![National Oceanic and Atmospheric Administration](/build/images/header/noaa.d87e0251.png)
![National Weather Service](/build/images/header/nws.4e6585d8.png)
![United States Department of Commerce](/build/images/header/doc.b38ba91a.png)
Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
362 FXUS64 KLIX 170253 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 953 PM CDT Fri Aug 16 2024 ...New UPDATE... .UPDATE... Issued at 950 PM CDT Fri Aug 16 2024 Have updated a couple times this evening, first was to remove mention of today`s heat related products. The second, more recent one, was to remove any mention of evening convection from the forecast. May update hourly temperature grids one more time, but do not anticipate an additional update to ZFP product being necessary. && .SHORT TERM... (This evening through Saturday night) Issued at 255 PM CDT Fri Aug 16 2024 Convective development has been noted across the area over the past hour or two, mainly along the lake and sea-breeze boundaries. This was a little earlier than expected but the lack of northerly flow aloft (especially across the southshore) and PW around 2.1 helped kick things off a little earlier than expected. A slight pocket of dry air between 500mb and 700mb is aiding in ample DCAPE across the area for these storms to work with. This has contributed to values upwards of 1100 j/kg across the area, supporting an isolated damaging wind risk with any storm that gets a strong core. The stronger the core, the more downward momentum it will have with that dry air in place. Something else also working for the strong gusty wind risk is the very high freezing level, which is around 16kft. This will support decent melting of the stronger core, promoting evaporational cooling and more downward momentum. So, to sum things up, expect isolated strong to severe winds in the strongest storms this afternoon and evening. Any convection that does form should dissipate shortly after sunset as we lose daytime heating. Tomorrow will be similar to today as the higher moisture content hangs around the area for one more day. PW will remain above the 75th percentile at around 2.1, so this, along with the departing ridge to the west will support coverage similar to today. Much of the coverage will be dictated by lake and sea-breeze boundaries once again during the afternoon and evening timeframe. With the ridge sliding to the west more tomorrow, we will be more firmly in northerly flow aloft. Typically for northerly flow, convective development is later in the afternoon and evening, so temps were bumped up a little bit to account for the extra heating expected before convection starts tomorrow. DCAPE will still be elevated across the area in the 1100-1200 j/kg range due to that same patch of dry air mentioned for today. Thus, strong to severe winds are possible again with any strong storm that forms tomorrow. Similar to today, any convection that forms should dissipate after sunset around 9 or 10pm. Outside of convection, although the upper-level ridge will be departing to the west, the surface high over the SE CONUS will continue to filter over the area tomorrow. This will cause temps to slightly high than today. As mentioned before, convective development will play a big role in high temperatures tomorrow, so since it is expected to happen a little later, we should reach heat advisory criteria during the late morning and afternoon tomorrow. && .LONG TERM... (Sunday through Thursday night) Issued at 255 PM CDT Fri Aug 16 2024 The aforementioned surface high will become centered over the area by late Saturday and Sunday. At the same time, a pocket of very dry air above 850mb will filter into the area from the north on the perifery of the mid-level ridge, causing PW to drop to around 1.6-1.7 inches (which is below the median for that day). The surface high combined with the upper-level dry air filtering in will cause lower rain chances and much higher temperatures. An excessive heat watch will likely be issued by tomorrow morning for Sunday due to the expected heat indices from 110-115 during the afternoon. Models seem to agree that a backdoor cold front will make its way across the SE CONUS Sunday and into the beginning of next week in response to troughing over that region. This is definitely a good sight to see in August, but the one thing to watch for is an MCS that comes along with it. If this were to occur, it would be at some point on late Sunday or Monday morning. The NAM tries to show some semblance of a complex moving through, but low-level dry air and unfavorable diurnal timing seems to be against any complex. If one does make it through the area, gusty winds will be the primary risk. Beyond Monday, very dry mid-level air behind the front will filter into the area. This will cause PW values to be lower than the 25th percentile on Tuesday and near the daily minimum on Wednesday. Needless to say it will be fairly dry across the area beyond Monday, but at least dew points are expected to be in the 60s, so it will not feel nearly as oppressive. && .AVIATION... (00Z TAFS) Issued at 627 PM CDT Fri Aug 16 2024 Isolated TSRA over downtown New Orleans will necessitate carrying VCTS for the first hour or two of the KNEW/KMSY forecasts until it dissipates. May need an amendment for KBTR if storms do not dissipate to their north in the next hour or so. Aside from that, generally VFR conditions through the forecast period. Confidence in development of TSRA tomorrow is not high enough to justify carrying in the forecast. && .MARINE... Issued at 255 PM CDT Fri Aug 16 2024 Mostly benign marine conditions will continue throughout the forecast period. Daily isolated to scattered rain chances remain mainly during the early morning timeframe each day. A surface high will set up over the area late Saturday and into Sunday, keeping winds calm. Then, a backdoor cold front is expected to at least make it into the area by Monday. So, expect slightly elevated northerly winds with the front before slacking off when the following surface high settles over later in the week. && .PRELIMINARY POINT TEMPS/POPS... MCB 75 97 74 99 / 10 30 10 10 BTR 79 99 79 101 / 10 30 0 10 ASD 78 96 78 99 / 10 30 0 20 MSY 80 96 79 99 / 10 30 0 10 GPT 79 93 79 97 / 10 30 10 20 PQL 78 97 77 100 / 10 20 10 30 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...Heat Advisory from 10 AM to 7 PM CDT Saturday for LAZ034>037-039- 046>048-056>060-064>071-076>090. GM...None. MS...Heat Advisory from 10 AM to 7 PM CDT Saturday for MSZ068>071-077- 083>088. GM...None. && $$ SHORT TERM...JZ LONG TERM....JZ AVIATION/UPDATE...RW MARINE...JZ