Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
744 FXUS64 KLIX 170415 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 1115 PM CDT Sat Aug 16 2025 ...New SHORT TERM, LONG TERM, AVIATION, MARINE... .SHORT TERM... (Today through Tuesday night) Issued at 1049 PM CDT Sat Aug 16 2025 A broad upper level ridge axis extending eastward from the Southern Plains and across the Gulf South will keep both a deep layer northerly flow pattern and drier in place in the mid and upper levels through the Tuesday night. The dry air aloft will lead to warmer temperature and weaker mid-level lapse rates and this will in turn reduce overall convective potential through the entire short term period. The drier aloft will also help to reduce PWATS to below the median of around 1.8 inches for this time of year. Values could fall as low as 1.5 inches at times. With this drier and more stable pattern in place, temperatures will be a few degrees warmer than average in the mid 90s and rain chances will decrease to between 20 and 40 percent each day. Fortunately, the drier air will mix down to the surface and allow dewpoints to fall into the lower 70s by the peak heating hours in the afternoon. This will keep heat index values generally between 103 and 108 degrees, or just below heat advisory levels. It will still be hot the next few days and everyone should take their proper heat precautions while working, playing, or exercising outside. Overnights will provide some relief as temperatures cool into the 70s. && .LONG TERM... (Wednesday through Saturday night) Issued at 1049 PM CDT Sat Aug 16 2025 The biggest change in the forecast from the past few days is a delay in the return of deeper moisture into the region as the arrival of a weak trough axis and associated surface boundary is delayed more until Wednesday night and Thursday. Winds will begin to turn more easterly on Wednesday, but a dry pocket of air in the mid-levels and continued more stable conditions will persist through Wednesday afternoon. PWATS will remain between 1.6 and 1.8 inches and overall convective chances will remain near or slightly below average at 20 to 40 percent in the afternoon hours. Temperatures will also be warm with readings climbing into the mid 90s and heat index values once again rising into the 103 to 108 range. The expected trough and associated boundary is progged by all of the models to slip into the Gulf South on Thursday and then stall over the region for Friday and Saturday. As winds turn more southerly over this period, deeper tropical moisture will begin to feed back into the area and this will allow the mid-levels to moisten and overall instability to increase. PWATS will rise to between the 75th and 90th percentile for this time of year or in hard numbers will range from 1.9 to 2.1 inches each day. The combination of moisture, instability, and weak forcing aloft associated with the trough will support more numerous shower and thunderstorm development each day. This is reflected by higher afternoon PoP values of 50 to 70 percent from Thursday through Saturday. The increased convective coverage and higher atmospheric moisture content will also keep temperatures closer to average in the low 90s. Heat index values are expected to remain below advisory levels despite higher dewpoints due to the combination of increased convection and lower ambient temperatures. There is still some concern that a series of mesoscale convective systems could form over the Arklatex region and then sweep southeastward following the theta e axis into the Gulf South as early as Friday. This is due to the split flow pattern forming over the Arklatex that could provide the additional forcing needed to foster the development of these convective complexes. We are several days out still, so confidence on this occurring is still very low. However, if it does happen, the convective threat could linger into the evening hours as these complexes sweep to the south and southeast. PoP is higher than average in the evening hours late this week to reflect this concern. && .AVIATION... (06Z TAFS) Issued at 1049 PM CDT Sat Aug 16 2025 A drier and slightly more stable airmass across the area tomorrow will keep thunderstorm activity more isolated. However, a weak area of convergence along the Atchafalaya Basin should support some widely scattered thunderstorm development near HUM and BTR generally between 18z and 00z. PROB30 wording is in place at these terminals to reflect the risk of convection directly impacting these terminals with gusty winds and lower visibilities. Outside of these convective concerns, VFR conditions will be the rule at all of the terminals through the evening hours. && .MARINE... Issued at 1049 PM CDT Sat Aug 16 2025 There are no significant concerns to the maritime community in the forecast through the end of the week outside of the normal shower and thunderstorm activity typically seen this time of year. Winds will be light from the north at less than 10 knots through Monday. These light winds will gradually turn more easterly on Tuesday and Wednesday before finally turning more southerly to end the week. Seas will remain calm at 2 feet or less through the end of the week. && .PRELIMINARY POINT TEMPS/POPS... MCB 75 94 74 95 / 20 20 20 30 BTR 77 95 76 95 / 10 30 20 40 ASD 76 94 75 94 / 20 20 20 30 MSY 80 92 80 93 / 10 30 20 40 GPT 78 92 77 91 / 20 20 10 30 PQL 76 92 76 92 / 20 20 20 30 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...PG LONG TERM....PG AVIATION...PG MARINE...PG