WPC Met Watch |
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Mesoscale Precipitation Discussion: #0605 (2019) |
(Issued at 420 AM EDT Mon Jul 15 2019
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MPD Selection |
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Mesoscale Precipitation Discussion 0605
NWS Weather Prediction Center College Park MD
420 AM EDT Mon Jul 15 2019
Areas affected...Far Eastern TX...Southwest to Central
LA...Southwest to Central MS
Concerning...Heavy rainfall...Flash flooding likely
Valid 150820Z - 151420Z
SUMMARY...Bands of heavy showers and thunderstorms will continue
to pose a significant flash flood threat through the early to mid
morning hours.
DISCUSSION...The latest radar imagery shows a strong and training
convective band with very heavy showers and thunderstorms across
areas southwest to central LA and beginning to edge into portions
of southwest MS. Over the past several hours, the heaviest
rainfall from this line has been over portions of Calcasieu,
Beauregard, and Allen parishes where as much as 8 to 12 inches of
rain has fallen. This includes the northern suburbs of the Lake
Charles metropolitan area. A Flash Flood Emergency is currently in
effect for these areas.
The band of heavy showers and thunderstorms is oriented in a
curved pattern around the southern and southeastern flanks of T.D.
Barry's circulation. A portion of this band extends actually as
far west as far eastern TX, and the leading edge of it is
beginning to advance into southwest MS. However, the most
concentrated and heaviest rainfall is over southwest to central LA
where the coldest clouds tops are seen in GOES-16 IR satellite
imagery. All of the activity continues to align itself along
localized areas of stronger surface moisture convergence and
within well-defined instability gradients that remain intact
around the far southeastern quadrant of T.D. Barry's circulation.
T.D. Barry continues to lift north and is moving into southern AR
early this morning. A northward motion will continue today, but
there will likely remain a rather focused axis of surface moisture
convergence across areas of far eastern TX, southwest to central
LA and also across portions of southwest to central MS that will
be conducive for multiple bands of training showers and
thunderstorms with very heavy rainfall rates.
Given the deep tropical moisture profiles as seen in CIRA-LPW data
sets and the 00Z RAOB soundings, there will continue to be
convection capable of producing extremely high rainfall rates that
may reach as high as 4 inches/hr. Warm rain processes will be key
in driving these extreme rates, and with a trend seen over the
last couple of hours of cooling cloud tops, it would appear that
these rates will be sustainable over the few hours.
The 00Z hires model consensus led by the HREF suite of guidance
supports additional rainfall amounts of 4 to 7 inches going
through mid-morning, with the heaviest amounts expected to be over
areas of central LA. Lesser amounts of as much as 2 to 4 inches is
supported elsewhere, but with locally heavier amounts.
Flash flooding is highly likely, and will be significant locally
where the core axis of training convection sets up. Will continue
to closely monitor.
Orrison
ATTN...WFO...HGX...JAN...LCH...LIX...SHV...
ATTN...RFC...LMRFC...WGRFC...
LAT...LON 33639009 33488952 33048913 32098923 31308998
30769083 30399172 29999362 30039460 30239519
30549505 30719406 31239266 31939182 32909110
33429083
Last Updated: 419 AM EDT Mon Jul 15 2019
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