Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
540 FXUS64 KHGX 291143 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 643 AM CDT Fri Aug 29 2025 ...New AVIATION... .KEY MESSAGES... Issued at 100 AM CDT Fri Aug 29 2025 - After a largely dry Thursday, storm coverage will see an increase today as another weak front approaches SE Texas. Some of these storms could bring locally heavy rainfall and gusty winds, with a marginal risk for excessive rain (threat level 1 of 4) across the area, as well as a marginal risk for severe weather (threat level 1 of 5) east of I-45. - The weak front pushes into SE Texas on Saturday, bringing greater rain chances over the weekend, along with modestly cooler temperatures. Isolated higher rainfall totals will continue to be possible in stronger storms, with a continuing marginal risk for excessive rain. - Rain chances decrease from north to south next week as drier air filters in behind the front. Labor day should generally be cooler and drier in the north, with isolated to scattered rain still in the forecast nearer the coast. && .DISCUSSION... Issued at 100 AM CDT Fri Aug 29 2025 We`re at the end of August, but it feels a little more like late Spring this evening as I watch thunderstorms make their way from North Texas into Southeast Texas and Southwest Louisiana in northwest flow this evening. Earlier storms have missed us to the east, and the next cluster of storms seems to have largely dissipated. This should keep things relatively status quo through the night. There`s still another cluster of storms up in North Texas that we`ll have to keep an eye on through the night. However, it seems to be pretty solidly tossing out outflow boundaries and the GLM instrument on GOES satellites indicates lightning is trending downwards. So, while I`m fairly confident this isn`t going to be much issue for us down here, I do keep some slight PoPs towards the Piney Woods north of Lake Livingston for the morning in case enough remnant showers survive to bring some brief rain up there. The better potential for rain and storms will come this afternoon as the front draws even closer to the area, and what looks to be a decent little shortwave trough rides around the ridge towards the Sabine Valley. We`ll have precipitable water values around/over 2 inches and a pocket of instability ahead of the front, especially in the afternoon at peak heating. This is not the greatest of setups for severe weather or heavy rain, but the threat isn`t going to be zero, either. Both WPC and SPC give at least a portion of our area a marginal risk for excessive rain and severe weather (primarily winds). The excessive rain threat is more area-wide with the broad area of high PWATs. Severe weather likely mostly misses us to the east like we saw earlier this evening, but with the upper ridge beginning to retreat westward, that could open up locations mainly east of I-45 to an isolated severe storm later this afternoon into the evening. Going into the weekend, coverage of daily rounds of showers and storms will only increase as the front makes its way slowly into and across the area. We won`t be looking at large swaths of rain, so no day of the holiday weekend should be a total washout, but plenty of us should expect a shower/storm at some point through the Saturday-Sunday stretch. Severe potential will probably be somewhat diminished as we`re not really in a solid warm sector anymore, further diminishing an already iffy environment. But that said, we`re in northwest flow aloft and the environment isn`t bad, either, so I don`t want to completely rule things out. What seems a little more of an obvious concern will be the continuing potential of locally heavy rain as the front won`t cleanly clear the area and moisture will not be scoured out. Like Friday, the somewhat marginal environment means rain should be quite manageable for most of us. But as with so many similar days in this area, the strongest storms will be capable of producing one, two, even more inches of rain before moving on or falling apart. We should finally start to see some change on Labor Day as drier air begins to filter in from the north. We`ll continue to see scattered to numerous showers and storms pop up yet again, peaking in the afternoon, but at least the heavy rain threat should be diminished well inland, mostly north of the Houston metro. The closer we get to the coast, the later any low-end threat for locally heavy rain will hang on. Deeper into the week as drier air continues to filter into Southeast Texas on persistent northeast flow, we should see daily storm potential finally abate. There may even be a reinforcing front Monday night or Tuesday morning. I don`t expect we`ll end up with any completely dry days, but while the early part of the forecast has plenty of opportunities at rain for everyone, Tuesday- Thursday looks more like isolated showers or a storm at most, and probably weighted pretty heavily to the coast, while those far inland have very little chance for rain. With less rain and cloud cover though, we should see temperatures in the afternoons claw back into the lower 90s. But, it should be a little more tolerable thanks to lower humidity and that should also allow us for some modestly cooler nights! Beyond that, we`re starting to get past the end of the scope of this forecast, but there are some interesting hints I wanted to toss out as something to keep an eye on. Ensemble means do indicated unseasonably high percentile zonal wind components (strong westerlies) at 500 mb and unseasonably low percentile meridional wind components (strong northerlies). This implies a pretty decently strong upper trough trying to dig down into the region late next week. So, after getting a couple opportunities with the typical ineffective late summer fronts so far...maybe late next week we might do a little better? I`m not going to promise anything at this range, but it was an interesting thing that stuck out to me... && .AVIATION... (12Z TAF Issuance) Issued at 633 AM CDT Fri Aug 29 2025 All terminals at VFR this morning. Light SW winds will become SE around 10 knots this afternoon. SHRA/TSRA will approach the region from the N during the afternoon hours and continue through around 02Z. Some storms could produce heavy rainfall and gusty winds. MVFR CIGs/VSBYs possible across northern terminals during the overnight hours into Saturday morning. Winds will be light and variable overnight. && .MARINE... Issued at 100 AM CDT Fri Aug 29 2025 Light to occasionally moderate onshore flow will persist through Saturday. A frontal boundary is expected to enhance shower and thunderstorm activity this weekend. Showers and storms could reach the coast as early as late afternoon or evening on Friday. Winds are expected to switch to a more northerly direction by Sunday behind the front for a brief stretch early next week, before turning back to being broadly onshore later next week. && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 96 76 92 75 / 30 20 50 40 Houston (IAH) 94 77 92 77 / 40 30 50 40 Galveston (GLS) 89 82 89 81 / 20 20 40 50 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ DISCUSSION...Luchs AVIATION...Adams MARINE...Luchs