re: TS Arthur - TS Warning for SE Texas and SW Louisiana - Flood Threat

The next 12 to 24 hrs will be the period to watch for heavy rain and flash flooding. The 21z HRRR has totals pushing 20" in SW Louisiana, while the 18z RRFS (New model that will replace some of the current hi-res models in August) has 20"+ across the Florida Parishes.

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What model is this and is it reliable?

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I don't know, since they didn't include a data source for the image.

Your mom’s getting all my 3.5” that’s for sure.

Gonna be one puddle in the road and a chair that fell over in a random back yard.

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Your mom’s getting all my 3.5” that’s for sure.

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Bayou_Tiger_225

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Mesoscale Precipitation Discussion 0439
NWS Weather Prediction Center College Park MD
800 PM EDT Wed Jun 17 2026

Areas affected...Southeast Louisiana

Concerning...Heavy rainfall...Flash flooding likely

Valid 180000Z - 180600Z

Summary...Showers and thunderstorms grow in coverage and intensity
through this evening over southeast Louisiana. Scattered flash
flooding can be expected through midnight before the focus shifts
farther inland. Expect repeating activity with rain rates of 2"+
per hour and 5"+ totals through midnight.

Discussion...As of 00Z, an MCV associated with a mid-level
circulation east of Arthur is tracking north toward the Louisiana
coast. Extremely high moisture and sufficient instability is
present ahead of this wave with PW around 2.6" (3.5 sigma above
normal) and SBCAPE around 2000 J/kg. Scattered showers and
isolated thunderstorms are across southeast Louisiana with rain
estimates generally 1 to 1.5"/hr from KHDC. Activity thus far has
avoided NOLA and Baton Rouge, but increasing coverage and
intensity will bring heightened threats to both these sensitive
areas as well as the rest of southeast LA through the evening
hours.

Notable differences are present in recent HRRR and RRFS output
with the HRRR unreasonably west (given MCV placement) over
south-central LA while the placement in recent RRFS to the east
(including NOLA) are reasonable. Both have 6hr QPF of 5-8" maxes
which is reasonable given the extreme PW and a forcing mechanism
slowly approaching the coast allowing redevelopment/repetition.
QPF of this magnitude (with locally higher 6hr max possible)
brings up a concern for considerable impacts to the flash flood
threat. Antecedent conditions are thankfully rather dry for much
of the area, but this amount of QPF over a potentially larger than
normal area warrants likely and considerable wording for this
flash flood threat through midnight.

The activity will be pushing farther inland overnight, but
additional localized heavy rain should warrant further discussion
for southeast LA let alone into through southern MS.

Jackson

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Upper-level winds have displaced convection well away from the center of the system.

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With what you said should this area still be under a TS warning?

Looks like some training bands trying to set up scattered between the basin and northshore

Driving back from Orlando tomorrow. Will this thing go North or am I driving through it?