Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
395 FXUS64 KHGX 312252 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 552 PM CDT Sun Aug 31 2025 ...New AVIATION... .KEY MESSAGES... Issued at 1220 PM CDT Sun Aug 31 2025 - Localized heavy rain continues through the weekend. A slight risk of excessive rain (threat level 2 of 4) is in place today. A marginal risk for excessive rain (threat level 1 of 4) continues on Labor Day. - Tranquil conditions expected mid-week as drier air filters into the region. Potential for showers and storms may start to work back in late in the week or during the upcoming weekend. - High temperatures will be in the 80s today and in the upper 80s to lower 90s on Monday. Temperatures will rise into the mid 90s by mid-week. At night, lows should gradually slide through the 70s towards the upper 60s inland as the drier air filters in. && .DISCUSSION... Issued at 1220 PM CDT Sun Aug 31 2025 A weak frontal boundary will continue to push towards the coastal areas of Southeast TX today while the mid-level high pressure continues to shift a little more west. A few vort maxes will also pass overhead today and with plenty of moisture to work with from the surface through the mid-levels, it will be of no surprise to see the development of showers and thunderstorms. We already had several clusters of showers and thunderstorms develop over the Brazos Valley and Piney Woods region this morning and we can expect these showers and thunderstorms to continue to progress southward throughout the day today. Chance for showers and thunderstorms will decrease later tonight as diurnal heating and instability decreases while the frontal boundary moves over the coastal waters, although, we may still see some isolated activity at times throughout the night. The active weather pattern is expected to persist into Monday as the frontal boundary meanders over the coastal waters. Although there is a chance for at least isolated showers over much of the region on Monday, the higher chances are expected to be focused mainly over areas near and south of I-10. So, are we at risk for flooding today into Monday? It is reasonable to say that we will have to see what locations the heavy rains set up, the storm movement, and how saturated the soils become. As of this morning, the GOES Imagery indicate total precipitable water amounts between 2.1 to 2.4 inches over much of Southeast TX and with a reasonable amount of moisture along the mid-levels, it will be of no surprise if stronger storms continue to produce heavy rainfall with rain rates of 2 to 4 inches per hour (as we have observed from this morning). The speed at which these storms move will also be a significant factor regarding the potential for higher accumulations over a short time period. This could lead to flooding issues along roadways as well as low lying and poor drainage areas, in particular over more urban regions. WPC has continued as a Slight Risk for excessive rainfall (level 2 of 4) across all of Southeast TX through late tonight. A Marginal Risk for excessive rainfall (level 1 of 4) continues for much of Southeast TX on Monday, although an upgrade to Slight Risk may not be out of the question for some of our coastal locations. Make sure to check the radar imagery and traffic conditions before you begin your commute this holiday weekend. Strong storms will be capable of also producing frequent lightning and gusty winds...make sure to have an alternative option for outdoors activities. Remember, when thunder roars, head indoors. Some isolated activity may remain over areas near and south of I-10 on Tuesday as the coastal boundary finally progresses further into the Gulf in response to a dry reinforcing frontal boundary approaching the Brazos Valley and Piney Woods region. By late Tuesday night, chance for rain ends as drier air moves pushes into Southeast TX. A dry weather pattern is expected to persist into the end of the work week. Rain chance may return during the upcoming weekend. With respect to temperatures, we will see high temperatures generally in the 80s today and in the upper 80s to lower 90s on Monday. Temperatures will then rise back into the lower 90s by Tuesday and the lower to mid 90s by Thursday. As for the low temperatures, we will begin to feel those cooler nighttime temperatures Tuesday night into Thursday night with lows dipping into the mid to upper 60s over areas north of I-10, the lower 70s over areas near and south of I-10, and the upper 70s along the coasts. Cotto && .AVIATION... (00Z TAF Issuance) Issued at 549 PM CDT Sun Aug 31 2025 TSRA has pushed offshore while lingering SHRA continues across the region. This SHRA activity should diminish this evening. Areas of low vis/cigs expected to develop overnight, mostly north of IAH. However, we cannot rule out sub-VFR conditions making it into the Houston area. Coverage of SHRA/TSRA is uncertain tomorrow. The activity today may have taken enough energy from the atmosphere to limit tomorrow`s SHRA/TSRA to isolated or widely scattered. For now, we have kept VCSH and PROB30 for -TSRA in the TAFs from IAH to the coast tomorrow. Winds will generally be light and variable. If TSRA develops tomorrow, then locally higher winds will be possible. && .MARINE... Issued at 1220 PM CDT Sun Aug 31 2025 Generally light and variable winds with seas of 2 feet or less are expected through the upcoming weekend. A weak frontal boundary slowly moving southward over SE TX will bring scattered to widespread showers and thunderstorms through Monday. The frontal boundary is expected to move into coastal waters later tonight into early Monday. Chance for isolated showers and thunderstorms will continue on Tuesday as the front gradually moves deeper into the Gulf. Strong winds, frequent lightning, and elevated seas may occur in and near stronger storms. Large clusters of storms may result in moderate to strong winds for several hours over a larger scale and may need the issuance of Caution flags or Small Craft Advisories. Drier conditions are expected mid-week into the end of the work week as a drier airmass moves into Southeast TX in the wake of the front, however, isolated showers and thunderstorms may still develop at times. Cotto && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 73 89 72 91 / 30 40 10 10 Houston (IAH) 75 89 74 92 / 30 50 20 20 Galveston (GLS) 79 88 79 90 / 60 50 40 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ DISCUSSION...Cotto AVIATION...Adams MARINE...Cotto