Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Thu Aug 29 2024 06:01:51

AWUS01 KWNH 290601
FFGMPD
MNZ000-NDZ000-291200-

Mesoscale Precipitation Discussion 0942
NWS Weather Prediction Center College Park MD
201 AM EDT Thu Aug 29 2024

Areas affected...Eastern NDak...Northwest MN...

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

Valid 290600Z - 291200Z

SUMMARY...Training/Back-building elevated thunderstorms may rates
of 1.5-2"/hr with streaks of 2-3" totals in 1-3 hours resulting in
possible localized flash flooding through overnight period.

DISCUSSION...GOES-E 10.3um depicts a broad cirrus canopy that
continues to strink and warm through much of the shield, with a
few remaining overshooting tops breaking through with the initial
stronger supercells that are taking a more weakening linear
appearance in the RADAR mosaic across SE NDak.  These cells
continue to be fairly potent but are on a slow downward trend as
they move into a more stable mid-level environment along and east
of the Red River Valley, where MUCAPE rapidly drops off.  Still,
strong flux in proximity to slowly lifting warm front across NE
SDak, has been maintaining some solid rates up to 1.75"/hr,
generally moving into naturally lower FFG values, so cannot rule
out a remaining low end flash flooding concern through this area
over the next few hours.

However upstream, height-falls are starting to press eastward out
of E MT as vorticity center rounds the base of the parent closed
low and low to mid-level flow starts to veer more westerly and
tighten flow.  Associated jet streak is weakening and lifting into
Canada with favorable diffluent pattern across central into
northeastern NDak.  Sfc to 925mb flow remains backed along the
warm front across NE SDAK into SW MN with southeasterly flow,
slowly veering with height and 850mb 50kts within the TROWAL
across central NDAK provide strong moisture flux convergence along
the western edge of the deep layer moisture plume.  Total PWats up
to 1.75" will increase on this 45-50kt 850-700mb flow while nose
of unstable air lifts up into central NDak where MUCAPE of
1750-2250 J/kg is analyzed in the RAP.  As such, RADAR and GOES-E
10.3um show increasing convective activity along the western edge
of the TROWAL/sfc occluded front.  Deep layer steering is strong
but also begins to align southwest to northeast to allow for some
potential for training/repeating while upstream convergence may
allow for some backbuilding before the stronger westerly low to
mid-level flow begins in earnest across central NDak by 09-10z.=20
So while individual cell residency may be limited, rates of
1.75"/hr are probable and southwest to northeast streaks of 2-3"
totals become more likely over the next few hours mainly across
central, north-central and northeast NDak, and  perhaps into far
NW MN by 12z.  This is still on the low end of FFG exceedance, so
widely scattered incidents of flash flooding are considered
possible.

Gallina

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!7V4pm44IA2_fBmUPfx99RGS6IZC8bxaTDpe97bk4hBQT6eoEH9o7ou3esMLDy9YKBtKm=
1GaJZbbm0jjdNX3VrO9wfLA$  for graphic product...

ATTN...WFO...BIS...FGF...

ATTN...RFC...MBRFC...NCRFC...NWC...

LAT...LON   49039770 48989661 48519608 47819575 46749576=20
            46159627 46099757 46089892 46169988 46219998=20
            47050037 47940098 48430094 48940074 49000025=20
            49029912=20

=3D =3D =3D
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