796 FXUS64 KLCH 161426 AFDLCH Area Forecast Discussion National Weather Service Lake Charles LA 926 AM CDT Mon Sep 16 2019 .UPDATE... Radar and satellite this morning depict a large swath of light to moderate tropical rainfall across the coastal waters associated with the mid/upper level trof that's been sitting out over the north central gulf over the past couple of days. So far, this activity has remained offshore, but the latest hi res guidance does show scattered showers working their way inland by this afternoon. The majority of this activity will remain south of the I-10 corridor. Short term guidance also in generally good agreement on a gradual lowering of precipitation coverage by late this afternoon into the overnight. This is reflected well in the current forecast. The only change made to the forecast this morning was to lower afternoon high temperatures a couple of degrees near the coast in anticipation of higher cloud cover. This better aligns with the latest model consensus. Jones && .PREV DISCUSSION... /issued 631 AM CDT Mon Sep 16 2019/ DISCUSSION... For the 16/12Z TAF Issuance. AVIATION... A mid to upper level low and associated surface trough over the northwest Gulf of Mexico will move westward into the mid to upper Texas coast on Tuesday. The outer cyclonic circulation of this system will bring elevated moisture along the coastal areas with daytime heating helping to develop showers and thunderstorms, mainly from late morning into the afternoon hours. This activity will have the potential to affect the terminals at KBPT/KLCH/KLFT/KARA. Meanwhile, besides the possibility of some early morning patchy fog, mainly VFR conditions expected at KAEX through the period, as convection is expected to stay to the south. Rua PREV DISCUSSION... /issued 428 AM CDT Mon Sep 16 2019/ DISCUSSION... Short Term [Today through Thursday] Satellite and radar imagery this morning show convection ongoing across the northern Gulf of Mexico associated with an upper level low. This upper level low is forecast to continue moving west across the northern Gulf of Mexico over the next several days before moving inland across southeast Texas on Wednesday. Satellite derived soundings indicate PWATs of 1.8"-2"+ are in place across the northern Gulf of Mexico in the vicinity of the upper level low. As the low moves westward today, model guidance indicates that the areas of more abundant tropical moisture with PWATs of 2"+ will move further inland. As a result, showers and thunderstorms are expected to be more widespread compared to the past several days. However, the greatest chances for precipitation are still expected to be confined to areas along and south of I-10. By Tuesday and Wednesday, the greatest chances of precipitation will move further inland and west as the low approaches the Texas coast. As the upper level system moves over land, there is some potential for the associated surface low pressure to become more organized along the Texas coast on Wednesday. The environment will be favorable for heavy rainfall and the latest model guidance has trended toward higher QPF totals. However, some of the model QPF amounts may be overdone as they develop a much more organized surface low. Despite the differences in individual model solutions, the overall trend is that it is becoming increasing likely that areas of heavy rainfall will occur across portions of southeast Texas from Wednesday through Thursday. As a result, WPC has issued a Slight Risk of flash flooding from Wednesday through Thursday. It should also be noted that a greater risk of flash flooding could develop, but WPC capped the risk of flash flooding at Slight due to the uncertainty in the location of the higher QPF amounts. Model guidance is in good agreement that beginning on Thursday the upper level low is expected to be picked up by a trough lifting across the Northern Plains. This will allow for the surface low pressure to lift northward and rainfall chances to gradually decrease. However, rain chances will remain elevated on Thursday particularly across Southeast Texas. Long Term [Friday through Sunday] The Long Term period will feature a return to a more typical September weather pattern. PWATs are forecast to return to around 1.7"-2" by the later half of the weekend as high pressure builds over the area. This will support the typical 20%-30% chance of afternoon showers and thunderstorms each day with highs in the low to mid 90s. MARINE... An upper level low will continue to move westward across the northern Gulf of Mexico over the next couple of days before moving inland across east Texas on Wednesday. This will result in elevated precipitation chances over the coastal waters through the middle of the week. Elevated easterly winds of 10 to 20 knots will continue today and Small Craft Exercise Caution headlines have been include in the forecast for the coastal waters. Winds will gradually subside and shift to southerly as the upper level low lifts northward during the middle part of the week. && .PRELIMINARY POINT TEMPS/POPS... AEX 96 70 95 70 / 20 0 20 0 LCH 91 76 90 76 / 50 20 50 30 LFT 91 74 93 74 / 50 0 30 20 BPT 89 76 87 76 / 60 40 60 40 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...None. TX...None. GM...Small Craft Exercise Caution until 7 PM CDT this evening for GMZ450-452-455-470-472-475. && $$ PUBLIC...66