Request an account for access beyond The Archives!
438 FXUS64 KLIX 102140AFDLIXArea Forecast DiscussionNational Weather Service New Orleans LA340 PM CST Mon Feb 10 2025...New SHORT TERM, LONG TERM, AVIATION, MARINE....SHORT TERM...(This evening through Wednesday night)Issued at 258 PM CST Mon Feb 10 2025A series of embedded shortwave features embedded within a zonalmean flow pattern in the mid and upper levels will be the maindriver of the forecast through the short term period. The first ofthese shortwave troughs will slide to the north of the areatomorrow. As this system approaches tonight, winds will veer tothe south as a low pressure system begins to form the Arklatexregion and weak warm frontogenesis takes hold. The main resultfrom this wind shift will be an increase in dewpoints andtemperatures as we move into tomorrow with highs quicklyrecovering back into the upper 70s and lower 80s. There may be aperiod of fog in the lakes and sounds later tonight, but confidence is too low at this time to issue a dense fog advisory for areas adjacent to these bodies of water. A weak front willalso stall just north of the area tomorrow afternoon throughtomorrow night, and this will serve as a focus for periods of showers and thunderstorms to impact the northern third of the CWA.Fortunately, the heavy rain threat is very limited tomorrow as themain axis of heavier rain remains more along the I-20 corridor. Wednesday will be the most active day of the short term period asa vigorous shortwave trough ejects out of Texas and across theLower Mississippi Valley. This stronger feature will produce apotent low pressure system over north Texas, and this low willquickly race to the northeast into the Tennessee Valley byWednesday night. As this occurs, it will drag a cold front acrossthe forecast area Wednesday evening. Gusty southerly winds willdevelop ahead of the front and some gusts could approach 35 mph attimes. This strong southerly flow off the Gulf will also allowtemperatures to climb into the lower 80s after starting off in the60s. As the front moves into the area, a line of showers and thunderstormswill accompany the front, and a few of the storms could be strongto potentially severe during the late afternoon and early eveninghours. A review of model sounding data indicates that a strong low level jet will be in place ahead of the front and that 0-6km speed shear will exceed 50 to 60 knots. Directional shear will also approach 200 to 300 m2/s2 in this 6 to 9 hour window from late afternoon into the evening hours. Although shear and forcing will be in place, the one limiting condition will be the amount ofinstability. MLCAPE values should peak near 1000 J/KG in the lateafternoon hours as mid-level lapse rates remain weak, and this could limit both updraft strength and duration as storms quickly turn cold pool dominated and collapse. Given this, any severe storm activity should be on the isolated side Wednesday afternoon into Wednesday evening. By late Wednesday night, any storm threat will be shifted well offshore as the front moves into the Gulf waters. &&.LONG TERM...(Thursday through Sunday night)Issued at 258 PM CST Mon Feb 10 2025Another fast moving and shallower shortwave trough will slidenorth of the area on Thursday, and this will help to reinforce thecooler and more stable airmass in place through Friday. However,the cold pool will remain fairly shallow and some overrunningmoisture into the area will keep cloud cover in place through theperiod. Some overrunning shower activity could also develop,especially for more coastal locations as the lingering stalled outfront slowly dissipates over the offshore waters. Overall, a cooland breezy stretch of weather is expected for Thursday and Fridaywith highs closer to average in the mid to upper 60s and lows inthe 40s and 50s. The next date of concern will be Saturday into Saturday night as avery strong and deep trough drives through the region. As thetrough approaches, winds will turn southerly and quickly advect ina much warmer and more unstable airmass by Saturday afternoon.Highs will easily climb into the upper 70s and lower 80s, and mayeven climb into the mid 80s in a few locations. Additionally, themore southerly track of the approaching trough will help lead togreater mid-level cooling and higher lapse rates. This will allowfor more instability as noted by MLCAPE of around 1500 J/KGSaturday afternoon and evening. This increased instability willallow for deeper and more sustained updrafts to develop, and thiswill result in stronger thunderstorm activity along a strong coldfront as it moves into the area Saturday afternoon and evening.The other factor to keep in mind is that shear parameters will befavorable for severe thunderstorm development, especially forareas north of the I-10 corridor. Speed shear will climb to around50 knots in the lowest 6km, and directional shear will peak outbetween 200 and 300 m2/s2. The combination of favorable shear,lift, and instability should all combine to produce a moresignificant severe weather episode Saturday evening with multiplesevere storms developing in the area. All convective threats willalso be possible given the shear parameters expected to be inplace. We will continue to monitor the situation and provideadditional updates as things progress through the week. All of the guidance is in good agreement that the trough axis andattendant front will be clear of the area by Sunday afternoon.Strong subsidence and dry air advection behind the front will leadto clearing skies by Sunday afternoon and mostly clear conditionsare expected by Sunday night. Cold air advection will also takeplace as a 925mb thermal trough axis slides into the region, andthis will help push temperatures below average. Highs will onlywarm into the 50s and lower 60s on Saturday and lows will coolinto the 30s.&&.AVIATION...(18Z TAFS)Issued at 258 PM CST Mon Feb 10 2025A prevailing broken deck ranging between 1500 and 2500 feet willremain in place through the evening hours. After 06z, the stratusdeck will begin to build down at all of the terminals, and the forecast calls for prevailing IFR conditions by daybreak at every terminal. GPT, NEW, HUM, MSY, and ASD will see the longest duration of IFR impacts as winds shift back to the east-southeast.This weak onshore flow will allow any fog offshore to slowly drift onshore and reduce visibilities down to less than a mile at times. The low stratus and fog will be slow to clear tomorrow morning with most locations still in IFR conditions through the end of the forecast period. At MSY, conditions should mix out intoVFR after 18z tomorrow. PG &&.MARINE...Issued at 258 PM CST Mon Feb 10 2025As southerly winds redevelop tonight, some moisture advection intothe area could support fog development late tonight over thesounds and lakes. However, confidence in this occurring is lowenough that a dense fog advisory has not been issued. Thesituation will continue to be monitored and a dense fog advisorymay be issued later this evening or overnight. Outside of the fogthreat tonight, winds will begin to increase tomorrow and furtherincrease into small craft advisory range on Wednesday. Thesestronger winds are associated with a low pressure system passingto the north of the waters. In the wake of the low, another frontwill sweep into the waters and advisory level winds will shift tothe north and northeast on Thursday and Friday. By Saturday, thedevelopment of another low over Texas and the shifting of the highto the east will quickly switch winds around to the south. Thesestronger winds of 15 to 25 knots will continue as a cold front moves into the waters Saturday night.&&.PRELIMINARY POINT TEMPS/POPS...MCB 56 78 60 79 / 10 60 70 90 BTR 61 80 65 81 / 10 40 50 90 ASD 61 78 64 80 / 10 40 30 80 MSY 63 78 67 80 / 0 40 30 70 GPT 61 73 63 75 / 20 50 30 80 PQL 61 75 64 77 / 30 50 40 70 &&.LIX WATCHES/WARNINGS/ADVISORIES...LA...None.GM...None.MS...None.GM...None.&&$$SHORT TERM...PGLONG TERM....PGAVIATION...PGMARINE...PG
