Colorado Mesoscale Discussion

Areas affected…New Mexico…Colorado

Concerning…Heavy rainfall…Flash flooding possible

Valid 111820Z – 120020Z

SUMMARY…Relatively slow-moving showers and thunderstorms with
heavy rainfall rates will pose a threat for some areas of flash
flooding this afternoon.

DISCUSSION…The latest GOES GeoColor RGB imagery is showing a
well-defined mid-level vort center over west-central NM along with
an elongated trough extension up to the north and northeast across
southwest to central CO. Along and east of this axis is a rather
robust plume of mid-level moisture as seen in 12Z RAOBs and the WV
channel suite. Convection has already begun to initiate over some
of the higher terrain of central/northern NM and into
south-central CO as diurnal heating continues to destabilize the
low levels of the column. This trend coupled with the evolution of
terrain-induced circulations will allow the convection to continue
to develop and expand in coverage going through the mid-afternoon

The vort center over west-central NM will be key in allowing for
locally more concentrated areas of convection along its track up
to the north-northeast through the afternoon, and already there
has been some cloud top cooling near its center involving Catron
and Cibola counties of western NM.

PWATs across the region are locally as much as 2 standard
deviations above normal with values of 1.0 to 1.2 inches in
vicinity of the vort and stretching north up across northwest NM.
The values are less anomalous for now over south-central CO, but
with deep layer south-southwest flow, the moisture of NM will be
riding northeast through south-central CO through the afternoon
and toward evening. All of this facilitate more efficient rainfall
processes for enhanced rainfall rates that are expected to reach
as high as 1.5 inches/hr.

The latest hires model consensus supports some rainfall totals of
as much as 2 to 3 inches which seems reasonable considering the
steering flow is relatively weak and thus the convective cells
will be slow-moving. Given this, a few instances of flash flooding
will be possible, and especially over the more sensitive
dry-washes, steeply sloped and/or channeled terrain and in
vicinity of burn scars.


…Please see for graphic product…



LAT…LON 39280576 39010529 37940488 37070479 36530484
35940491 35380494 34870481 34240486 33530499
33150519 33220556 34210557 34400590 33640655
32910672 32710770 32790870 33130975 33481032
34171054 34651020 34770965 35240911 36380874
37710807 38610742 39250661

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