573
AWUS01 KWNH 141428
FFGMPD
AZZ000-UTZ000-NVZ000-142025-

Mesoscale Precipitation Discussion 1049
NWS Weather Prediction Center College Park MD
1026 AM EDT Fri Aug 14 2026

Areas affected...Northern AZ...Southern UT...Far Southern NV

Concerning...Heavy rainfall...Flash flooding possible

Valid 141425Z - 142025Z

SUMMARY...Robust thunderstorms tracking over areas with saturated
and sensitive soils could lead to areas of flash flooding.

DISCUSSION...GOES West shows a strong subtropical jet oriented
SSW-NNE over the Lower CO River Valley this morning. The 12Z VEF
sounding showed 250mb winds of 80 kts, which is above the 90th
climatological percentile and right around the max moving average
for mid-August. The jet streak overhead is providing excellent
diffluence overhead while the atmosphere remains weakly capped and
fairly saturated. Storms developed over the Grand Canyon County,
the northern tier of the Mogollon Rim, and as far south just east
of Lake Havasu. Storm motions should be progressive, although near
uniform SSWrly flow aloft is also contributing to upshear Corfidi
vectors that are around 10 kts. Some backbuilding and training
could occur as a result, particularly in areas where higher
terrain is orthogonal to the SSWrly flow within the 850-300mb
layer.

PWs are forecast to range between 1.0-1.25" in the highlighted
area, and MLCAPE should rise up to ~1,000 J/kg over the Lower CO
River Valley by this afternoon. With the presence of the jet
streak aloft fostering upper-level ascent, unusually high vertical
wind shear paired with above normal moisture will support hourly
rainfall rates that could surpass 1.5"/hr in the more intense
storms. Localized rainfall totals over 3" could occur, especially
in areas where training thunderstorms unfold. Soils remains
unusually saturated for much of the at-risk area as well with NASA
SPoRT-LIS showing >90th climatological percentile soil saturation
within the 0-10cm layer. Flash flooding is possible today with
those areas sporting saturated soils, as well as in areas with
rugged terrain, slot canyons, and dry washes.

Mullinax

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...FGZ...SLC...VEF...

ATTN...RFC...STR...NWC...

LAT...LON   38891286 38841171 38321113 37331088 36361100
            35621094 34791141 34391235 34401355 34361396
            34431423 34691436 34991453 35261464 35711468
            36591460 37511426 38391377