Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
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512 FXUS64 KHGX 051012 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 512 AM CDT Fri Jul 5 2024 ...New AVIATION... .SHORT TERM... (Today through Saturday Night) Issued at 400 AM CDT Fri Jul 5 2024 We`ll have one more solid day with mid/upper level high pressure directly overhead leading to temperatures this afternoon peaking in the upper 90s to right around 100F for most of Southeast Texas (except along the coast). Elevated humidity will keep heat index values mainly in the 107-111F range, so a Heat Advisory remains in effect for all of Southeast Texas through 7pm CDT this evening. For those keeping count, this is the 11th day in a row with a Heat Advisory for at least part of Southeast Texas...and we might make that 12 days in a row tomorrow. Before we get to that though, let`s talk about a cold front that will approach from the north later today. As an upper level trough swings through the Upper Midwest, it`ll serve to break down the ridge aloft and nudge it eastward. This reduces the amount of subsidence aloft, but that portion of it will play more of a factor on Saturday. The parent surface low for this frontal boundary will be in the Great Lakes region, so we`ll be on the very tail-end of it. The front itself may partially push into portions of the Brazos Valley late Friday night/Saturday morning and carry some scattered showers/storms along with it. Rain chances will be highest east of I-45 in association with this weak frontal boundary, and this is probably a good time to mention that we`ll also have our typical afternoon isolated to scattered seabreeze convection on top of that. As previously mentioned, with the reduction in subsidence aloft by Saturday, we`ll likely see increased coverage of rainfall. To give y`all an idea of what that looks like...PoPs on Friday are ~20% and on Saturday they`re bumped up to 40-60%. A weaker ridge and higher rain chances means a slight decrease in high temperatures. Saturday`s highs will top out in the mid to upper 90s with the hotter temperatures west of I-45. Moisture convergence due to the front being nearby will lead to PW values surging to near 2.3-2.4" Saturday afternoon, so plenty of moisture to work with! With PW values well above the 90th percentile (~2.10"), there will be potential for locally heavy rainfall. As a result, WPC has outlined most of Southeast Texas in a marginal risk (level 1 of 4) for excessive rainfall. That also means plenty of humidity as well as we`ll face yet another day with heat index values in the 106-111F range, so there is potential for another Heat Advisory. Later in the day on Saturday, another upper level trough swings into the Northern Plains and that creates an area of weakness over the state of Texas between the approaching trough and the departing ridge. This may play a factor in the track of Beryl and is one of the numerous reasons that uncertainty remains in the forecast for where it makes landfall. For additional details on Beryl, see the "Tropical" discussion down below. Batiste && .LONG TERM... (Sunday through Thursday) Issued at 400 AM CDT Fri Jul 5 2024 This part of the forecast is heavily influenced by the future track and intensity of Beryl. Based on the latest National Hurricane Center forecast from early this morning, expect increasing shower/thunderstorm coverage for our area (locally heavy rainfall the primary severe weather threat) as Beryl makes landfall near/around the South Texas coast Sunday night or early Monday morning and works its way generally northwestward then northward inland through Tuesday night and Wednesday. Locations experiencing the strongest winds/rains look to be closer to Beryl`s track which at this time would be our western areas, roughly from in/around the Matagorda Bay area northward to in/around the Bryan/College Station area. Shower and thunderstorm chances will continue Tuesday through Thursday for much of the area. The Weather Prediction Center has parts of our area in their Excessive Rainfall Outlooks beginning on Sunday (Marginal Risk in/around the Matagorda Bay area) with increasing coverage and risk on Monday and Tuesday (Slight Risk increasing across almost all of the area by Tuesday). The Storm Prediction Center has areas in/around Matagorda Bay in a Marginal Risk for severe weather in their Day 3 Outlook (7 AM Sunday through 7 AM Monday). A lot can change with our forecast depending on where Beryl decides to go, how strong she gets and how fast she moves, so stay tuned for future updates. 42 && .AVIATION... (12Z TAF Issuance) Issued at 512 AM CDT Fri Jul 5 2024 VFR conditions prevail at the majority of the area terminals with the lone exception being LBX as of right now. Winds will remain on the light side generally less than 10 knots. Some isolated showers may develop in the afternoon near the I-10 corridor, and additional convective development is expected north of I-10 and east of I-45 this afternoon. The northern convection may last into the late evening hours. && .MARINE... Issued at 400 AM CDT Fri Jul 5 2024 A light to occasionally moderate onshore flow will prevail through the next few days. Winds and seas will be on the rise later this weekend into the first half of the upcoming week as first Beryl moves into the Gulf of Mexico and towards the South Texas coast and then another round of deep tropical moisture surges into the western Gulf. Elevated water levels along the bays, high surf and strong rip currents are possible. Multiple rounds of showers/storms that could result in higher winds/seas can be expected. Continue to monitor the progress of both Beryl and the second slug of Gulf moisture as any additional changes in the track/intensity of these systems are possible during the next few days. 42 && .TROPICAL... Issued at 400 AM CDT Fri Jul 5 2024 As of ~4am CDT, Beryl is now a category 2 hurricane and is just off of the coast of the northeastern portion of the Yucatan Peninsula where it`ll make landfall later this morning. It is currently moving west-northwestward and will make its way into the southwestern Gulf by Friday evening. The 06Z suite of models trended a bit more northward compared to the 00Z models with most consensus pointing toward a South TX landfall Sunday night/Monday morning. There are still a few factors at play that will determine Beryl`s final landfall including where Beryl emerges from the Yucatan Peninsula later today (what latitude is it at when it enters the Gulf), how quickly the ridge currently over the SE CONUS moves eastward (and subsequently how deep is the upper level trough that will push the ridge eastward), and how much it can intensify over the Gulf (stronger tropical cyclones tend to drift more poleward). While uncertainty remains for the end of the forecast track/final landfall, there is at least some certainty that rainfall chances will increase early next week along with an increasing risk of rip currents. Please continue to monitor the latest forecasts and updates from the National Hurricane Center at www.hurricanes.gov as any significant changes in the track and/or intensity forecast could lead to significant changes in our area forecast. Batiste && .CLIMATE... Issued at 400 AM CDT Fri Jul 5 2024 The first four days of July have been very warm. The average temperature for the Houston area was 89.0 degrees, which was 5.0 degrees above normal. This is their second warmest start to the month (1st place is 89.3 degrees in 1980). Records date back to 1889. The average temperature for Houston Hobby was 88.9 degrees, which was 4.9 degrees above normal. This is their warmest start to the month (second place is 88.1 degrees in 2023. Records date back to 1931. The average temperature for Galveston was 87.8 degrees, which was 2.8 degrees above normal. This is their second warmest start to the month (1st place is 88.1 degrees in 2005). Records date back to 1874. The average temperature for Palacios was 86.5 degrees, which was 1.5 degrees above normal. This is their sixth warmest start to the month (1st place is 89.1 degrees in 2023). Records date back to 1943. The average temperature for College Station was 87.6 degrees, which was 3.6 degrees above normal. This is their eighth warmest start to the month (1st place is 89.5 degrees in 2009). Records date back to 1889. 42 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 98 77 95 77 / 10 20 40 10 Houston (IAH) 99 79 96 79 / 20 20 60 20 Galveston (GLS) 93 81 92 83 / 20 20 40 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...Heat Advisory until 7 PM CDT this evening for TXZ163-164-176>179- 195>200-210>214-226-227-235>238-300-313-335>338-436>439. GM...None. && $$ SHORT TERM...Batiste LONG TERM....42 AVIATION...Batiste MARINE...42