Extended Streamflow Guidance
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000
FGUS65 KSTR 201704
ESGAZ

NATIONAL WEATHER SERVICE
COLORADO BASIN RIVER FORECAST CENTER
SALT LAKE CITY, UTAH

FEBRUARY 20, 2019

                        FLOOD POTENTIAL OUTLOOK
                                ARIZONA

The flood potential for Arizona Rivers and streams is above average at
this time.

Because the nature of flooding in Arizona is associated with rainfall
events versus snow melt it`s difficult to determine with much certainty
the flood threat over a season. Existing streamflow, soil, and snowpack
conditions are analyzed for their potential contribution to streamflow
levels during future rainfall events.

Seasonal October-January precipitation was 105 percent of average in
the Salt-Verde River Basin, 95 percent in the Gila Basin and 110 percent
for the Little Colorado Basin. January precipitation was 95 percent of
average in the Salt-Verde River Basin, 70 percent in the Gila River Basin,
and 100 percent of average for the Little Colorado Basin.

February 1st snowpack was 75 percent of average in the Salt-Verde Basin,
near 75 percent of average in the headwaters of the Little Colorado Basin.
Snowpack conditions were near 65 percent of average in the upper Gila
drainage.

Modeled soil moisture states were much below average at the beginning of
the water year. However, soil moisture states have increased dramatically
over the past several months to above average. February through May runoff
volumes are primarily influenced by the frequency and magnitude of winter
rain events.

Due to the presence of a possible weak El Nino, a persistent Madden-Julian
Oscillation, above average soil moisture states, and an active weather
pattern into late February, the flood potential for Arizona is above
average at this time.

CBRFC

NNNN

$$



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