Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
179 FXUS64 KHGX 030002 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 702 PM CDT Fri Oct 2 2026 ...New AVIATION... .KEY MESSAGES... - Periods of showers and thunderstorms are expected through early Sunday. Locally heavy rain will be possible and could lead to instances of flash flooding. Best chance of heavy rain in our coastal counties. - Cold front pushes through early next week bringing drier air and slightly cooler temperatures. && .DISCUSSION... Issued at 1146 AM CDT Fri Oct 2 2026 Those of us in Southeast Texas find ourselves in a soupy atmosphere. This is evident in surface observations, where much of the area is warming into the 80s with dew points well into the 70s. These can also be seen via the satellite derived PWAT, showing widespread values over 2.0 inches. The soupiness is also evident via water imagery, revealing deep tropical moisture pushing in from the Pacific thanks to a strong sub-tropical jet between a cut-off low near the TX Bid Bend region and a ridge over SE CONUS. In addition, there`s a mid/upper low over the SW Gulf with a mid to lower trough extending northeastward from the low. Scattered deep convection is occurring over the central Gulf near the trough axis. Meanwhile, we are mostly dealing with widely scattered showers and thunderstorms in southeast Texas. We should see some increased scattered thunderstorms develop across our southern zones where there`s an increasingly diffused sfc boundary and a more unstable environment. The forecast this weekend becomes tricky due to a plethora of atmospheric moving parts. The aforementioned Gulf trough will push westward, placing it on a trajectory towards the NW Gulf. We`ll likely start seeing an increase in showers/thunderstorms offshore tonight into Saturday morning as a result. The diffused front is expected to push southward while the subtropical Pacific jet weakens overhead. Despite the lost tropical connection from the weakening jet, the SE Texas atmosphere will establish a new tropical connection via the deep moisture plume enveloping the Gulf trough. There`s some uncertainty regarding the trough`s structure as it approaches our region. It should become increasingly stretched and less organized. But it may also contain some embedded LL/ML vort maxes, the track of which will be difficult to forecast. What we know is that there will likely be an elongated region of enhanced lift, deep tropical moisture, and modest LL convergence. What we don`t know is whether or not these conditions will line up along the coast, or just offshore. The moving parts in the paragraph above result in a tricky rainfall forecast this weekend. For now, we are going with 1-3 inches near the coast, with mostly under an inch inland. But given the moisture profile, there will be potential for locally much heavier totals (particularly in our coastal zones). The general trend in both the deterministic and ensemble guidance has favored the heaviest rainfall occurring just offshore over the Gulf. But a small nudge to the north and west would significantly increase the chance of localized 5-6" totals at the coast. One thing worth mentioning is that water levels at the coast will be higher than normal. If a locally heavy thunderstorm happens over a coastal community during high tide, the risk of flooding would increase. Currently, high tide is occuring during the evening and overnight hours. The primary focus lately has been the short term showers and thunderstorms. But there does appear to be some goodies for us in the long term. By Tuesday and beyond, the pattern takes a drier and more comfortable turn. The mid/upper flow pattern gradually becomes more amplified, with the Lone Star State feeling the influence of a deep layer trough over E CONUS. Expect lower humidity with temperatures in the 80s. Overnight lows are forecast to drop into the 60s away from the coast and outside the urban heat island, though I couldn`t rule out a night or two falling into the upper 60s in the heart of Houston`s urban core. Self && .AVIATION... (00Z TAF Issuance) Issued at 701 PM CDT Fri Oct 2 2026 VFR conditions prevail overnight before the arrival of widespread MVFR cigs in the morning. While model guidance suggests MVFR cigs are less likely over HOU, a SCT020 BKN035 was written for this period to hint at the potential for cigs lowering. VFR conditions return for our metro TAF sites by 18Z tomorrow. A southward moving cold front will lead to MVFR cigs remaining at CLL and UTS throughout this period, while also raising the chance of isolated to scattered showers and thunderstorms for all TAF sites along and north of I-10. Therefore, a PROB30 was written to highlight the greatest rain chance for these TAF sites between 20 and 00Z. Showers and thunderstorms that develop over these terminals carry the potential to bring sub-VFR cigs/vis and gusty winds. Additionally, a westward moving trough in the Gulf will create persistent showers and thunderstorms along the coast tomorrow, warranting -SHRA and PROB30 -TSRA with MVFR cigs for LBX and GLS. && .MARINE... Issued at 1146 AM CDT Fri Oct 2 2026 The two primary concerns through this weekend will be locally heavy thunderstorms and the potential for occasional Small Craft Advisory conditions over the Gulf. An approaching trough will steepen the pressure gradient, increasing NE winds to 15-20 knots with occasional gusts to 25 knots. Winds over the open Gulf could occasionally be sustained over 20 knots. There will likely be an increase in Gulf seas to 4-5 feet over the weekend. During the Monday-Wednesday time frame, we expect shower/thunderstorm chances to linger offshore, while areas closer to the coast are forecast to be mostly dry. Meanwhile, northeast winds may increase further, increasing the chance of Small Craft Advisories. In addition, we cannot rule out offshore seas up to 6-7 feet during this time frame. && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 70 84 69 81 / 30 50 50 40 Houston (IAH) 75 88 74 83 / 30 50 50 60 Galveston (GLS) 80 87 78 85 / 60 80 80 80 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ DISCUSSION...Self AVIATION...JMG MARINE...JM