ZCZC SPCSWOMCD ALL
ACUS11 KWNS 290806 
SPC MCD 290806 
AZZ000-291400-

Mesoscale Discussion 2172
NWS Storm Prediction Center Norman OK
0206 AM CST Fri Nov 29 2019

Areas affected...Portions of northern and central AZ

Concerning...Heavy snow 

Valid 290806Z - 291400Z

SUMMARY...Heavy snow, with rates in excess of 2" per hour, will
likely occur for at least a few hours above 4000' this morning.

DISCUSSION...A large upper low over CA will continue moving slowly
eastward early this morning. Strong large-scale forcing will
overspread AZ as a 60-70+ kt mid-level southwesterly jet moves
across the Southwest. Plentiful moisture at low/mid levels
originating from the sub-tropical Pacific will be lifted through
both isentropic and orographic processes across northern/central AZ,
focused generally along/near the Mogollon Rim. Cooling of
mid/upper-level temperatures will occur from west to east over this
region as the upper low moves eastward, and a transition from rain
to snow will occur above the wetbulb zero height, which should be
around 4000-4500 feet per model forecast soundings. Given a deep,
saturated profile through the entire dendritic growth zone and the
very strong lift expected, enhanced snowfall rates of 2-3 inches per
hour appear likely, with locally higher rates possible. These higher
rates should be focused in a relatively narrow band of precipitation
that appears to be organizing over western AZ at 08Z, and they
should persist for at least a few hours as the band develops
eastward. Strong/gusty surface winds will also reduce visibilities
to near or below 1/4 mile, with near-blizzard conditions possible.

..Gleason.. 11/29/2019

...Please see www.spc.noaa.gov for graphic product...

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

LAT...LON   34671345 35181380 36001381 36401342 36611268 36491193
            35891169 34931115 34481017 34170931 34010908 33540908
            33250941 33511026 33961156 34351271 34671345 

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