Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
140 FXUS64 KHGX 282348 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 648 PM CDT Mon Sep 28 2026 ...New AVIATION... .KEY MESSAGES... - Hot and slightly more humid conditions continue Tuesday with isolated coastal showers/storms. - Periods of showers and storms are expected each day, peaking from Wednesday to Saturday. Locally heavy rain will be possible. - Rain chances and increased cloud cover will keep temperatures near seasonal levels through most of the forecast period. && .DISCUSSION... Issued at 145 PM CDT Mon Sep 28 2026 One more day of hot and humid weather is on tap before the pattern transitions to become more cloudy, rainy, and slightly cooler... Looking at where things are today...we have the ridge axis bisecting the state this afternoon with an amplified trough moving into California from the Pacific. As this trough continues to move inland through the day and into the overnight hours it will continue to nudge the ridge axis eastward. Once the trough approaches the Four Corners, it is expected to be met by what will then be the remnants of Polo from the Baja California area (Hurricane Polo is expected to move inland into Mexico early Tuesday morning and quickly weaken as it moves NE and interacts with the high terrain). Polo`s remnants will merge into the overall flow of this trough and continue a slow eastward progression through the rest of the week. So, for Tuesday, expecting southeast Texas to still have influence from the ridge as the axis moves across our area during that time. Highs across the area will still be in the 90s, and with increasing humidity, expect to see heat indices in the upper 90s to around 105F. Our coastal locations and southern most locations may see some isolated to scattered development in the afternoon, particularly as the sea breeze moves in and begins to interact with the moisture in the area. Wednesday, the mid- upper level trough moves into New Mexico and extends into the central portion of Texas. Models continue to show the eastward progression of the trough and its associated cold front slowing down on approach to North/Central Texas as high pressure builds across the eastern CONUS. This trough, along with Polo`s remnants will pull moisture into the mid-upper levels from the Pacific. At the surface, persistent onshore flow will bring moisture into the area from the Gulf of America. As a result we will see PWAT values increase to around 2.0". Weak impulses in the eastern periphery of the trough will move across the area Wednesday and interact with the moisture, bringing isolated to scattered showers and thunderstorms through Southeast Texas. Thursday into Friday appears to be the peak rainfall days for this event. At this point models show a pre-frontal surface trough developing in the vicinity of southeast Texas. This will provide moisture convergence in the lower levels. The moisture convergence from the pre- frontal trough combined with the arrival of the mid-upper level plume of moisture from the Pacific will consequently result in PWAT values increasing to around 2.5" (as mentioned by previous forecaster this is around 2 to 3 standard deviations above normal). This setup will be favorable for heavy rainfall and instances of flash flooding. WPC has maintained a slight risk for portions of the Brazos Valley on Wednesday, and for most of the area (including the City of Houston) on Thursday. This continues to be an evolving forecast, and will be largely dependent on how much the trough slows down, where the frontal boundary stalls, and for how long as well as how any outflow boundaries from the Hill Country area behave. Guidance has gradually shifted the axis of highest rainfall westward (Hill Country NEward into Dallas receiving the highest amounts); however, Hi-Res guidance will provide more insight and confidence in the next day or two. At this time, confidence is increasing in most of the area seeing at least 1-2" of rainfall through the latter part of the week with locations across the Brazos Valley and Piney Woods seeing around 3-4". Confidence on details pertaining to the frontal boundary and where any of the heavier convective showers may occur remain low. Continue to monitor the forecast over the coming days for updates. Rain chances are projected to continue into the weekend as moisture lingers and the front gradually moves through. Temperatures during the day will be in the 80s this weekend through early next week. Nighttime lows will generally be in the 70s with a few locations in the Brazos Valley/Piney Woods dipping into the upper 60s. Bailey && .AVIATION... (00Z TAF Issuance) Issued at 646 PM CDT Mon Sep 28 2026 VFR conditions to dominate the forecast cycle. Winds are from the SE between 5-10 kts and slightly stronger by the coast and bays. Winds will relax tonight between 2-6 kts by 02-05Z. Around sunrise on Tuesday, brief MVFR VSBYs possible in low-lying areas. Isolated pockets of morning MVFR CIGs are also possible, mainly east of I-45, and dissipate by late morning. By this times, winds pick back up out of the SE between 5-10 kts. Around 18Z Tuesday, winds begin gusting between 15-20 kts, and last until late evening. PoPs are low (10- 30%) mainly east of I-45 and south of I-10 throughout Tuesday morning, but an isolated sea breeze storm is possible throughout the region in the afternoon. Coverage of any afternoon TS/SH development is too low to include in TAFs at this time. BSM && .MARINE... Issued at 326 PM CDT Mon Sep 28 2026 Light onshore winds and low seas will persist through at least Tuesday along with isolated showers and storms. Rain and storm chances will increase after Tuesday as a disturbance moves over the Plains and pushes a frontal boundary off the coast sometime upcoming weekend. Therefore, a daily risk of showers and storms can be expected during the second half of the week, peaking Thursday and Friday. Elevated winds and building seas (up to 7-8ft) are also anticipated. A Small Craft Advisory will likely be needed late Tuesday or Wednesday. && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 71 96 75 96 / 0 10 10 50 Houston (IAH) 75 93 78 93 / 0 10 20 50 Galveston (GLS) 82 88 83 89 / 0 30 40 40 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ DISCUSSION...Bailey AVIATION...BSM MARINE...Bailey