SUMMARY...Monsoonal shower and thunderstorm activity will be
developing soon over areas the Southwest U.S. with notable
concerns for more flash flooding expected over the normally dry
washes and the area burn scar locations. This is especially the
case for the burn scar complex involving the Sacramento Mountains
in central NM and the Lincoln National Forest.
DISCUSSION...Monsoonal moisture remains deeply entrenched over the
Southwest U.S. again today and visible satellite imagery shows an
elongated axis of MCV energy stretching from central AZ through
northwest NM which is leftover energy from last evening's
convective activity.
PWs over the region remain anomalously high with values that are
locally 2 to 3 standard deviations above normal, and especially
from southern AZ through northwest NM. Strong diurnal heating has
already resulted in SBCAPE values as high as 1500 to 2500 J/kg.
Convective initiation is in the early stages of occurring over the
higher terrain of the Mogollon Rim in AZ and the higher terrain of
central through western NM as differential heating boundaries and
localized upslope flow into the terrain focuses convective growth.
The Sacramento Mountains in central NM with a focus on the Lincoln
National Forest continue to be extremely sensitive to heavy shower
and thunderstorm activity given the burn scar complex involving
the Blue-2, South Fork and McBride burn areas. This region this
afternoon and evening is expected to see additional heavy rainfall
from monsoonal convection and thus will be susceptible again to
enhanced runoff impacts and flash flooding including debris flow
activity.
Elsewhere across much of central and eastern AZ through western
and northern NM. Monsoonal convection is expected to initiate and
gradually expand in coverage in a scattered to broken fashion.
The proximity of the MCV energy will also gradually help focus
expanding areas of convection. Given the level of moisture and
instability, rainfall rates throughout the Southwest are expected
to be capable of reaching 1 to 2 inches/hour, with some isolated
storm totals by this evening of 2 to 4 inches. Some spotty heavier
totals will be possible where any cells become anchored near the
higher terrain.
The normally dry washes and area burn scars again will be
particularly vulnerable to flash flooding impacts.