Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
780 FXUS64 KLIX 250540 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 1140 PM CST Sun Nov 24 2024 ...New AVIATION... .SHORT TERM... (This evening through Tuesday night) Issued at 256 PM CST Sun Nov 24 2024 A progressive zonal flow regime will remain in place through Tuesday night across the Gulf South. In the low levels, increased southerly flow on the western periphery of a broad surface ridge will allow for increased warmth and moisture to feed into the region. This will gradually push PWATS up to around 1.5 inches by tomorrow night. Temperatures will be warmer than average through tomorrow night with readings around 10 degrees above climatology. This will keep lows in the 50s and 60s and highs in the upper 70s and lower 80s. Although boundary layer winds will be elevated at 15 to 20 knots tonight, fog probabilities remain high enough in the Pearl River basin to support some fog development A fast moving shortwave trough axis and associated front will slip through the area Monday night into early Tuesday. Just enough forcing along the front will support the development of showers, especially across northern and western portions of the forecast area from late Monday evening through early Tuesday morning. Fortunately, conditions will remain very stable, so thunderstorm activity is not anticipated as this frontal boundary moves through. The front will also be weakening as it approaches the coast due to the parent shortwave trough quickly pulling away from the area late Monday night. The end result will be little in the way of rainfall reaching the coastal areas and very muted cold air advection. At most, temperatures will cool back to near average Tuesday into Tuesday night. && .LONG TERM... (Wednesday through Saturday night) Issued at 256 PM CST Sun Nov 24 2024 Wednesday into Wednesday night will be a transitional period as deep layer zonal flow continues to dominate the region. Increased onshore flow on the backside of a departing surface high will support some warm air and moisture advection back into the region with PWATS once again rising to near 1.5 inches by Thursday morning. A deepening longwave trough will begin to approach the area over this period, and a broad region of increasing omega associated with positive vorticity advection ahead of the trough will support increasing cloud cover and some shower development by late Wednesday night. The trough axis and an associated strong cold front is expected to sweep through the forecast area Thursday afternoon, and scattered convective activity will develop along and ahead of the trough and front. Fortunately, a review of model sounding data indicates that overall instability will remain limited and the threat of any severe weather will be extremely low. At most, a few weak thunderstorms could develop across the northern third of the CWA Thursday afternoon where mid-level temperatures will cool enough to increase CAPE values to near 1000 J/KG. Temperatures will peak in the early afternoon in advance of the front, but will cool quickly after the front moves through. The remainder of the forecast period will see dry conditions and temperatures well below average as deep layer northwest flow takes hold of the area. A 925mb thermal trough over the area will support highs only warming into the mid to upper 50s for most locations on Friday. The coldest night of the season, so far, is expected Friday night as lows fall into the low to mid 30s along and north of I-12 and the upper 30s and lower 40s south of I-12. Probabilities are approaching 60 to 70 percent for temperatures falling to or even slightly below freezing across portions of southern Mississippi and Northshore. Temperatures will remain below average Saturday and Saturday night, but some slight modification into the upper 50s and lower 60s for highs and the upper 30s to mid 40s for lows is expected as the heart of the 925mb thermal trough axis pushes slightly to the east. && .AVIATION... (06Z TAFS) Issued at 1136 PM CST Sun Nov 24 2024 The main concern overnight will be fog development, which is looking to be a little more widespread than originally thought. Despite stronger boundary layer winds, fog has started to develop already for some southern areas. Knowing this, added in TEMPO groups for HUM. Also added similar in for MCB as fog is beginning to develop there already as well. Kept the same conditions as earlier at ASD and GPT with fog probabilities high for the early morning hours in those areas. Once all the fog clears away shortly after sunrise, VFR conditions will takeover for all terminals. && .MARINE... Issued at 256 PM CST Sun Nov 24 2024 No significant impacts to the the boating and marine community are expected through Wednesday as winds remain around 10 knots and seas stay below 3 feet. Winds will be somewhat variable as a series of high pressure systems and a weak front slide through the waters, but nothing that will cause large concerns. Conditions will turn rougher starting Wednesday night and continuing through the end of the week as a stronger cold front sweeps through the area on Thursday. Winds will rise into exercise caution range Wednesday night and will rise into advisory range of 20 to 25 knots starting Thursday night and continuing into Friday night as a much colder airmass advects into the area. Seas will respond and increase to 5 to 7 feet in the open Gulf waters. && .PRELIMINARY POINT TEMPS/POPS... MCB 53 79 56 70 / 0 0 60 30 BTR 58 81 61 71 / 0 0 40 20 ASD 55 79 63 73 / 0 0 30 20 MSY 60 79 66 73 / 0 0 20 20 GPT 58 76 65 74 / 0 0 20 20 PQL 55 77 64 74 / 0 0 20 10 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...PG LONG TERM....PG AVIATION...HL MARINE...PG