Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
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769 FXUS64 KHGX 061118 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 618 AM CDT Sat Jul 6 2024 ...New AVIATION... .SHORT TERM... (Today through Sunday Night) Issued at 429 AM CDT Sat Jul 6 2024 I know most of you are here to see the latest on Beryl, so for that you can go ahead and skip to the next paragraph. A weak and rather diffuse frontal boundary is sitting over portions of the Brazos Valley this morning. The front diminishes later this morning, but the remnant surge in moisture leaves elevated PW values above the 90th percentile (~2.10"). Combine that the ridge axis shifting eastward as a longwave trough digs through the northern CONUS leading to reduced subsidence aloft along with increasing PVA and we`ll see higher chances for showers/storms this afternoon. Convection will likely begin along the sea breeze in the late morning/early afternoon with additional convection further north in the afternoon during peak heating. With PW values being on the high side, there is some potential for locally heavy rainfall. WPC has outlined areas north of I-10 in a marginal risk (level 1 of 4) for excessive rainfall today. On the plus side, the higher rain chances and decreased subsidence mean slightly "cooler" temperatures with highs in the mid to upper 90s. Heat index values will be in the 102- 107F range with some isolated spots potentially reaching 108F. As a result, our Heat Advisory streak will FINALLY come to an end at 11 days. Now let`s Beryl into the tropics...Beryl is currently a tropical storm in the southern Gulf of Mexico moving west-northwestward. With some southerly shear and dry air intrusion on the southern end of the circulation, it`ll take a little while for Beryl to get her act together enough to intensify back into a hurricane (this is expected to occur Sunday afternoon). The eastward shift in the track has come to a halt at least for the 06Z model suite, which means most of the consensus remains for a final landfall along the mid Texas coast. Some uncertainty does remain though of course given how much things have changed over the past few days, but we`re hopeful that the track forecast can become more solidified if the 12Z model suite reflects a similar solution as well. While the bulk of the impacts from Beryl in our area are expected on Monday, we are anticipating some rain bands to move into our area as early as Sunday. Rain chances will of course be higher along the coast and gradually shift inland throughout the day and into Sunday night. Sunday night into Monday morning is when we`ll really have to monitor both heavy rainfall and potential severe weather closely. If any of these rainbands on the eastern side of the circulation train over an area (possible with a due north trajectory), then we could see rainfall amounts build up fairly quickly. On top of that, low- level rotation becomes favorable south of I-10 to the east of Beryl`s center of circulation as these rainbands come ashore (especially with dew points in the upper 70s). This means there will be a risk of tornadoes, especially Sunday night into Monday morning. As a result, SPC has outlined areas south of I-10 in a slight risk (level 2 of 5) south of I-10 for Sunday. There is also a slight risk of excessive rainfall (level 2 of 4) south of I-10 on Sunday as well with a marginal risk extending up to the Brazos Valley. The heavy rainfall threat continues going into Monday, for more on that see the long term discussion down below. Also, for further details on Beryl, check out the tropical discussion down below. Batiste && .LONG TERM... (Monday through Friday) Issued at 429 AM CDT Sat Jul 6 2024 The current National Hurricane Center forecast has Beryl making landfall around the Matagorda Bay area as a hurricane during the day on Monday and moving northward across our western and northern counties on Monday night and Tuesday. Locations near/around Beryl`s circulation center will see the strongest winds, and almost all of the area will see showers and possible thunderstorms. Locally heavy rain will be possible (the higher totals will be 5 to 10 inches with locally higher amounts possible - see WPC`s Day 3 Excessive Rainfall Outlook), and some of the storms could become tornadic beginning late Sunday night and continuing into the daytime hours on Monday (see SPC`s Day 2 and Day 3 Convective Outlooks). Beryl will exit the area on Tuesday night, but decent shower and thunderstorm chances will continue for the remainder of the week as precipitable water values remain on the high side (at or above 2 inches). Any locally heavy rainfall from strong storms and or training activity on already saturated grounds could lead to localized flooding, especially in/near already elevated creeks/bayous/rivers. 42 && .AVIATION... (12Z TAF Issuance) Issued at 618 AM CDT Sat Jul 6 2024 VFR conditions and light winds will persist at all area terminals throughout the day, but convection is expected to develop later this morning along the coast and drift inland going into the afternoon hours. Most of the convection will dissipate shortly after sunset with winds becoming light and variable once again. Rain bands from Beryl may move in as early as Sunday morning for locations near the coast leading to periods of heavy rainfall and gusty winds. Batiste && .MARINE... Issued at 429 AM CDT Sat Jul 6 2024 Light to occasionally moderate onshore flow is expected today. Increasing winds, elevated seas, coastal flooding and higher rain and storm chances are expected to begin as early as tonight across our offshore waters and peak Sunday night through Monday morning/afternoon as Beryl makes landfall around the middle Texas coast and works its way inland. A Hurricane Watch remains in effect for Matagorda Bay and its coastal Gulf waters. For now, no watches are in effect for Galveston Bay and its coastal Gulf waters, but continue to monitor the forecast for any changes over the weekend. Lowering winds and seas can be expected Tuesday night through Wednesday night, but rain and storm chances will remain in the forecast during this period. 42 && .TROPICAL... Issued at 429 AM CDT Sat Jul 6 2024 Current Hazards: - A Hurricane Watch is in effect for the TX coast from the mouth of the Rio Grande northward to San Luis Pass, TX. This includes the Brazoria Islands, Coastal Brazoria, Coastal Jackson, Coastal Matagorda, and Matagorda Islands. - A Storm Surge Watch is in effect for the TX coast from the mouth of the Rio Grande northward to High Island, TX. This includes Coastal Galveston and Coastal Harris County as well. Remember, a Hurricane Watch means that hurricane conditions (sustained winds of 74 mph or higher) are possible within the next 48 hours. A Storm Surge Watch means that there is a possibility of life-threatening inundation from rising water moving inland from the shoreline generally within 48 hours. As of ~4am CDT, Beryl remains a tropical storm traveling west- northwestward in the southern Gulf of Mexico. The latest forecast still points toward a landfall along the mid Texas some time on Monday. Potential impacts from Beryl in portions of Southeast Texas include heavy rainfall, storm surge, strong winds, tornadoes, and elevated rip current risks. Please continue to monitor the latest forecasts and updates from the National Hurricane Center at www.hurricanes.gov. For more localized forecasts and updates, please visit www.weather.gov/houston. Batiste && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 95 76 96 77 / 50 20 20 20 Houston (IAH) 95 79 93 79 / 70 20 50 40 Galveston (GLS) 91 82 90 82 / 40 30 60 60 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...Hurricane Watch for TXZ335>337-436-437. Storm Surge Watch for TXZ214-313-335>338-436>439. GM...Hurricane Watch for GMZ330-350-370. && $$ SHORT TERM...Batiste LONG TERM....42 AVIATION...Batiste MARINE...42