Mesoscale Precipitation Discussion 0932...Corrected
NWS Weather Prediction Center College Park MD
513 AM EDT Sun Oct 07 2018

Corrected for areas affected

Areas affected...Central/Eastern AZ

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

Valid 070910Z - 071510Z

Summary...Heavy showers and a few thunderstorms will continue to
settle southeast across areas of central and gradually eastern AZ
through the early morning hours. Some flash flooding will be
possible and especially given the wet antecedent conditions.

Discussion...The latest WV satellite imagery shows a strong trough
continuing to amplify down into the Southwest U.S. which has been
facilitating an axis of locally heavy showers and thunderstorms
across central AZ over the last few hours.

PWATs across the region remain quite modest with values of 0.50 to
0.75 of an inch, and instability profiles are rather weak with
MUCAPE values in the 500 to 1000 j/kg range. However, the
upper-level jet support is very impressive and the latest WV
imagery depicts a highly divergent mid/upper-level flow pattern
owing to strong 500/300 mb layer left-exit region jet forcing.
Meanwhile, a well-defined mid-level vort center and associate
trough axis can be seen advancing toward the Mogollon Rim.

The strong dynamics associated with the amplifying trough will
compensate for the relative lack of moisture and instability and
will continue to drive a threat for locally heavy rainfall going
through the early morning hours.

The latest hires model consensus, including recent runs of the
HRRR, actually favors some intensification of the current line of
convection as it advances east through central and gradually
eastern AZ over the next several hours. Much of this will be
relative to the deep layer forcing as mentioned, but also a bit
better low-level convergence and perhaps some uptick in
instability given steepening mid-level lapse rates.

Expect as much as 1 to 2 inches of rain with locally heavier
amounts over the higher terrain, and especially the eastern end of
the Mogollon Rim. This will maintain the threat for flash flooding
locally over the next several hours, and especially considering
the wet antecedent conditions.

Orrison

ATTN...WFO...FGZ...PSR...TWC...

ATTN...RFC...CBRFC...

LAT...LON   35650965 35310921 34560917 33620984 33011079
            32741191 32781305 33191343 33581318 34421207
            35451067