FXUS64 KHGX 051659 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 1159 AM CDT Sun Jul 5 2026 ...New DISCUSSION, MARINE... .KEY MESSAGES... - Dangerously hot conditions will continue through the forecast period. Daily widespread heat indicies of 105-107F (41-42C) with locally higher values over 108F (43C +) are likely. - Isolated (10-30% chance) showers and thunderstorms will be possible this afternoon, with chances increasing slightly for Monday and Tuesday afternoon. - There is potential for strong to marginally severe storms late this afternoon and into this evening, mainly for northern parts of the forecast area. Damaging wind gusts and locally heavy rainfall would be the main hazards. - High pressure builds into the area by midweek, reducing precipitation chances Wednesday and Thursday. Rain/storm chances return late in the week and into next weekend. && .DISCUSSION... Issued at 1159 AM CDT Sun Jul 5 2026 Recent GOES-19 clean IR imagery over the last few hours shows a few north-to-south advancing outflow boundaries moving through the forecast area, caused by a storm complex that moved across NE and far E TX overnight. These outflow boundaries may enhance seabreeze showers and thunderstorms (10-30%) later this afternoon, though most locations stay dry. Brief heavy downpours and cloud-to-ground lightning will be the main hazards with seabreeze activity. By late this afternoon and into early this evening, focus will shift on a cluster of thunderstorms, currently developing along a frontal boundary near the Red River in N Texas. Though some uncertainty does exist, guidance shows these storms pushing southeastward towards the forecast area, potentially clipping portions of the northern tier counties (mainly Houston/Trinity/Polk Counties and perhaps adjacent counties) by early/mid evening. Sufficient CAPE and marginally sufficient bulk shear will support a low chance of marginally severe thunderstorms as they quickly move through the area..then out of the area by late evening. Forecast soundings from the HRRR indicate inverted-v profiles, especially early on in the evening, and would suggest damaging wind gusts up to 60 mph would be the primary hazard, with the potential for small hail, assuming storms can survive and remain organized. The Storm Prediction Center has included the far northern part of the CWA in a Marginal Risk (level 1) of severe storms for this afternoon and evening. For what it is worth, guidance (specifically the 12Z HRRR) shows a secondary complex of storms developing northwest of the area, behind the first complex, late this evening and into the overnight hours, but this complex is anticipated to weaken and decay before it moves into the forecast area. If this scenario were to verify, however, it would likely produce and throw another outflow boundary or two into forecast area, which may affect and enhance seabreeze/thunderstorm development for Monday afternoon. Otherwise, the more widespread primary concern over the next several days continues to be the typical scorching summer heat. Strong ridging will continue to slide westward over the Desert Southwest and Four Corners regions by this evening, allowing for a very weak trough over the Midwest region to stretch and slide over the area Monday and Tuesday. The main sensible changes with this weak trough will be low precipitation chances during the morning and evening hours, as well as enhanced seabreeze/boundary interaction showers and thunderstorms in the afternoon. Limited PoPs to around 30-40% both days for now, but PoPs may need to be adjusted and raised if models trend wetter or have a better signal for preicip. Daytime temperatures may cool off a degree or two compared to recent days, especially with a slight bump in cloud cover and rain chances, but temperatures likely won't change too much, despite. The weak trough is expected to lift out of the area during the daytime Wednesday. This may temporarily shut-off rain chances and increase temperatures back into the mid-upper 90s on Wednesday and Thursday. Medium-range guidance shows another weakness in the riding occurring late in the week and into next weekend, which may increase diurnally-driven precipitation chances and lower temperatures slightly again by the weekend. && .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 1159 AM CDT Sun Jul 5 2026 Light onshore flow will persist into early this upcoming week. Overall, Gulf seas are expected to average 1 to 2 feet, occasionally up 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. Small craft exercise caution winds and seas may develop by Thursday as the gradient continues to steepen, with Gulf seas increasing to 3 to 4 feet by the end of the upcoming week. && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 77 95 77 95 / 0 20 10 10 Houston (IAH) 79 95 79 95 / 20 20 10 30 Galveston (GLS) 82 90 83 90 / 10 20 10 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ DISCUSSION...Mejia AVIATION...Castillo MARINE...Mejia