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

------------=_1564518949-118394-2289
Content-Type: text/plain

AWUS01 KWNH 302035
FFGMPD
NMZ000-AZZ000-310230-

Mesoscale Precipitation Discussion 0689
NWS Weather Prediction Center College Park MD
435 PM EDT Tue Jul 30 2019

Areas affected...Southern/Central AZ

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

Valid 302030Z - 310230Z

Summary...Two areas of concern across portions of AZ: (1)
convection continuing over the terrain in central AZ and (2)
convection expecting to blossom across portions of southern AZ
associated with mid-level energy moving in from the south. Rain
rates across both of these areas expected to be above 1 inch/hour
at times which may result in the potential for flash flooding
through the next several hours.

Discussion...Ridging east of the Four Corners region will continue
to advect higher moisture and mid-level energy from northwest
Mexico into southern AZ. The gradient of precipitable water and
instability will migrate northward through the afternoon into
early evening.  Precipitable water values will climb above 1.75
inches with instability of >3000 J/kg MUCAPE adjacent to the
Mexico border.  This combined with ample mid-level lift and a weak
surface trough should be enough to promote convection later this
afternoon into the evening hours across southern AZ. The hindrance
may be an MCV, as seen on satellite, moving from southeast AZ
northwest which could promote a bit of subsidence to the south and
west of this feature. Also, another weak MCV across southwest AZ
is lifting northwest as well. Both of these areas of circulation
may limit convection initiation, though the hi-res models do not
illustrate this as seen by fairly high QPF amounts.

Speaking of hi-res, most guidance depicts 6-hourly storm total
precipitation as high as 2-3+ inches in some locations.  Much of
this precipitation will fall in a short amount of time with hourly
rain rates expected to exceed 1 inch/hour. Another reason for
concern will be the slow storm motion and training potential
across southern AZ.  This would only exacerbate the flooding
potential as flash flood guidance is as low as 0.75-1 inch within
an hour.  Therefore, feel this area has the best potential for
flash flooding.

Convection ongoing across the higher terrain in central AZ will
likely dwindle in the coming hours as forcing diminishes. However,
given storms have remained across the terrain and thus soils have
become saturated within this region, can not rule out isolated
flash flooding.  There is some concern that the aforementioned MCV
moving northwest into this region may help promote slow moving
convection longer than initially anticipated.  Therefore, have
added a hatched area to denote another region that has slightly
higher probability of flash flooding.

Pagano

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

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

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

LAT...LON   36111164 35361077 34701000 34120930 33710902
            31660906 31320952 31341119 31671224 31891305
            32271344 32731342 33021284 33421227 33891243
            34411281 35171282 35751247


------------=_1564518949-118394-2289
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.
------------=_1564518949-118394-2289--

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