FXUS64 KHGX 051121 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 621 AM CDT Sun Jul 5 2026 ...New AVIATION... .KEY MESSAGES... - Dangerously hot conditions will continue today. Widespread heat indicies of 105-107F (41-42C) with locally higher values over 108F (43C +) are likely. - Isolated to widely scattered showers and thunderstorms will be possible this afternoon. Generally across the southeastern half of the area, including the Houston Metro. Chance of isolated to scattered seabreeze showers/storms increases slightly early next week. - High pressure builds into the area by midweek, reducing precipitation chances for the second half of the workweek. && .DISCUSSION... Issued at 1205 AM CDT Sun Jul 5 2026 The stout ridge that dominated the weather pattern across the eastern U.S has continued to break down. The transient ridge that developed across Southwest Texas and eastern New Mexico yesterday will break down today. This will allow for a decrease in heights across our region this afternoon through Tuesday afternoon. This will allow for a greater coverage in afternoon showers and thunderstorms. Towards the middle of the week, heights look to build back in as mid-level ridging increases. Quiet conditions are seen across the region. The main change with this package was to introduce a broad area of 20% PoPs across the Gulf Coast and southern portions of the Western Piney Woods and Southeast Texas. The 00z CAMS want to develop showers and thunderstorms where outflow boundaries to the north and the seabreeze to the south interact. THe 00z HRRR in particular depicted robust thunderstorms across Harris County this evening. There remains uncertainty in coverage of storms due to somewhat limited moisture, so PoPs were kept isolated with this package. If trends continue amongst the CAMS with the 12z package, shower coverage may need to be increased to scattered. Heights look to continue to fall Monday and into Tuesday across the area. Meanwhile, moisture looks to increase across the region. This would support isolated to scattered showers and storms during the afternoon hours across the region. The hot weather will continue for the foreseeable future across the region. Heat indices could approach Heat Advisory criteria of 108F (43C +) across isolated portions of the forecast area today, especially in locations that do not see showers and storms. Temperatures look to drop a degree or two on Monday and Tuesday due to height falls and increased cloud cover from scattered showers and thunderstorms. As we head towards the middle of the week, ridging looks to build back into the region. This will decrease rain chances && .AVIATION... (12Z TAF Issuance) Issued at 620 AM CDT Sun Jul 5 2026 Patchy fog has developed again this morning which will lead to brief MVFR vis over the next hour or so. Otherwise, VFR conditions and light south-southwest winds will prevail through this TAF cycle. Have continued with the mention of PROB30 for TSRA for most sites after 00Z to account for activity developing along outflow boundaries heading our way from the north. Amendments will likely be needed to better refine the timing once convection develops. && .MARINE... Issued at 1205 AM CDT Sun Jul 5 2026 Generally light onshore flow will persist through today and into early this week. Overall, 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. Winds and seas begin to increase by the middle to later part of next week, with a gradually steepening pressure gradient. Onshore winds are forecast to increase to 10 to 15 knots by Tuesday and Wednesday, before increasing further to the 15 to 20 knot range by Thursday. Seas may increase to 3 to 4 feet by the end of the upcoming week. && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 96 77 95 77 / 10 0 20 10 Houston (IAH) 97 79 95 79 / 20 20 20 10 Galveston (GLS) 90 82 90 83 / 10 10 20 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ DISCUSSION...Williams AVIATION...Castillo MARINE...Williams