289
AWUS01 KWNH 132153
FFGMPD
COZ000-WYZ000-AZZ000-UTZ000-IDZ000-140229-

Mesoscale Precipitation Discussion 0877
NWS Weather Prediction Center College Park MD
553 PM EDT Tue Aug 13 2024

Areas affected...Intermountain West

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

Valid 132152Z - 140229Z

Summary...Scattered convection continues across the Intermountain
West. Maintenance of storms within a region of comparatively
higher buoyancy and PWATs will continue the threat of isolated to
scattered flash flooding through this evening.

Discussion...Radar and satellite mosaic across the Intermountain
West continue to track scattered thunderstorms along the western
flank of an elongated monsoon moisture plume. Over the last
several hours, several Flash Flood Warnings and reports of flash
flooding have occurred as these cells periodically trained with
maximum estimated rainfall rates of 1-1.5"/hr.

The efficient, training nature of these cells likely remain tied
to several factors, including 1-1.1" PWATS (above the 90th
percentile for the region), 1000-3000 J/kg of MUCAPE, and
unidirectional wind profiles organized with sufficient speed shear
to support some organization and longevity of individual cells.
Accordingly, these storms with 1-1.5"/hr rainfall rates are
expected to continue through the next several hours as this
favorable environment interacts with several shortwave
perturbations and strengthening left exit forcing from a
jet-streak approaching from the west.

Thus, the risk of isolated to scattered flash flooding will
continue for the next several hours before loss of daytime heating
results in a decline in convective coverage and intensity. As
usual, slot canyons and burn scars remain particularly sensitive
to rainfall impacts.

Asherman

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

ATTN...WFO...FGZ...GJT...PIH...RIW...SLC...

ATTN...RFC...CBRFC...MBRFC...NWRFC...NWC...

LAT...LON   43621246 43610971 39650860 36810975 36481203
            37241260 39781229 42231292