125 FXUS64 KLCH 120238 AFDLCH Area Forecast Discussion National Weather Service Lake Charles LA 938 PM CDT Sat Apr 11 2020 .UPDATE... 00Z KLCH RAOB observed a dramatic increase in low level moisture with PWAT values jumping from 0.86 to 1.56 in the last 12 hours. A 2 degree C cap was also observed around 800 MB which has effectively kept a lid on most of the precipitation across the area this evening. Despite the increase in low level moisture, the surface warm front appears to still be working its way onshore judging by the 10 degree difference in dewpoint from BPT to LFT. Best estimate of its present location is roughly from near Jasper TX to Jennings LA and just west of Abbeville. Expect the front to continue to lift north through the remainder of the night lifting dewpoints into the lower 70s. The forecast is on track and no changes were made to it or the present hazards. The overall forecast philosophy remains unchanged as a deepening surface low will dig southeast overnight with a steadily tightening pressure gradient resulting in strong southerly winds ahead of a cold front which will push through the area during the day. There remains some uncertainty with regards to the southward extent of an associated squall line. The more reliable short range guidance does show significant convection across parts of central Louisiana within SPC's moderate risk area, but a much weaker, or in some cases nearly nonexistent, line closer to the I-10 corridor. Still, given the uncertainty and a primed atmosphere, there was little reservation in maintaining severe wording in the text products. Jones && .PREV DISCUSSION... /issued 846 PM CDT Sat Apr 11 2020/ DISCUSSION... For the 04/12/20 0000 UTC TAF package. AVIATION... Mostly VFR across the area early this evening, though KLCH has dipped into MVFR and cloud cover has been on a steady increase near KAEX and the Acadiana terminals through afternoon. Guidance is unanimous in lowering CIGS into MVFR during the mid to late evening hours, with some potential for IFR CIGS during the overnight to early SUN morning period. Some improvement is possible SUN morning, but generally expect MVFR to continue until clearing takes place from W to E during the afternoon and early evening. S to SW winds will remain elevated this evening and through the overnight, and increase markedly and become quite gusty by mid to late morning through the rest of this forecast period. Convective activity remains a bit difficult to pin down in terms of timing/areal extent, so have opted to use VC verbiage to denote the most likely temporal window at each terminal. 13 PREV DISCUSSION... /issued 444 PM CDT Sat Apr 11 2020/ SYNOPSIS... Vsbl satellite imagery shows clouds already returning acrs western portions of the area, as gusty southeast winds usher low level moisture back over the region. Sfc front remains parked over the gulf, poised to return as a warm front late tonight into early Sunday. Aloft, the low spinning over the SW is slowly starting to move east. Disturbances emanating from the base of the system continue to translate acrs the region, and this is resulting in clusters of convection along the Red River Valley, with additional convection developing acrs SE TX. 24 DISCUSSION... Warm southeast winds and increasing clouds will keep temperatures warmer tonight, with lows only falling into the upper 60s to lower 70s. The warm and humid conditions will be reinforced late tonight into Sunday as a warm front lifts north acrs the region. Convection will increase acrs TX late this aftn into this evening as the upper low evolves into an open wave and ejects east acrs the southern plains. This activity could affect portions of our SE TX counties by early this evening. Sufficient instability and shear could promote an isolated strong to marginally severe storm or two, but overall risk appears to be mitigated by capping per recent fcst soundings. Southerly winds will strengthen late tonight into the day Sunday as sfc low pres rapidly deepens west of the region, in response to the approaching upper trough. A Wind Advisory is in effect for lower SE TX and much of SW/Cntl LA roughly southeast of a line from De Quincy to Alexandria. The potent upper system will cross TX on Sunday, with convection initiating west of the area late tonight, then spreading eastward through the day. There is still an enhanced to moderate risk of severe weather with the system as it moves through the region, as strong deep layer shear, increasing instability and strengthening winds aloft align to promote an environment for sustained and long-lived supercells. The latest guidance suggests the best potential for most of the severe weather will be just north of the area, where mid and upper support will be greatest. However, MLCAPE values of 1500-3000 J/kg, low level helicity values from 200-300 m2/s2, and steep midlevel lapse rates will be in place acrs our region, so the risk of all severe modes (damaging winds, large hail and tornadoes) will be in place. The upper level system will quickly transit east on Sunday, with convection ending from west to east through the aftn. Westerly winds will develop behind a pre-frontal boundary on Sunday, with the main cold front sweeping through the area Sunday night. This front will bring a much cooler and drier continental airmass into the region. Mostly dry weather will prevail through much of the week, with temperatures well below normal from Monday through Wednesday. The coolest temperatures are expected Wednesday morning, with lows falling into the middle and upper 40s acrs much of the area. Aftn highs will be fairly comfortable with max temps each day in the upper 60s to lower 70s. A warming trend will develop by late in the week. Another shortwave will quickly cross the region Friday into Satuday, bringing a chance of showers or isolated tstms. 24 MARINE... Southerly winds will continue to strengthen tonight into Sunday as low pressure rapidly deepens west of the area. Small Craft Advisories are in effect for the coastal waters through the day Sunday as winds strengthen and seas build and become very rough. The strong southerly flow will cause tide levels to increase along the coast. Have issued a Coastal Flood Warning as water levels are expected to climb to between 1.5 to 2.5 FT abv normal astronomical tides, especially around time of high tide. Showers and storms are expected to increase along and ahead of the sfc low and its associated cold front, with a few strong storms possible. This activity will occur along a pre-frontal boundary, which will be followed by westerly flow. A stronger front will sweep through the area Sunday night, with strong offshore flow developing overnight into Monday. Elevated northeast winds are then expected to persist into early next week. By midweek, a sfc low is expected to develop along the stationary front acrs the Gulf. This could briefly increase northeast winds Tuesday into Wednesday, and bring a few showers or isolated storms before lifting to the northeast Wednesday night. 24 && .PRELIMINARY POINT TEMPS/POPS... AEX 65 82 54 70 / 40 70 10 0 LCH 71 83 59 76 / 30 50 0 0 LFT 71 85 61 78 / 30 60 10 0 BPT 72 85 58 75 / 40 50 0 0 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...Coastal Flood Warning from 5 AM to 7 PM CDT Sunday for LAZ052>054-073-074. Wind Advisory from 7 AM to 7 PM CDT Sunday for LAZ028-029- 031>033-041>045-052>055-073-074. TX...Coastal Flood Warning from 5 AM to 7 PM CDT Sunday for TXZ215. Wind Advisory from 7 AM to 7 PM CDT Sunday for TXZ215-216. GM...Small Craft Advisory until 7 PM CDT Sunday for GMZ450-452-455- 470-472-475. Small Craft Exercise Caution from 7 AM CDT Sunday through Sunday evening for GMZ430-432. Small Craft Exercise Caution until 7 AM CDT Sunday for GMZ435. && $$ PUBLIC...66