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Public Information Statement
National Weather Service Lake Charles LA
327 AM CDT Thu Jul 18 2024

An upper level trough shifts off the SETX Coast into the western Gulf.  Concurrently, a shortwave trough with positive tilt further upstream over the central Plains will continue to amplify toward the ARKLAEX and Mississippi Valley into Sunday morning. Together, both features develop a series of minor perturbations in the pressure pattern aloft to sweep through the area, thus providing multiple rounds of Isolated to periodically widespread showers and storms through Sunday. In addition the frontal pattern along with increased cloud cover will trend down daytime high temperatures toward mid – upper 80’s through the start of the weekend. Should be noted, that sfc – 3km moisture transport continues to remain from the Gulf / Caribbean driven easterlies which are forecast to develop a healthy moisture jet keeping the pattern fairly we throughout the remainder of the short term.  That said, despite the influx of tropical moisture, per most recent guidance from NHC, no tropical development forecast to develop in the next 7 days.

Zooming in to the weather at hand, a southward moving cold frontal boundary over central LA continues to stall, becoming stationary along the SETX and SWLA Gulf Coast briefly. Last night’s evening sounding data calculates PWAT of 1.88” which has been congruent with prior day’s forecast suite. With that in mind, northern portions of SETX and SWLA are in a Slight Risk (level 2 of 4) for excessive rainfall with the greater surrounding counties and parishes under a marginal risk(level 1 of 4).  The stationary front will be the focal point for more widespread and heavier rainfalls to occur throughout today as it shifts southward. By tonight the front become stationary near the coast while the aforementioned shortwave amplifying south continues to shift east toward central AR. 
Additional speed divergence and vorticity are generated along central and southern portions of LA including SETX counties, therefore another night of nocturnal rainfall will occur into Friday morning. Here, the stationary front hangs along the coast remaining the focus area of thunderstorm genesis throughout the day. That said, periodic breaks to allow broken cloud cover is not out of the question. By Saturday morning, the parent shortwave shifts eastward over the TN while keeping a positive tilt toward the LA Gulf Coast lifting the boundary north again toward the ARKLTEX region. Upstream, another shortwave trough begins to deepen south of the central plains developing a weak surface trough over southern AR. Referring back to the earlier mentioned sfc- 3km moisture transport strengthening across the Gulf into the interior regions of TX / LA /MS, we continue to stay the course for further rounds of precipitation continuing into Sunday morning.  

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