Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
022 FXUS64 KHGX 041241 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 741 AM CDT Mon Aug 4 2025 ...New UPDATE... .KEY MESSAGES... Issued at 1137 PM CDT Sun Aug 3 2025 - Look for a short stretch of hotter weather in the middle of the week. The higher temperatures will pair with modestly lower humidity, but heat index values will be near the heat advisory threshold, particularly Wednesday and Thursday. - Isolated to scattered showers and storms, mostly near the seabreeze front, will be a feature of the afternoon each day this week. - Tropical Storm Dexter has been designated in the open Atlantic Ocean off the eastern US coast, and will pose no threat to Southeast Texas. && .UPDATE... Issued at 716 AM CDT Mon Aug 4 2025 An MCS is currently moving into the Brazos Valley/Piney Woods area this morning. KFWS radar is showing strong velocity returns with a bowing segment on the southern flank of the line. Mesoscale analysis suggest this to be a slightly more favorable environment for MCS maintenance the further west you go of I-45, especially with a north/northwest flow regime in place over the region, where storms have a tendency to overperform compared to CAMs. Model guidance such as the HRRR is still keen on this MCS fizzling out over the northern zones... though it`s structure is rather impressive right now, such that it`s very feasible it survives longer that this guidance anticipates. FV3/NSSL would seem aggressive in isolation, as they bring these storms to the coast, though I wouldn`t rule it out at this point. Haven`t seen any severe-strength wind gusts or storm reports from our neighboring WFO though I wouldn`t completely rule out a few stronger gusts. Bottom line, there is a risk of strong straight-line winds across portions of SE Texas early today. Gusts to 30-40 mph have been observed with these storms, though there is a non-zero risk of getting a gust to 58 mph or more. This wind threat should diminish over the next few hours as this system loses strength, though its disorganized will likely push further south towards around the I-10 corridor at least. 03 && .DISCUSSION... Issued at 1137 PM CDT Sun Aug 3 2025 Midweek heat will likely be the most impactful weather of the upcoming week, so let`s start there. Despite being on the fringe of a building midlevel ridge over New Mexico, 500 mb heights look to meaningfully build into the midweek. By Tuesday evening, these heights will be increasing above the 90th percentile per both the NAEFS and EPS means, peaking Wednesday afternoon/evening above the 97th to 99th percentile. So, even though we`re only on the edge of this strong ridging, I expect we`ll see temperatures rising safely above average...you know...only the highest average temps of the year for the area. Safe to say, it will be hot, and the support goes beyond the ensemble means. In looking at LREF cluster analysis (NAEFS and EPS combined), both of the top two clusters are actually stronger with this ridge than the grand ensemble. These clusters account for roughly 3/5 of the LREF members. The only cluster without a 600 dm contour is cluster 3, which does account for 23 percent of the LREF members. There may be some issues with the envelope here, because that cluster is nearly 2/3 of the GEFS members, and 2 percent of the Euro members. The one mitigating factor here is that we do indeed still look to be on the fringe of this ridge and should escape the most significant subsidence while still managing to mix some dry air down to limit the upper bound of afternoon heat index values. Still, if my forecast is perfect (which would be really cool if it were), we`re looking at heat index getting into that 103-107 range, just a bit below the threshold for a heat advisory. This means we`ll be looking at Wet Bulb Globe Temp values in the high risk range, indicating the need for those exercising and working strenuously outdoors to keep heat safety at front of mind. For those who can stay or at least retreat to climate controlled spaces for lengthy stretches, the heat concern will be lower. For the early and late week, we`ll be looking to see conditions a little more like the usual level of peak summer heat, which is still pretty significant, again particularly if you are really exerting yourself out in the sun. But this time of year, we really just have to take whatever wins we can get, even if it`s a heat index closer to 100 than 105. Though I don`t expect us to have any completely dry days due to our location on the fringe of the strong ridging, afternoon storm coverage in the midweek should be more isolated and likely restricted more closely to the seabreeze front, while we should manage a little more scattered development at the beginning and end of the week. && .AVIATION... (12Z TAF Issuance) Issued at 637 AM CDT Mon Aug 4 2025 CLL experiencing MVFR CIGs, all other sites at VFR. MCS currently making its way SE from DFW area. Anticipate arrival to CLL around mid to late morning. Included PROB30 for TSRA at all sites for this afternoon as the MCS pushes through. Gusty N/NW winds will be possible along the leading edge of the system. Reduced VSBYs will also be possible with any heavier showers/storms. Otherwise, expect VFR to prevail through the day with rain clearing out of the area later this evening. Winds will generally be east this morning, becoming E/SE this afternoon. Winds should remain light outside of any stronger storms. Adams && .MARINE... Issued at 1137 PM CDT Sun Aug 3 2025 Persistent low seas and generally light to occasionally moderate winds driven by the daily seabreeze and landbreeze cycle prevail. Expect daily opportunities for isolated to scattered showers and thunderstorms over the next several days as well. Stronger winds and rougher seas can occur in the vicinity of any thunderstorms. In some cases, thunderstorm winds can extend far from the associated storm. Late in the week, winds may increase modestly, pushing seas more into the 2 to 3 foot range. && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 92 74 95 75 / 40 10 20 10 Houston (IAH) 93 77 95 78 / 40 10 30 10 Galveston (GLS) 91 82 91 83 / 30 10 30 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ DISCUSSION...Luchs AVIATION...Adams MARINE...Luchs