Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
966 FXUS64 KHGX 090006 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 706 PM CDT Sat Aug 8 2026 ...New AVIATION... .KEY MESSAGES... - Scattered seabreeze showers and thunderstorms expected on a daily basis through early next week. - Showers/storms could become more numerous on Monday, especially in our southern and coastal counties. - Pattern turns drier and hotter by mid/late week. && .DISCUSSION... Issued at 1143 AM CDT Sat Aug 8 2026 At first glance, the pattern today appears to be a carbon copy of yesterday. But subtle differences become apparent once one takes a closer look at the atmosphere. Our large scale synoptic features remain relatively in stasis, with a ridge over W CONUS, another ridge off the E CONUS coast, and modest troughing over the Mid Atlantic and Mississippi River Valley. One subtle, yet not insignificant, difference is the presence of a weak mid/upper trough that extends from S Illinois to NE Texas. This trough is apparent on WV imagery as well as 500 MB RAP analysis. We are even beginning to see (as of 1130AM) some convective initiation along the trough axis in Arkansas. The other difference is the higher PWATs pushing in from the Gulf. Yesterday, PWAT values averaged 1.60-1.80 inches. Today, we have values as high as 2.0-2.1 inches. Therefore, today`s atmosphere features less ridging and more moisture, likely resulting in at least a little more scattered shower/thunderstorm activity than we saw yesterday. In addition, the higher PWATs suggest showers/storms could result in locally very heavy downpours. We are also watching convection and boundaries to the north of our CWA that could result in a few thunderstorms in our northern Piney Woods counties later this afternoon and evening. Regarding temperatures, expect another August day with highs in the 90s and moderate humidity. Sunday looks similar to today, though CAMs guidance suggest slightly less shower/thunderstorm coverage. Many locations will not receive a shower or storm this weekend. But those that do, could easily experience brief very heavy downpours, frequent lightning, and gusty winds. Over the Gulf looms a pool of deep tropical moisture. When looking vertically at the plume of higher PWAT currently moving into SE Texas, you`ll see high RH extending up to about 450-500 MB. But the deeper plume of moisture over the Gulf extends to 250-300MB. Monday will feature the same diurnal and mesoscale forcings that bring us coastal / offshore isolated to scattered showers/storms in the morning and seabreeze related showers/storms in the afternoon. But on top of those processes, Monday`s atmosphere will be more moisture rich. Therefore, showers/storms may end up being more numerous, especially in our southern and coastal counties. The expected environment also suggests a higher risk for locally heavier rainfall. Despite the higher chance of rain, Monday`s temperatures are still forecast to be well into 90s. Humidity levels are likely to be higher due to the lack of drier air to mix down. Ridging is expected to build by Tuesday and beyond, resulting in increasing temperatures and decreasing PoPs as we head into the middle to later part of next week. Some inland hot spots could be reaching 100 degrees by week`s end. Self && .AVIATION... (00Z TAF Issuance) Issued at 654 PM CDT Sat Aug 8 2026 For the 09/00Z TAF update, a summertime diurnal pattern will continue through the forecast period as another round of -TSRA/VCTS convection are expected to proceed through the airspace by 09/18Z-23Z. Until then, patchy FG is likely to redevelop by 06/12Z-15Z as winds slacken to near calm by 09/06-15Z. Southerly surface winds will regain speed in earnest by 09/18Z through the end of the period. Cassel && .MARINE... Issued at 1043 AM CDT Sat Aug 8 2026 Light to moderate south to southeast winds and 1-3 foot seas are expected over the next several days, along with a daily risk of showers / thunderstorms. For the coast and offshore areas, the highest chance of a thunderstorm will be during the morning hours. The bays have a risk of seeing a shower or storm during the morning and early afternoon hours. Beyond Monday, the chance of showers/storms decreases. Onshore winds are expected to increase somewhat during the second half of the week, which may result in 2-4 foot (locally 5 ft offshore) seas by Thursday and Friday. && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 75 95 75 95 / 10 10 0 10 Houston (IAH) 78 94 78 93 / 10 30 10 50 Galveston (GLS) 82 89 82 89 / 10 30 50 70 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ DISCUSSION...Self AVIATION...Cassel MARINE...Self