291 FXUS64 KLCH 090547 AFDLCH Area Forecast Discussion National Weather Service Lake Charles LA 1147 PM CST Wed Jan 8 2020 .DISCUSSION... 06Z TAFS && .AVIATION... A strong pressure gradient between surface high pressure over Georgia and a strengthening low over Kansas is keeping southeasterly winds elevated tonight. 00Z KLCH RAOB observed 30+ knot winds between 2 and 3kft this evening validating the onset of the forecast wind shear. This shear will continue through mid morning before daytime mixing allows some of these stronger winds to work their way to the surface reducing the vertical wind gradient. Strong southeasterly winds will prevail from mid morning through the evening before becoming more moderate Thursday night. The low and mid level moisture being advected into the region on this southeasterly flow will allow for continued development of MVFR conditions through the early morning. CIGs will likely alternate between MVFR and VFR especially this afternoon although current thinking is that MVFR will prevail for much of the day. A few isolated showers are expected this afternoon into this evening within the very moist low level environment, but coverage is not expected to be high enough to warrant inclusion in TAFS attm. Jones && .PREV DISCUSSION... /issued 905 PM CST Wed Jan 8 2020/ UPDATE... With south winds above the surface continuing to increase tonight, clouds should also begin to increase, and this will help keep temperatures steady or even rise overnight. Still looks like overall atmospheric profile will be relatively dry, along with some capping, and this should prevent any significant shower activity overnight. Just made some minor adjustments to temperatures and cloud cover based on latest observations and trends in the hi-res guidance. Rua PREV DISCUSSION... /issued 559 PM CST Wed Jan 8 2020/ DISCUSSION... 00Z TAFS AVIATION... Decent pressure gradient between high pressure centered to the east across central Georgia and an intensifying surface low over the midwest will keep winds somewhat elevated overnight becoming strong out of the southeast by mid morning Thursday. A developing low level jet across the region is expected to result in increasing low level wind shear through the morning with the higher winds aloft then mixing down to the surface through the day. The strong southerly flow will quickly increase moisture through the lower atmosphere tonight allowing for increasing cloud cover although VFR CIGs will prevail through the early morning before lowering to MVFR by mid to late morning. Jones PREV DISCUSSION... /issued 358 PM CST Wed Jan 8 2020/ SYNOPSIS... UA pattern acrs the CONUS depicts a trough east of the Great Lakes and another trough over the intermountain West per recent WV imagery and UA analysis. In between, low amplitude quasi-zonal flow is noted acrs the southern CONUS. At the sfc, high pres continues to shift east acrs the SE states, with winds transitioning more southeasterly. The combination of high pres and a dry airmass have resulted in a rather pleasant January day, with mostly sunny skies and temperatures in the middle and upper 60s. 24 DISCUSSION... Ongoing southeast flow and return of low level moisture will continue to modify the airmass acrs the region tonight. This will result in a moderation of temperatures, with lowest readings likely occurring during the evening, then holding steady or gradually rising through early Thursday. Clouds will increase on Thursday, with a few showers possible mainly acrs the western half of the area, as flow aloft becomes more southwesterly in response to shortwave energy digging into the western US trough. The deepening trough will progress east through Friday, with sfc low pres developing acrs TX in response. The threat for a widespread, and possibly significant, severe weather event remains apparent as the intense system moves into the region. SPC has outlined much of the area in an Enhanced (ENH) risk on Day 3 (Friday into early Saturday), with SLGT risk acrs the Acadiana region. The ENH also contains a risk for a significant severe weather event (defined by SPC as hail at least 2 inches in diameter or larger, wind gusts of 75 mph or greater, or a tornado that produces EF2 or greater damage). Multiple parameters continue to appear aligned to support the potential for nmrs svr storms between Friday night and Saturday aftn. Low level jet will rapidly strengthen to 60-70 KT acrs SE TX into LA Friday night, helping to advect rich Gulf moisture inland, with dewpoints climbing into the upper 60s or near 70. Meanwhile, mid-level lapse rates will steepen, with MLCAPE values between 800-1300 J/kg, providing sufficient instability. In advance of the front, discrete storms are expected to develop within the warm sector from late aftn into the overnight hours. Strong vertical shear, along with SRH values of 200-300 m2/s2 in the low levels, will result storms quickly acquiring supercellular characteristics capable of producing all svr hazards, some possibly significant. As the front moves into the area during the overnight hours into Saturday morning, an ongoing QLCS will cross the area, bringing an additional threat for strong damaging winds and tornadoes. The strongest convection will move east early Saturday, and should be exiting the eastern CWA by midday or early aftn, with drier air quickly bringing an end to the showers and storms from west to east during the day. Dry weather will prevail Sunday as sfc high pres rapidly moves acrs the area. Rain chcs will return by Monday however, as a warm front begins to lift back northward. The disturbed weather pattern will remain in place through at least midweek as the frontal boundary stalls over the region under zonal flow aloft. Regarding temperatures, prior to the front early Saturday, temperatures will be abv seasonal normals with lows in the 60s Friday morning and highs in the middle to upper 70s. Temps will cool in the wake of the front, with near normal values expected on Sunday. A gradual warmup will return early next week with lows back into the 60s and highs in the 70s by Tuesday and Wednesday. 24 MARINE... Modt to occasionally strong onshore flow will persist through Friday, between high pres to the east and deepening low pres acrs TX. Inserted Exercise Caution headlines for tonight as winds strengthen to 15 to 20 KT. A few showers will be possible Thursday, with showers and thunderstorms bcmg more sctd Friday as a strong storm system approaches from the west. A strong cold front will move through the region late Friday night into early Saturday, accompanied by nmrs showers and storms, with a few strong to svr storms possible. Winds will quickly shift west to northwest in the wake of the front and strengthen. Small Craft Advisories may be required for strong southerly flow ahead of the front on Friday as well as for strong offshore flow after FROPA on Saturday. Winds will gradually diminish and become vrbl on Sunday as high pres transits the region, a generally east wind bcmg established early next week as a warm front lifts north. Shower and tstm chcs will increase as the warm front moves into the area. 24 && .PRELIMINARY POINT TEMPS/POPS... AEX 64 44 70 61 / 0 0 20 30 LCH 66 53 72 64 / 0 10 20 20 LFT 65 50 72 64 / 0 0 20 20 BPT 67 57 74 65 / 0 10 20 30 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...None. TX...None. GM...Small Craft Exercise Caution through Thursday morning for GMZ450- 452-455-470-472-475. && $$ AVIATION...66