841 FXUS64 KLCH 190554 AFDLCH Area Forecast Discussion National Weather Service Lake Charles LA 1154 PM CST Thu Jan 18 2024 ...New AVIATION... .UPDATE... Issued at 946 PM CST Thu Jan 18 2024 Main update this evening was to issue a Dense Fog Advisory for the counties/parishes along I-10 to the coast, as well as a marine Dense Fog Advisory for our coastal lakes/bays and all nearshore waters. Several observations across these regions have been and continue to report 0.25-0.50 sm. With RH values near or at 100% and very light to calm winds its likely this fog will persist until the passage of a cold front later tonight. The advisory may need to be cancelled early if the front is able to move through quicker than anticipated, but for now most guidance shows VIS improving between the 4-5AM time frame. Otherwise, the forecast looks to be on track tonight. 17 && .SHORT TERM... (Tonight through Saturday night) Issued at 330 PM CST Thu Jan 18 2024 Local 88Ds show scattered showers associated with good WAA (sfc obs indicate temps well into the 60s for much of the forecast area) and an approaching mid/upper-level disturbance (per water vapor imagery) developing over mainly the sern 1/3 of the forecast area where a little deeper/better low-level moisture was analyzed (per regional 12z and forecast soundings). Meanwhile, mid- afternoon sfc analysis shows an area of low pressure located over the Red River Valley with a trailing cold front over nrn TX. Outside of the precip, skies were generally cloudy. Ongoing shower activity is expected to move out of the area into the early evening as lift from the approaching disturbance and heating wane. Meanwhile, the sfc low is progged to lift newd through tonight, pulling the upstream cold front across the area with increasing nrly winds developing towards sunrise. With CAA developing late, we should temperatures drop into the 35-40 degree range for much of the area, with some climatologically cooler locations possibly touching the freezing mark prior to sunrise. Prior to the arrival of the front, patchy fog could again be an issue...however due to the (hopefully) short-lived nature of this fog, no advisories are planned for issuance at this time. The onset of the cooler air will absolutely be felt on Friday as cold high pressure builds back over the region. Blended guidance is advertising highs in the upper 40s to lower 50s (some mid 40s possible across e-cntl LA)...but add in nrly winds approaching 20 knots at times and apparent temps will be held in the 40s, especially across the nrn zones. A Wind Advisory may be needed for tomorrow...will allow later shifts to review this and issue if needed. If you're over exceedingly cold weather, bad news is coming. As the core of the next Arctic high begins settling over the region, temperatures for Friday night/Saturday sunrise will once again be quite frigid with lows in the lower/mid 20s for all but right along the coastline. Due to the likelihood of these very cold temps, a Hard Freeze Watch has been issued for tomorrow night (through mid-morning Saturday) for the I-10 corridor nwd, except Jefferson County...plan to protect the four P's yet again. Combine that with nrly winds still expected to be running at 10-15 knots and wind chills should be back down into the 10s...and another Wind Chill Advisory will likely be needed for portions of the forecast area. Saturday/Saturday night look to be general repeats of Friday/Friday night albeit with less wind as the sfc high settles overhead. High temps Saturday are again progged to peak in the 40s (with some spots possibly remaining in the upper 30s over the nern zones) while Saturday night temps are again likely to be in the 20s with slightly colder wind chills. 25 && .LONG TERM... (Sunday through next Wednesday) Issued at 330 PM CST Thu Jan 18 2024 One last day of cold and dry weather is expected to start the long term, with a shift toward a wetter and warmer pattern expected for the workweek. On Sunday, the area will still be under the influence of cold air pressure centered over the OH Valley. After another unusually cold morning with lows in the upper teens across central LA to the upper 20s across coastal portions of SE TX and SW LA, temperatures will only warm into the middle 40s to near 50 as surface winds become more easterly during the day. Meanwhile, modest shortwave ridging aloft will translate east through the day, with southwesterly flow developing, ushering increased cloud cover over the region. This will mark a significant shift in the pattern aloft as the first of what will be several disturbances moves into the southwestern states. Southwesterly flow aloft will become established, and persist through the week, favoring good moisture advection over the region. PWATs are expected to rapidly climb Sunday night into Monday, from less than an inch to beyond the 90th percentile (peaking around 1.5 to 1.6 inches Monday night into Tuesday). Forecast soundings become increasingly saturated while the combination of favorable jet dynamics and a developing surface trough across southern TX support the development of showers initially Sunday night, with showers and storms becoming more widespread across the area Monday. There continues to be a good signal for some heavy rainfall, especially from late Monday into Tuesday, and WPC has outlined much of the area in a SLGT risk for excessive rainfall on their Day 5 outlook (12z MON through 12z TUE), with a MRGL risk over our eastern zones. QPF values during this timeframe look to range from 1 to 3 inches with locally higher amounts likely, while NBM probability of exceedance shows at least a 20% chance of exceeding 3 inches across the southern half of the area for this 24 hour period. Another item that will need to be monitored Monday into early Tuesday is the potential for severe weather. While the primary threat is expected to be the heavy rainfall, forecast soundings do show some decent deep layer shear and pronounced SRH in the lower levels, sufficient to support organized updrafts and rotation in some storms. On the other hand, instability and lapse rates will be on the weak end of the spectrum, factors that would inhibit overall storm intensity. Thus, this remains a low confidence scenario, with quite a bit of uncertainty in the guidance regarding timing of upper level impulses and evolution of surface features. By Tuesday, the initial shortwave will eject northeast over the plains, while another piece of energy digs over the southwest, carving a more amplified trough from the Four Corners into northern Mexico. This feature is expected to only slowly move east through the week, as intermittent disturbances pass through its base and eject over the southern plains. This will maintain southwesterly flow aloft and elevated PWATs between 1.3 and 1.7 inches across the area, with multiple rounds of showers and storms expected through and beyond the end of the forecast period. Better details will emerge as the event approaches, such as timing individual rounds of convection, ascertaining when and where the heaviest rain will occur as well as QPF amounts. In addition, there could be another risk for severe weather, especially later in the week as a strong midlevel jet approaches the region with an elongated surface trough/cold front in place. Forecast storm total QPF amounts continue to increase, and will likely continue until an end to this pattern is noted. NBM probabilities suggest a 40 to 60 percent chance of reaching or exceeding 4 inches of rainfall from Monday through Thursday morning across much of the area. A marked warmup will also accompany this increasingly wet timeframe as surface winds become more southeasterly. From Tuesday through Thursday, highs are expected to reach the upper 60s to lower 70s, with lows in the middle and upper 50s. One additional note for marine interests, thanks to the recent cold outbreak, there will be an increased risk for marine fog over the coastal waters as the warmer airmass advects over the relatively chilly shelf waters. 24 && .AVIATION... (06Z TAFS) Issued at 1126 PM CST Thu Jan 18 2024 Widespread clouds and (primarily) dense fog are spread over the region and impacting all terminals. A cold front is preparing to pass down through the region from the northwest; as soon as it does, visibilities and cloud decks will notably improve. Observations and satellite imagery are already beginning to reflect this improvement in southeast Texas. A line from Woodville, TX to Toledo Bend Dam has notably cleared in the last hour. This airmass of better conditions will move southeast in the coming hours with VIS increasing to 4 to 6 SM at AEX and BPT by 09Z, and LCH by 10 to 11Z. Lower Acadiana is reporting fog but they have not fully socked in, thus tempo groups were included here for dense fog through 09Z, with BR at 4SM prevailing. All ceilings will lift from VV to MVFR just prior to 12Z. As dry air continues filtering in, skies will become clear around 15Z for BPT, LCH and AEX; 18Z for LFT and ARA. The other major point of this TAF package is the wind forecast. Where winds are high enough to report a direction, they're reporting northwest. This indicates the frontal wind shift has moved through. Winds will quickly pick up after 12Z this morning, washing out any remaining fog and driving upward any low ceilings. Winds prevail from the north at a gusty clip - sustained winds 15 to 20 knots with gusts up to 28 knots can be expected through the afternoon. The gradient relaxes after sundown, allowing winds to diminish to around 10 knots for the remainder of the TAF period. 11/Calhoun && .MARINE... Issued at 330 PM CST Thu Jan 18 2024 Will be issuing an SCA for the coastal waters/lakes and bays this afternoon as a strong post-frontal nrly flow is expected. Meanwhile, expect areas of fog, sometimes dense, to continue on the waters through fropa later tonight. 25 && .PRELIMINARY POINT TEMPS/POPS... AEX 61 34 47 20 / 10 0 0 0 LCH 65 40 52 26 / 10 0 0 0 LFT 68 41 51 26 / 20 10 0 0 BPT 66 41 54 27 / 10 0 0 0 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...Hard Freeze Watch from late Friday night through Saturday morning for LAZ027>033-044-045-141>143-241>243. Dense Fog Advisory until 4 AM CST Friday for LAZ044-045-055-073- 074-141-152>154-241>243-252>254. TX...Hard Freeze Watch from late Friday night through Saturday morning for TXZ180-201-259>262-516-616. Dense Fog Advisory until 4 AM CST Friday for TXZ515-516-615-616. GM...Dense Fog Advisory until 5 AM CST Friday for GMZ430-432-435-436- 450-452-455. Small Craft Advisory from 5 AM Friday to 6 AM CST Saturday for GMZ430-432-435-436-450-452-455-470-472-475. && $$ SHORT TERM...17 LONG TERM....24 AVIATION...11