Area Forecast Discussion
Issued by NWS Lake Charles, LA
Issued by NWS Lake Charles, LA
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328 FXUS64 KLCH 161733 AFDLCH Area Forecast Discussion National Weather Service Lake Charles LA 1233 PM CDT Sun Jun 16 2024 ...New AVIATION... .UPDATE... Issued at 1030 AM CDT Sun Jun 16 2024 The start of the moisture increase has begun across the forecast area with dew points this morning in the mid 70s and also with a few showers and storms showing up around the Lower Atchafalaya Basin and adjacent coastal waters. Moisture should continue to increase and with little inhibition seen on the morning sounding from KLCH, shower activity should spread to the west with daytime heating and enhanced sea breeze. Made some minor adjustments to the grids based on latest radar and short term guidance trends. Will go into more detail with the afternoon package as far as heavy rain, above normal tides, and marine conditions. There is the potential of a flood watch, a coastal flood watch, and small craft advisory being issued this afternoon with hazards starting on Monday. Rua && .SHORT TERM... (Today through Tuesday night) Issued at 414 AM CDT Sun Jun 16 2024 Today we will see a shift into a more active period with multiday scattered to numerous PoPs and flooding potential. The upper ridge that kept us unseasonably warm and dry has moved off, centering itself over the Southeastern States. An inverted trough over the southern gulf and its associated plume of deep moisture is spreading over the Gulf and Gulf Coast States. This disturbance is expected to move west over the period and there is a 60 percent chance of development into a depression. Regardless of development, this system will bring heavy rainfall and breezy conditions. Potential threats include river/flash flooding, higher seas/tides, coastal flooding. Over the day, we will see an increase in PWATs as the plume of moisture steadily moves westward. That along with diurnal processes will be sufficient to get isolated to numerous showers and storms kicked off during the late morning to evening hours. Forecast PWATs along the coast and in the Acadiana region today are in the 1.8 to 2.2 inch range. Going into the work week, we could see near 2.7 inch PWATs. Rainfall totals just over the short term period area in the 1- 4 inch range north of the I-10, with 4 to 8 inches south of there. Locally higher amounts will certainly be possible. As of now, there is a Slight (lvl 2 of 4) to Marginal Risk (lvl 1 of 4) of excessive rainfall every day of the short term with a Moderate Risk (lvl 3 of 4) for Tuesday night into Wednesday morning. Keep in mind that the potential for greater and or additional flood threats will exist over this period. Stigger/87 && .LONG TERM... (Wednesday through Sunday) Issued at 414 AM CDT Sun Jun 16 2024 Heavy rainfall and flood potential will remain a concern going into Wednesday with an inverted trough aloft over the western Gulf of Mexico and possible tropical cyclone over the SW Gulf. Deep SE to S flow through the column from the SFC to above 500 MB will continue to funnel an anomalously moist airmass over the region with PWAT values of at least 2.5 or higher inches across portions of SE TX and SW LA. The best likelihood for heavy rainfall will be confined to far SW LA and SE TX as the trough and its associated surface feature move west into TX and NE Mexico during the day. WPC has maintained a Slight Risk (level 2 out of 4) for excessive rainfall on Day 4 (Wed into Thu) although most of the risk will occur during the day Wednesday. This will come on the heels of a Moderate Risk on Tuesday and, depending on how conditions evolve, a Moderate Risk for parts of SE TX could be warranted in upcoming outlooks. Along the coast, a prolonged and strong easterly fetch will likely produce elevated tide levels, especially along the Jefferson and Cameron coasts. P-ETSS guidance ensembles suggest the potential for significant coastal flooding early Wednesday although guidance spread is still fairly large. At this time, deterministic values suggest water levels between 2.5 and 3 feet above astronomical predicted levels will be possible from Calcasieu Pass to Texas Point. Conditions should begin to improve Wednesday night into Thursday as a ridge axis aloft migrates into the region in the wake of the tropical disturbance. PWATs, while elevated, should trend closer to the daily mean at least for a day or two, and this should be sufficient to produce some scattered and mainly diurnally induced convection Thursday and Friday afternoon. Daytime highs should begin to climb back to around 90 or into the lower 90s each afternoon as coverage of clouds and showers decreases. By next weekend, a similar scenario to what is expected in the short term could start unfolding again as a tropical wave advances west over the Gulf of Mexico aloft and lower pressure develops in the Bay of Campeche. Rain chances are again expected to increase Saturday into Sunday as another plume of tropical moisture advects into the region. 24 && .AVIATION... (18Z TAFS) Issued at 1228 PM CDT Sun Jun 16 2024 Best axis of moisture and instability is over south central Louisiana so KLFT and KARA will have the best chance of seeing showers and storms this afternoon and have placed TEMPO groups for those terms for timing purposes. Otherwise, away from shower and storms, VFR conditions are expected. Shower activity is expected to end this evening between 17/02z-03z with VFR conditions prevailing. With the expected influx of deep moisture, nocturnal shower activity is likely over the Gulf overnight and a few of these showers may reach southern terminals after 17/09z. For Monday, widespread shower activity is expected by mid morning with breezy east-southeast winds. Rua && .MARINE... Issued at 414 AM CDT Sun Jun 16 2024 A trough will gradually move west across the southern Gulf of Mexico from early to mid week. Deep moisture will be associated with this system that will bring widespread shower activity. The gradient between the trough and high pressure to the northeast will bring moderate to strong east to southeast winds at or above 20 knots going into tomorrow morning to afternoon that will continue through mid week. This prolonged wind field will allow for a significant increase in wave heights and swells. Small craft advisories will likely be needed during this period. Also, tides will be 1 to 2 feet above normal predicted levels that may lead to coastal flooding. && .PRELIMINARY POINT TEMPS/POPS... AEX 94 73 86 71 / 30 20 90 20 LCH 91 76 86 75 / 40 40 90 50 LFT 91 75 86 76 / 60 40 90 40 BPT 93 76 87 76 / 20 50 90 50 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...None. TX...None. GM...None. && $$ SHORT TERM...87 LONG TERM....66 AVIATION...07