Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
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054 FXUS64 KHGX 221950 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 250 PM CDT Sun Sep 22 2024 ...New SHORT TERM, LONG TERM, MARINE, TROPICAL... .SHORT TERM... (This evening through Monday Night) Issued at 250 PM CDT Sun Sep 22 2024 Hmm...the calendar says that it`s the first day of Fall, but when I walk outside it still feels all summer-like. Why is it hot and humid in Fall and where`s my FROPA?! The temperatures will eventually simmer down a bit later this week due to a FROPA, but that`s in the long term period. Here in the short term, we`re still on the tail-end of influence from an upper level ridge. That`s combined with onshore flow pulling in low-level moisture and increased humidity from over the Gulf creating the hot and humid conditions we`re all used to (and sick of at this point). The main ridge axis will continue sliding off to the east as an upper level trough drifts eastward from the Four Corners region over to the Central Plains. This upper level trough has already spurred the development of surface low pressure in W/NW Texas, and as this low transitions northeastward it will drag a cold front towards SE Texas. Now it won`t push through in the short term forecast window though...so expect high temperatures in the low to mid 90s both today and Monday. As the front gets closer on Monday, it will lead to a surge in PW values (1.6-2.0") as moisture converges along the frontal boundary. As a result, we could see isolated to scattered showers as early as Monday morning along the coast. Rain chances extend further inland in the afternoon, but the higher end of the chances generally remain near and south of I-10. Another impact from the increase in low level moisture is patchy fog during the overnight/early morning hours mainly for areas west of the I-45 corridor. Nighttime temperatures will remain above normal both tonight and Monday night with lows in the low to mid 70s inland and upper 70s closer to the coast. For portions of the Brazos Valley, this does depend a bit on where the frontal boundary stalls out at as some deterministic guidance has the front ever so partially into SE Texas on late Monday night. Batiste && .LONG TERM... (Tuesday through next Saturday) Issued at 250 PM CDT Sun Sep 22 2024 Will see some active weather regionally and some changes locally during the long term period. Locally, onshore flow along with heat and humidity will continue through Monday...but an approaching cold front along with a developing low pressure system over the NW Carribean, SW Gulf (more on this later) will lead to winds backing from SE to NE...to finally north as the cold front pushes through late Wednesday or Thursday. This southward push of cooler...drier air is aided by a tropical cyclone tracking northward across the Eastern Gulf. Bottom line...locally we expect continued hot and humid conditions with isolated rain showers over the next few days...then a higher chance of showers and thunderstorms with the approach and passage of a cold front from Tuesday until Thursday morning. This will be followed by cooler and much less humid conditions for the Thursday night through much of the weekend. Looking more regionally...all eyes will be on a developing area of low pressure over the NW Carribean...which will likely develop into a tropical depression or tropical storm over the next 2 or 3 days. Details of track and speed are uncertain but should generally move into the Gulf of Mexico...possibly via the Yucatan Channel... late Tuesday or Wednesday and then track fairly quickly northward toward the northeastern Gulf Coast. Track and speed remain uncertain but potential to reach the Florida Panhandle or West Coast of Florida as a hurricane as early as Thursday. At this point should have minimal impact on the Texas coast other than an elevated rip current risk, some elevated surf from long period swells being generated by the hurricane...and some elevated seas in the marine area. Its doubtful we`ll have any coastal flood concerns given offshore flow despite some degree of wave runup...setup. Reilly && .AVIATION... (18Z TAF Issuance) Issued at 1215 PM CDT Sun Sep 22 2024 VFR conditions will continue throughout the remainder of the day with southeasterly winds generally around 10 knots. Winds trend to light and variable this evening. Some patchy fog will be possible again on early Monday morning in the usual trouble spots (CXO/LBX/SGR) and lead to intermittent decreased visibilities. High-res model guidance continues to point towards the development of isolated to scattered showers as early as Monday morning along the coast and drifting further inland in the afternoon. VCSH has been added for the coastal sites at 15Z and at IAH after 21Z. Batiste && .MARINE... Issued at 250 PM CDT Sun Sep 22 2024 Light to occasionally moderate onshore flow will continue over the next few days with isolated streamer showers possible. Winds across the marine area will gradually back from SE to NE by mid week...ahead of a cold front and on the NW fringe of a large cyclonic circulation developing over the Gulf. This is part of the environmental winds around a developing tropical cyclone which will likely be tracking into and northward across the Eastern Gulf of Mexico Wednesday and Thursday. The passage of the cold front and the aforementioned passage of a tropical cyclone...possibly at hurricane intensity will lead to winds shifting to the north and increasing...possibly to advisory levels by late Wednesday or Thursday. Reilly && .TROPICAL... Issued at 250 PM CDT Sun Sep 22 2024 The National Hurricane Center (NHC) continues to monitor an area of disorganized convection in the Northwestern Caribbean Sea associated with a broad area of low pressure. Conditions are favorable for this area of low pressure to further develop, and is likely to result in the development of a tropical depression or tropical storm as it moves northward through the Gulf of Mexico over the next few days. As of the Sunday afternoon update, the NHC has a 40% (Medium) chance of formation over the next two days and an 80% (High) chance of formation over the next seven days. Model/ensemble trends continue to point towards this system remaining in the eastern half of the Gulf of Mexico and eventually impacting the northeastern Gulf Coast. While direct impacts do not look likely at the moment for SE Texas, it will be worth keeping an eye on the latest forecast updates from the NHC (www.hurricanes.gov) as this system continues to evolve. For those with marine interests, this system may result in increased rip currents and hazardous marine conditions towards mid to late week along Texas beaches. Batiste && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 74 93 74 92 / 0 10 10 30 Houston (IAH) 76 93 76 93 / 0 20 10 50 Galveston (GLS) 80 87 79 87 / 20 30 10 40 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ SHORT TERM...Batiste LONG TERM....Reilly AVIATION...Batiste MARINE...Reilly