Graphic for MPD #0113

Mesoscale Precipitation Discussion 0113
NWS Weather Prediction Center College Park MD
639 PM EDT Mon Mar 25 2024

Areas affected...central/eastern Louisiana into southern/central
Mississippi

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

Valid 252238Z - 260438Z

Summary...Localized training/cell mergers are supporting spots of
2 inch/hr rain rates at times - especially in central Louisiana. 
These heavier rain rates should translate eastward, posing an
isolated flash flood threat especially in sensitive/urbanized
areas.

Discussion...A couple of SSW-NNE oriented convective bands have
materialized over central Louisiana over the past 2-3 hours.  The
bands have generally organized along and ahead of a remnant
outflow from prior convection that was currently located from near
SRC (Searcy, AR) to near BPT (Beaumont, Texas).  Over the past
half hour or so, this outflow has made enough eastward progression
to undercut some of the central Louisiana convection, with
remaining storms likely elevated but leveraging just enough
instability aloft to maintain heavy rainfall atop areas that have
experienced 2-3 inches of rainfall.  Rates in most areas have
fallen below areal FFG thresholds (generally holding in the 2.5-3
inch/hr range), and much of the flash flood threat has remained
fairly isolated.  These trends should keep the flash flood threat
isolated in the short term.

Over time, convection will continue to translate eastward,
eventually crossing the Mississippi River as surface-based storms
generally from US 82 southward.  As this occurs, models suggest
limited opportunity for training to develop especially where 1)
surface-based instability exists to support deeper/stronger
updrafts and 2) where the eastward-moving outflow boundary can
slow its forward progression, allowing for more opportunity for
training/repeating and cell mergers.  This scenario (which should
support 1.5+ inch/hr rain rates) is most likely to unfold along an
axis from near Alexandria, LA to Jackson, MS through the evening. 
These rates are still likely to fall below one- and three-hour FFG
thresholds except on an isolated basis, and flash flood potential
should remain isolated and localized near urban and/or low-lying
areas.

Cook

ATTN...WFO...JAN...LCH...LIX...LZK...MEG...SHV...

ATTN...RFC...LMRFC...SERFC...WGRFC...NWC...

LAT...LON   33929033 33658911 32848885 32078885 31588926
            30789116 30419309 31039324 31819297 32879217
            33629127
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Last Updated: 639 PM EDT Mon Mar 25 2024