Flash Flood Guidance
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000
AWUS01 KWNH 212109
FFGMPD
TXZ000-OKZ000-220245-

Mesoscale Precipitation Discussion 0106
NWS Weather Prediction Center College Park MD
508 PM EDT Thu Mar 21 2024

Areas affected...Southern Oklahoma to Northern Texas

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

Valid 212107Z - 220245Z

Summary...Isolated flash flooding is possible across portions of
southern Oklahoma into northern Texas as a shortwave trough moves
eastward near the Red River and convection begins to grow upscale
in coverage and intensity this afternoon.  Localized rainfall
totals of 2 to 4 inches remains possible where cell motions are
reduced close to the ejecting trough/low.

Discussion...Radar showed convection beginning to grow either side
of the Red River in proximity in the vicinity of a pair of
shortwave troughs, a weak dryline in the area, and a
quasi-stationary front located to the north.

The HRRR runs from late this morning and this afternoon have been
showing run to run differences in placement of the heaviest
rainfall...but a consistent theme has been for the axis of
heaviest rain to be along and immediately south of the track of
the trough where greater surface-based instability should result
from better daytime heating/steeper low/mid level lapse rates.
Surface flow is fairly weak into the region and 850 mb flow is
modest...15 to 20 kts at best as shown by latest VWPs from the
Gulf coast region northward into central/eastern Texas...but the
flow was favoring moisture transport ahead of the trough/low.

Flash flood guidance was generally at or above 2.5 inches per hour
and closer to 3 inches per 3 hours hour across MPD area. Thinking
is that localized maximum rainfall amounts of 2 to 4 inches are
possible should the cells slow down in response to the approach of
the upper system...so instances of flash flooding rainfall may
occur but should be isolated in coverage.

Bann

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...FWD...OUN...SJT...

ATTN...RFC...ABRFC...WGRFC...NWC...

LAT...LON   34559881 34469786 34129710 33559663 33179667
            32769690 31929791 31349894 31300006 31920005
            32909947 33469953 34319984


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