Area Forecast Discussion
Issued by NWS Lake Charles, LA
Issued by NWS Lake Charles, LA
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255 FXUS64 KLCH 311131 AFDLCH Area Forecast Discussion National Weather Service Lake Charles LA 631 AM CDT Fri May 31 2024 ...New AVIATION... .SHORT TERM... (Today through Sunday night) Issued at 400 AM CDT Fri May 31 2024 A very active and unstable weather pattern will continue into Saturday before thunderstorm chances decrease slightly on Sunday. Once again for today, a very moist and unstable air mass will be in place. PWAT values are expected in the 1.8 to 2.1 inch range which is over the 90th percentile of SPC daily climo. Meanwhile, CAPE values are expected to recover during the morning hours back above 2500 j/kg with 0-3km shear over 30 knots. Timing for the convection is tricky as short term guidance has not been handling the evolution of upper level energy and associated meso storm complexes. For today, looking at a MCS coming out of central Texas that will enter the forecast area by mid-morning. This activity should re- intensify as it moves across through the afternoon hours. Parameters are in place that damaging straight line winds will be possible with the thunderstorms as bow segment features are expected. There is also a low end probability of some quick spin up tornadoes embedded with this features as 0-1 helicity values will get over 150 m2s2. SPC has outlined the southeast Texas, and central and southwest Louisiana portions of the forecast area in Slight Risk (level 2 out of 5) and a Marginal Risk (level 1 out of 5) for the remainder of the forecast area. With the high moisture and PWAT values, high rainfall rates are likely with the storms with 1 to 3 inch per hour probable. Therefore, the forecast area has a Slight Risk (level 2 out of 4) for excessive rainfall that may lead to flooding. A second MCS is expected to enter and move across during the late afternoon into early evening hours. However, there is less confidence in this feature, as well as just how strong it will be if it does develop as the air mass may be still worked over from the first. On Saturday, still plenty of moisture around to go along with expected moderate to high instability, and a general weakness aloft. Therefore, scattered to numerous showers and thunderstorms are expected to develop with daytime heating. Any storm that develops with have a chance to produce downburst wind gusts and heavy rainfall. A Marginal Risk for both severe storms and excessive rainfall will be outlined for the forecast area. On Sunday, upper level ridge will try to build into the forecast area with lower PWAT air and no strong upper level energy noted. Therefore, more seasonal diurnal shower and thunderstorm activity is expected. Rua && .LONG TERM... (Monday through Friday) Issued at 400 AM CDT Fri May 31 2024 Monday continues into an unsettle rainfall pattern with a fairly active subtropical jet upstream along Baja while localized pattern consists of mainly zonal flow with some subsidence ridging in the lower troposphere. Do note, while the movement is rather zonal, there are perturbations of pressure which remain consistent of setting the stage for isolated activity to organize into more scattered / widespread storm clusters. Timing and location are aspects that will remain uncertain until this period comes closer into the range of the CAM guidance. Thus, POPs do not completely diaspora through mos of the long range, but remain lowered to reflect the confidence in timing given this nature of the unsettled wet pattern. While daytime highs climb to the upper 80`s and 90`s with periodic clearing of skies, forecast dewpoints will remain primarily in the mid 70`s which will elevate risk of heat related illnesses for more sensitive populations during prolong periods of physical activity without proper hydration. Meanwhile, as the week progresses, an upstream shortwave stalls along NW Mexico which enhances upper level flow across S`rn Tx and Gulf of Mexico trending through Wednesday morning with another wave developing downstream, closer to home, over the E`rn GOM. As it stand presently, this upper level feature appears to produce much of the precipitable rain east of the the Mississippi, across the SECONUS while shifting over the Florida Peninsula Thursday. Models show the potential in a drying trend late week with departures of temperature and dewpoint growing stronger as a broad upper level ridge develops over the Midwest. Again, should be noted this long range outlook remains unsettled with more variable solution s as the northern jet and the subtropical jet begin to interact over the Midwest late in the upcoming work week. Therefore, while there are some signals, particularly in the national blend of models for some drying trend, consistency has not been demonstrated. Kowalski/30 && .AVIATION... (12Z TAFS) Issued at 625 AM CDT Fri May 31 2024 Starting out at mainly VFR conditions at the terminals. This is expected to change, however there is still some uncertainty as to just how the storm complex over Texas evolves as it moves into the immediate area. Expect the current MCS to weaken some this morning, then refire by 16z and move eastward across the terminals. MVFR to IFR conditions will accompany the line of storms with the possibility of strong and gusty winds. There is also some uncertainty if another thunderstorm complex will develop later this afternoon into the evening. At this time only went with the current complex and will let later shifts update as confidence grows in the latter portion of the forecast. Rua && .MARINE... Issued at 400 AM CDT Fri May 31 2024 Surface high pressure will ridge westward across the northern Gulf of Mexico into the coastal waters. This will provide a light to occasionally modest onshore wind flow with mainly light seas through the weekend into early next week. There will be a chance for complexes of thunderstorms to move across the coastal waters this morning into the afternoon, then again this evening. Strong wind gusts and frequent lightning can be expected with these storms. Scattered showers and thunderstorms can be expected on Saturday, before rain chances begin to decrease on Sunday into early next week as an upper level ridge builds in. Rua && .PRELIMINARY POINT TEMPS/POPS... AEX 85 69 85 70 / 80 50 80 30 LCH 86 75 86 75 / 60 40 70 20 LFT 87 75 88 75 / 70 40 70 20 BPT 87 75 88 76 / 60 40 60 10 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...None. TX...None. GM...None. && $$ SHORT TERM...07 LONG TERM....30 AVIATION...07