained quality
generally at or above 10% in most locations. With some recent
locally drier conditions, 10-hour fuels have fallen a bit towards
7%. With the cooler and more humid winter season, only minimal fire
activity should be expected before the spring.


Climate Summary...

Heavy rainfall in October brought year-to-date rainfall totals near
or above average in many locations in central and eastern Arizona,
however far Western Arizona and SE California are still lagging
closer to 50-75% of normal. Totals and rankings are given below
(please note some stations have a limited historical record and
rankings may not be as significant).

                  Since    Since    Dept     Percent     Rank
                  Jan 1    Jan 1    from    of Normal   Driest
                  2018     Normal   Normal

Phoenix AZ        9.15      7.83    +1.32      117       95th
Scottsdale AZ     9.26      9.93    -0.67       93        Msg
Casa Grande AZ    7.58      8.87    -1.29       85       48th
Yuma AZ           2.32      3.44    -1.12       67       54th
Blythe CA         2.33      3.72    -1.39       63       21st
Tucson AZ        12.66     11.38    +1.28      111       93rd
Flagstaff AZ     21.25     21.39    -0.14       99       84th


Precipitation/Temperature Outlook...

The approximate probability values for above, below, or near normal
temperatures and precipitation for January and the 3-month period
January-February-March are given below and valid for Southeast
California and Southwest and South-central Arizona. These
probabilities are derived from outlooks issued by the Climate
Prediction Center and are accessible through their website listed
below. The temperature outlook corresponds to the average
temperature during the period, while the precipitation outlook
comprises the total precipitation over the period.

Temperatures have a better chance of being above normal during the
month of January, as well as the 3-month period of January through
March. Precipitation totals have a nearly equal chance of
falling above, below, or near average in January. There is a
slightly better chance of above normal precipitation in the
January through March period.

                               Temperature        Precipitation
                               Probability         Probability
                             Above/Near/Below    Above/Near/Below
                                  Normal              Normal
January 2019...............   43 / 33 / 24        33 / 33 / 33
Jan-Feb-Mar 2019...........   42 / 32 / 26        39 / 33 / 28


Hydrologic Summary and Outlook...

Reservoir levels remain well below levels recorded at the same time
last year and are similar to levels in 2016. October rainfall did
little to help reservoir levels as the water contributed primarily to
the recharge of very dry soils. Better winter rain and snow will be
needed to see better recharge heading into next spring.

                   12/24/2018     12/24/2017      12/24/2016
                    ---------      ---------       ---------
Roosevelt             40              57              36
Horse Mesa            92              95              93
Mormon Flat           95              96              94
Stewart Mtn           94              91              93
Total Salt            49              64              47

Horseshoe              4               9               9
Bartlett              46              60              52
 Total Verde          30              40              35

 Total System         47              61              45


Next Issuance Date...

This will be the last Drought Information Statement issued for this
event until Extreme Drought reemerges over the local forecast area.

&&

Related Websites:

Additional information is available at the following locations:

NWS Forecast Office Phoenix: weather.gov/Phoenix
National Integrated Drought Information System: drought.gov
US Drought Monitor: droughtmonitor.unl.edu
Climate Prediction Center: www.cpc.ncep.noaa.gov
Arizona State Climate Office: azclimate.asu.edu
Arizona Dept of Water Resources: new.azwater.gov/drought
Western Regional Climate Center: wrcc.dri.edu
US Geological Survey: water.usgs.gov

Acknowledgement:

Information included in this statement was compiled from various
federal, state, and local agencies.

Questions or Comments:

National Weather Service Phoenix
E-mail: w-psr.webmaster@noaa.gov


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