Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Mon May 05 2025 02:22:20

AWUS01 KWNH 050221
FFGMPD
AZZ000-050730-

Mesoscale Precipitation Discussion 0223
NWS Weather Prediction Center College Park MD
1020 PM EDT Sun May 04 2025

Areas affected...Southwest to south-central Arizona...

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

Valid 050220Z - 050730Z

SUMMARY...Very narrow updrafts in proximity to anomalously
deep/moist upper-low will remain slow moving for highly focused
areas of .75-1.5" totals and possible flash flooding.

DISCUSSION...GOES-W WV suite and 00z RAOB analysis depicts a
fairly stacked anomalously deep (2.5-3.5 Std. Dev.) upper low
centered just west of the Lower Colorado River northeast of
Blythe.  Similarly atypical moisture values exist though the deep
low with total PWats of .75-1".   RAP analysis denotes the slow
downward trend/loss of unstable air (given loss of solar
insolation), but an axis of steeper mid-level lapse rates but
solid upper-40s to low 50s Tds exists across the Sonoran Desert
toward Sun Valley and the western edges of the Mogollon Rim.=20
General, southwest to southerly confluence in the low to
mid-levels is providing sufficient convergence to result in some
new destabilization/convective development in that axis from east
of Yuma toward central Maricopa into southwest Yavapai county.=20
The limited 500-750 J/kg CAPE and modest, even if anomalous,
moisture is resulting in narrow updraft/downdraft cores.

The key toward intense rain-rates and excessive rainfall potential
is the orientation to a steering flow col within that SW-ENE
confluence zone as the upper-low slowly wobbles/re-forms eastward.
As such, 15-20kts of cloud base in flow of increasing moisture
should support increased duration of .5-.75"/hr rates potentially
resulting in localized totals up to 1.5".  Given desert/hard-pan
ground conditions, highly focused flash flooding may result and is
considered possible through the next few hours as the cells
exhaust/seek out the remaining instability patches.

Gallina

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!6MnkT-lixCg6lOMDSJq5brlZIqLWIPPYF_ZtxhQYEnj5JwRO6bQJwH1PSwwCY7LRCwIr=
leYeWfe0DITiCv8F0SSbX5g$  for graphic product...

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

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

LAT...LON   34951338 34831238 34271126 33721115 32941162=20
            32321235 31841298 32131404 32401446 32951423=20
            33421390 33631383 34521396=20

=3D =3D =3D
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