Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Thu Jun 15 2023 20:05:59

AWUS01 KWNH 152005
FFGMPD
NEZ000-COZ000-WYZ000-160107-

Mesoscale Precipitation Discussion 0490
NWS Weather Prediction Center College Park MD
404 PM EDT Thu Jun 15 2023

Areas affected...High Plains...Central Rockies

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

Valid 151907Z - 160107Z

Summary...Showers and thunderstorms are developing along the
terrain across High Plains. Slow moving thunderstorms containing
rainfall rates upwards of 1-1.5"/hr could cause some flash
flooding through the evening.

Discussion...Visible satellite trends depict an uptick in slow
moving thunderstorm coverage and intensity atop the terrain in the
High Plains in response to vigorous diurnal heating and upslope
flow with an approaching front, coupled with strengthening DCVA
and diffluence aloft. A recent particularly intense pulse storm
south of Denver recently contained MRMS estimated rainfall rates
of 1-1.5"/hr, prompting a Flash Flood Warning.

Recent RAP mesoanalysis depicts modest elevated instability around
1000-2000 J/kg has developed between the two low centers, with a
belt of anomalous Eastern Pacific moisture (PWAT anomalies 2-3
sigma above climatology) noted across the Intermountain West and
High Plains. Moreover, a glancing blow from a departing jet streak
over the Northern Rockies supported modest bulk shear profiles of
20-30 kts over central and southwest WY which will allow for some
organized convection there. Further southeast over CO and
southeast WY, weak vertical shear will yield largely pulse storm
modes, albeit with slower vertical storm motions less than 10 kts
and generally better instability owing to strong southeasterly
flow in place.

Through this afternoon thunderstorm coverage is expected to expand
with continued insolation and forcing for ascent from the
shortwave activity. Rainfall rates could eclipse 1-1.5"/hr within
the most intense convective cores. Due to the lack of vertical
shear, the activity over Colorado should wane with diurnal heating
this evening but could be more intense given the better
instability feed. In contrast, storms should stick around longer
further north and west in Wyoming but with less instability to
work with. Accordingly, the HREF shows spotty 1-2" rainfall totals
through 0z across the region, where flash flooding is considered
possible over much of the High Plains and Central Rockies as 1 HR
FFGs are quite low (.75-1"/hr).

Asherman

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!7Hyt4qkE2L173M6Y1T8uuQ8pOXhaGO3TDaRFGX3VtQdmoZf4sYM2GK_mn9QuS4rzcRbB=
-bUxICy9oEZ09WyRp_wKHZ4$  for graphic product...

ATTN...WFO...BOU...BYZ...CYS...GJT...PUB...RIW...UNR...

ATTN...RFC...ABRFC...CBRFC...MBRFC...NWC...

LAT...LON   44850776 43620574 42770487 41930430 40460370=20
            38860396 38840571 39900725 41380844 42420916=20
            44060959=20

=3D =3D =3D
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