Area Hydrologic Discussion
— Latest
Threat
POTENTIAL IMPACTS: Locally considerable flash and urban flooding WHERE: Southeast Arizona WHEN: Through tonight
Rainfall & Conditions
QPF: 1 - 2", locally higher" (HRRR/REFS) Rain Rates: Up to 2"/hr (WPC) Soil Moisture: Below normal (NASA SPoRT) Streamflows: Normal to below normal
Discussion
The primary threat from the rainfall tonight will be flash and urban in nature, with potential impacts including flooded roadways and low-water crossings, as well as rapid rises in small streams, arroyos, and slot canyons. The impacts that occur will be primarily driven by the high rainfall rates and the complex terrain of the mountainous regions within the area of concern. Rates are high enough that locally considerable impacts can not be ruled out.
The National Water Model SRF has a robust response given this region tends not to have strong signals, with isolated stream reaches exceeding the 50 - 10% annual exceedance probability (AEP) thresholds, and pockets of rapid onset flood probabilities greater than 25%. Confidence in the exact placement and magnitude of flooding impacts remains low, but nonetheless there is potential for locally considerable flash and urban flooding impacts, especially if training occurs over an urban area such as Tucson.
Addressed To
WFO: FGZ, EPZ, PSR, TWC RFC: STR, WPC
000 AGUS74 KWCO 170148 AHDNWC Area Hydrological Discussion #150 - EXPERIMENTAL NWS National Water Center - Tuscaloosa, AL 842 PM CDT Thu Jul 16 2026 POTENTIAL IMPACTS: Locally considerable flash and urban flooding WHERE: Southeast Arizona WHEN: Through tonight FORECAST RAINFALL AND ANTECEDENT CONDITIONS... QPF: 1 - 2", locally higher" (HRRR/REFS) Rain Rates: Up to 2"/hr (WPC) Soil Moisture: Below normal (NASA SPoRT) Streamflows: Normal to below normal DISCUSSION... The primary threat from the rainfall tonight will be flash and urban in nature, with potential impacts including flooded roadways and low-water crossings, as well as rapid rises in small streams, arroyos, and slot canyons. The impacts that occur will be primarily driven by the high rainfall rates and the complex terrain of the mountainous regions within the area of concern. Rates are high enough that locally considerable impacts can not be ruled out. The National Water Model SRF has a robust response given this region tends not to have strong signals, with isolated stream reaches exceeding the 50 - 10% annual exceedance probability (AEP) thresholds, and pockets of rapid onset flood probabilities greater than 25%. Confidence in the exact placement and magnitude of flooding impacts remains low, but nonetheless there is potential for locally considerable flash and urban flooding impacts, especially if training occurs over an urban area such as Tucson. GRAPHICAL REPRESENTATION: weather.gov/owp/operations-ahd Additional National Water Center products are available at: weather.gov/owp/operations //Bliss ATTN...WFO...FGZ...EPZ...PSR...TWC ATTN...RFC...STR...WPC