Area Forecast Discussion
Issued by NWS Lake Charles, LA
Issued by NWS Lake Charles, LA
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190 FXUS64 KLCH 130926 AFDLCH Area Forecast Discussion National Weather Service Lake Charles LA 426 AM CDT Mon May 13 2024 ...New SYNOPSIS, SHORT TERM, LONG TERM, MARINE... .SYNOPSIS... Issued at 407 AM CDT Mon May 13 2024 An active pattern continues tonight, with a strong storm moving east across the Lakes Region toward western LA. Additional scattered showers and an isolated storm or two are noted on KLCH/KPOE radars across the area. Regionally, multiple convective clusters are noted across the central and N LA into MS. These storms remain rather potent, even without the added energy of daytime heat, thanks to a rather robust impulse crossing the region aloft. The latest WV imagery and UA analysis shows the main low system driving this extended active pattern spinning over SW KS as it moves slowly east. South of this feature, an active subtropical jet continues to supply copious moisture over the area, while lower in the atmosphere, elevated southerly winds continue to advect Gulf moisture northward. At the surface, a warm front is draped from inland SE TX (north of I-10 east and southeast toward the lower Atchafalaya Basin). North of this front, temperatures remain in the middle to upper 60s, while to the south, a warm and muggy airmass has returned with temperatures in the upper 70s and dewpoints only a degree or two lower. A Flood Watch remains in effect for today north of the I-10 corridor to Hwy 190 corridor in LA. Radar estimated rain amounts of at least 2 inches fell across much of the flood watch area yesterday, with localized amounts of up to 4-5 inches. The area remains in a Slight Risk (level 2 out of 4) for excessive rainfall today. But perhaps the greater concern for today will be severe weather, and SPC has recently upgraded their Day 1 outlook to an Enhanced Risk (level 3 out of 5), with damaging wind gusts and large hail the primary threats. 24 && .SHORT TERM... (Today through Wednesday night) Issued at 407 AM CDT Mon May 13 2024 The mid/upper low and its attendant surface reflection will slowly migrate east across the central US. This will lift the warm front further inland, allowing a more buoyant warm sector to overspread the area. Warming in the lower levels will provide substantial destabilization today, with surface based CAPE values increasing to 3000-4000+ J/kg while midlevel lapse rates steepen to 8+ C/km. Enhanced midlevel westerlies translating over the region amid of series of perturbations aloft, will provide sufficient deep layer shear to support organized updrafts once convection initiates by midday across portions of central/SE TX. CAM guidance suggests convection will evolve into a squall line/MCS as it progresses east into our area later this afternoon/evening. Timing and overall coverage remain somewhat uncertain however, and CAMs have struggled with convective initiation/evolution in this rather complex pattern. Given the strong midlevel lapse rates, there is a significant risk (greater than 10%) for hail larger than 2 inches across the area. This will be in addition to the potential for damaging wind gusts within any bowing segments as well as a few isolated QLCS-type tornadoes. Beyond the risk for severe weather, there is an ongoing concern for flooding. While the axis of extreme PWATs (greater than 2 inches) looks to shift east toward SE LA, values over the region will continue to be between 1.7 and 1.9 inches (still at least 2 standard deviations from the mean). This will support efficient rainfall production with high rainfall rates within some of the storms. HREF LPMM rain accumulations indicate multiple 1 to 3 inch swaths across the area (with localized higher amounts). Again, there is some uncertainty regarding where these belts of higher rain totals could set up and CAM storm total solutions vary quite a bit. At this time, will opt to leave the Flood Watch as it is, but an extension southward may be needed should the axis shift closer to I-10 (as the HRRR seems to indicate). The last of the convection for this round should be exiting to the east late tonight into the overnight hours as the main trough axis moves into the region. The passage of this low system will drag a weak cold front through the area on Tuesday, allowing for a much needed but short-lived break in the wet pattern. Any coolness associated with the front will be felt mainly overnight, with lows possibly falling into the lower to middle 60s by Wednesday morning. Otherwise, daytime temperatures will remain near or even warmer than normal, with the potential for highs around 90 degrees across southeast TX on Wednesday. Unfortunately, the next round of rain will return to our doorstep Wednesday night as the next disturbance moves toward the region. 24 && .LONG TERM... (Thursday through Monday) Issued at 407 AM CDT Mon May 13 2024 Precip chances return Thursday as a warm front lifting North out of the gulf is overrun by a couple of disturbances aloft ahead of a cold front that will then push through the region over the weekend. Guidance has been in consistently good agreement on deep moisture pooling with forecast PWAT values climbing to near or slightly above 2 inches. This will allow for rounds of torrential rainfall that could lead to flash flooding especially across parts of Southeast Texas that have seen well above normal rainfall this spring. There is more uncertainty regarding the timing of the end of the precip following fropa. The most widespread activity looks to be Thursday through Friday morning with the better upper level energy, but the moisture will remain in place until the fropa sometime Saturday afternoon to Sunday morning. The airmass behind the front won`t be appreciably cooler or drier as it`s getting rather late in the season for airmass changing cold fronts, but it will scour out the moisture aloft bringing precip to an end through early next week. Jones && .AVIATION... (00Z TAFS) Issued at 640 PM CDT Sun May 12 2024 For 00z TAFS, starting out VFR to MVFR for southern sites as most of the storms have passed now, and IFR is expected at times as the thunderstorms pass through KAEX. By the 02 to 04z range, expect patchy fog and lower ceilings to develop due to all the rain seen today to warrant IFR forecasts through the overnight hours. MVFR to VFR returns in the morning Monday, before another round of thunderstorms is expected later in the afternoon. && .MARINE... Issued at 407 AM CDT Mon May 13 2024 Moderate southerly winds will continue through tonight, but should relax below exercise caution levels this morning. Shower and thunderstorm chances are expected to increase later today into tonight. A few strong to severe storms will be possible, with strong wind gusts, large hail and isolated waterspouts possible. Winds will shift westerly on Tuesday, then offshore Tuesday night with the passage of a weak cold front. Winds will turn back to the east and southeast by Wednesday night, with rain chances returning by Thursday as another low pressure system approaches the area. 24 && .PRELIMINARY POINT TEMPS/POPS... AEX 82 64 86 61 / 70 50 0 0 LCH 83 67 88 65 / 60 50 10 0 LFT 85 70 89 68 / 80 70 10 0 BPT 85 68 89 66 / 60 50 0 0 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...Flood Watch through Tuesday morning for LAZ027>032. TX...Flood Watch through Tuesday morning for TXZ180-201-259>262. GM...None. && $$ SHORT TERM...24 LONG TERM....66 AVIATION...15