FXUS64 KHGX 151816 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 116 PM CDT Mon Jun 15 2026 ...New DISCUSSION, MARINE... .KEY MESSAGES... - The potential for life-threatening flooding is increasing, upwards of 6 inches of rain has fallen and an additional 4-7" is possible. Rainfall rates have exceeded 2-5" per hour in some locations and this trend is likely to continue. - Trough/Low could meander into the northwest Gulf late Tuesday. 50% chance of tropical development. Moderate to strong winds could develop over the coastal waters. Cannot rule out gusts possibly to Gale. - Moderate to high risk of rip currents each day. Elevated tides may lead to minor coastal flooding, especially on Wednesday/Thursday. && .DISCUSSION... Issued at 115 PM CDT Mon Jun 15 2026 A rather dangerous set up is taking shape over the area, as a frontal boundary drifts southward and stalls. South of the boundary, a steady stream of moisture has sent PW values above the climatological max for this time of year. Combined with a weak low level jet, enough forcing is in place for areas of showers and thunderstorms to continue through the afternoon. Unfortunately, the heavier rain is falling across areas generally along and north of the I-10 corridor, and this trend should continue for the next few hours. The initial jet will shift eastward through the day, and rainfall rates may lessen. That said, we've seen some report of 3"+ of rain earlier so far and any additional rainfall may cause more concerns heading into the afternoon. The pattern remains active headed into Tuesday, as cyclogenesis occurs over southern TX/northern Mexico. Guidance remains in somewhat fair agreement on timing and placement, with some slight differences among global models. Given the proximity to the Gulf, and the potential for the low to move over water and develop tropical characteristics, NHC maintains a 40-50% chance for tropical development. Regardless if it moves and/or stays over water long enough, a tropical airmass will remain in place with the above normal PWs increasing the threat for very heavy rainfall. As the low tracks to the northeast late Tuesday night, the chance for heavy rainfall will increase once again, with an additional 4 to 6 inches of rain likely through Thursday. Of course, the heavier rain will occur on the eastern/right side of the low and uncertainty remains high on where that will eventually move. That said, confidence is high enough that the Flood Watch has been extended through Wednesday, with the increasing potential for life-threatening flooding. Further refinements to the storm total rainfall forecast is expected and some areas may exceed the forecast values if training of storms occurs. In addition to the flash flood threat, winds will also increase as the low moves along the coast. Again, where the highest winds occur will depend on the eventual track of the low. Regardless of tropical development, winds will increase Tuesday into Wednesday, with widespread gust up to 30 mph and some gales over the waters. Additionally, the prolonged southerly flow will create some coastal flooding concerns, with rises occuring Wednesday into Thursday. It can't be emphasized enough that this scenario is likely, regardless on if tropical development occurs. The low will move well northeast of the area by Friday, with ridging building back into the region. This will bring a return to hot and humid conditions and heat indices will climb into the triple digits over the weekend. && .AVIATION... (18Z TAF Issuance) Issued at 1218 PM CDT Mon Jun 15 2026 Areas of moderate to heavy SHRA/TSRA will continue to impact the Houston Metro this afternoon. Heavy rainfall, low vis/cigs, and frequent lightning are the primary concerns with TSRA. We cannot rule out brief 25-30 knot gusts in the heaviest cells, especially closer to the coast. SHRA/TSRA activity should decrease in coverage and severity late afternoon into the evening. SHRA may linger this evening near the coast. Overnight and into the morning, SHRA/TSRA activity is expected to lift back northward from the Gulf and into SE Texas. Flight conditions are generally expected to remain IFR-MVFR. But periods of VFR are possible, especially near the coast. && .MARINE... Issued at 115 PM CDT Mon Jun 15 2026 Moderate to occasionally strong onshore winds and seas of 3 to 6 feet are expected today, with onshore flow increasing on Tuesday and Wednesday. A passing disturbance along the Texas coast may bring moderate to strong onshore winds and higher seas late Tuesday night through early Friday morning, though there remains some uncertainties on the timing of the higher winds and seas. Gusts to gale cannot be ruled out. A moderate to high risk of rip currents is anticipated almost daily through the upcoming week with slightly elevated high tides. && .TROPICAL... Issued at 249 AM CDT Mon Jun 15 2026 A trough of low pressure currently over northeastern Mexico is expected to drift north-northeastward over the next few days. Late Tuesday night into mid week, this feature may move into the northwestern Gulf near the Texas Coastal Bend. Currently this low is not expected to develop into a Tropical Cyclone, with formation chances from NHC at 50% within the next seven days. Though regardless of tropical development, heavy rainfall is likely and dangerous marine conditions are possible. Rainfall rates are expected to be around 2-4"/hr, with 5"/hr possible near the coast. Moderate to strong winds could develop across the waters and bays late Tuesday night through Thursday. Gusts to gale are possible. Seas may reach 7 to 10 ft, possibly up to 14 ft. 03 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 80 73 82 74 / 90 70 60 10 Houston (IAH) 84 75 81 75 / 80 80 90 50 Galveston (GLS) 88 80 85 81 / 40 70 90 70 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...Flood Watch through Thursday morning for TXZ163-164-176>179- 195>200-210>214-226-227-235>238-300-313-335>338-436>439. GM...Small Craft Should Exercise Caution through Tuesday morning for GMZ330-335-350-355-370-375. && $$ DISCUSSION...JTC AVIATION...Self MARINE...JTC