FXUS64 KHGX 040540 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 1240 AM CDT Sat Jul 4 2026 ...New DISCUSSION, MARINE... .KEY MESSAGES... - Dangerously hot conditions expected today. A Heat Advisory is now in effect for Harris County for heat indices between 105-109F (41- 43C). - Elsewhere, widespread heat indices of 105-107F (41-42C) with locally higher values over 108F (43C +) are likely this weekend. - Isolated showers/thunderstorms are possible today and on Sunday. Chance of isolated to scattered sea breeze showers/storms increases early next week. && .DISCUSSION... Issued at 1232 AM CDT Sat Jul 4 2026 The dominant mid-level ridge that setup across the eastern U.S over the last several days has begun to slowly break down. As the atmosphere reshuffles from the massive ridge, mid-level heights look to briefly increase across our region this weekend. This will help promote slightly drier and slightly warmer conditions across the area. Currently, quiet weather conditions is seen across our area. Winds are generally light at 5 mph out of the south. The biggest change with this forecast package was the issuance of a Heat Advisory for inland and coastal Harris County. A combination of slightly higher temperatures and lower shower/thunderstorm coverage placed a majority of Harris County in a range of max heat indices between 107-109F (42-43C). With several events ongoing today and greater than fifty percent of the county exceeding Heat Advisory Criteria, it was prudent that a Heat Advisory was issued. Heat indices of 108F (43C) or higher will be more isolated in occurrence outside of Harris County and thus a Heat Advisory was not considered elsewhere. Heat indices look to remain just under the 108F threshold on Sunday as well, although it could be close once again in Harris County. A brief decrease in maximum temperatures will be possible on Monday and Tuesday as ridging relaxes some. However, maximum heat indices look to remain elevated as increased moisture moves into the region. Tuesday in particular could be close to reaching Heat Advisory criteria depending on shower/thunderstorm coverage in the afternoon. Guidance shows ridging building back into the region towards the latter half of next week, which will keep the heat threat around for the foreseeable future. Isolated seabreeze showers/thunderstorms will continue today and Sunday, but slightly drier conditions should limit coverage compared to the past couple of days. Models show a mid to upper- level impulse swing down the eastern Southern Plains early next week. This will help lower mid-level heights Monday and Tuesday. It remains unlikely that we will see any direct effects from the mid to upper-level impulse, but it should allow for an increase in seabreeze showers/thunderstorms each afternoon. Ran chances look to diminish once again towards the latter half of next week. && .AVIATION... (00Z TAF Issuance) Issued at 616 PM CDT Fri Jul 3 2026 Chances for shower/storm activity diminishes this evening as outflows from earlier storms have stabilized the atmosphere. VFR conditions will prevail through TAF period with the low probabilities of VIS concerns for most terminals between the coast and KCXO from 10-13Z. Winds will then become mostly S/SSW'ly near 5-7 kt before switching to mostly S'ly winds at 7-9 kts with the seabreeze moving through from 17-20Z. Hi-res model wants to keep most of any seabreeze convection closer to the coastal areas between KLVJ and KGLS, but confidence is low enough to add any TEMPO groups to KHOU, but this will be something that will be carefully monitored with the overnight forecast trends and radar Saturday morning. && .MARINE... Issued at 1232 AM CDT Sat Jul 4 2026 Light onshore flow will continue over the next several days. Gulf seas are expected to average 1 to 3 feet. Isolated coastal and Gulf showers will be possible each morning, with a chance of isolated thunderstorms along the sea breeze in the afternoon. By the middle to later part of next week, a gradually steepening pressure gradient may allow for an increase in south to southeast winds, along with a corresponding increase in the seas. For now, the forecast shows onshore winds increasing to 10-15 knots by Tuesday/Wednesday, before increasing further to the 15-20 knot range by Thursday. Seas may increase to 3-4 feet by week's end. && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 77 95 77 95 / 0 0 0 0 Houston (IAH) 79 96 79 95 / 10 10 0 20 Galveston (GLS) 83 90 83 89 / 0 0 0 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...Heat Advisory from 11 AM this morning to 7 PM CDT this evening for TXZ213-313. GM...None. && $$ DISCUSSION...Williams AVIATION...Enriquez MARINE...Williams