Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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492 FXUS64 KHGX 220900 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 400 AM CDT Sun Sep 22 2024 ...New SHORT TERM... .SHORT TERM...
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(Today through Monday Night) Issued at 400 AM CDT Sun Sep 22 2024 The upper level ridge and onshore flow in the lower levels will remain in place today, continuing the stretch of heat and humidity. Highs for today and Monday will be in the 90s inland and in the upper 80s along the coast. The synoptic pattern will begin to transition as the mid-upper level ridge axis slides to the east and a cold front moves into the state Sunday into Monday. Strong onshore flow Sunday evening will draw in a deeper layer of moisture, and with moderate moisture convergence at the surface, this should be enough to trigger showers and thunderstorms along the coast overnight Sunday and during the day Monday. Rain chances will decrease going into Monday night. Lows for tonight and Monday night will be in the 70s area wide. Some locations in the Piney Woods could dip into the upper 60s. Adams
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&& .LONG TERM... (Tuesday through next Saturday) Issued at 1126 PM CDT Sat Sep 21 2024 The region will still be under the influence of an upper level high pressure centered over the Gulf on Tuesday, so expect continued summer-like weather with high temperatures in the low to mid 90s for much of the area (the immediate coast will likely stay in the upper 80s). There will be some isolated showers and storms developing along the seabreeze in the afternoon, and the rain from these storms will help cooler temperatures down a few degrees locally. The upper-level pattern begins to change late Tuesday into a Wednesday as a low pressure system drops down from the Northern Plains, but there is still some uncertainty on how this system evolves through the rest of the week. Both the GFS and the EC transition the trough into a closed low by Thursday, but the GFS does so over the Midwest and the EC does it over the Southern Plains. Either solution will likely cause increased moisture convergence over our area on Wednesday leading to greater chances of showers and thunderstorms further inland (not just along the sea breeze). Starting Thursday, the forecast gets a bit more murky because if that upper level low ends up further east over the Midwest, it will sweep a weak cold front through the area ushering in cooler and drier conditions (and thus less rainfall chances in our area). If that upper level low stays over the Southern Plains, then we will stay a tad warmer (though cloud cover will help limit some daytime heating) the moisture stays with it leaving to increased chances of showers through the remainder of the week. At this point, I am leaning more towards the GFS/further east location of the closed low as it has been fairly consistent with this solution over the past few days and there might be a tropical system moving through the eastern Gulf (more on this in the tropical section below) that will help "tug" this upper level low further east. Temperatures on Wednesday will be about 3 to 5 degrees cooler than Tuesday with high temperatures in the mid to upper 80s and low 90s for much of the area (the Piney Woods may stay in the low 80s due to the scattered showers around). Low temperatures Wednesday night will be in the mid 60s to low 70s for much of the area. There is a wide spread in the potential high temperature on Thursday thanks to the uncertainty of the passage of that cold front. The 90th percentile of the NBM brings the temperatures into the low to mid 90s on Thursday (the no front solution), while the 10th percentile keeps temperatures in the low 80s (the progressive front solution). I trended the forecast to the cooler side with the front, but not as cold as the NBM10Pct, with high temperatures in the mid 80s for much of the area. The low temperatures Thursday night has a similar spread, but lows in the mid 60s to low 70s will be the most likely solution with the FROPA. There will likely be a gradual warming through the remainder of the week with temperatures rising a couple of degrees each day. If the forecast trend moves more towards a later/no front solution, then expect the temperatures to rise in later forecasts. Fowler && .AVIATION... (06Z TAF Issuance) Issued at 1126 PM CDT Sat Sep 21 2024 VFR conditions will generally prevail overnight, with light and variable winds continuing. A few instances of patchy fog may reduce visibilities to below VFR levels just before sunrise, but otherwise conditions should remain fairly benign. Tomorrow, a light SE wind will develop with wind speeds generally remaining below 10 knots. Cloud levels will remain around 2000 - 4000 ft. Cady && .MARINE... Issued at 1126 PM CDT Sat Sep 21 2024 Light to occasionally moderate onshore flow (5-10kt during the day, then 10-15kt during the overnight and early morning hours) and low seas (1-3ft) will continue through midweek next week. There will be increased chances of scattered showers and thunderstorms over the coastal waters beginning Sunday night and continue through at least midweek next week. A cold front may move through the coast waters on Thursday bringing moderate to strong northerly winds, but the exact timing is fairly uncertain at this time - or even if the front moves through at all. The NHC is monitoring an area of low pressure as it tracks through the Caribbean and into the Southern Gulf by the middle of next week. The NHC currently has a 70% (high) probability of formation over the next 7 days. This system has not yet developed, so it is still far too early to determine it`s track, intensity, or any specific impacts from it - but mariners should continue to monitor forecast updates for it from the NHC through the next several days. Fowler && .TROPICAL... Issued at 1126 PM CDT Sat Sep 21 2024 The National Hurricane Center (NHC) continues to monitor the northwestern Caribbean Sea and southern Gulf of Mexico as a broad area of low pressure could develop by the early to middle part of next week. Gradual development of this system is possible and could strengthen as it moves into the Gulf of Mexico through the end of next week. The NHC currently has a 70% (High) probability of formation over the next 7 days. This system has not yet developed, so it is still far too early to determine it`s track, intensity, or any specific impacts from it. Don`t put too much stock into any single deterministic model run. Please continue to monitor the latest forecasts and updates from the NHC at www.hurricanes.gov. Batiste/Fowler && .PRELIMINARY POINT TEMPS/POPS...
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College Station (CLL) 94 73 93 72 / 10 0 10 10 Houston (IAH) 93 75 93 75 / 10 0 20 10 Galveston (GLS) 87 80 87 78 / 20 10 20 10
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&& .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ SHORT TERM...Adams LONG TERM....Fowler AVIATION...Cady MARINE...Fowler