This is a multi-part message in MIME format...

------------=_1564600240-118394-2833
Content-Type: text/plain

AWUS01 KWNH 311910
FFGMPD
NMZ000-AZZ000-010115-

Mesoscale Precipitation Discussion 0694
NWS Weather Prediction Center College Park MD
310 PM EDT Wed Jul 31 2019

Areas affected...Eastern and Central Arizona

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

Valid 311915Z - 010115Z

Summary...Convection blossoming in a destabilizing environment
aided by Monsoon moisture will become more widespread through the
afternoon. Rain rates of 1-2"/hr could be sufficient to produce
flash flooding, especially where training or repeated rounds of
thunderstorms occur.

Discussion...Morning cloud cover from an MCV has eroded across
southern AZ this afternoon as evidenced on GOES-16 visible
imagery. This has allowed instability to recover quickly across
the area, with recent RAP analyzed SBCape now exceeding 2000 J/kg,
and MUCape as high as 3000 J/kg. This instability is combining
with PWATs that are 1.5-2 inches, 2-2.5 standard deviations above
the climatological mean, to produce a thermodynamic environment
favorable for heavy rainfall. Moisture will continue to be
enhanced through the afternoon as well, as low/mid level flow
around the periphery of the ridge of high pressure to the east
advects pooled 2-2.25" PWATs from the Gulf of California into
Arizona.

As destabilization continues and moist advection persists, ascent
will be driven by broad diffluence to the north as well as weak
700mb convergence. Additionally, any outflows will be capable of
producing new thunderstorms in the unstable column. Recent radar
from KEMX, Tuscon, AZ, had estimated rain rates around 1"/hr in
the developing convection, and the HREF neighborhood probabilities
show an increasing likelihood for these rates to continue, or
enhance, across the area. With FFG as low as 0.75-1.5"/1hr, these
rates will be capable of producing flash flooding.

Storm motions across southern AZ will be modest, 5-10 kts as noted
by RAP 0-6km mean wind vectors, with parallel Corfidi vectors as
low as 5 kts. Towards the Mogollon Rim and points north, mean
cloud layer wind increases to 15-20 kts, so despite similar FFG
the flash flood potential appears to be lower due to these faster
storm motions. Where storm motions remains modest, and training is
possible, several rounds of heavy rain producing thunderstorms may
affect any individual area. Should this occur, rainfall may reach
2-3" as shown by some of the high-res CAMs, and should exceed FFG
which is in agreement with the 06Z HREF v2 exceedance
probabilities. It is across this area which has the best overlap
of moisture, instability, and potential for storm
training/mergers, where the flash flood potential is greatest.

Weiss

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

ATTN...WFO...ABQ...EPZ...FGZ...PSR...TWC...

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

LAT...LON   35731086 35551011 35200949 34620908 34270891
            33650878 33010863 32430855 31920863 31490896
            31270931 31181003 31231085 31531172 32021243
            32751279 33961273 33971274 34311273 34681275
            34981269 35171256 35381216 35501175


------------=_1564600240-118394-2833
Content-Type: text/plain; charset="US-ASCII"
Content-Disposition: inline
Content-Transfer-Encoding: 7BIT

= = =
To unsubscribe from WX-STORM and you already have a login, go to
https://lists.illinois.edu and use the "Unsubscribe" link.  Otherwise email
Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
------------=_1564600240-118394-2833--

--- SBBSecho 3.07-Linux
 * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)