504 FXUS64 KLCH 121244 AFDLCH Area Forecast Discussion National Weather Service Lake Charles LA 744 AM CDT Fri Apr 12 2019 .DISCUSSION... For the 04/12/19 1200 UTC TAF package. && .AVIATION... Frontal boundary has stalled just SE of KARA per latest SFC/radar observations, with only some light isolated showers noted across parts of east/south central LA. The front is expected to retreat back to the north this afternoon and tonight, with isolate/scattered convection possible by mid to late morning. Inserted VCTS at all sites, with activity expected to generally shift north of the area late tonight. Return of warm and moist airmass will yield the development of widespread MVFR CIGS, lowering into IFR along with increasing SE SFC winds tonight. 13 && .PREV DISCUSSION... /issued 506 AM CDT Fri Apr 12 2019/ SYNOPSIS... Cold front currently bisects the area, extending from east of AEX to LCH to the Jefferson County coast. KLCH/KPOE radars show a band of showers and tstms, a few exhibiting the possibility of gusty winds and small hail in the stronger cells, along the boundary. A nice temperature gradient also accompanies the front, with temps near 70 ahead of the it, and upper 50s to lower 60s in its wake. Aloft, low pres continues to migrate north over the upper midwest per WV imagery and UA analysis. Deep moisture associated with this low extends from the Great Lakes south/southwest to the NW Gulf coast. A large scale trough is seen over much of the western CONUS, and this trough is in the process of digging/deepening over the desert SW and NW Mexico. 24 DISCUSSION... The sfc front over the area will drift southeastward early this morning, gradually bcmg stalled as it reaches the Acadiana region. The front will briefly bring northeasterly winds, slightly cooler temperatures and slightly lower dewpoints acrs much of the area this morning. However, this airmass will be fairly shallow, and overrunning moisture in southwesterly flow aloft will maintain cloudy skies and the possibility of a few showers over the area. The boundary will meander over the area today, serving as a focus for shower and tstm development through the aftn. With cooler air filtering into northern portions of the area, expect high temps only reaching the lower to middle 70s from cntl LA to the Lakes region of SE TX. Further south, temperatures could warm to around 80 acrs SW LA and lower SE TX, with lower 80s in Acadiana where the warm airmass should more or less stay in place. The front will continue to linger acrs the area tonight, with a chc for showers continuing. Overnight lows will range from the middle 60s north to lower 70s south. By Saturday, a deep trough digging over the SW CONUS will begin moving east over the southern plains. Sfc cyclogenesis is expected to develop over srn/cntl TX early in the day in response to lowering heights aloft. The low pres system will rapidly deepen as it pivots over the Red River Valley, with the sfc low quickly sliding toward the ArkLaTex. Strengthening LLJ of 50-60 KT will slide over the area, accelerating the frontal boundary back north as a warm front and allowing a rapid northward transport of warm moist air. The ingredients still look to be coming together, in concert with peak daytime heating, for a substantial severe weather event on Saturday. SPC's Day 2 Outlook continues to indicate an Enhanced Risk for severe storms acrs much of the area north of I-10, with a MDT risk just touching our northern CWA border, and a SLGT risk elsewhere acrs the area. Fcst soundings indicate some capping early in the day, but as mixing develops with ample daytime heating, CAPE values in excess of 2000 J/kg develop by midday into early aftn. This, combined with a strong wind profiles and deep layer shear, will allow for supercellular convection to develop acrs the area. SRH values in the 1 and 3 KM layers are progged to be between 200-400 M2/S2, and the resultant rotating updrafts will be capable of producing tornadoes, in addition to other svr weather modes of damaging winds and large hail. At this time, the best potential for the strongest storms is expected along and north of a line from Woodville to Kinder to Opelousas. CAM guidance continues to show some variance with respect to timing and placement of convection, with the Nested NAM depicting the potential for a cluster of strong storms developing acrs SW LA along and south of I-10 during the aftn. The bottom line is that all areas of the CWA could be under the gun for svr storms during the day Saturday, and individuals are encouraged to remain alert for any watches or warnings issued by the NWS. Convection will transition to a semi-organized band by evening as the frontal boundary moves into the area. There is still the potential for storms to produce heavy rainfall as well. The best focus for heavier rainfall will be north of the area, along and east of the sfc low and along the warm frontal boundary. Area average rainfall totals are expected to range from less than an inch acrs lower SE TX and SW LA to nearly 2.5 inches acrs cntl LA. However, heavy downpours in some storms could produce intense rainfall rates, with localized higher amounts and flooding possible in a few locations. Convection will quickly shift east during the evening and overnight as drier air wrapping around the upper low spreads into the region. Dry weather is expected to prevail from Sunday through Tuesday with high pres making a quick transit acrs the region. Slightly cooler temperatures are expected Sunday into Monday, with temperatures moderating Tuesday into Wednesday as return flow develops. Showers and tstms will increase again on Wednesday and continue into Thursday as another shortwave and sfc low pres system crosses the southern plains into the lower MS Valley. 24 MARINE... A weak front will slide south over the western portions of the marine zones early this morning, accompanied by a few showers. This will also produce a brief period of east to northeast winds over the coastal waters west of Cameron this morning. Otherwise, expect onshore flow to prevail through Saturday. The southerly flow will strengthen and seas will build late tonight into Saturday as strong low pressure develops over Texas. Small Craft Advisories will likely be required from late tonight into Saturday as winds strengthen to 20 to 25 KT and seas build to between 8 to 11 FT. Showers and thunderstorms are expected to increase during the day Saturday as the low moves over the region. A few strong to severe storms will be possible, capable of producing strong wind gusts, waterspouts and hail. The low will move NE Saturday night, sweeping a strong cold front through the region and bringing an end to the storms from west to east late Saturday night into Sunday morning. Moderate to strong offshore flow will develop behind the front, with additional advisories possible. Winds will diminish by Monday as high pres transits the region, with onshore flow expected to resume by Tuesday. 24 && .PRELIMINARY POINT TEMPS/POPS... AEX 74 65 77 51 / 40 50 90 60 LCH 80 70 80 52 / 40 40 70 50 LFT 80 70 81 56 / 40 30 70 70 BPT 79 71 78 51 / 40 50 70 30 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...None. TX...None. GM...None. && $$