Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
276 FXUS64 KHGX 011934 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 234 PM CDT Thu Oct 1 2026 ...New DISCUSSION, AVIATION, MARINE... .KEY MESSAGES... - Periods of showers and thunderstorms are expected each day, peaking today through early Sunday. Locally heavy rain will be possible and could lead to instances of flash flooding. - The heavy rainfall threat shifts from the Brazos Valley on Thursday/Friday to the coast on Saturday/Sunday. - Daytime temperatures are expected to drop to more seasonal levels in response to rain and increased cloud cover. - Cold front pushes through early next week. && .DISCUSSION... Issued at 228 PM CDT Thu Oct 1 2026 WV imagery shows a deep plume of moisture associated with the low pressure that is now centered over the TX/OK panhandles. This plume of moisture encompasses the eastern half of the state, and PWAT values have certainly increased in response. Current satellite derived PWATs show a pocket of 2.3" west of the I-10 corridor, with most of southeast Texas seeing 2.0" values. Surface analysis shows the cold front currently positioned in a S to N orientation from Del Rio to just west of Wichita Falls with a line of storms traversing the Hill Country and DFW. Out ahead of this line, strong moisture convergence and continued onshore flow in the lower levels has resulted in scattered showers with isolated thunderstorms moving northward through the area from the Gulf. Expecting this line of storms to reach the Brazos Valley area around mid-late afternoon and slowly progress eastward through the evening hours. Given the moist profile over our area, expect that some of these showers and thunderstorms could produce heavy rain rates of 3- 4"/hr. The storms this afternoon at least have some good forward motion, so they aren`t sticking around long enough to drop heavy rain for a prolonged period. A bit difficult to tell exactly where the front stalls as it becomes more diffuse the further it gets into southeast Texas. Latest guidance seems to have it stall more across the coastal counties as opposed to just offshore. With less favorable dynamics aloft, storms should weaken as they approach the Houston Metro. Several locations around the Houston Metro have received anywhere from a trace to around an inch of rain so far today, courtesy of discrete cells out ahead of the main line. Expected rainfall amounts through tomorrow night range from a trace to around 1" along the coast into the Houston Metro. Further north and west, expected amounts increase to around 2-3". Brazos Valley area remains in a Moderate Risk for rainfall, and while 2-3" doesn`t sound like a lot...this is more generalized. What we are monitoring is the potential for this line to slow down significantly as it enters the Brazos Valley and for heavy rainfall rates within the overall line. While widespread higher totals aren`t anticipated, any locations that experience the prolonged period of higher rainfall rates may also experience flooding. Soils are dry enough to be able to handle most of the rainfall, but if we do have prolonged periods of heavy rainfall it may be difficult for the rate of absorption to keep up. So, as we get into early Friday morning most of the area will see a lull in activity. The focus shifts more towards the area south of I- 10 and west of I-45 with the looming cold front, a closed low over Mexico providing mid-level support and continued moisture advection. This area is also able to handle a few inches of rainfall, so not anticipating much in the way of flooding concerns at this time. Through the day Friday we will see showers and thunderstorms push develop over inland areas as we remain in a moist environment and vort maxes move overhead. Will need to pay attention to how strong moisture convergence is along the coast Friday, and to a coastal trough that will be in the Gulf. Most of the expected rainfall continues to remain offshore, but could squeeze out another 2-4" this weekend. WPC does maintain a marginal to slight risk for the coastal areas through the weekend. Next week is anticipated to bring cooler and drier weather into southeast Texas (fall fanatics rejoice!). An upper level trough is projected to dip down into the northern/NE CONUS and a cold front will push through the E CONUS with high pressure following in from behind. The tail-end of this front looks to arrive in our area sometime Monday into Tuesday. Not expecting a substantial cooldown; however, the weather will feel noticeably drier and cooler. Until then, our high temperatures remain in the upper 80s to low 90s with lows in the 70s. Bailey && .AVIATION... (18Z TAF Issuance) Issued at 228 PM CDT Thu Oct 1 2026 For the Houston area terminals, scattered SHRA/isolated TSRA are ongoing with a recent 27 knot gust at KHOU. Expect this activity to continue for another 2-3 hours before diminishing. Brief periods of MVFR ceilings, wind gusts to 25 knots and visibilities possible in the heavier showers. For Houston terminals generally isolated SHRA for tonight/early Friday with SHRA/TSRA coverage increasing again after 15Z Friday. For KLBX/KGLS, generally VFR conditions expected with isolated - SHRA. Coverage of SHRA/TSRA expected to increase after 15Z Friday. For KCLL/KUTS, SHRA/TSRA will increase in coverage this afternoon. Periods of MVFR ceilings/visibilities and gusty winds are possible 20-03Z with the stronger cells. Expect a brief break 03-08Z before another round of stronger convection moves in late tonight/Friday morning, again with the potential for MVFR ceilings/visibilities and gusty winds. 35/MM && .MARINE... Issued at 228 PM CDT Thu Oct 1 2026 Moderate southeasterly winds and gradually building seas (peaking in the 5-7 ft range) will persist through late Thursday. Small craft should exercise caution through tonight. Water levels peak around or just above 3.0-3.3 ft MLLW during high tide over the next few days, so not enough for coastal flooding hazards but high enough for mariners to take note. Daily chances of showers/storms continue especially during the overnight to early morning hours over the Gulf. Rain chances look to peak over the weekend along the coast and the Gulf as a frontal boundary and a coastal weather system interact. && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 72 84 70 83 / 80 70 60 80 Houston (IAH) 77 89 75 87 / 40 70 50 80 Galveston (GLS) 82 89 80 86 / 30 60 80 90 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...High Rip Current Risk until 8 PM CDT this evening for TXZ436>439. GM...None. && $$ DISCUSSION...Batiste AVIATION...35 MARINE...Bailey